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A FRAMEWORK FOR PRODUCTION MANAGEMENT OF
RENOVATION PROJECTS

presented by

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YASH PRATAP SINGH

 

 

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'- ' MANAGEMENT

 

 

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A FRAMEWORK FOR PRODUCTION MANAGEMENT OF
RENOVATION PROJECTS

By

Yash Pratap Singh

A THESIS

Submitted to:
Michigan State University
in the partial fulfillment of the requirements
for the degree of

MASTER OF SCIENCE
Construction Management

2007

ABSTRACT

A FRAMEWORK FOR PRODUCTION MANAGEMENT OF RENOVATION
PROJECTS

By
Yash Pratap Singh
Renovation projects exhibit complex characteristics due to the presence of constraints
that lead to their cost and schedule overruns. Numerous researchers have concluded that
the performance of renovation projects is typically lower than that of new construction
projects (Krizek et a1. 1996, Mitropoulos et a1. 2002, Attalla et al. 2003). The overall goal
of this research was to develop a framework for production management of renovation
projects that will be used by construction professionals for improving the schedule
performance of renovation projects. The goal was achieved by conducting literature
review and interviews of construction professionals. Literature of state-of-the-art
construction performance measurement systems, renovation projects, and production
management of construction projects was reviewed to identify essential attributes that a
production management system should possess in renovation projects. Interviews of 6
contractors and 4 subcontractors were conducted for identifying state-of—the-art practices
of production management in renovation projects. The research concluded that there is a
lack of a formal process in practice for production management of renovation projects,
and the state-of-the-art performance measurement systems find limited application in
managing renovation projects. The developed framework proposed two major processes;
production planning, and production performance assessment. This framework will assist
contractors in renovation projects for improving their production planning techniques in

the presence of constraints, and meeting the owners’ requirements.

 

Dedicated to my father, Mr. B.P. Singh for his consistent support and having faith in
me, my mother, Mrs. Shagun Singh for her unconditional love and sacrifice, and my
loving brother, Chandra for giving me the courage to succeed at every step throughout
my education.

 

iii

 

ACKNOWLEDGEMENTS
I would like to express my up most gratitude and appreciation to Dr. Tariq Abdelhamid
for not only firmishing his invaluable guidance, support, and insight throughout this
research as the major advisor but also being an excellent mentor, inculcating in me the
confidence and new knowledge during the hard stages of this thesis and masters program.
I would also like to thank Professor Timothy Mrozowski for serving as the co-chair and
providing his helpful inputs. I would also like to thank Dr. Nam-Kyu Park for serving as

the external committee member and sharing her views for renovation projects.

I would particularly like to extend my respect and warm regards to Dr. Matt Syal for his
special advices on different aspects of masters program. I express sincere thanks to other
faculty members, staff, and colleagues at the Construction Management Program at MSU

which supported me during my degree fulfillment.

I would also like to thank Don Schafer and Surabhi Rao for being outstanding coworkers
in this research since the beginning. I would like to thank my colleague, Shilpi Mago,
who provided the enormous support and encouragement during this long journey. I am
also thankful to my old friends, Samarth Jain and Amanjeet Singh, who stood by me and

shared some unforgettable moments during the final phases of this research.

Finally, I would like to express my deepest respect, gratitude, and appreciation to my
family for their constant motivation, support, and sacrifices, without which this research

would not have been possible.

 

TABLE OF CONTENTS

CHAPTER 1

INTRODUCTION

1 . 1 Introduction ........................................................................ 2

1.2 Need statement .................................................................... 8

1.3 Research questions ................................................................ 13

1.4 Research goals and objectives ................................................... 14

1.5 “Production Performance” definition for this research ....................... 15

1.6 Research scope ..................................................................... 18

1.7 Chapter summary .................................................................. 19

CHAPTER 2

LITERATURE REVIEW

2.1 Introduction ........................................................................ 21

2.2 Concept of performance measurement ......................................... 21

2.3 Performance measurement in the construction industry ..................... 22
2.3.1 Limitations of traditional performance measurement systems ...... 23
2.3.2 State-of-the—art construction performance measurement systems 25
2.3.3 Performance indicators of state-of-the-art construction
performance measurement systems ............................................. 26
2.3.4 Performance measurement methods of state-of-the-art systems. . 34
2.3.5 Role of performance measurement in realizing strategies ............ 38
2.3.6 Implementation methods of state-of-the-art systems .................. 40

2.4 Discussion of state-of-the—art construction performance measurement
systems literature .................................................................. 44

2.5 Literature review of renovation projects ....................................... 47
2.5.1 Constraints of renovation projects ....................................... 49
2.5.2 Scheduling techniques for renovation projects under constraints. . .. 55

2.6 Discussion of renovation projects literature .................................... 60
2.6.1 Reiteration of constraints .................................................. 61
2.6.2 Critical activities in renovation projects ................................ 67

2.7 Literature review of production management in construction ............... 68

2.8 Essential attributes of a production management system in renovation
projects ............................................................................. 77

2.9 Chapter summary ................................................................. 78

CHAPTER 3

RESEARCH METHODOLOGY

3.1 Introduction ........................................................................ 80

3.2 Existing knowledge, research drivers and research 82
contribution ........................................................................

3.3 Phase-1 Literature review ....................................................... 86
3.3.1 State-of-the-art construction performance measurement systems... 86
3.3.2 Renovation projects ......................................................... 89

 

 

 

3.3.3 Production management in construction ................................. 92

3.3.4 Essential attributes identified from Phase-1 ............................. 92
3.4 Phase-2 Conduct interviews ...................................................... 93
3.5 Phase-3 Framework development ............................................... 95
3.6 Phase-4 Framework demonstration ............................................. 95
3.7 Phase-5 Framework verification ................................................ 96
3.8 Chapter summary 97
CHAPTER 4

DATA COLLECTION AND FRAMEWORK DEVELOPMENT,
DEMONSTRATION AND VERIFICATION

4.1
4.2

4.3

4.4

4.5

4.6

4.7

4.8

Introduction ........................................................................ 99
Interview Procedure .............................................................. 99
4.2.1 Interview questions ......................................................... 101
4.2.2 Data collection .............................................................. 103
4.2.3 Synthesis and analysis of data collected ................................. 104
4.2.4 Process maps of interviewed contractors and subcontractors ........ 109
4.2.5 Interview conclusions ...................................................... 110
Essential attributes of a production management system for renovation
projects .............................................................................. 1 14
Interface between renovation projects & state-of-the-art performance
measurement systems ............................................................. 115
Introduction to the production management framework for renovation

projects ............................................................................ 121
Stages in framework development ............................................. 123
4.6.1 Step-1 Identify constraints and critical activities ...................... 132

4.6.2 Step-2 Interdependency relationships between constraints. . . . . . . . 132
4.6.3 Step-3 Impact levels of constraints on estimated production

schedule of critical activities ..................................................... 138
4.6.4 Step-4 Identification of weighted impacts of constraints on the
production schedule of critical activities ....................................... 142
4.6.5 Step-5 Quantification of additional production duration of critical
activities based on project conditions ........................................... 149
4.6.6 Step-6 Enter and move production assignments in lookahead

schedule .............................................................................. 176
4.6.7 Step-7 Match production assignments and resource capacities ....... 178
4.6.8 Step-8 Activity execution plan ............................................. 180
4.6.9 Step-9 Production performance evaluation .............................. 186
4.6.10 Step-10 Production failure analysis ..................................... 189
4.6.11 Summary of developed framework for renovation projects ......... 193
Demonstration of the framework ................................................ 194
4.7.1 Scope of work and required resources .................................... 196
4.7.2 Estimated duration of work ................................................ 197
4.7.3 Assessment of project conditions & identification of constraints. . .. 197
Steps suggested by the framework ............................................. 199

vi

4. 8. 1 Step-1 Identification of constraints & critical activities” 201
4. 8. 2 Step-2 Mapping the interdependency relationships between

constraints ........................................................................ 201
4.8.3 Step-3 Mapping the impact levels of constraints on estimated
production schedule of critical activities ....................................... 201
4.8.4 Step-4 Identification of weighted impacts of constraints on the
production schedule of critical activities ....................................... 202
4.8.5 Step-5 Quantification of additional production duration of critical
activities based on project conditions ........................................... 213
4.8.6 Alternate approach to production planning using dependency
relationships between constraints-Approach 2 ................................. 230
4.8.13 Comparison between Approach 1 and 2 ............................... 266
4.8.14 Step-6 Enter and move production assignments in lookahead
schedule ............................................................................. 266
4.8.15 Step-7 Match production assignments and resource capacities ....... 267
4.8.16 Step-8 Activity execution plan ........................................... 268
4.8.17 Step-9 Production performance evaluation ............................. 271
4.8.18 Step-10 Production failure analysis ..................................... 272
4.9 Framework verification ........................................................... 275
4.9.1 Verification procedure ...................................................... 275
4.9.2 Verification findings ........................................................ 276
4.10 Chapter summary .................................................................. 279
CHAPTER 5
SUMMARY AND CONCLUSIONS
5. 1 Introduction ........................................................................ 282
5.2 Research overview ................................................................ 282
5.3 Research goal and objectives .................................................... 284
5.4 Conclusions and inferences ...................................................... 286
5.5 Research benefits and contribution ............................................. 289
5.6 Future areas of research ........................................................... 292
5.7 Chapter summary .................................................................. 293
APPENDICES
APPENDIX-l Contractors’ and subcontractors’ interview responses ............. 295
APPENDIX-2 Analytical Hierarchy Process ................................................... 302
REFERENCES ........................................................................................................... 308

vii

Table 3.1

Table 4.1

Table 4.2

Table 4.3

Table 4.4

Table 4.5

Table 4.6

Table 4.7

Table 4.8

Table 4.9

Table 4.10

Table 4.11

Table 4.12

Table 4.13

Table 4.14

Table 4.15

Table 4.16

Table 4.17

Table 4.18

LIST OF TABLES
Constraints and Project Conditions for Renovation Projects .......

Correlation Matrix-1 a for an Example Selective Demolition
Activity ....................................................................

Constraint Reduction using CM- 1 a ....................................
Correlation Matrix-1 (Approach-1 ) ....................................

Correlation Matrix-l (Approach-2 for Reduced Number of
Constraints) ................................................................

Scale of Importance Levels in AHP ....................................
Mapping of AHP and Correlation Matrix-1 Scales ..................
Pair-wise Comparison Matrix for All Constraints for Appraoch-l
Final Weights for All Constraints through Approach-1 .............

Pair-wise Comparison Matrix for Approach-2 (Limited Number
of Constraints) ............................................................

Final Weights for Limited Number of Constraints ...................

Constraint Assessment Matrix for an Example Selective
Demolition Activity (Approach- 1) .....................................

Constraint Assessment Matrix for an Example Selective
Demolition Activity (Approach-2) .....................................

Activity Execution Plan ..................................................

Actual Daily Production Documentation for Production Failure
Analysis ....................................................................

Scope of Work and Required Resources ..............................
Example Project Conditions and Constraints Generated ............
Correlation Matrix-1 ......................................................

Mapping of AHP and Correlation Matrix-1 Scales ..................

viii

91

136

137

141

141

142

145

148

148

148

148

155

165

182

192

196

198

202

203

 

Table 4.19

Table 4.20

Table 4.21

Table 4.22

Table 4.23

Table 4.24

Table 4.25

Table 4.26

Table 4.27

Table 4.28

Table 4.29

Table 4.30

Table 4.31

Table 4.32

Table 4.33

Table 4.34

Table 4.35

Table 4.36

Table 4.37

Pair-wise Comparison Matrix ........................................... 205

Pair-wise Comparison Matrix (Integer Form) ........................ 205
Normalization Matrix .................................................... 206
Final Relative Weights ................................................... 206
Random Index Values ................................................... 208
Multiplication of Pair—wise Comparison Matrix with Final

Weights .................................................................... 208
Pair-wise Comparison Matrix ........................................... 210
Pair-wise Comparison Matrix (Integer Form) ........................ 210
Normalization Matrix .................................................... 211
Final Relative Weights ................................................... 211

Multiplication of Pair-wise Comparison Matrix with Final
Weights ................................................................... 212

Constraint Assessment Matrix for Selective Demolition of
Ceiling Suspension System ............................................. 218

Constraint Assessment Matrix for Installation of Ceiling
Suspension System ...................................................... 224

Interdependency Relationships between Constraints for Selective
Demolition (Correlation Matrix-1a) .................................... 235

Interdependency Relationships between Constraints for the
Installation of Ceiling Suspension System (Correlation Matrix—

la) .......................................................................... 235
Constraint Reduction for Selective Demolition ....................... 237
Constraint Reduction for Ceiling Installation ......................... 237

Correlation Matrix-1 for Selective Demolition based on Reduced
Number of Constraints ................................................... 238

Correlation Matrix-1 for Ceiling Installation ......................... 239

ix

Table 4.38

Table 4.39

Table 4.40

Table 4.41

Table 4.42

Table 4.43

Table 4.44

Table 4.45

Table 4.46

Table 4.47

Table 4.48

Table 4.49

Table 4.50

Table 4.51

Table 4.52

 

Pair-wise Comparison Matrix ........................................... 240

Pair—wise Comparison Matrix (Integer Form) ........................ 240
Normalization Matrix .................................................... 240
Final Relative Weights ................................................... 240
Pair—wise Comparison Matrix ........................................... 241
Pair-wise Comparison Matrix (Integer Form) ........................ 241
Normalization Matrix .................................................... 241
Final Relative Weights ................................................ 242

Multiplication of Pair-wise Comparison Matrix with Final
Weights .................................................................... 242

Multiplication of Pair-wise Comparison Matrix with Final
Weights .................................................................... 243

Constraint Assessment Matrix for Approach-2 for Selective
Demolition of Ceiling Suspension System ............................ 247

Constraint Assessment Matrix for Approach-2 for Installation of

Ceiling Suspension System ............................................. 257
Example of Lookahead Schedule for the Demonstration. . . . . . . . 267
Activity Execution Plan for Selective Demolition Activity. . . . . 270

Actual Daily Production Documentation of Selective Demolition
Activity for Production Failure Analysis .............................. 274

Figure 1.1
Figure 1.2
Figure 1.3
Figure 2.1
Figure 2.2
Figure 2.3
Figure 3.1
Figure 3.2

Figure 3.3

Figure 4.1

Figure 4.2

Figure 4.3

Figure 4.4

Figure 4.5
Figure 4.6
Figure 4.7
Figure 4.8

Figure 4.9

Figure 4.10

LIST OF FIGURES

Growth in Expenditure on Renovation Projects ....................... 3

Earned Value Analysis .................................................... 9

Earned Value Analysis in Renovation Projects. 10
Objective of Last Planner System TM ................................... 71
Activity Definition Model ............................................... 73
Metrics Introduced by Mitropoulos in Make-ready Process. . . . . 77
Phased Research Methodology ......................................... 80
Detailed Research Methodology ....................................... 84

Emphasis Areas of State-of-the-art Performance Measurement
Systems ................................................................... 88

Snapshot of Consolidated Spreadsheet of Contractors’ Responses 103

Snapshot of Consolidated Spreadsheet of Subcontractors’
Responses ................................................................. 104

Interface between Renovation Projects & State-of-the-art
Performance Measurement Systems .................................... 1 19

Developed Framework for Production Management of

Renovation Projects ...................................................... 128
Function onuery Node-1 in the Framework. . . . . . . . . . . 178
Activity Definition Model adopted in the Framework ............... 185
Components of Production Performance .............................. 188 '
Function of Query Node-3 in the Framework ........................ 191
Plan of Elevator Lobby to be Renovated .............................. 195
Approach 1 and 2 for Demonstration of Framework ................ 200

xi

1?" m1

CHAPTER-1

INTRODUCTION

 

”“5"!“

1.1 Introduction

A renovation project is defined as a process of restoring or improving a built structure
that includes modifications, conversion or phased complete replacement (Attalla et a1.
2003). Being a large part of the construction industry, renovation projects characterize
about one third of the total expenditure spent on construction projects (Mitropoulos et al.
2002). In the late 90’s, a study conducted in the United States concluded that renovation
projects including remodeling, reutilization and rehabilitation constituted up to 50% of
the total construction budget expended (McKim et al. 2000). In commercial and
institutional sectors, the annual expenditure on renovation projects has increased from
close to $20 billion in 1992 to approximately $80 billion in 2002 (U .S. Census Bureau
1992, 1997, 2002).

Figure 1.1 shows a graph of the marked increase in annual expenditure on
renovation projects during the 10 years from 1992 to 2002. This increasing investment in
renovation projects has been attributed to the growing needs of public owners and
governmental institutions, which represent a major clientele for renovation projects, in
order to maintain and upgrade their infiastructure and built facilities (Attalla et a1. 2003).
Moreover, renovation projects mostly offer an economically viable alternative for public
owners in comparison to new construction, as multiphase renovation projects tend to

eliminate the need to close owner’s operations during construction (McKim et al. 2000).

l I

70'

I O I
In Billion
j J l

 

 

 

 

or 30 '
20 «
10 j
o I V I
1992 1997 2002
Year

Figure 1.1 Growth in Expenditure on Renovation Projects (Commercial & Institutional)
(US. Census Bureau. 1992, 1997, 2002)

In spite of being a growing sector of the construction industry, it has been
observed that the performance of renovation projects is typically lower than that of new
construction projects in terms of time, cost and quality (McKim et al. 2000, Attalla eta].
2003). Previous research has concluded that renovation projects, unlike new construction
projects, involve considerable risks and uncertainty in existing conditions that adversely
impact the project performance (Krizek et a1. 1996, Mitropoulos et a1. 2002, Attalla et a1.
2003). Renovation of an operational facility imposes additional constraints on its
construction process, which if not considered during project planning and controlling

processes, could lead to project underperformance (Mitropoulos et a1. 2002).

This issue of underperformance that plagues renovation projects is extensively
investigated for new construction, as illustrated by the Sixth Annual Owner Survey
conducted by the Construction Management Association of America (CMAA 2005).
According to this survey, building trust and integrity in construction processes was the

prime concern of the survey owners. The owners stated that trust and integrity are

necessary for procuring successful projects that meet the desired performance levels of
cost, time and quality. In addition, one of the greatest challenges for delivering successful
projects lies in controlling the inefficiency in construction processes and not the cost of
labor, materials, and equipment (CMAA 2005). To address these concerns, CMAA
identified the need for a change in traditional development of contract documents
between owner and contractor that would clearly state the desired project outcomes and
goals so that contractors could achieve required performance levels (CMAA 2005).

However, changes in contract documents would partially achieve the desired
performance and a greater effort needs to be extended at the operational level to
strengthen trust and integrity, and reduce construction process inefficiencies. Various
researchers and practitioners in the field of Lean Construction view traditional
construction project management to be narrowly focused on managing transactions and
contracts, ignoring the production aspect of construction operations (Ballard 2000,
Ballard et a1. 1998, Koskela 1999). According to these researchers and practitioners, the
performance improvement in construction projects is a function of the way contractors
manage construction processes on daily basis and cause the work to flow between trades
for generating desired value to owners (Ballard 2000, Mitropoulos 2003).

In addition, controlling the cost of inefficiencies requires determination of their
causes, which is facilitated by production measurement at the operational level that
measures how efficiently and effectively the contractor is performing (Cain 2004).
Production performance assessment discloses the true inefficiencies inherent in
construction processes by identifying the value and non-value adding activities (Ballard

2000, Koskela et a1. 2001).

 

In 1998, as a vital contribution to the UK. Construction Best Practice Program,
the Egan Report titled “Rethinking Construction” emphasized that contractors need to
reduce high levels of inefficiency and waste in construction processes. According to the
Egan Report, this was the principal concern that owners had about the UK. construction
industry. This report underscored the need for development of performance measurement
of both the quality and efficiency of construction processes for building strong
relationships between owners and contractors (Cain 2004, Beatham et a1. 2003).

Both, CMAA’s owner survey and the Egan Report bring forward the significance
of performance measurement in current construction practices to control the cost of
inefficiencies and successfully deliver projects to owners that would reinforce the trust
and integrity between owners and contractors. However, Lean Construction supplements
this View by emphasizing performance measurement at the production level to minimize
waste in construction processes and maximize the value for project owners (Ballard
2000).

Adoption of performance measurement in current construction practices has also
been driven by the dissemination of Total Quality Management Principles (TQM) and
1809001: 2000 standards, as potential solutions to increasing complexities of
construction processes, competitiveness, and wasted efforts in reworks (Costa et al 2000).
Consequently, construction firms have begun to investigate on “what is to be measured”
and “how is it to be measured” so that the desired results are achieved (Samson et a1
2001). Therefore, performance measurement has been recognized as a vital aspect of

project controls for providing the basis for monitoring and controlling construction

 

 

activities by bringing to surface their inefficiencies (Costa et a1. 2000, Alarcon et al
2000)

A performance measurement system, whether in construction or any other
industry, begins with the identification of a balanced set of indicators through which
performance can be measured (Alarcon et a1. 2000). Numerous studies have investigated
adequate set of performance indicators for measuring the financial and non-financial
aspects of construction processes that define their true performance. These studies have
also focused on reviewing some of the state-of-the-art performance measurement systems
being developed by collaborative benchmarking initiatives among construction
companies across the globe. These state-of-the-art performance measurement systems
were developed for the purpose of providing guidance in performance measurement of
construction projects and establishing benchmarks for identifying best practices. Some of
these state—of-the-art systems are: Key Performance Indicators (U .K.), National
Benchmarking System (NBS-Chile), Construction Industry Institute Benchmarking and
Metrics (CII BM&M, USA) and, Performance Measurement System for Benchmarking
in the Brazilian Construction Industry (SISIND) (Costa et a1. 2006).

One of the major outcomes of the studies that investigated these state-of—the-art
performance measurement systems is their limited implementation in construction firms
due to their incompatibility with the organizational capabilities. This has also been
attributed to the complexity of construction projects comprising of different participants
in a temporary organization (Lantelme et a1. 2000). Some of the systems still focus on
financial and contractual measures, ignoring those which are important to competitive

success (Beatham et a1. 2003). In addition, past research efforts have not reached a

rfi-r-‘fl‘ ‘i'

consensus on the most appropriate set of performance indicators suggested by different
state-of-the-art systems (Korde et a1. 2004). Therefore, it has been observed that these
state-of-the-art performance measurement systems still find limited application in the
construction projects which are more Complex, Uncertain and Quick (CUQ) (Costa et a1.
2006, Beatham et a1. 2000, Ballard 2000).

The CUQ level increases in case of renovation projects due to the presence of
various constraints and consequently, the investigation of “what is to be measured”
becomes extremely difficult (Mitropoulos et al.2002, Attalla et a1. 2003, Krizek et al.
1996). Moreover, previous studies have concluded that these constraints make traditional
project planning and monitoring techniques inappropriate for measuring and controlling
performance in renovation projects (Mitropoulos et a1. 2002, McKim et a1. 2002).
Therefore, in order to assess the impact of constraints on production level and measure
the performance, it is essential to identify an appropriate set of performance indicators for
improving the construction throughput in renovation projects. Measuring performance at
the production level of renovation projects also requires an understanding of the complex
nature of unforeseen conditions, which is one of the biggest constraints contributing to
the uncertainty in construction planning processes (Krizek et a1. 1996).

The challenges of renovation projects have driven previous researchers to focus
on identifying and analyzing various constraints encountered in renovation projects, and
to propose planning techniques for coping with these constraints. However, there is a
need to develop assessment methods for ascertaining the impacts of these constraints on
production level performance of renovation projects. Hence, this research focuses on

constructing a framework for production planning, execution and performance

assessment of construction Operations in renovation projects under the impact of

constraints identified in these projects.

1.2 Need Statement

Traditionally, renovation projects are evaluated by assessing achievements against the
project objectives of budget and schedule, through measurement of Cost Variance (CV)
and Schedule Variance (SV) as success indicators through the technique of Earned Value
(EV) analysis (Beatham et al. 2003). The traditional method of EV analysis is shown in
Figure 1.2, which measures the CV and SV based on the Budgeted Cost of Work
Scheduled (BCWS), Budgeted Cost of Work Performed (BCWP) and Actual Cost of

Work Performed (ACWP) (N assar 2005). The equations for assessing CV and SV are:

CV: BCWP — ACWP equation 1.1

SV= BCWP — BCWS equation 1.2

In the traditional project management approach, a corrective action is taken only
when the CV and/or SV trigger a negative value, which would mean that the project is
over-budget and/or behind schedule respectively (Ballard 2000). Thus, the traditional
project control model is based on a reactive approach, which has been concluded to be a
deficient approach of controlling projects rather than controlling production (Ballard

2000, Koskela et a1. 2001).

 

 

 

8 ‘ Budgeted
2 BCWS ’ ‘ Quantity
.5 >1 .
r , _. - m
g a
El
E l
H
O
.9
«t l
51 l
U)
o
C.)
i 1
Current Data Date

Time

Figure 1.2 Earned Value Analysis (Nassar 2005)

The traditional performance indicators of CV and SV being focused only on cost
and time have been extensively criticized for their inability to identify the real causes of
results and predict the performance during construction process (Beatham et al. 2003).
Being outcomes of the projects, these customary performance indicators of cost and time
provide information about the results of a process and not the process itself. In other
words, these performance indicators are incapable of establishing the cause—effect
relationships between the results and their sources (Alarcon et a1. 2000). Moreover, these
indicators do not support rapid decision-making necessary for corrective actions, as the
information retrieval usually gets delayed (Lantehne et al. 2000). In general, these
indicators are the focus of construction performance measurement systems currently in
practice. Therefore, the new move in current research in performance measurement is on
identifying process-oriented indicators that provide relevant information for improving

the on-going processes to achieve desired performance levels (Beatham et al. 2003).

Additionally, renovation projects are characterized by a number of constraints that make
the establishment of cause-effect relationships even more difficult. As shown in Figure
1.3, it becomes an extremely complex task of investigating the negative deviations of CV
and SV for a renovation project, as their source could be a single constraint or multiple
constraints (Krizek et al. 1996). One of the major constraints identified is the uncertainty
of unforeseen conditions, which is an inevitable aspect of renovation projects (McKim et
al. 2002). This uncertainty relates to unknowns in pro-existing conditions, which can
adversely impact the performance of construction activities, if not accounted for in their
production planning. There are other constraints in renovation projects that add to this
difficulty including space limitations, design coordination with existing conditions, traffic
limitations, owner’s operations limitations, pollution control, safety constraint, and

limited capacity of existing utilities (Krizek et al. 1996, McKim et al. 2002).

 

Unforeseen
Conditions

 

Space
Constraints

 

Coordination
Constraints

’—

 

Traffic
Constraints

 

Pollution Control
Constraint

Cost/Labor Hrs./Work—in-Place

 

 

 

Safety
Constraint

 

 

Regulatory
Constraint

 

 

 

Figure 1.3 Earned Value Analysis in Renovation Projects (Modified from Nassar 2005)

10

Past studies have concluded that compared to new construction, renovation
projects have been delivering lower performance levels of cost, time, and quality. Below
are the excerpts from some of the studies of renovation projects that investigated the

performance levels between new construction and renovation projects.

”Comparing several new and reconstruction projects, the latter showed significantly

higher time and cost overruns. " (Krug 1997)

“New construction projects perform much better than reconstruction projects that

exhibited higher schedule and cost overruns. " (McKim et al. 2000)

“Typically, the performance of renovation projects is much lower than new construction,

in terms of their cost, schedule, and quality performance. " (Attalla et al. 2003)

These studies attribute the lower performance levels of renovation projects to the
presence of various constraints, as mentioned above (Krug 1997, McKim et al. 2000,
Attalla et al. 2003). Operationally, these constraints impact the production of construction
activities and increase the variability in their production rates. This leads to an unreliable
workflow between trades decreasing the overall performance at the project level (Ballard
2000, Koskela 1999).

Numerous researchers and practitioners in the field of Lean Construction have
investigated different methods to improve the reliability of workflow and the project
throughput. They have reached on a consensus that production planning in regard of the
constraints causes the events to conform to the plan by planning quality production

assignments through communication with construction crews and addressing potential

11

constraints upfront (Mitropoulos 2003, Ballard 2000, Koskela 1999). By identifying and
analyzing the potential constraints of the upcoming work, a realistic production is
planned than ‘can’ be achieved by the crew instead of what ‘should’ be achieved
according to the original project plan. The constraint analysis makes the planned
production ready by pulling required resources rather than pushing them on to the
original plan (Koskela et al. 2001). Once the production is planned and executed, the
application of performance measurement at the production level provides quantitative
information that could be utilized to reduce production variability between different tasks
and to identify the actual causes of poor performance (Ballard 2000). Therefore, by
studying the constraints of renovation projects, it is possible to better plan for these
constraints and to minimize their impacts on the production of construction activities and
overall performance of the project.

Although the reviewed state-of-the-art construction performance measurement
systems focused on identifying key performance indicators for general construction, there
is a need to investigate their application to production management in renovation
projects. This could result in either revising the current methods to plan and assess
production performance in renovation projects or deveIOping new methods. In addition,
as past researches have not collectively concluded the adequate set of performance
indicators for general construction (Korde et al. 2004), it becomes essential to investigate
the feasibility of additional performance indicators for assessing the impacts of
constraints on the production cost, time, and quality in renovation projects. This would
lead to better production planning, execution and assessment methods for renovation

projects in the presence of constraints.

12

From a systems perspective, this investigation necessitates development of a
framework for production management that integrates various constraints with current
production planning and performance assessment methods, and defines appropriate
performance indicators to be measured at the production level of renovation projects.
Reviewing state-of-the-art construction performance measurement systems in the context
of renovation projects will provide a thorough understanding of current measurement
methods and the basis for developing the intended framework.

Therefore, the unique nature of renovation projects, an expanding division of the
entire construction industry, and their increasing underperformance in cost, time and
quality (Krizek et al. 1996, Mitropoulos et al. 2002, Attalla et al. 2003) reinforce the need
to investigate ways to make production planning in renovation projects more adept and

reliable.

1.3 Research Questions

The research need underscores the importance of examining state-of-the-art construction
performance measurement systems for their application to production management in
renovation projects As the complex nature of renovation projects is defined by the
presence of various constraints which lead to cost and schedule overruns, it becomes
imperative to investigate these constraints, and develop assessment methods for their
impacts on the cost and schedule of the production in renovation projects. This research
primarily addresses the following three questions:

1) What are the limitations of state-of-the-art construction performance measurement

systems for managing production in renovation projects?

13

2) What are the complexities of renovation projects that lead to underperformance in
cost, time and quality?
a) What constraints are prevalent in renovation projects that impact the production
of construction activities?
b) What activities are critical in renovation projects with greatest contribution in
budget, schedule, and quality performance?
3) What methods plan the impact of constraints on the production of critical activities in

renovation projects and assess their production performance accordingly?

1.4 Research Goals and Objectives
The overall goal of this research is to develop a framework for production management
of renovation projects to improve schedule development and execution. The goal is
achieved by fulfilling the following objectives:
1. Document state-of-the-art construction performance measurement systems and
production management practices for renovation projects.
Objective-l is fulfilled by performing the following steps:

a. Conduct literature review of state-of-the-art construction performance
measurement systems, complexities of renovation projects, and production
management of construction operations.

b. Identify essential attributes of a production management system for

renovation projects from literature review.

14

c. Draft interview question and conduct interviews of contractors and
subcontractors regarding their production management systems for
renovation projects.

2. Develop a framework for production planning, execution and performance
assessment of construction operations in renovation projects.
Obj ective-2 is fulfilled by performing the following steps:

a. Based on the interview responses, prepare modifications and/or additions
to the essential attributes identified from literature review. This includes
modifying the critical activities, constraints, performance indicators, and
their measurement methods.

b. Develop the intended framework.

0. Demonstrate the developed framework with a hypothetical example of
renovation projects.

d. Verify the developed framework with second round of interviews on the

production planning and assessment method suggested by the framework.

1.5 “Production Performance” Definition for this Research

In general, performance is defined as the ability to implement actions and achieve desired
results. A major driver for this ability is continuous measurement and improvement of
processes (Sahninen 2004). Thus, performance measurement is a method of quantifying
what has happened in the processes and identifying the scope for improvement in future

actions (Hao et al. 2005).

15

In the construction industry, performance at the project level has been extensively
discussed as the ability to finish projects on time, within budget and that meet the desired
quality levels. Therefore, construction performance measurement typically entails
assessing the actual project cost and schedule performance against what was estimated
for identifying negative Cost Variance (CV) and Schedule Variances, and applying
corrective actions. This assessment is typically performed through Earned Value (EV)
analysis and Critical Path Method (CPM) techniques (Alarcon et al. 2000, Samson et al.
2004)

However, various researchers in the field of construction production management
disagree with the conventional approach of construction project management towards
performance measurement. The disagreement lies in the fact that traditional performance
measurement techniques using EV analysis and CPM schedules are based on a ‘reactive’
model that triggers only when negative deviations are identified (Ballard 2000, Koskela
et al. 2001). Project controls track the completion of each activity by determining
whether the activity and project are within the cost and schedule limits. These traditional
techniques fail to address possible constraints, resource capacities, pre-requisite work,
and the quality of the state of the system upfront for the production of an activity. Thus,
traditional performance measurement techniques do not assure a reliable work-flow
between trades (Ballard et al. 1998, Koskela et al. 2001). The focus has been on
managing contracts and CPM schedules by pushing more and more resources to speed
the completion, which consequently adds more waste, the non-value adding activities at

the production level (Ballard 2000, Koskela 1999).

16

Therefore, at the production level, performance has been defined as the ability to
complete production assignments that are scheduled on weekly basis per the existing state
of the system (Mitropoulos et al. 2003). These production assignments are established
based on the analysis of constraints prevailing in prerequisite work, site conditions, and
resource availability that could impact the production of construction activity. Production
assignments signify what “can” be performed under the impact of existing constraints
rather than what “should” be performed, as planned in the CPM schedule. The intention
of planning and assessing production in the presence of constraints is to make the
workflow more reliable between trades that minimizes waste in construction activities
and reduces the variability in their production rates (Ballard 2000, Chitla 2000).

Management of production in renovation projects poses a question of ‘what
constitutes production performance in a renovation project’. Several studies have
concluded that the constraints of renovation projects by their complex nature negatively
impact the production of construction activities leading to schedule and cost overruns
(McKim et al. 2000, Mitropoulos et al. 2002, Attalla et al. 2003). Being an inherent part
of renovation projects, these constraints are generated due to numerous project
conditions. Failure to address these constraints before planning production of each
activity could result in cost and schedule deviations (Mitropoulos et al. 2002).

This research posits that the ability to define production assignments by
proactively identifying and assessing the impact of constraints in the production of
critical activities, as well as completing the production assignments within budget, on

schedule, and at desired quality defines the “production performance” of contractors in

17

renovation projects. This definition of production performance is considered in the

development of the intended framework throughout this research.

1.6 Research Scope

The scope of this research is governed by the following factors:

1.

The research focused on production management of renovation projects of
institutional buildings that involves interior remodeling of occupied built
facilities.

The research investigated production evaluation of construction activities and not
the employees and craft labor of the firm. This research has not attempted to
assess the performance of socio-economic factors of construction firms.
Production planning and assessment of construction activities of renovation
projects forms the extent of this research. Design performance evaluation and the
life-cycle performance evaluation do not form a part of this research.

The developed framework for production management of renovation projects
focuses on planning and assessing only the production schedules of construction
activities. Due to the complexities involved, the fiamework does not suggest any
methods to assess the impacts of constraints on the production cost and quality of
construction activities.

In order to obtain pertinent data from construction professionals, this research
conducted interviews of six contractors and four subcontractors, based in

Michigan due to geographical constraints.

18

1.7 Chapter Summary

This chapter provided an overview of the scope of this research by outlining its goals and
objectives. It explained the need for a framework for production management of
renovation projects in the construction industry. The chapter also discussed the
contribution of this research in terms of its expected benefits to the project owners and

contractors involved in renovation projects.

19

CHAPTER-2

LITERATURE REVIEW

20

2.1 Introduction

This chapter discusses the literature in three categories of; state-of-the-art construction
performance measurement systems, renovation projects, and production management in
construction. The literature was obtained in the form of theses, dissertations, journals and
articles from University library sources and the web. Each category of literature was
reviewed to bring forward its emphasis areas for achieving the research objectives.

The purpose of reviewing state-of-the-art construction performance measurement
systems was to obtain an understanding of their objectives for development, performance
indicators, performance measurement processes, and implementation strategies. The
literature of renovation projects was reviewed to understand its complex nature and scope
of additional requirements for managing construction operations. This included review of
various constraints that act as the primary sources of cost and schedule overruns in
renovation projects. Construction production management literature provided an
overview of performance assessment processes at the production level of construction
operations. It also brought insights into how inefficiencies of construction process
operations at the production level were previously addressed. The following sections

discuss each category of literature in detail.

2.2 Concept of Performance Measurement

The performance of any process is the result of the abilities of its sub processes and
individuals to implement desired actions. Measurement is the process of ascertaining this
ability and comparing it with the standards or planned targets. Measurement of

performance, both quantitatively and qualitatively, reveals the inefficiency and scope for

21

improvement in the process. Therefore, performance measurement is the process of
quantifying what has happened in the processes and identifying the scope for
improvement in future actions (Hao et al. 2005). As a starting point for upgrading any
process, performance measurement provides essential information about the status quo of
the process and improvement opportunities in that process (Beatham et al. 2003).

In management sciences, a central objective of measuring performance is to
improve the competitive ability of a company in reducing operational costs and
increasing the profits. This forms the prime reason for increasing interests of companies
in every sector in performance measurement (Sahninen 2004). Prior to measuring
performance, it is essential to determine what to measure, how to measure, and the data
collection and analysis methods. The decision about what to measure depends on what to
improve in a process. The question of how to measure determines what methods will be
used to take the measurement. The data collection and analysis methods define the team
responsible for collecting the measured data and analyzing it appropriately to compute

the performance (DOE 1996).

2.3 Performance Measurement in the Construction Industry

The construction industry is characterized by its dynamic nature, complexity of
processes, and involvement of several stakeholders in different processes that need to be
kept in control for achieving project success. The competitive ability to control
construction processes under desired performance levels has been identified as one of the
most significant factors in defining a company’s grth (Beatham et a1. 2003).

Consequently, performance measurement has been a major issue of concern in the

22

construction industry over past 15 years (Bassioni et al. 2004). This has also been driven
by increasing demands of owners for measuring construction performance due to
tremendous increase in reworks and wasted efforts in construction processes that lead to
projects being over-budgets, behind schedule and poor in quality (Beatham et al. 2003).
In spite of growing significance of performance measurement systems in the
construction industry, it has been widely recognized that traditional performance
measurement practices that focus only on cost and schedule deviations, do not provide an
accurate assessment of construction projects (Costa et al. 2006). The traditional
performance measurement systems have been extensively criticized by numerous
researchers for their multitude of limitations in the context of current construction
practices. The following section provides an overview of these limitations of traditional

measurement systems.

2.3.1 Limitations of Traditional Performance Measurement Systems

Previous studies indicate that there is a growing dissatisfaction with the traditional
performance measurement systems focusing only on financial indicators. Samson et al.
(2002) stated that financial indicators are unable to explain the status of a continuing
process and therefore, do not form the basis for future actions. These indicators have been
referred to as being “lagging” measures because they only explain the outcomes of any
action after its occurrence and do not offer the opportunity to change or improve
performance during the process. Therefore, these indicators do not support continuous
improvement due to their inability to define the cause-effect relationships between the

results and causes (Beatham et al. 2003).

23

The traditional performance measurement systems have also been criticized for
being based on easily quantifiable measures such as cost, productivity, and schedule
deviation. Measuring factors that contribute to competitive success has been neglected
(Beatham et al. 2003). Instead, measurement of performance at process level, and even,
operational level, has been observed to give a better indication of current and future
performance (Alarcon et al. 2000). Samson et al. (2002) stated that the essential
characteristics of performance indicators that an effective measurement system should
possess are; i) the ability to identify causes of results and ii) the ability to identify
improvement opportunities based on the result analysis.

As the financial measures are not linked with the value-adding activities, they
cannot fully explain the causes of inefficiencies in the process. It restricts the process
transparency where the non-value-adding activities become invisible, as the traditional
indicators are focused on conversion activities, ignoring the flow activities (Alarcon et al.
2000). In addition, these indicators have a short-term focus of making profit instead of a
long-term strategic focus, as they are not linked with the strategies and objectives of
construction companies (Beatham et al. 2003).

In addition to the indicators being used, there are some limitations of the
measurement process of traditional performance measurement systems (Costa et al. 2000,
Samson et a1. 2002):

0 There is a use of too many measures focused intemally on the administrative
issues and few measures focused externally on the actual construction processes.
0 The cycle time to generate information from the measurement data is usually too

long to make decisions.

24

The indicators are not related to the critical processes that contribute to the overall
performance.

The measurement methods for the indicators are not clearly defined.

The performance does not relate to the operational costs and the system tends to
be backward focused.

There is a tendency to blame individuals for underperformance instead of

identifying the right process to improve.

The limitations of traditional performance measurement systems have driven previous

researchers to make recommendations for the essential characteristics of performance

indicators. The authors have suggested that the indicators should be (Costa et al. 2000,

Samson et a1. 2002, Beatham et al. 2003):

Able to realize company’s goals and objectives.

Able to identify causes of results.

Able to identify improvement opportunities in the processes for better
performance.

Easy to measure and simple to understand.

Related to the key business processes that impact the performance.

Able to generate information that support expedited decision-making.

2.3.2 State-of-the-art Construction Performance Measurement Systems

The limitations of traditional performance measurement systems led numerous

researchers to focus on developing what have been termed as state-of—the-art performance

measurement systems for the construction industry. As per a study conducted from 1994

25

to 1996, it was concluded that the rate of appearing each new article pertaining to
performance measurement was five hours of every working day (Beatham et al. 2003).
Although, not all of these systems were related to construction, but they illustrated that
performance measurement has been an issue of concern in all the industries.

These state-of-the-art performance measurement systems have investigated
different models for measuring and analyzing construction performance but the overall
focus was on identifying appropriate indicators that could measure the performance of
construction processes. Some of these systems also developed the measurement methods
of performance indicators at the project level, trade level, and activity level (Korde et al.

2004)

2.3.3 Performance Indicators of State-of—the-art Construction Performance
Measurement Systems

A performance indicator represents a quantitative or qualitative assessment of any data
that is used to evaluate performance of business operations against the desired targets
(Hao et al. 2005). In the construction industry, the performance indicators have been
extensively recognized as Key Performance Indicators (KPI), as most of the state-Of-the-
art performance measurement systems employ this terminology (Robert et a1. 2003).

The key performance indicators for construction operations have been extensively
studied and analyzed by numerous researchers in order to achieve at the most favorable
subset that collectively measures the efficiency and effectiveness of construction
processes. Some of the studied indicators measure the success of results, i.e., construction

projects while others measure the construction processes to achieve successful results.

26

The former are called “lagging” indicators and the latter are termed as “leading”
indicators (Beatham et al. 2003). In numerous studies, these KPIs have been used
synonymously with Critical Success Factors (CSF), although the purpose of both KPI and
CSF is to assess the performance of construction projects or operations. The following
section provides an overview of various studies that focused on identifying the
performance indicators or success factors for construction projects.

Chan et al. (2004) developed a framework for assessing construction success that
involved identification of KPIs for assessing project success. The identified KPIs were
time, cost, value and profit, health and safety, environmental performance, quality,
fiinctionality, user expectation and satisfaction and, participants’ satisfaction.

In 2004, Salminen developed a performance measurement system for construction
site operations, which was divided into three parts; preconditions, the operation
processes, and the results. The author investigated the essential elements of construction
site performance and their measurement methods. Further, the relationships between
performance elements were analyzed and most important performance elements were
identified. Each of the three parts of the developed performance measurement system
consisted of performance factors as:

1. Preconditions-This part relates to the preconditions of the site created by
the owner, designer, and consultants.

2. Operation Process- Management system, work behavior, and leadership
formed the main factors that contribute to operation performance.

3. Results- Cost, schedule deviation, quality, and safety were the main

factors for measuring results of any construction project.

27

rn

(J

The research conducted forty-seven case studies of four construction firms that
generated three hundred performance variables. The author reduced this number by
combining similar variables through discriminant analysis. It was concluded that cost,
schedule deviation, quality, and safety were the main factors that contribute to project
success.

Attala et al. (2003) identified thirty six CSFs of reconstruction projects, under
broad categories of cost, schedule, quality, scope, communication, safety and site for
developing a performance prediction model. For investigating the factors in fifiy-four
case studies, they were further reduced to seventeen through statistical application for
making the research manageable and controllable. The authors categorized these
seventeen indicators under project phases of scope definition and planning, tendering
stage, schedule control, cost control, quality control, communication, safety control and
project completion. It was concluded that the most critical phases for performance in
reconstruction projects are management and control of planning, tendering and
scheduling.

Beatham et al. (2003) analyzed KPIs developed by seven organizations in the
UK construction industry, with the objective of developing an integrated business
improvement system. Among the investigated KPIs, the Construction Best Practice
Program (CBPP) was considered one of the foremost systems that included ten headline
KPIs during its initial launch in 1998; client satisfaction-product & service, profitability,
productivity, defects, safety, predictability-time & cost, construction time and
construction cost. In 2000, CBPP KPIs were increased to 38, to be measured in seven

criteria of time, cost, quality, client satisfaction, change orders, business performance and

28

health and safety, and they were further organized in a hierarchical model of headline,
operational and diagnostic level measurement (Beatham et al., 2003).

After analyzing the KPIs of all organizations, the authors concluded that most of
the systems had employed post result lagging indicators and they do not offer an
opportunity to change the performance during process. Some of the examples of lagging
KPIs were defects, client satisfaction, time, cost, profitability, productivity, risk, reuse of
design etc. It was found that some of the KPIs could be employed as leading indicators if
used during the process such as defects, client satisfaction, time, cost etc. The authors
suggested European Foundation of Quality Management (EFQM) categorization for the
investigated KPIs in three broad categories of Key performance indicators, key
performance outcomes and perception measure. This categorization would facilitate
appropriate application of KPIs for measuring both process performance and project
performance (Beatham et al., 2003).

Chua et al. (1999) identified CSFs of a construction project for different
objectives of budget, schedule and quality. As per the authors, the need to assign
resources appropriately for each objective necessitated this categorization of success
factors. The authors compiled sixty seven CSFs from literature review that involved
previous studies dealing with identification of CSFs for different aspects of construction
projects such as project execution strategies, project performance, project management,
project partnering, contracting methods and contract disputes.

The identified CSFs were investigated for their relative contribution to different
project objectives of cost, time and quality. In order to understand this relative

importance of CSFs, the authors organized them under different levels of focus where a

29

comparative analysis could be performed at each level. This was achieved by developing
a hierarchical model for construction project success that categorized the CSFs in four
main project aspects of i) project characteristics, ii) contractual arrangements, iii) project
participants and, iv) interactive processes. Under each project aspect, the CSFs were
analyzed for their relative importance in contributing to different project objectives.

The authors conducted survey of twenty construction experts having
approximately fifteen years of industry experience and they were requested to perform a
pair-wise comparison of sixty-seven CSFs for achieving the project objectives of budget,
schedule and quality. This pair-wise comparison was based on Analytical Hierarchy
Process (AHP) importance scales and the collected data was analyzed through Expert
system software that could perform the AHP calculations. As per the analysis results, it
was concluded that each project objective had different set of top ten CSFs, however,
‘adequacy of plans and specifications’ and, ‘constructability’ figured out as the leading
success factors for all the three objectives. The other common CSFs for cost, time and
quality, each having different importance levels, were PM competency and, PM
commitment and involvement.

Further, these top ten CSFs for each project objective were reviewed for their
hierarchy under four main project aspects, as stated above. For instance, under the
‘external project characteristics’ project aspect, the top most CSFs for budget
performance, schedule performance and quality performance are economic risks,
technical approval authorities and, site limitations and location respectively. This analysis

helped the authors to understand the nature of CSFs under different project aspects and

30

their contribution to different project objectives. This would also make the resource
allocation to each project objective appropriate for each project aspect.

In 2001, Samson et al. emphasized the importance of effective performance
indicators to make the traditional performance measurement systems more adapt to the
emerging trends in the construction industry. These trends refer to high costurner’s
requirements, environmental awareness, high competition and continuous improvement
of construction business processes. The authors discussed some of the essential
characteristics of performance indicators that an effective measurement system should
possess, which are; i) ability to identify causes of results and ii) the ability to identify
improvement opportunities based on the result analysis.

At a conceptual level, the authors developed a performance measurement
framework based on five essential dimensions, each representing a different perspective
of construction business. These perspectives were innovation and learning, processes,
projects, stakeholders, and financial. Performance measurement from each of these
perspectives has been suggested and explained, to obtain an integrated and holistic
performance where each perspective has its designated role in measuring and improving
the performance of different aspects of construction business. For instance, performance
from learning and innovation perspective contributes in expanding the knowledge base of
a company, while from project perspective, performance is the ability to deliver projects
on time, within budget, and of right quality that satisfies client needs.

In addition, in order to measure the performance from each perspective, the
authors have identified performance indicators based on these five perspectives. These

indicators have been further grouped into process indicators, performance driver

31

indicators and result indicators. This categorization helped the authors to clearly define
the scope and function of each performance indicator.

In 2000, Alarcon et al. presented a classification system of construction
performance indicators based on the results, processes and variables that support
decision-making for taking corrective actions. Through this categorization, the decision
maker gets equipped with the ability to identify the root causes of the problems. On the
other hand, the authors have criticized current selection of traditional indicators, i.e., cost
and schedule, for measuring performance and, have emphasized the significance of
incorporating process oriented indicators for their ability to identify non-value adding
activities in the processes.

Through an extensive literature review, followed by a thorough investigation by
different participating companies, the research formulated a list of twenty performance
indicators that would achieve the research main objective by supporting management
decisions, encouraging continuous improvement and benchmarking. However, while
implementation in case studies, it was identified that the application of proposed
indicators would be limited to the capacity of the existing control systems used by
different companies and it was suggested to commence with few and easily measurable
indicators. Further, the authors extended the need to incorporate the measurement of
operational level indicators (e. g. rework, transportation, waste, cycle time) that would
support waste identification at the task level of construction processes. As a part of
benchmarking initiative, the research developed a baseline from the results of five recent
projects, each from seven construction companies, which helped in understanding the

variability in the distribution of various indicators within companies.

32

Nassar (2005) developed an integrated project performance hierarchical structure
that provided a basic framework for defining the success factors from the perspectives of
project team, construction organization and client organization. The amalgamation of
different perspectives in a single framework facilitated a balanced performance
measurement approach, comprising of eight performance indices; safety performance
index, client satisfaction index, quality performance index, schedule performance index,
cost performance index, billing performance index, project team satisfaction index and,
profitability performance index. The author assigned relative importance to each index in
contributing to the overall project performance index, through application of Analytical
Hierarchy Process (AHP). Based on the relative weights of performance indices, overall
performance index can be ascertained, representing the performance at management level
and Operational level. However, the author stated that the importance levels of
performance indices are functions of the type and status of the project. For instance, in
the project closeout stage, the relative importance of cost performance index would be
lower than schedule performance index as major fraction of the estimated budget has
been spent by that time and, finishing the project on schedule becomes more essential.

For measuring each success index, the author identified its respective essential
attributes as performance indicators, which were identified on the basis of the author’s
fifteen years of industry experience, but due to the uniqueness of construction projects,

the author suggested formulating these indicators by contractors themselves.

33

it

Of

 

2.3.4 Performance Measurement Methods of State-of-the-art Construction
Performance Measurement Systems

Measurement of any performance indicator, quantitatively or qualitatively, brings
forward the efficiency and effectiveness of a certain aspect of the products, services and
the processes that produce them (DEC 1996, Hao et al. 2005). Quantitative measurement
results in a number and a unit of measure, which represent the magnitude and the nature
or meaning of performance indicator respectively. For instance, construction
productivity, being measured in $/hour or units/hour provides the magnitude of labor
efficiency on construction sites. Being in a project-oriented industry, construction
companies have been struggling in defining the appropriate methods for assessing the
performance of various aspects of construction. This has been attributed to the
uniqueness and complexity of construction projects (Costa et al. 2004).

On the theoretical front, conflicting views for measuring performance under
qualitative and quantitative aspects of construction can be found. The Department of
Energy (DOE) suggests quantitative measures rather than qualitative due to their
subjectivity and unclear interpretations (DOE 1996). However, in 1998, Williams stated
that performance is not a result of common views, rather it holds different meanings to
different stakeholders and therefore, performance measurement involves both hard
financial and non-financial measures and, soft measures such as client satisfaction,
employees attitudes etc. In addition, Kast et al. (1985) incorporated ‘participant
satisfaction’ as one of the measures in performance because the success of any process

depends'on the satisfaction of its enablers (Salminen 2004).

34

Despite the importance of performance measurement method in construction, a
very few authors have discussed the appropriate methods for measuring performance
indicators both objectively and subjectively. The major emphasis has been on
identification of performance indicators and the implementation methods of the proposed
performance measurement systems and not on the performance measurement methods
(Attalla et al. 2003). Although, some authors have investigated the hierarchy or relative
importance of performance indicators for measuring overall performance of construction
projects, but it is essential to understand the methods for measuring the indicators for
their appropriate application.

Attalla et al. (2003) suggested calculating Process Performance Factor (PPF), as a
quantifiable and objective indicator of overall performance of reconstruction projects.
The main three components of PPF were change order cost, rework cost and schedule
delay and each component was assigned a relative weight in contributing to the overall
performance as shown in the equation below.

PPF = X x [l-Change orders cost/original contract value] x 100

+ Y x [1-Cost of rework/original contract value] x 100

+ Z x [l-Schedule delay/original schedule] x 100

Chua et al. (1999) assigned relative weights to project objectives of budget,
schedule, and quality in achieving construction project success through Analytical
Hierarchy Process (AHP) among which schedule performance was found to be a major

contributory factor as compared to other two objectives. For each project objective, top

35

ten CSFs were analyzed for their relative importance but the measurement methods for
the CSFs were not investigated.

Chan et al. (2004) categorized the identified KPIs under objective and subjective
measures and presented their quantitative and qualitative methods of measurements. The
application of identified KPIs and their measurement methods were also investigated on
three hospital projects where the authors concluded that the time and cost performance
get impacted by the adopted project procurement method, traditional and design build.

Alarcon et al. (2000) suggested measurement methods for the identified
performance indicators of project results, processes, and variables. The authors stated the
objective of measuring each indicator as benchmarking, continuous improvement, waste
identification, variability reduction, process improvement, and reduce cycle time. In
addition, performance measurement at operational level was also emphasized with the
identification of Lean based performance indicators to be measured at task level with
their appropriate measurement methods.

McKim et al. (2000) developed quantitative methods of Cost Performance Factor
(CPF) and Schedule Performance Factor (SPF) for controlling cost and time performance
in reconstruction projects. The equations of CPF and SPF are:

CPF (%) = [Total value of change order/original contract value]. 100

SPF (%) = [Total project delay/original project duration].100

In addition, the authors also suggested three quantitative measures for the Quality
Performance Factor (QPF) as i) estimated cost of rework and repair, ii) number of
rework/or repair requests and iii) number of users’ complaints related to noise, dust,

smoke etc.

36

Nassar (2005) adopted the earned value method for measuring the performance
indicators of eight success indices. For instance, measurement of cost performance index
entailed measuring its lower level performance indices such as indirect cost performance
index (CPII), engineering cost performance index (CPIE), labor cost performance index
(CPIL), material cost performance index (CPIM), construction equipment cost
performance index (CPIC), subcontractor cost performance index (CPIS) and,
tools/consumable cost performance index (CPIT). Each indicator has been suggested to
be measured by dividing its earned value by its actual value.

Nassar (2005) also suggested a qualitative rating system based on the calculated
value of each index. For measuring the qualitative success index such as client
satisfaction or project team satisfaction, earned value of each lower level performance
index is the product of its priority weight and its achieved value on a qualitative scale of
1-10. This quantitative method for qualitative aspects would eliminate any biases in the
reviewer’s opinions. The overall performance is the algebraic sum of the weighted
contribution of each performance index (N assar 2005).

Russell et al. (1997) suggested the s-curve method of time dependent variables for
predicting performance of construction projects. The authors developed s-curves of
continuous project variables such as contractor construction efforts hours expended,
invoices paid by the contractor, total commitment for materials and equipment, cost of
owner project commitments and cost of contractor project commitments, and designer
project cost. These variables are time dependent as their values change during the course
of the project. Through case studies of 54 projects, s-curves of these variables were

plotted for both ‘successful’ and ‘less than successful’ projects. Depending on the status

37

of the project, project managers could identify the applicable variables and ascertain their
actual value and compare them with the developed s-curve of ‘successful’ projects for

predicting the performance of those variables.

2.3.5 Role of Performance Measurement in Realizing Strategies

“In order to control a strategy, it has to be measured

(Bassioni et.al., 2004)

There has been a consensus among researchers and industry experts that
performance measurement is an integral aspect of strategic planning and controlling
process. For an organization, performance is the ability to implement desired strategies
(Salminen 2004). Therefore, a performance measurement system should be developed on
the basis of company’s strategies and objectives. There should a clear link between the
measures adopted and strategic objectives, which establishes a cost-benefit analysis of the
chosen strategies and assesses the appropriateness of selected measures for realizing the
strategies (Lantehne et al. 2000). Several authors view performance measurement as an
effective manner of supporting and implementing strategies.

Beatham et al. (2003) brings forward the significance of strategic control system
in construction performance measurement. A strategy outlines the important dimensions
of any performance measurement system by clarifying: what are the reasons for
measuring performance, what is a good performance, what are the priorities, what is the
trade-off between performance measure, and when to take actions on underperformance.
The authors developed an Integrated Business Improvement System (IBIS) that defined

the critical success factors and their respective performance measures based on the

38

business objectives and the overall vision of the company. Therefore, the fulfilhnent of
business strategies is governed by achieving desired performance in critical success
factors.

Costa et al. (2002) having conducted a literature review of current performance
measurement systems such as Balanced Scorecard, Performance Pyramid etc. and, case
studies of five medium and small sized construction firms, identified the need to develop
a construction based performance measurement system that should be linked to
companies’ competitive strategies. During case studies, the authors analyzed the
companies’ strategies through a strategy map that clearly linked different functional
strategies to achieve companies’ objectives. The case studies were critically investigated
against well-defined constructs of; measure definition, alignment of measures to
strategies, insertion of measures into company routine, and learning achievement through
measurement.

These constructs provided a comprehensive structure for identifying some of the
best practices in performance measurement, and improvement opportunities in those
practices. The key best practices identified were: development of a quality management
system, employee rewards program, alignment of measures to company strategies and
critical processes, and decentralization of decision-making. These practices not only
revealed the companies’ competitive abilities to measure the performance but also
provided the authors with a foundation for formulating the guidelines. The proposed
guidelines primarily centered on defining the company’s competitive strategies,

objectives and, developing performance measures to support those strategies. In addition,

39

appropriate use of information systems for supporting decision-making and taking
corrective actions, was another concluding concern.

Being a part of business improvement system, performance measurement supports
the implementation of business strategies. In 2000, Lantelme et al. conducted nine case
studies of construction firms with the objective of developing implementation guidelines
for performance measurement systems. The authors concluded that strategic planning
provided a framework for the development of performance measurement system where
the measures were structured hierarchically in the organizational structure and there
existed a clear link between higher-level measures and company’s goals and objectives.

However, Price et al. (2003) stated that the use of strategic planning is not
widespread in the construction industry for being focused only on operational cost
effectiveness, ignoring the strategic positioning of the company and consequently,

performance measurement would not be used as a strategic deployment tool.

2.3.6 Implementation Methods of State-of-the-art Construction Performance
Measurement Systems

The construction industry has been deprived of successful implementation of developed
performance measurement systems (Beatham et al. 2003, Costa et al. 2002). A number of
studies have investigated the nature of barriers inherent in construction companies that
confine this implementation and have come across two types of problems. The first is
associated with the design of performance measurement system and the second relates to
the organizational capabilities to handle the developed systems. The limitations in

traditional design of performance measurement systems involve inappropriate selection

40

of performance indicators and associated measurement methods. The organizational
capabilities relate to managers’ disinclined attitude towards systematic performance
measurement, employees’ lack of training for understanding the system, and lack of an
appropriate data management system (Costa et al. 2002). Researchers have concluded
that successfirl implementation of a performance measurement system requires creating a
continuous measurement culture through the engagement of users in understanding and
appreciating the system (Beatham et al. 2003).

In 2000, Lantelme et al. conducted research on the implementation phase of
performance measurement systems, being used by the construction companies in Brazil.
The research need followed from the implementation problems associated with the
SISIND (System of Quality & Productivity Indicators for the Construction Industry)
Project in Brazilian construction companies, which was developed as a performance
measurement system by the Building Research Group (N ORIE) of the Federal University
of Rio Grande, do Sul (UFRGS). The main objective centered on developing
implementation guidelines of performance measurement system in construction firms. To
achieve this, the authors first identified prevailing problems associated with the
implementation process of performance measurement by conducting interviews with
managers of nine firms (six construction and three manufacturing firms) and then
proposed the implementation guidelines based on literature review of lean production
principles and organizational learning.

The literature review provided a basic understanding of those management
approaches that sustain the implementation of performance measurement through

application of Lean Construction principles. These principles emphasized the importance

41

of measuring performance of production systems at the operational level, which
facilitates process transparency, and decentralization of decision-making. In addition, the
concepts of organizational learning helped in understanding the cyclic mechanism of self-
assessment process and implementation of corrective actions based on performance
evaluation.

Since the sample size of interview process consisted of diverse companies that
varied by size and trade type, the data analysis gave an insight into those barriers that
restricted successful implementation of performance measurement and, those practices
that made the implementation process successfirl. Lack of organizational capability for
handling the data pertinent to performance measurement and, managers’ behavioral
aspects of short-term focus and reluctance to use appropriate tools and techniques for
data analysis were identified as the main barriers among interviewed companies.

From the barriers, the authors formulated implementation guidelines for
performance measurement that also incorporated successful practices identified in
interviewed companies. The guidelines mainly emphasized on improving the process
transparency by information sharing, establishing a system thinking for identifying
causes of under-performance, reducing cycle time in information retrieval and making the
corrective action, use of simple and easy to understand measures, and use of
benchmarking for continuously improving the processes by evaluation against best
practices.

Similarly, Costa et al. (2000) suggested guidelines for implementing performance
measurement systems in construction companies which involved strategy corrununication

at all levels, creation of a measurement environment, systematic performance

42

measurement at designated intervals referred to as ‘formal moments’, employees’
empowerment including their training and decision making authorities and, managers’
participation in systematic data collection and analysis processes.

Samson et al. (2001) developed a framework for performance measurement
system to be applied in Tanzanian Construction Industry which was based on five
essential dimensions, each representing a different perspective of construction business.
These perspectives were innovation and learning, processes, projects, stakeholders and
financial. Performance measurement from each of these perspectives has been suggested
and explained to obtain an integrated and holistic view of performance where each
perspective has its designated role in measuring and improving the performance of
different aspects of construction business.

The authors discussed organizational strategies required for the implementation of
the proposed framework of performance measurement in construction firms. These
strategies are i) leadership commitment that involve self involvement and motivation, ii)
employee involvement and empowerment for decision-making at the operational level,
and iii) information management that maintains a continuous learning cycle based on the
results. The suggested strategies would drive the functional nature of the framework for
its intended purpose and enable the performance drivers to implement the system and
produce desired results in processes.

Beatham et al. (2003) having identified the implementation barriers of political,
infrastructure, and focus nature, suggested a four step methodology for successfully
implementing the proposed Integrated Business Improvement System (IBIS) in

construction companies. Communication of IBIS structure and its measurement process

43

to employees is the first step, and mutual agreement of business objectives and
measurement areas among all managers by empowering them is the next step. Bringing
transparency and consistency in performance measures, and employing senior managers
for encouraging the measurement process among lower level employees by using it as a

key management tool define the last two steps.

2.4 Discussion of State-of-the-art Construction Performance Measurement Systems’
Literature

State-of—the-art practices in construction performance measurement systems facilitated
the understanding of current performance measurement processes, their performance
indicators, measurement methods and implementation strategies for successfully
integrating the measurement systems with current construction practices. Although each
system had some limitations, but collectively they provided some of the essential
attributes of a production management system required for renovation projects.

The study by Chua et al. (1999) presents a comprehensive approach of
understanding the nature of CSFs for different project objectives. The categorization of
CSFs in four main project aspects facilitated i) the development of hierarchical model for
project success and ii) application of mathematical tools such as AHP in assigning the
relative importance to CSFs, which figures out as a vital approach for achieving the
research intent. The research proved the common misconception that for each project
objective the critical success factors and even their hierarchy remain the same.

Samson et al. (2001) research brings forth the significance of performance

indicators’ attributes in the effectiveness of a construction performance measurement

system. The authors’ approach of first identifying the limitations in current practices and
then addressing them through development of the framework, illustrates an effective
contribution to the Tanzanian construction industry. However, the authors did not discuss
the measurement effectiveness and performance forecast abilities of the proposed
performance indicators, which could also have provided some insight to their
measurement methods.

The research conducted by Alarcon et al. (2000) underscores the use of those
indicators that facilitate establishment of cause- effect relationships and support decision-
making for taking corrective actions. However, the authors failed to present any
theoretical and analytical explanation for selection of proposed indicators from the
literature. Moreover, the research could have investigated development of relationships
between the performance indicators and, assigning priorities in achieving overall
performance. This could have delivered an improved understanding of managing the
performance amongst project participants through sharing the impact of performance
indicators on overall project throughput. Although the research focused on identifying
new performance indicators, it could have been oriented towards the identification
process from system thinking perspective.

Costa et al. (2002) research presented a comprehensive approach of analyzing the
companies’ performance measurement systems from their strategic standpoint. It
underlined the need to develop strategic objectives as a basis for setting the desired
performance levels and measuring the processes. The authors’ illustration of a company’s
strategic map, through literature review, helped in understanding the scope of each

functional strategy type, and the implicit link between performance measures and

45

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. competitive strategies. Moreover, it created a framework to categorize performance
indicators, as measures of processes to support strategies. Identification of critical
processes through this framework can be an effective way of mapping the performance in
overall process. The adopted method for selecting case studies based on the criteria of
existing performance measurement systems was a thoughtful approach of examining the
right processes for achieving the research objectives. Although the research is ongoing,
its intermediate results and even the adopted methodology can be a useful tool for other
investigations focusing on identifying the current best practices in performance
measurement for construction industry. It would assist in assessing the inefficiencies in
current construction practices and, bridging the gap between theoretical awareness and
practical applications.

The research conducted by Lantelme et al. (2000) is helpful in understanding the
nature of barriers prevalent in construction industry for measuring the performance. The
authors’ approach of comparing performance measurement systems implemented in the
construction companies with those in the manufacturing companies presents an
exploratory way of identifying the best practices outside the realm of construction
industry. The proposed guidelines can be viewed as a starting point for assessing the
effectiveness and identifying the inefficiencies of performance measurement systems
used by any construction firm. However, there is a lack of facts and figures, which could
support the validation of successfiil practices identified in the manufacturing industry. In
addition, for implementing the guidelines in construction companies, further research is
required for identifying the organizational and production management changes to be

made in construction industry.

46

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(a

Overall, the reviewed performance measurement systems underscore the
identification of key performance indicators of critical activities of construction projects
that majorly contribute in projectperforrnance. The performance indicators suggested by
the reviewed performance measurement systems need to be analyzed for their effective
application in renovation projects. Moreover, the major performance categories of the
reviewed performance measurement systems figure out as cost, time, quality, and safety.
The literature also suggested possible quantitative methods such as Analytical Hierarchy
Process (AHP) that was applied by this research to the essential attributes for developing

the intended framework for production management of renovation projects.

2.5 Literature Review of Renovation Projects
Renovation projects have been distinguished from new construction projects due to their
unique nature and complexity of construction processes (Jimenez 1999). These projects
are characterized by constantly changing environment, which is attributed to unforeseen
events in the preexisting conditions that have prominent impact on the project success.
Apart from the unforeseen conditions, the renovation projects become much more
unpredictable due to the presence of constraints which define their dynamic environment
and complex nature. These constraints are those factors, which are typically outside the
project scope, but still cause frequent changes in the planned scope of work and impact
the estimated budget, schedule and quality of the project (Krizek et al. 1996, Mitropoulos
et al. 2002).

For instance, if a contractor encounters asbestos while demolition of any sort, that

was not foreseeable, it would have to stop the demolition activity or any other work near

47

that area. This would not only impact the next trades’ scheduled work but also the overall
schedule of demolition activities, which was coordinated with owner’s operations for
minimizing the disruption (Rush 2002).

In addition, if the contractor had ordered the materials for installation right after
demolition, it would have to arrange for a temporary storage area for stacking the
materials until the asbestos is removed and demolition is completed. In an operational
building, where the occupants have taken over rest of the building area, it becomes
extremely difficult for the contractor to find adequate material storage space for such a
short notice (Jimenez 1999). The contractor would have to transport the materials back to
the suppliers and get them redelivered, and reschedule all the work as per the owner’s
operations. This would probably delay the overall project, which could also have adverse
repercussions on the owner’s estimated budget. The owner’s money spent on leasing the
swing space for the period of asbestos removal would be wasted, as the owner could have
started to occupy the swing space once the demolition starts after the asbestos removal.
Therefore the actual leasing period would exceed its estimated schedule and cost more to
the owner (U .S. GAO 2003). This is an outcome of uncertainty constraint in the
preexisting conditions of renovation projects. These circumstances could also emerge due
to utility constraints if, during demolition, the contractor breaks any utility pipes such as
mechanical, plumbing or electrical, that was serving the building occupants (Krizek et al.
1996)

In this environment of constant changes and uncertainty in the scope of
renovation projects, where the external constraints have negative impacts on the project

outcomes, traditional project planning and controlling techniques that only consider

48

“what is inside the project” prove to be inadequate for delivering successful results
(Wayne et al. 1988, Jimenez 1999). Numerous studies have investigated the complex
nature of renovation projects and concluded that their increasing overruns in cost and
schedule are due to the presence of these external constraints. These studies have shown
that the external constraints impose additional challenges for managing a renovation
project, which require extensive pre-construction planning for encountering and coping
with the constraints (Attalla et a1. 2002, Mitropoulos et al. 2002).

In a multiphase renovation project, where the construction is carried out in an
operational facility, the impact of external constraints on project scope gets accentuated
due to the development of process friction between owner’s operations and construction
activities (Attalla et.al 2002, McKim et al. 2000). In the absence of any swing space, this
friction generates more external constraints that are required to be managed for project
success. This friction makes multiphase renovation projects most difficult in achieving
successful completion. The constraints not only impact the construction process but also
the design process leading to reworks and design iterations (Mitropoulos et al.2002). The
following section provides an overview of previous studies that dealt with the constraints

of renovation projects and their scheduling techniques.

2.5.1 Constraints of Renovation Projects

Various researchers have explored the challenging nature of renovation projects and they
have concluded that it is essential to plan ahead for these challenges in order to minimize
their impacts on the project success and plan the production of an activity based on the

existing constraints. These constraints of renovation projects have been investigated for

49

both institutional and commercial buildings where the ongoing academic and office
operations are of critical nature and require extensive construction pre-planning efforts
(Rush 2002, Mitropoulos et al. 2002).

In 1996, Krizek et al. investigated the project teams’ experiences gained through
the first five phases of multiphase reconstruction of an intuitional building, with the
purpose of accumulating and transferring their learning to further phases. This study was
carried out by analyzing the contract documents and conducting interviews of owners,
designers, and contractors involved in the project, and the authors identified those
external constraints that impacted the performance of the reconstruction project. These
constraints were physical, coordination, utility, pollution, and uncertainty.

Physical constraint constituted height limitations, site access limitations and
inadequate load conditions at the work area for performing construction activities. It also
included space limitations for installing any new services in the existing structure and,
storing materials near the work area. Coordination constraint referred to the additional
efforts for scheduling or sequencing the construction activities for minimizing the
disturbance to owner’s operations. This constraint also involved monitoring and
controlling those activities that generate pollution during their execution and disturb the
health and safety of building occupants. Demolition activities that generate dust, debris,
noise, vibration, and odor, were among the top most disturbing activities that were
required to be taken care of by the contractors.

Utility constraints involve those efforts on the part of contractors required for
avoiding disruption to the existing services of the building such as electrical and

mechanical. Consideration of utility constraint was of particular importance in case of

50

demolition activities as they might break any hidden services to the building occupants.
In addition, shutting doWn of any service for a new equipment installation required
additional coordination with the existing building operations for avoiding disturbance to
occupants.

Uncertainty is one of the major constraints in renovation projects that greatly
impact the project scope and cause schedule and cost overruns. The unforeseen
conditions encountered by contractors while demolition or uncovering activities could
reveal major disparities between plans and specifications, and actual site conditions.
Sometimes, the actual conditions could only be ascertained after the demolition activities.
Therefore, the conditions, which were not foreseeable by the contractors, were the main
factors that contribute to the unpredictability of renovation projects.

After analyzing these constraints in a case study, the authors suggested a
graphical simulation of construction operations that could simulate appropriate sequences
of construction activities with possible conflicts or constraints discussed above.
Therefore, the simulation would produce the adjusted schedule of the construction project
that incorporates most of the physical, utility and coordination conflicts with the
construction activities’ schedule for minimizing disruption to owner’s operations.

The authors also concluded that from a contractual standpoint, it is imperative for
the contractors to be fully aware of these constraints prior to commencing the work on
site. For handling uncertainties, the contractors should anticipate possible events that
might be encountered and then prepare the bid accordingly and submit a detailed price

breakdown of the same.

51

The study conducted by Rush in 2002 on renovation of school projects, is another
major example of institutional buildings’ renovation projects that focused on identifying
external constraints. The author stated that in a renovation project that also involves
additions to the existing building, the decision to first construct the addition or renovate
the existing building depends on the availability of the swing space and financial
constraint of the owner. One of the cost saving alternatives could be to construct the
addition first and use it as the swing space, and then renovate the existing building once
the occupants have moved to swing space. In such case, maintaining a safe circulation of
construction workers and building occupants between construction zone and swing space
becomes the key constraint.

In a renovation project, the uncertainty constraint increases as the function of the
building age. For an aged building, the absence of original construction documents
presents considerable risks of encountering unforeseen conditions that would impact the
estimated budget and schedule. The presence of preexisting hidden services and/or
asbestos is a prime example of these circumstances. This requires extensive effort for
examining the existing conditions before proceeding to design and construct its
renovation. Even in the presence of as-built drawings, it becomes imperative to check the
adequacy of plans and specifications with the current building conditions that might have
been deteriorated and/or require additional specifications as per prevailing regulatory
codes (Rush 2002).

In this study, the author identified important issues that need to be considered
while planning the construction operations of a multiphase renovation project for an

institutional building. These issues were utility services, preparation for construction,

52

salvage, air quality, disposal, schedule and sequence, and the age and maturity of
building’s current occupants.

Utility services refer to non-disruption of existing services and arrangement of
temporary services for construction operations. Preparation for construction and salvage
require on-site temporary arrangements for weather protection, traffic control, storage of
unsafe materials and equipment, and recyclable material management including its
identification, deconstruction, storage and removal. The issue of air quality imposes
pollution constraint on the contractor for maintaining control measures for minimizing
dust and debris being generated due to construction operations, specifically during
demolition process. Disposal of hazardous materials, such as asbestos, requires
considerable coordination with owner’s operations for safe material movement, space
designation for disposal, and disposal methods. Schedule and sequence of construction
activities need to be coordinated with the occupants’ current operations. The age and
maturity of building occupants impose constraint for installing additional construction
signs for maintaining students’ safety and safeguarding stored materials against
vandalism.

It has been stated that these external constraints not only impact the construction
processes but also affect the design process leading to number of design changes and
rework. In an extensive study of an office renovation project, Mitropoulos et al. (2002)
analyzed the causes of design iterations and reworks. The authors examined problems
encountered during construction phase and identified two major constraints that

potentially impacted the design process: i) preexisting and hidden conditions that were

53

not predicted, and ii) the incapacity of the downstream utility system, which was not
accounted in the design process to support new services proposed in the renovation work.

It was identified that the project characteristics imposed these constraints that
caused design changes and impacted the estimated project budget and schedule. In the
absence of any as-built drawings of the building, the uncertainty constraint was the prime
factor that gave rise to unforeseen conditions. In addition, limitation of adequate space
above the ceiling for installing new mechanical, electrical and plumbing services imposed
physical constraints that caused design modifications in the proposed architectural ceiling
layout for accommodating the mechanical and electrical fixtures.

In this study, Mitropoulos et al. (2002) developed a graphical representation of
chronological events actually occurred in the design and construction phase of the
renovation project. Through this chain, the authors identified those events that caused
major design iterations and impacted the estimated budget and schedule. Most of these
events were encountered in the demolition phase where unfavorable and unforeseeable
conditions necessitated frequent design changes. One of the prime examples was
encountering of the vertical pipes after uncovering the columns that were not expected.
Since the proposed design required all columns to be exposed, the presence of these
vertical pipes initiated a design change for covering all columns with wood veneer and
increased the estimated cost. Another example was associated with the incapacity of
existing utilities to support new services. The mechanical system design was changed
tremendously, as the existing capacity of the system was insufficient and caused the
redesign of the overall mechanical system to be a stand-alone. This change caused major

increase in the estimated mechanical system cost and schedule.

54

Another major impact on the overall project schedule was caused by the
regulatory constraint that required the existing concrete ceiling to be fireproofed and
approved by the city authority. This process caused a delay of two months in the overall
schedule. Similarly, the authors exemplified numerous events that were caused by
different constraints and impacted the project cost and schedule. In order to cope with
these constraints, the authors suggested some preventive strategies among which
accelerated discovery of existing constraints was of prime importance. Discovering the
constraints by investigating the existing building conditions that could impact the
proposed project cost and schedule, prior to design, could avoid the rework and design
iterations. For this purpose, it was suggested that exploratory demolition should be
initiated before the design process commences.

This study brings forward factual examples of renovation project’s problems that
could be anticipated in any reconstruction project. The events, as explained by the
authors, could develop into generic constraints for renovation projects that need to be
incorporated in their project planning and controlling techniques. The authors’ approach
of creating a chain of events was a comprehensive method of analyzing the causes and

effect of each constraint on the project schedule and budget.

2.5.2 Scheduling Techniques for Renovation Projects under Constraints

Due to the schedule and coordination constraints of renovation projects, the traditional
Critical Path Method schedules have been criticized to be incomplete for managing the
production of multiphase renovation projects (Jimenez 1999). Various researchers have

developed different scheduling techniques for incorporating external constraints and

55

making the schedule much more adaptable to the changing conditions of renovation
projects.

In 1988, Wayne et al. developed Disturbance Scheduling Technique for managing
renovation projects that integrated the production planning of renovation projects with
the ongoing building operations. This technique dealt with incorporating three constraints
typically encountered in renovation projects (coordination, physical and disturbance) with
the traditional construction logic and network analysis models. These constraints have
been stated to be unique for renovation projects, which require scheduling considerations
in production planning for obtaining a better flow of the tasks without any disruptions.

Coordination constraint requires consideration of owner’s operations during
renovation, while preparing construction schedules. Physical constraint deals with space
limitations for accessing the site, loading and storing the materials and equipment,
installing any new services, and movement of materials, both vertical and horizontal,
through designated passageways in the absence of service elevators. Disturbance
constraint refers to those activities’ considerations that might cause disruptions to owners
operations. Installing any new services that might require temporary shut down of
existing utilities or demolition activities that might require temporary enclosures around
construction zones to prevent dust, debris and odor, are the prime examples of disruption
activities that have cumulative impacts on owners’ operations.

Focusing on these constraints, the author developed disturbance scheduling
technique that attempts to eliminate the constraints in four phases in their decreasing
order of intensity. Phase-1 involved traditional schedule development based on CPM

logic that assumes the building to be unoccupied. Phase-2 primarily dealt with

56

 

 

establishing constraints’ category and their hierarchy for the specific project. Phase-3
involved modifications of the initial schedule based on constraints’ hierarchies and their
categories for developing a plan that allows minimum operations of the existing building
throughout renovation. In the final phase, the constraint of resource limitations available
per day was applied to the modified schedule for developing it into a workable plan.

Similarly, in 1999, Jimenez suggested a soft-logic approach in construction
scheduling, when operating in the uncertain and dynamic environment of renovation
projects. The soft-logic introduces flexibility in construction schedule to absorb the
dynamic nature of renovation projects so that any unforeseen condition could be
incorporated in the schedule without major changes. The author stated that traditional
project planning techniques, being rigid in nature, do not provide the opportunity to
adjust the project plans with the changing conditions and therefore, are not suitable for
renovation projects. The author identified those characteristics of renovation projects that
have major project impacts and need to be considered in project planning. These
characteristics included sequencing of project activities, unforeseen conditions,
scheduling issues, space confinement, and operations reach.

Sequencing of project activities refers to organizing and restructuring the
construction operations depending on the technical requirements of a building’s normal
operations, in case of a multiphase renovation project. Due to unforeseen conditions
expected in renovation projects, it becomes imperative to develop multiple project plans
based on the assumptions of different possible scenarios, and for incorporating expected

major changes, the project contingencies are usually high.

57

Scheduling issues involved the assignment of appropriate durations to each
construction activity according to the building constraints and expected unforeseen
conditions. This assignment, being extremely crucial, requires expert judgments and
considerable experience of project teams in managing renovation projects. Space
confinement refers to the limitation of physical space for performing construction
activities for causing minimum disruption to the existing structure. Operations reach
applies to simultaneous construction of several renovation projects at multiple locations
of a single building. In an uncertain environment, where situations change dynamically,
operations reach involves managing resources such as labor and/or equipment between
different locations and according to the coordinated construction schedule with owner’s
operations.

These characteristics of renovation projects impose additional constraints on
traditional project planning techniques that require thorough investigation of these
constraints in the existing conditions for establishing reliable and accurate budgets and
schedule. Therefore, the author suggested a soft logic approach, as an alternate to hard
logics of traditional Critical Path Method so that frequent changes in renovation projects
can be accommodated.

In 2003, Harman et al. discussed the adoption of a Short Interval Production
Schedule (SIPS) to manage the production of the Pentagon renovation project. The
overall sequence of the Pentagon renovation was governed by the movement of
occupants to an off-site swing space from wedge-2 to wedge-5. Since the off-site swing
space had the capacity of accommodating only one wedge’s occupants, only single

wedge was available, at one time, for renovation with rest of the wedges being

58

operational. Once the wedge was renovated, the contractor would hand it over to its
occupants who were in the swing space, and move to the next wedge from where the
occupants have moved out to the available swing space. This cyclic arrangement imposed
two major project constraints on the contractor for managing the project: 1) non-
disruption to building operations in other wedges, and ii) efficient handover of renovated
wedge to the occupants and moving to the next wedge.

To manage the project under these constraints, SIPS were developed both at the
project level with a broader perspective, and trade contractor level with production
perspective. The main purpose of SIPS was to handle construction operations, usually
one at a time, at the production level by breaking them down into smaller activities,
identify their durations, and assign appropriate crew sizes as per the estimated quantity of
the work. In a typical SIPS development, the authors suggested to plan appropriate
buffers to absorb the variability between trades’ production rates that might be generated
due to the constraints of renovation project. Two types of buffers were discussed for
Pentagon renovation project; time, and resources. All project weekends were suggested to
be used as time buffer to finish any disrupted work as per the planned schedule. The
intent of resource buffer was to offer flexible resource capacities to accommodate any
variability in the workflow. Therefore, the authors suggested planning the production
with under utilization of resources so that in case of any conflicts generated from the
constraints, high levels of utilization could be employed without major disruption in the

schedule.

59

2.6 Discussion of Renovation Projects’ Literature

The overall literature review of renovation projects and construction performance
measurement systems underscores the significance of managing construction processes
under the constraints of renovation projects. In the literature of renovation projects, the
importance of external constraints has been emphasized because of their major impacts
on the project success (Krizek et al. 1996). This requires considerable pre-construction
planning effort for minimizing the impacts of constraints on the estimated cost and time
(Mitropoulos et al. 2002).

In addition, the literature also explains the conditions or factors that generate
these constraints and contribute to project cost and time overruns. In other words, the
constraints are composed of various conditions or factors, which may or may not be the
part of a project’s scope but are present in the project location. Successful assessment of
these conditions or factors would lead to a better constraint assessment and therefore, a
better production management of renovation projects. These conditions or factors are
required to be assessed for coping with the constraints. Therefore, these conditions or
factors could define the performance indicators for assessing the impact of constraints of
renovation projects.

As stated before, the major performance categories of the reviewed state-of-the-
art performance measurement systems were cost, time, quality, and safety. Therefore, in
the context of renovation projects, it becomes essential to investigate the impacts of

identified constraints on the cost, time, quality, and safety of renovation projects.

60

2.6.1 Reiteration of Constraints
This research incorporates the constraints identified from various literary sources of
renovation projects as a prime essential attribute of production performance management
system. A brief overview of all the identified constraints and their conditions or factors
from the literature review has been presented below:
1. Physical constraint- The physical constraint refers to limitation of physical space, such
as limited height and/or limited area, for performing construction activities (Krizek et al.
1996). This constraint could be generated by various conditions at any location:

a. Space limitations for construction

b. Space limitations for material storage

c. Space limitation for installing new equipment/material
2. Utility constraint- This constraint is generated by the limited capacity of the existing
services for their use in construction activities and/or to support the load of proposed
systems in renovation project. The incapacity of existing services could impact the design
of proposed systems and delay the project, if not accounted in the project planning. In
addition, during construction, there could be disruption limitations over the existing
services, imposed by the owner (Krizek et a1. 1996, Mitropoulos et al. 2002). Therefore
the conditions that give rise to utility constraint are:

a. Limited capacity of downstream systems

b. Non-disruption to existing utilities

c. Impact of existing utilities and/or structural systems on the design of new systems
3. Pollution Constraint- The constraint of pollution control could be generated by various

infection control procedures, imposed by the owner, that are required during construction

61

operations (Rush 2002). The infection control procedures may require the contractor to
perform temporary construction activities before commencing the actual work.
Installation of temporary drywall around the construction zone before starting any
demolition activity to prevent any dust, debris and/or odor, is an example of temporary
construction. The control factors that generate pollution control constraint are:

a. Noise control

b. Dust control

c. Debris control

d. Odor control

e. Vibration control
4. Uncertainty constraint- The uncertainty in preexisting hidden conditions has been
stated as one of the major constraints that impacts the performance of renovation projects.
This constraint could be generated by the non-availability of as-built drawings of the
renovation area and/or presence of any unforeseen conditions in the preexisting structure
that do not conform to the design drawings and specifications of the renovation area
(Krizek et al. 1996). Other type of unforeseen conditions is those, which cannot be
anticipated while design and can only be ascertained during construction. A prime
example of this type of unforeseen conditions is the presence of asbestos in hidden
structures that can only be ascertained after the demolition (Rush 2002). Therefore, the
conditions that generate uncertainty constraint are:

a. Non-availability of as-built drawings
b. Presence of unforeseen conditions

c. Presence of any hazardous materials

62

5. Coordination constraint- Coordination constraint primarily arises in an operational
building where the construction activities need to be coordinated with owner’s
operations. This coordination creates a process friction that needs to be managed by the
contractor in creating minimum disruption to owner’s operations. An example of a
condition that generates coordination constraint is the restriction and/or additional
monitoring of demolition or noise generating construction activities during owner’s
operation timings (Krizek et al. 1996, Wayne et al. 1988). Similarly contractor’s
mobilization and demobilization according to the owner’s relocation from the renovation
area to swing space and then from swing space to the renovated area, defines other
condition. In a renovation project, since the end-users of renovated space are always
available at the owner’s end, there could be multiple inspections by end-users for
approving the final ergonomics and finishes, which may disrupt construction operations’
planned schedule and/or even change the scope of work at the last moment. Therefore,
broadly, the conditions that generate coordination constraint are:

a. Timing limitations due to owner operations

b. Relocation of owner operations to and from swing space

c. Owner furnished equipments

(1. Removal & reinstallation of owner's furniture

e. Multiple inspections by end-users and owner’s representatives
6. Regulatory constraint- Regulatory constraint arises when the specifications of the
existing materials in or around the renovated area do not conform to the current building
codes. This situation is most often encountered in old-aged buildings being renovated

after the demolition or uncovering of hidden conditions (Mitropoulos et al. 2002, Rush

63

2002). An example of such condition is non-conformance of structural concrete
insulation with the current fire codes, which only gets ascertained once the concrete is
uncovered. In such situation, the contractor would have to replace the existing insulation
with the one conforming to the current codes and obtain the permit from the city
authority before covering the concrete. This would probably delay the project and
increase the estimated project cost. The same situation could arise if the loading capacity
of the structural frame has been deteriorated over time and does not conform to the
loading requirements of the current building codes. Therefore, the condition that
generates regulatory constraint is:
a. Non-conformance of existing materials and/or conditions with the current
codes.
7. Schedule constraint- Scheduling issues in a renovation of an operational building has
been discussed by most of the researchers. The owner’s restrictions on certain types of
construction activities of disruption nature for specific times may compel the contractor
to reschedule or re-sequence those activities for the time when owner’s operations are not
going on. This could change the construction logic, initially planned by the contractor or
impact the material deliveries being ordered or impact the next trades’ scheduled work
(Wayne et al. 1988).

Sometimes, restrictions are imposed during construction when the occupants feel
too disrupted with the construction going on in an adjoining area. This could be a result
of non-involvement of existing occupants around the renovated area in the pre-
construction planning process (Jimenez 1999). Since the occupants were not involved in

the planning process, their disruption becomes unpredictable which only gets ascertained

64

during construction. Therefore, for a contractor, it becomes imperative to involve the
end-users or occupants of the area around renovation in construction planning processes
to avoid future changes in construction logic.

In some situations, the scheduling constraint is also generated by the uncertainty
constraint of renovation projects. Since the existing conditions of hidden structure cannot
be completely foreseeable, the contractor may have to include some buffer activities in
the construction schedule to absorb any schedule disruption from the unforeseen
conditions. These buffers could be in the form of overtime shifts during nights and/or
weekends, which will allow the completion of disrupted work as per the schedule
(Horman et al. 2003). Similarly, schedule constraint may also be generated by the
coordination constraint where the owner’s operations timings could impose schedule
limitations of certain construction activities (Krizek et al. 1996). Therefore, the schedule
constraint in a renovation project is generated by the following conditions:

a. Additional duration due to work restructuring

b. Impact on crew productivities
8. Safety constraint- In a renovation project of an occupied building, the contractor is
responsible for the safety of not only his/her employees and labor but also for the users
and visitors of the building (Rush 2002). Even if the regular users are provided with clear
instructions for any safety hazard from the construction, safety monitoring of the public
users will still be required as they are unaware of the construction activity. Unlike a new
construction project, the contractor may be unable to completely enclose the construction
zone in a renovation project due to the presence of physical constraints and may have to

employ a permanent safety engineer during that particular construction activity. If the

65

cost of the safety engineer was not accounted for in the project estimate, this would
probably increase the overall project cost. In case of any public injury or fatality due to
the construction activities, the contractor would have to bear the cost of public litigations.
Therefore, the safety constraint in a renovation project arises from:
a. Safety restrictions for users and public
9. Traffic constraint — The movement of labor, materials, and equipment is of critical
nature in a renovation project. The owner may provide designated corridors and elevators
to the contractor for moving materials both horizontally and vertically, from the storage
area to construction zone. However, in the absence of any designated corridors, the
contractor bears the risk of disrupting owner’s operations, building’s existing conditions
and affecting the safety of building users and visitors through movement of materials and
equipment (J irnenez 1999). An example of such condition could be the absence of service
elevators in an operational building undergoing renovation on upper floors. In such case,
the contractor would have to use the public elevators for carrying materials and
equipment which imposes tremendous risk of disrupting user’s circulation, safety, and
building’s existing finishes. To avoid this, the other option could be to use an external
crane for lifting the materials to the upper floors. This condition, if not accounted in the
project planning stage, would probably increase the estimated budget because of the cost
of external crane. In addition, in order to properly use the external crane, the weather
conditions should be adequate and appropriate physical space should be available outside
the building. the conditions that generate traffic constraint in a renovation project are:
a. Limitation of materials and equipment movement

b. Limitation of labor movement

66

2.6.2 Critical Activities in Renovation Projects

The constraints identified from the literature primarily impact specific activities of
renovation projects where the occurrence frequency of constraints’ conditions becomes
highest. For this research, these specific activities that involve maximum frequency of the
constraints’ conditions are termed as critical activities. These activities become critical in
nature, as their execution requires additional planning and control of constraints to finish
the project on time, within budget, and of desired quality. Therefore, consideration of
constraints in the critical activities’ planning could provide a possible solution for
minimizing their impacts.

The researcher has identified these critical activities from the analysis of
renovation projects’ literature that explains the complexities of specific processes due to
the presence of constraints. For instance, demolition process has been discussed by
various authors in that it requires considerable attention due to pollution constraint,
uncertainty constraint, and physical constraint. Therefore, selective demolition becomes
one of the critical activities in renovation projects that impact the performance. Similarly,
other critical activities in a renovation project are:

1. Preparation of plans and specifications
2. Site investigation by contractor

3. Preparation of site logistics plan

4. Mobilize and demobilize

5. Temporary construction

6. Selective demolition

7. Material and equipment procurement

67

8. Demolition waste management

9. MEP rough-inns
The critical activities were assimilated from the literature review of renovation projects’
processes that are mostly impacted by the external constraints, and therefore are likely to
have major contribution to the overall performance of renovation projects. These above
mentioned critical activities do not form an exhaustive list and could be modified or

added with the nature of renovation projects.

2.7 Literature Review of Production Management in Construction
In industrial engineering, the term production had been used synonymously with
manufacturing or making things. Since the beginning of 20th Century, the automotive
industry in America and Europe primarily viewed production as manufacturing, and
began the movement of mass production, which involved producing as many parts as
possible and as cheaply as possible (Liker 2004, Ballard 2000). Mass production focused
on the efficiency of individual processes and ignored the aspects of flexibility and
customer choice in manufactured products. However, various influential production
management theorists such as Taiichi Ohno and W. Edward Deming criticized mass
production for generating waste (non value adding activities) and not being focused on
the flow and value aspects of production (Koskela 1999).

With the advent of lean production about six decades ago, the term production
began to be viewed as designing and making things with an integrated view of
transformation, flow and value. Lean production has also been termed as the Toyota

Production System, as it was developed on the foundational principles of the Toyota

68

Way, reflecting the production culture of Toyota of eliminating waste and generating
customer value. Therefore, a production process began to be conceived from three
perspectives; i) conversion of inputs to outputs, ii) flow of materials and information
through time and space, and iii) generation of value for the customer (Koskela et al. 2001 ,
Ballard 2000).

Consequently, in the construction industry, the movement of Lean Construction
emerged in the early 905 as a response to increasing waste and rework in construction
processes. Lean Construction theorists support the integrated View of transformation,
flow, and value for managing construction processes that tend to eliminate waste and
improve their efficiency and effectiveness. These theorists have criticized the traditional
project management practices of the construction industry for being narrowly focused on
transformation, transactional contracts and activities while ignoring the flow and value
aspects of operations (Koskela et a1. 2001, Ballard et al. 1998).

Ballard (2000), one of founders of Lean Construction, stated that project control
in the construction industry functions on a reactive model being focused on detecting cost
and schedule variances rather than proactively dealing with the management of
production at the site level. The emphasis has been on only the transformation aspect of
construction processes assuming the workflow and value generation as inherent parts.
Mitropoulos (2003) stated that traditional project control methods in the construction
industry are based on the thermostat model that identifies negative deviations from target
levels and applies corrective actions to bring the project back on track.

Howell and Ballard (1998) differentiated the traditional project control prevalent

in construction industry from production control being followed in lean manufacturing

69

industries. A project control system works on the thermostat model as stated above by
pushing resources (labor, material and equipments) according to the original plan
developed, and then monitoring cost and time deviations. On the other hand, a production
control system firnctions on pull principle that releases the resources into a system based
on the current state of the system. The current state is analyzed for the amount of work in
progress, potential constraints in site conditions and quality of available assignments, and
accordingly establishes production assignments for the resources.

In support of this view, in 1999, Koskela proposed the following five principles for
establishing production assignments:

o The assignment should not start until its pre-requisite conditions are fulfilled.

o The realization of the assignment should be measured in terms of its Percent Plan
Complete (PPC), which is the number of planned activities completed divided by
the total number of activities planned, expressed as a percentage.

0 If the PPC of an assignment is low, its causes should be identified and removed.

0 An activity buffer (work backlog) should be created so the crew can be utilized
when an assigned activity is not possible to begin.

0 Apply a pull system in scheduling by looking ahead to assess whether upcoming
tasks can be started.

Koskela (1999) stated that a production control system in construction should function on
these five principles for managing day to day production at the construction site level.
Numerous other researchers in the Lean Construction arena have been focusing on
developing appropriate production control systems that would conform to the integrated

transformation, flow and value aspect for improving performance and reducing waste.

70

A major milestone was established by the introduction of the Last Planner System
(LPS) TM of production control, designed by Glen Ballard in 2000. This system stressed
the importance of formation of production assignments through communication with
construction crews or those individuals or groups that implement the assignments. The
person or group who prepares the production assignments is termed as the last planner.

As shown in Figure 2.1, the main objective of this system is to act as a filtering
criterion for selecting only those activities fiom the plan that ‘can’ be done based on the
site conditions rather than what ‘should’ be done according to the master plan. In
deciding what ‘can’ be done, the analysis of constraints prevailing in site conditions plays
a major role for establishing production assignments. Two key functions of LPS are
production unit control and work flow control. Production unit control establishes the
production assignments, directs the crew in completing them, measures the percentage of
assignments completed in terms of PPC and identifies the causes of failures. Work flow

control maintains and coordinates the flow of work between trades.

 

LAST PLANNER
PLANNING
PROCESS

 

 

 

Figure 2.1 Objective of Last Planner SystemTM (Ballard 2000)

71

Both these key functions are facilitated by the lookahead process which is the
backbone of the Last Planner System TM. A lookahead process typically retrieves from the
master schedule the upcoming activities for next 3 to 12 weeks, which are further
subjected to constraint analysis, activity definition, and load and capacity matching for
establishing weekly production assignments.

The constraint analysis screens the assignments for the upcoming l or 2 weeks
under possible constraints and makes the work ready by pulling necessary resources. The
constraint analysis ensures that the production assignments are released for execution
only when all the applicable constraints have been satisfied or removed. This ensures that
the potential problems or constraints have been addressed and resolved upfront to avoid
their impacts on the production level later on. The possible constraints to be encountered
are analyzed through an activity definition model (ADM) that categorizes the constraints
under; directives, prerequisite work, and resources. The directives are defined by the
instructions or guided procedure provided to the labor for executing any work.
Prerequisite work, as the name suggests, is the work performed by other trades or any
information that provides an input for the planned work. The term “resource” includes
those sources that have production capacities and associated cost such as labor, tools,
equipment, and even space. This process of identifying possible constrains through ADM
is termed as explosion as it provides a greater detail for executing each activity (Ballard
2000, Ballard et a1. 1998, Koskela et al. 2001).

Another important aspect of ADM is the assessment of “output” of any activity
after its execution, and comparing it with the required criteria. If after the comparison, the

output meets the required criteria, the work is released to the next trade; otherwise, it

72

should be redone to meet the required criteria (Ballard et al. 1998). A typical ADM is

shown in Figure 2.2.

 
   

  

Meets
Criteria?

  

Release

   
 
 

 

 
      

Prerequi-

site Work Process

  

 

 

 

Resources

Figure 2.2 Activity Definition Model (Lean Construction Institute 2004)

Constraint analysis represents a proactive approach of planning production
assignments which is in contrast with the traditional throw-it-over-the-wall approach of
assuming everything and then reacting to the deviations. Overall, the Last Planner System
TM causes the events to conform to the plan by planning quality production assignments
through communication with construction crews and addressing potential constraints
upfront. This system makes the planned production ready by pulling required resources
rather than pushing them on to the original plan (Ballard 2000, Koskela et al. 2001).

In 2003, Mitropoulos presented a detailed explanation of making the ‘planned

work ready’ by proposing project metrics to evaluate the status of upcoming work and the

quality of lookahead process. Building on the work of previous Lean Construction

73

theorists, this research criticized the traditional schedule controls using Critical Path
Method (CPM) and Earned Value (EV) analysis techniques for being narrowly focused
on correcting negative deviations from project goals rather than controlling and
stabilizing the workflow between trades. The term ‘control’ in traditional project
management is used synonymously with controlling contracts rather than production at
the construction site level. Mitropoulos (2003) stated that traditional project control
methods do not employ any mechanism for assessing the status of upcoming works,
which limits the abilities of project teams to proactively identify and address potential
problems before they are encountered. Therefore, in the traditional system, any corrective
action implemented based on the analysis of only past actions without assessing the status
of upcoming work might result in wasted efforts.

This research emphasized the importance of a “make-ready” process in the
assessment of upcoming work by identifying and removing possible constraints. The
analysis of constraint enables the make-ready process to produce sound assignments that
‘can’ be completed by crews, and stabilize the flow of work between trades. In addition,
the assignment of resources to the upcoming work would be balanced by matching
required capacities. The make-ready metric proposed by Mitropoulos is an extension to
the make-ready process proposed by Ballard in 1997. Ballard (1997) proposed five steps
of a make-ready process which are:

1. Develop a lookahead schedule
O This retrieves the activities for upcoming 3 to 12 weeks.

2. Analyze constraints

74

O This involves identifying and analyzing potential constraints to evaluate
the upcoming work in the lookahead schedule for deciding whether to
make it ready for implementation.

Develop action items

0 Action items are the outcome of constraint analysis which is targeted to

remove the identified constraints.
Develop Weekly-Work Plans (WWP)

O The activities in the upcoming work for following week, for which the
constraints have been removed, are selected to develop their weekly work
plans.

Track PPC and analyze plan failures

0 After every WWP execution, the PPC should be measured to identify the

effectiveness of the weekly planning process and a lower level of PPC

should be reason out to identify causes of plan failures.

From the analysis of five steps mentioned above, Mitropoulos identified three additional

purposes that a make-ready process should fulfill for the assessment of upcoming work,

which are: i) assessment of how much work will be ready to perform out of the planned

work, ii) assessment of the accuracy of forecast of expected amount of work, and iii)

assessment and improvement of organization’s ability to make work ready. In order to

fulfill these additional purposes, Mitropoulos (2003) proposed to introduce three metrics

in the make-ready process proposed by Ballard.

The first metric is the planned work ready (PWR) that indicates the percentage of

planned activities which according to the project teams are ready and could be performed

75

for each week in the lookahead window. This also facilitated in calculating and planning
for the eamable man-hours in the lookahead window as per the available labor capacity.
The second metric assesses the accuracy of forecasting the planned work ready by
comparing the work expected to be performed with the work actually performed. The
third metric assesses the organization’s ability to remove identified constraints through
the measurement of three deltas which deal with measuring the number of constraints
identified vs. expected to be removed vs. actually removed, and number of constraints
identified vs. actual constraints found. A lower value of these ratios suggests a lower
organizational capacity to identify and remove constraints. Figure 2.3 shows these three

metrics proposed by Mitropoulos in the make- ready model of Ballard.

76

 

 

 

 

ACTIVITIES ________________ ®

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Lookahead Plan: “WSW“ wwp: Week-1 work Wok
W011i that 51101“ be expected to ire released 8. workable D I
performed performed In backlog performed
lookahead nonzon ‘
E _______ rk n _____ :
omplete
-------------------------------------- qr—--—------I
Constraints that Constraints analysis: Constraints
should be removed Action items removed: Action
(Action items . pro mised to be ‘ . ire ms
identified) completed completedlAlC)

 

 

 

 

 

 

 

 

 

 

   

 

 

 

 

 

 

 

 

CONSTRAINTS
Reasons For Reasons For
_ Re
Constraints N01 Promised Constraints mimigm
511396191170 39 Not Removed Antici ted
Removed pa

 

 

 

 

 

 

 

 

 

 

 

 

REASONS

Figure 2.3 Metrics Introduced by Mitropoulos in Make-ready Process (Mitropoulos 2003)

2.8 Essential Attributes of a Production Management System in Renovation Projects
The literature review of state-of-the-art performance measurement systems, renovation
projects, and production management provided an overview of some of the essential
attributes that a production management system should posses in renovation projects. For
instance, the “constraints” of renovation projects to be analyzed in production planning
forms one of the essential attributes of a production management system. Similarly,

“critical activities” of renovation projects that are mostly impacted by the constraints

77

presents another essential attribute. Other essential attributes include; project conditions
that generate constraints, performance indicators and their measurement methods, broad
performance categories, planned production, and production failure analysis. The
essential attributes identified from the literature review are discussed in detail in Chapter

4.

2.9 Chapter Summary

This chapter provided an overview of previous research that focused on state-of-the-art
performance measurement systems, renovation projects and construction production
management. Each category of literature is extensively discussed to explain its
contribution in the fulfillment of research goal and objectives. The performance
indicators, performance measurement methods, and implementation strategies suggested
by state-of-the-art performance measurement systems are discussed. The complex nature
of renovation projects is explained through the discussion of various constraints that are
prevalent in these special projects. Production management techniques for construction
activities are presented to apply them in renovation projects. Overall, the literature review
brings forth the essential attributes such as constraints, critical activities, and performance
indicators that were addressed in developing the intended framework for production

management of renovation projects.

78

CHAPTER - 3

RESEARCH METHODOLOGY

79

3.1 Introduction

The research goal is to develop a framework for production management of renovation

projects. To accomplish this goal, a five—phased methodology was adopted as a basis for

achieving the research objectives. The research is based on a rationalistic approach in

which the existing literature facilitated creating a conceptual framework, which is further

verified against actual practices (Salminen 2004). Figure 3.1 shows the adopted phased

methodology in which each phase produces a deliverable, which becomes the input for

the next phase.

r_._
, Literature

 

l

j__ Essential _ _‘

Review j Attributes 1
“PHASE? —‘

r-
; Conduct Interviews

PHASE-2

. _

Interview

Re

spouses

T i

 

Develop Intended
Framework

PHASE-3

 

Framework

1

_ __ _I__,._

 

I Demonstrate
Framework

1W _

 

PHASE-4

Figure 3.1 Phased Research Methodology

1
I
,.

_ 1

Demonstrated
Framework

1
LL:

I Verify I
j Framework

_—PHASE-5

The first two phases were instrrunental in achieving the first objective and the last three

phases formed the basis for achieving the second objective. The five phases are defined

as:

1. Literature review

2. Conduct interviews

80

3. Framework development

4. Framework demonstration

5. Framework verification
The next section provides a brief overview of all the five phases which is followed by a
detailed discussion of the contribution of each phase in achieving research objectives.

In order to develop a framework for production management of renovation
projects, it becomes essential to investigate the literature of all the three facets of research
goal namely, i) state-of-the-art construction performance measurement systems, ii) the
complexities of renovation projects that affect production performance and iii) production
management of construction processes. The literature review was conducted in phase-l.

Figure 3.2 shows the detailed methodology adopted for this research where the
phases are broken down further explaining their lower level tasks. The literature review is
broadly divided under the three categories mentioned above and the background study of
each category helped in understanding its emphasis areas for achieving the research
objectives. The overall literature review contributed in identifying the essential attributes
that a production management system should posses for its effective application in
renovation projects. Essential attributes, as a deliverable from Phase-1, became the input
for the next phase.

Phase-2, as shown in Figure 3.2, involved conducting interviews of contractors
and subcontractors regarding their production performance management systems for
renovation projects. The essential attributes Obtained fiom the literature review assisted in

drafting the interview questions.

81

In Phase-3, the intended framework for production management of renovation
projects was developed on the basis of literature review and per the interviews of
contractors and subcontractors.

Phase-4 involved demonstration of the developed framework through a
hypothetical case example of a construction activity in an institutional renovation project.
Phase-5, the concluding phase of the research, involved verification of the framework

through a second round of interviews.

3.2 Existing Knowledge, Research Drivers, and Research Contribution

This research entailed reviewing the existing knowledge through Phase-l of
literature review from which, the main drivers for conducting the research from Phase-2
through Phase-5 were determined. The research drivers provided clear directions for
investigating the performance measurement systems of interviewed contractors, and
assisted in developing the intended framework. The research drivers were comprised of
essential attributes of a production management system for renovation projects, which
helped in formulating the questions for conducting interviews with contractors and
subcontractors. As the essential attributes have not been explicitly discussed in a specific
literature, this research has assimilated them from the overall available literary sources of
renovation projects, state-of—the-art performance measurement systems, and production
management.

Figure 3.2 shows a clear distinction of existing knowledge, research drivers, and
research contribution in the adopted research methodology. The main contribution of this

research begins from Phase-2 where a sample of current performance measurement

82

practices were documented in the form of the interview responses. In Phase-3, the
intended fiarnework for production performance management of renovation projects was
developed driven by the essential attributes and interview responses. Phase-4
demonstrated the framework and in the last phase of the research, the developed
fiamework was verified with the help of suggestions from the interviewed contractor.

The following sections present a detailed discussion of each phase with its contribution

towards achieving the research objectives.

83

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3.3 Phase-1 Literature Review- Detailed Discussion of Contribution to Objective-1
Objective-1 Document state-of-the-art construction performance measurement systems
and production management practices for renovation projects.

The research reviewed an extensive amount of literature in the three categories discussed
above, in the form of published theses, journals and articles available in various libraries
and on the web. Each category of the reviewed literature is discussed next with an

explanation of why the literature in that category was reviewed.

3.3.1 State-of-the-art Construction Performance Measurement Systems

As per Lean Construction, the production of any construction operation should be
conceived from an integrated View of transformation, flow, and value (Ballard 2000,
Koskela 1999). Therefore, production planning and control processes should incorporate
the assessment of construction operations based on these three perspectives, in order to
eliminate wasted efforts and rework.

Assessment of construction operations based on only the “transformation” (cost,
time, and quality) perspective has been the focus of traditional performance measurement
systems practiced in the construction industry, as a result of which the level of
inefficiency in construction projects increased tremendously (Ballard 2000, Koskela
1999). In order to address these inefficiencies through appropriate performance
assessment methods of construction projects, numerous researchers focused on
developing what have been termed as state-of-the-art performance measurement systems
that investigated different models for measuring construction performance (Korde et al.

2004)

86

As the research goal is to develop a framework for production management of
renovation projects, it became imperative to understand how the state-of-the-art
performance measurement systems that primarily focus on measuring cost, time and
quality performance i.e. “transformation” focus only, address production management,
and what are the shortcomings in their application to renovation projects. In addition, the
literature of state—of-the-art construction performance measurement systems was
reviewed to identify those attributes that need to be emphasized for developing the
intended framework.

As shown in Figure 3.3, these systems were reviewed to form an understanding of
their objectives, performance criteria, performance measurement processes and
implementation methods. The performance criterion of each system represents the scope
of its metrics, as defined through performance indicators (PI) under qualitative and
quantitative aspects of construction. The categorization of P15 under ‘process orientated’
and ‘result orientated’ provides the purpose for measuring each PI (Alarcon et al. 2000).
The measurement methods of these performance indicators were also reviewed to
understand their application to production management in renovation projects.

The review of performance measurement processes suggested by state-of-the-art
systems facilitated understanding the process links between essential attributes of a
performance measurement system such as critical processes, performance indicators, and
measurement methods. The implementation strategies for the performance measurement
systems suggested by these systems identified the implementation barriers prevalent in
the construction industry and the important aspects of performance measurement systems

that make the implementation successful.

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3.3.2 Renovation Projects

The literature of renovation projects was reviewed to understand their complex nature
and scope of additional requirements for managing their construction process. The
literature review identified those external constraints that affect the production in
renovation projects and lead to schedule and cost overruns. These constraints are
generated from those conditions in which typical renovation projects are undertaken and
are not controllable by the contractor for the majority of cases (Mitropoulos et al. 2002,
Krizek et al. 1996).

For instance, a physical constraint defines the space limitation for construction
operations and material storage at the job location for any activity such as ‘erect scaffold’
(Krizek et al. 1996). These limitations cannot be overcome by increasing the available
space. However, the contractor can get around this constraint by effectively planning the
production of this construction activity on day-to-day basis. If the constraint is not taken
into account while planning different tasks of this activity, it may adversely impact the
performance of any task, which could be related to cost, time and/or quality. Some other
examples of these constraints are utility constraint, safety constraint, pollution control
constraint, traffic constraints, etc (Mitropoulos et al. 2002, Krizek et al. 1996, Attalla et
a1. 2003)

Through the identified constraints, this research captured some critical activities
that have significant contribution in performance of renovation projects. These activities
are critical in nature as they involve constraints during their execution and, if their
production is not planned appropriately with the nature of constraints, they could result in

underperformance in time, cost, quality, and/or safety.

89

For the purpose of production planning, each constraint was analyzed to identify
the project conditions which generate that constraint and lead to cost and schedule
overruns in renovation projects. For instance, a physical constraint for any construction
activity is generated due to; i) Space limitations for construction, ii) Space limitations for
material storage, iii) Space limitations for newly designed equipment, and iv) Space
limitations on site access (Krizek et al. 1996). A thorough assessment of these conditions
will dictate the production that could be achieved in the presence of a physical constraint.
Therefore, these project conditions can be regarded as the performance indicators for
getting around physical constraint for a construction activity. For example, measuring the
performance for an activity such as ‘erecting scaffold’ that is under a physical constraint
will involve measuring its actual production against what was planned based on the
project conditions.

Table 3.1 lists some of the constraints applicable in renovation projects and their
appropriate project conditions identified from the literature that discusses the
complexities of renovation projects. Table 3.1 does not present an exhaustive list, as the
constraints and project conditions would change from project to project.

As this research is focused on assessing the schedule impacts of constraints,
assessment methods of their project conditions to estimate the additional duration of an
activity were investigated. This investigation was facilitated by the literature review of
state-of-the-art construction performance measurement systems. The assessment methods

of project conditions are further explained in Chapter-4.

90

Table 3.1 Constraints and Project Conditions for Renovation Projects

 

Constraints

Project Conditions

 

Utility Constraint

Limited capacity of downstream system

 

Non-disruption to existing utilities

 

Impact of existing utilities and/or structural
systems on the design of new systems

 

Physical Constraint

Space limitations for construction

 

Space limitations for material storage

 

Space limitation for installing new
equipment/material

 

Pollution Constraint

Noise Control

 

Dust Control

 

Debris Control

 

Vibration Control

 

Odor Control

 

Uncertainty Constraint

Non-availability of As-built Drawings

 

Presence of unforeseen conditions

 

Presence of hazardous material

 

Coordination Constraint

Timing limitations due to owner operations

 

Relocation of owner operations to and from
swing space

 

Owner furnished equipments

 

Removal & reinstallation of owner's
fumiture

 

Multiple inspections by end-users and
owner’s representatives

 

Regulatory Constraint

Non conformance of existing materials or
project conditions with current codes

 

Traffic Constraint

Limitations of materials and equipment
movement

 

Schedule Constraint

Additional duration due to work
restructuring

 

Impact on crew productivities

 

 

Safety Constraint

 

Users & public safety

 

91

 

3.3.3 Production Management in Construction

Review of construction production management literature provided insights into how
inefficiencies of construction process operations at the production level were previously
addressed. Production management practices such as Last Planner System TM provided an
understanding of operational shielding from various constraints of renovation projects by
effective planning and assessment of performance at production level. In addition, studies
that focused on the impact of variability on crew production rates and reliability of hand-
offs were reviewed due to the importance of stabilizing the workflow against the impact

of constraints in a renovation project.

3.3.4 Essential Attributes Identified from Phase-1

Phase-1 was instrumental in identifying the following essential attributes of production

management systems for renovation projects:

1) Critical activities to be managed

2) Constraints to be identified for each critical activity

3) Weighted impacts of constraints in impacting the production of critical activities

4) Project conditions that result in each constraint

S) Broad performance categories (Cost, Time, Quality & Safety)

6) Performance indicators of State-of-the-art performance measurement systems as
applicable to renovation projects

7) Measurement methods of performance indicators

8) Interrelationships between constraints as they impact production

9) Planned production from constraint analysis

92

10) Production failure analysis

These essential attributes formulated the basic construct of the framework in Phase-3.

3.4 Phase-2 Conduct Interviews— Detailed Discussion of Contribution to Objective-1
Phase-2 involved two sequential tasks; i) conducting interviews of contractors and
subcontractors, and ii) constructing a comprehensive process map of production
management systems employed by the interviewees in renovation projects.

For conducting interviews, 6 contractors and 4 subcontractors were selected from
a sample set, which formed a part of another research project entitled “Vendors’
Performance Assessment” (VPA) underway at the School of Planning, Design &
Construction, MSU. The sample set comprised of approximately 10 to 15 contractors and
subcontractors, which were suggested by the Physical Plant division of MSU for
conducting the VPA project mentioned above (Mrozowski et al. 2007).

From the results of Phase-l, the interview questions were drafted with the goal of
understanding the process of planning and assessing the production performance of
construction activities and not any employee’s job performance. These questions mainly
addressed; i) the constraints encountered in renovation projects, ii) the project conditions
that generate these constraints, iii) the critical activities that contribute to schedule
performance, and iv) production planning techniques in the presence of constraints.

In addition to the developed questions, this research also incorporated data
obtained from the responses of contractors to some of the questions developed for the
VPA project. This was conducted because the VPA project involved some of the

common attributes for both new construction and renovation projects as applicable to this

93

research, such as the critical success factors for a construction project, their measurement
methods etc (Mrozowski et al. 2007). The responses of contractors and subcontractors on
these common questions provided insight into how they perceived differences between
new construction and renovation projects with respect to performance measurement. The
developed interview questions along with the responses are presented in Appendix-l of
this thesis.

The target group of interviewees comprised of construction managers, site
superintendents, project engineers and field engineers. The interviews were conducted in
a one-on-one basis to eliminate any group favoritism in opinions and arrive at a clearer
understanding of the production management systems adopted.

Based on the interview responses, the research intended to document the
implemented production management systems by constructing a comprehensive process
map. The purpose of constructing this process map was to depict the interaction between
essential attributes of performance measurement systems being adopted by contractors by
illustrating the sequence of activities involved in the processes of planning, measuring
and evaluating the production in renovation projects. Therefore, for identifying the scope
for improvement in current practices, this process map’s intent was to form the basis for
documentation and analysis of current performance measurement systems being
employed. However, the research could not construct this process map, as any relevant
data was not obtained from the interviews of contractors and subcontractors. It was
concluded after the interviews that the interviewees did not have a formalized process of
production management in renovation projects. Further explanation is provided in

Chapter—4.

94

3.5 Phase-3 Framework Development - Detailed Discussion of Contribution to
Objective-2

Objective—2 Develop a framework for production planning, execution and performance
assessment of construction operations in renovation projects.

This phase involved developing the intended framework for production
management of renovation projects. The framework established links between essential
attributes for their application in a suggested process of production planning and
assessment of renovation projects. This process is based on defining the dependency
interrelationships within different constraints, their importance levels in impacting the
production schedule of critical activities, and the assessment of project conditions of each
constraint for quantifying the additional duration of critical activities. The framework
incorporated quantitative techniques such as correlation analysis and Analytical
Hierarchy Process (AHP) for production planning.

The framework incorporated any additional essential attributes obtained from the
interview responses. This addition involved some critical activities, additional
constraints, and project conditions of constraints. The developed framework for

production management of renovation projects is demonstrated in the next phase.

3.6 Phase-4 Framework Demonstration - Detailed Discussion of Contribution to
Objective-2
In Phase-4, the developed framework is demonstrated with a case example of a

construction activity in an institutional renovation project. The example is completely

95

hypothetical and its intent is to illustrate the application of the developed framework for
production planning and assessment in renovation projects.

The demonstration presented a production management system that not only
assesses the production performance for the demonstrated activity but also plans its
production schedule in the presence of constraints. This involved application of
quantitative tools such as AHP and correlation analysis to the constraints of renovation
project, which represent the primary essential attributes that impact the schedule
performance of construction activities. All quantitative information as required by the

framework was assumed for the demonstration example.

3.7 Phase-5 Framework Verification- Detailed Discussion of Contribution to
Objective-2

In the final phase of this research, the developed framework was verified as to
whether it can be employed in renovation projects. This was done through a second round
of interviews of contractors. The interviewees were presented with the demonstration
example and asked to provide feedback on the appropriateness and limitations of the
essential attributes identified. The interviewees also responded on the production
planning and assessment methods proposed in the framework. The responses from this
round also helped in formulating recommendations for firture areas of research in

production management of renovation projects.

96

3.8 Chapter Summary

This chapter provided an overview of a systematic approach that this research adopted for
achieving the research goal and objectives. The research methodology outlined how the
research utilized state-of-the-art construction performance measurement systems,
complexities of renovation projects, and the principles of construction production
management. The literature review and interview procedure are discussed in detail to
bring forward the significance of each step in arriving to an understanding of the
theoretical knowledge and actual practice of production management of renovation
projects. The chapter mentioned where the quantitative tools such as AHP and correlation
analysis for analyzing the essential attributes of production management system were
used in this research. In addition, the framework development process, and how it was

demonstrated and verified are briefly discussed.

97

CHAPTER - 4
DATA COLLECTION AND FRAMEWORK DEVELOPMENT,

DEMONSTRATION AND VERIFICATION

98

4.1 Introduction
As the main research contribution, this chapter provides a detailed account to Phase-2
through Phase-4 of the research that includes interview process, data collected, and
development and demonstration of the intended framework for production management
of renovation projects. The interviews are documented based on the common themes
observed in the responses of 6 contractors and 4 subcontractors. A consolidated process
map was intended to be constructed from the interview data that could illustrate a general
production management process of renovation projects currently in practice.
Concurrently, the intended framework was primarily developed from essential
attributes of production management systems identified in literature review, and
subsequently incorporating any additional essential attributes identified in the interviews.
The framework development encompassed constructing a comprehensive process of
production planning, execution, and control of renovation projects, by capturing their
essential attributes identified above. In the last section of this chapter, in order to provide
a better understanding of the developed framework to the reader, its application has been
demonstrated with an example of a construction activity of a renovation project. This
framework is finalized in Phase-5 as the main research product, after its verification in

the second round of interviews.

4.2 Interview Procedure
As stated in chapter 3, the contractors and subcontractors to be interviewed were selected
from a sample set of another research project entitled “Vendors’ Performance

Assessment” (VPA), underway at the School of Planning, Design & Construction,

99

Michigan State University (MSU). Initially, the Physical Plant of MSU suggested 10 to
15 contractors and subcontractors, each to be interviewed for the VPA research project.
From this sample set, 6 contractors and 4 subcontractors were interviewed after making
initial contacts based on their availability and participatory interests (Abdelhamid et al.
2007).

The interviewed contractors varied in terms of their company sizes and project
types. One of them was a large sized contractor; the other was a mid-size contractor,
while all others were small sized contractors. The value of projects that the interviewed
contractors typically undertake ranges from $15 Million to $500 Million for large sized,
$5 Million to $100 Million for mid sized, and $10,000 to $23 Million for small sized
contractors. The collective project portfolio of these contractors included institutional,
commercial, hospitals, utilities, infrastructure, waste water treatment plants, hospitality,
manufacturing plants, restoration, municipal projects, and conservation projects. The
interviewed contractors primarily work as general contractor or construction manager on
these project types for both new construction and renovation works.

At the production level of renovation projects, the subcontractors are directly
involved in addressing project conditions and constraints. While identifying the
interviewees, the researcher selected subcontractors, as they would provide better
feedback on production management in renovation projects. The interviewed
subcontractors involved two plumbing, one electrical, and one HV AC subcontractor that
undertake different project types. Different trade contractors were interviewed, as they
could provide an insight to different types of critical activities in renovation projects with

their encountered constraints and project conditions. The project types of the interviewed

100

subcontractors include institutional, commercial, hospitals, auto plants, underground, and
industrial work.

The interviews were conducted on one to one basis for avoiding any group
favoritism, and the research team conducting the interviews typically involved 2 to 3

members for precise data collection.

4.2.1 Interview Questions

As the VPA project involved some of the attributes for new construction projects’
performance assessment systems, which were useful for this research in context of
renovation projects also, the interview questions to be asked for this thesis were
combined with the interview questions of the VPA project. As a result, common
interviews were conducted for both the project and this research, which also reduced the
interview time (Abdelhamid et al. 2007).

Some of the common attributes between the VPA project and this research were;
critical success factors, their measurement methods, and their hierarchies in terms project
success. Therefore, some of the questions for VPA project that dealt with these attributes
also included an additional question for obtaining answers in context of renovation
projects. For instance, one of the questions for the VPA project is:

Define in your own terms project success (critical success factors), i.e. what is a
successful project to you?

In order to orient this question towards renovation projects, the typical additional
question added after this was:

Is this the same for renovation?

101

The purpose of inserting this additional question in some of the VPA questions
was to obtain data concerning the interviewed contractors’ and subcontractors’ views of
differences in the performance assessment systems between new construction and
renovation projects.

In addition to the common questions of VPA project, 5 additional questions were
short listed from a list of 10 questions drafted in this research specifically for renovation
projects. These questions were based on the essential attributes identified from the
literature review. The short listing was done to reduce the interview time and obtain
objective data which was not specific to any renovation project. For instance, the
question drafted to obtain the “hierarchies of constraints impacting project schedule” was
not selected from the list, as it could generate subjective responses specific to any
renovation project. Instead, the question drafted to obtain “project conditions in
renovation projects that impact the estimated budget, schedule, and quality the most” was
selected, as it was more generic in nature and lesser time consuming to respond.

These 5 questions were placed in a separate section of “Renovation projects” in
the main interview questions of the VPA project. These questions mainly dealt with the
contractor’s and subcontractor’s process for planning daily crew assignments in
renovation projects, the encountered constraints or project conditions that impact the cost,
time and quality of renovation projects, and their critical activities that impact the
schedule performance. The interview questions were common for contractors and

subcontractors.

102

4.2.2 Data Collection

The data collected from each interview was documented in two consolidated
spreadsheets, each for 6 contractors and 4 subcontractors, which involved all the
responses for each question. This facilitated the data synthesis and analysis in identifying
any commonalities and differences in the responses for all questions. Snapshots of
consolidated spreadsheets are shown in Figure 4.1 and 4.2. The completed spreadsheets
of all interview questions and the common questions from the VPA project and this

research are included in Appendix — l.

 

 

No. Questions Responses

 

 

Vendor Performance Assessmgnt Questions
VP2 Define In your own terms project success 1- Profitable project2. 0" time 3- Owner
(critical success factors), i.e. what is a sahsfacben4.vendor satisfactien .

 

 

successful project to you? Yes

Is this same for renovation projects? When it meets and exceeds all of client's
expectations. Profit is not the main aim of the
firm,

Yes, both are client dn’ven.

When the end user is happy, the company
makes profit and no one gets hut. , g ,_ . g,
Yes (it is more invasive when owner is
occupyi nlthe premises)

For a successful project we consider
following factors fulfilled: A Happy Owner,
future work, On schedLIe, Good
relationships, Make profit, Good quality
product, Add value to the life of entity,
negotiate more work.

Yes

A successfu project is which is done on time,
its on budget (which makes owner happy),
should have a good profit margin

Yes.

Schedule completion, Within Budget, Owner
completely satisfied with process and
product ..

Yes

 

 

 

 

 

 

 

 

 

 

Figure 4.1 Snapshot of Consolidated Spreadsheet of Contractors’ Responses
(Abdelhamid et al. 2007)

103

 

No. I Questions I Responses

 

Vendor Performance Assessment Questions
VP2 Define in your own terms project success 1.Finishing Projects on time 2. Within
(critical success factors), i.e. what is a budget and 3.Happy owners
successful project to you? Yes
Is this same for renovation projects?

 

 

That the owner should be happy, project
completed in time, make profit
Yes

 

customer satisfaction, profit, learning
from project, better relationship.
Yes

The critical success factors for any job
would be a good Profit margin, high level
of owner satisfaction, no repair calls,
lack of warranty issues.

Yes

 

 

 

 

 

 

Figure 4.2 Snapshot of Consolidated Spreadsheet of Subcontractors’ Responses
(Abdelhamid et al. 2007)

4.2.3 Synthesis and Analysis of Data Collected

This section presents the data synthesis and its analysis based on the consolidated
spreadsheets for contractors and subcontractors. This is done first for the common
questions of VPA project followed by the renovation project questions, as discussed
below.

4.2.3.1 Interview Responses to VPA Questions

In response to the common interview questions for the VPA project and this research,
none of the respondents differentiated in the performance assessment systems for
renovation and new construction projects. Both contractors and subcontractors reported
that the critical success factors, their consistencies, hierarchies, and measurement
methods were same for new construction and renovation projects. The most commonly

stated critical success factors were; on time, on budget, customer satisfaction, and quality.

104

Three of the interviewed contractors had employed a formal vendor performance
evaluation system for their construction projects. These contractors included one large,
one mid size, and one small contractor and stated that they use the same evaluation form
for renovation projects also. In addition, these contractors stated that the frequency of
filling out the performance evaluation form remains the same for both new construction
and renovation projects. The other three small sized contractors who did not have a
formal vendor performance evaluation system in place stated that if they would develop a
vendor performance evaluation form, all the factors they would look to evaluate vendors
on will remain same for both new construction and renovation projects. Some of these
stated factors include: change order rate, RFI rate, working style of personnel, safety,
quality, timeliness, responsiveness, and interaction with the owner. This data was
obtained as responses to questions VP 14, VP 17, and VP 32 of Vendor Performance
Assessment section.

These responses reflect that currently, there are no perceived differences in practice
regarding project success between renovation and new construction projects. However,
the literature states that the nature of renovation projects is more complex than new
construction projects, as the former involve a number of additional constraints, not
encountered in new construction. These constraints may adversely impact the project
success of renovation projects and lead to schedule and cost overruns. Numerous
researchers have investigated methods for coping with the constraints of renovation
projects for improving their performance (Krizek et al. 1996, Mitropoulos 2002, Wayne
et al. 1988). None of the respondents in the interviews reported that coping with these

constraints was a critical success factor of renovation projects.

105

Moreover, the literature of state-of-the-art construction performance measurement
system states that the definition of critical success factors and their hierarchy should be a
function of project type, objectives and company’s strategies for achieving project
success (Costa et al. 2006, Beatham et al. 2003). For instance, in a renovation project of
an occupied building, “safety of the occupants” becomes an important factor that defines
the project success. Moreover, “non-disturbance to owner’s operations” also becomes an
important factor that should be considered by the contractor, when performing
construction in an operational building. Both these factors do not directly relate to cost,
time, or quality of a project, and were not reported by any respondent, as being a critical
success factor for renovation projects. i

Overall, the similarity of critical success factors between new construction and
renovation projects, as reported by the interviewed contractors and subcontractors reflects
that the project objectives, and contractors’ and subcontractor’ strategies for managing
construction remain constant when moving from new construction to renovation projects.
Under budget, on-time, and desired quality were stated as critical success factors whether
a new construction or a renovation project is being undertaken.
4.2.3.2 Interview Responses to Renovation Project Questions
In response to the “renovation project” questions, only one of the respondents, a mid-size
contractor, had a formal documented process of planning daily crew assignments, based
on the project conditions of renovation projects. However, detailed information could not
be obtained due to proprietary reasons. Four other interviewed contractors stated that
their superintendent or foreman is responsible for planning crew assignments. One of

these contractors’ consented with the literature stating that forecasting crew assignments

106

is difficult due to the uncertain and dynamic nature of renovation projects. Another
contractor stated that any formal process has not been employed for establishing crew
assignments. The reader is directed to Appendix - 1 for reviewing the responses to
“renovation project” questions.

From the interviewed subcontractors, the plumbing subcontractor stated that daily
crew assignments are established based on the evaluation of self work area and the other
trades’ work areas to avoid any potential conflicts. These evaluations are based on the
type and size of the renovated work. The electrical subcontractor reported that they used
daily log reports for documenting crew assignments but a formal documented process of
arriving at and establishing crew assignments was still absent. The HVAC and other
plumbing subcontractor stated that crew assignments are established by their foreman
and/or superintendents, but on an informal basis.

In response to the question 2 of renovation projects (RP2 in Appendix-1), the project
conditions stated by all the respondents that impact the estimated budget, time, and
quality were similar to what were identified in the literature of renovation projects. The
stated project conditions involve; inadequate design, concealed conditions, poor as-built
drawings, unforeseen conditions, presence of hazardous materials, suitability of
infrastructure or accommodate project requirements, aesthetic maintenance, inaccessible
project location, and undoing of old installation (demolition). These project conditions
stated by respondents were also found in the literature of renovation projects that
generate various constraints for construction and lead to cost and schedule overruns.

As renovation projects are characterized by constantly changing project conditions, it

became imperative to understand the contractors’/subcontractors’ frequency of

107

addressing project conditions of renovation projects with regard to establishing crew
assignments and their associated processes involved, which was the focus of question 4
(RP4 in Appendix-1). Different answers were obtained for this question. Three
contractors including the large and mid-sized stated that the project conditions are
addressed as soon as they are identified while one other contractor stated a daily
frequency. The other two contractors did not give any frequency and stated that they
address the project conditions as it becomes necessary.

From the interviewed subcontractors, only plumbing and electrical subcontractor
mentioned that the project conditions are addressed on a daily basis or as the changes
occur. The other two subcontractors did not state any frequency. Overall, none of the
respondents had a standardized process of addressing project conditions in renovation
projects.

As this research is focused on analyzing the schedule impacts of constraints on
renovation projects, one of the renovation project questions (RPS in Appendix-1) was
directed towards identifying the critical processes/activities that impact the schedule
performance of renovation projects the most. Similar to the responses obtained for project
conditions in question RP2, most of the critical processes stated by the respondents were
also identified by this research in the literature review. The stated critical
processes/activities involve; hazardous material abatement, demolition, mobilization,

ductwork, flooring, finishes, and taking care of the existing structure.

108

4.2.4 Process Maps of Interviewed Contractors and Subcontractors

This research initially contemplated on constructing a comprehensive process map
currently in practice for production management of renovation projects. This process map
would have depicted the sequence of activities of contractor or subcontractor for
planning, measuring, and evaluating the production assignments in renovation projects
based on the project conditions and constraint analysis. In addition, the linkages between
essential attributes of a production management system would have also been reviewed in
the process map by the researcher.

For constructing this process map, the researcher intended to obtain relevant
documented data from Question 1 of renovation projects category (RP 1) of interview
questions. However, based on the analysis of the interview data, the researcher concluded
that any pertinent data could not be obtained to accomplish this step. This was attributed
to the informal processes of production planning being undertaken by the interviewees.

As discussed in the previous section, the researcher did not obtain, from the
responses of contractors and subcontractors, any formal documented procedure of
establishing daily crew assignments in renovation projects. Most of the respondents
stated that either they did not have a standardized documented process or the process was
informally communicated between their superintendents and crew foremen.

Half of the interviewed contractors stated that they did not have any formal
process of establishing daily crew assignments, as their superintendents and foremen take
care of this issue through informal communication and any standardized procedure is not
practiced. Two contractors stated that either the superintendent or the foreman plans the

crew assignments based on the project conditions, and for this purpose, one of the

109

contractors referred to their daily logs. Nonetheless, the process of how the crew
assignments in daily logs are planned and arrived at, and the process of analyzing project
conditions and the constraints of renovation projects prior to planning crew assignments
were not documented in a standard format by any interviewed contractor. Similar
responses were obtained from all the interviewed subcontractors stating that the crew
assignments are established by their foremen and superintendents without following any
documented standard procedure.

From the interview responses, the researcher concluded that the procedure of
establishing crew assignments was an understood fact in the form implicit knowledge
possessed by the foremen and the superintendents of the interviewed contractors and
subcontractors. However, this knowledge of arriving at suitable crew assignments has not
been documented which could restrict developing a standardized procedure of addressing
project conditions of renovation projects. In addition, none of the respondents stated any
sequence of activities for planning daily production of construction crews in renovation
projects. Therefore, in the absence of any formal documented process of production
planning obtained from the interviewees, the researcher did not construct any process

map, as intended, for its application to the framework development.

4.2.5 Interview Conclusions
From the interviews of contractors and subcontractors, it could be observed that the state-
of-the-art performance assessment systems in practice do not involve major changes from

new construction to renovation projects. This is exemplified by the critical success

110

factors, measurement methods and their hierarchies mostly reported as same for new
construction and renovation projects.

However, numerous researchers have concluded that the performance of renovation
projects is typically lower than that of new construction projects, as the former involve
much more risks, uncertainty, and dynamism in their project conditions not encountered
in new construction. This has also been attributed to various constraints generated by the
project conditions of renovation projects (Krizek et al. 1996, Mitropoulos 2002, Wayne et
al. 1988). Flaming and controlling the impact of these constraints and project conditions
on the critical success factors stated by the interviewed contractors and subcontractors
would result in better performance. In other words, if the impact of constraints on the
cost, time, quality, and customer satisfaction is planned and controlled, the performance
of renovation projects can be improved.

In addition, the critical success factors reported by the interviewees were on a broad
level of a project such as quality, repeat business, and client satisfaction. There was no
success factor reported that dealt with the production level of construction activities such
as percentage of plan completed (PPC), and quality work delivered to the next trade. The
literature of production management supports the use of these production level indicators
for managing projects which are complex, uncertain, and quick (CUQ). As the CUQ level
increases in renovation projects due to the presence of constraints, use of production level
indicators becomes imperative for managing construction on daily basis and assessing the
production performance of a construction crew.

As observed in the responses to renovation project questions, most of the project

conditions and constraints stated in literature were also reported in the interviews to be

111

encountered in actual practice. These constraints involve; uncertainty, dynamic nature,
irregularity in plans and specifications, coordination with owner’s operations, and traffic
conditions. These stated constraints adversely impact the time, cost and quality
performance of renovation projects.

Although the interviewees agreed on the complexities of renovation projects and the
constraints involved, but it could also be concluded that on a major scale, there was a lack
of a formalized documented procedure of assessing project conditions and constraints of
renovation projects for establishing crew assignments. An implicit process between the
superintendents and foremen for establishing crew assignments was mostly stated in the
interviews, which reinforces the need for developing a formal process that could be used
by contractors or subcontractors for managing production in the presence of constraints.

Overall, the interviews of contractors and subcontractors suggest that there is a lack
of a formal system for production planning, execution and assessment in renovation
projects. This is exemplified by informal processes of production planning in practice and
the similarities in performance assessment systems for renovation and new construction
projects, as reported by most of the respondents. As renovation projects experience lower
performance levels in terms of cost, time and quality, the interview data underscores the
need to develop a production management system for renovation projects that could be
employed to deliver better performance level.

In addition, production management of renovation projects should be viewed from a
perspective that involves thorough analysis of constraints during production planning of
crew assignments. This would deliver quality production assignments for the crews

which could be attainable in the presence of constraints. This would also reinforce the

112

performance assessment of construction crews with regard to their ability of coping with
the constraints. Thus, a production management system for renovation projects should
involve constraints’ identification and assessment for planning production assignments
and assessing performance of construction crews accordingly.

The following section presents some of the essential attributes of a production
management system for renovation projects that this research has captured from the

interviews and literature review.

113

4.3 Essential Attributes of a Production Management System for Renovation

Projects

Although in the literature, the essential attributes of a production management system

have not been explicitly stated in context of renovation projects, this research has

assimilated them from the principles of state-of-the—art performance measurement

systems, complexities of renovation projects that impact the production of construction

activities, and practices of production level planning of construction processes. These

essential attributes are:

1) Critical activities to be managed

2) Constraints to be identified for each critical activity

3) Weighted impacts of constraints in impacting the production of critical activities

4) Project conditions generating each constraint

5) Broad performance categories (Cost, Time, Quality & Safety)

6) Performance indicators of State-of-the-art performance measurement systems as

applicable to renovation projects

7) Measurement methods of performance indicators

8) Interrelationships between constraints in impacting production

9) Planned production from constraint analysis

10) Production failure analysis

As stated before, this research has not attempted to retrieve all of the above stated

essential attributes from the interviews due to the subjectivity involved in the nature of
some attributes and a limited sample size of 10 contractors and subcontractors. For

instance, a limited number of interviews with contractors cannot provide a definitive

114

hierarchy of constraints in impacting production, as it could change from contractor to
contractor and project to project.

In support of this view, the developed framework has defined possible
interactions between essential attributes by incorporating hypothetical figures to their
subjective assessment. In addition, the main purpose of developing this framework lies in
presenting a comprehensive process of production planning, execution and assessment by
linking these essential attributes in a systematic approach, which could be adopted by

contractors in renovation projects for improving their schedule performance.

4.4 Interface between Renovation Projects & State-of-the-art Construction
Performance Measurement Systems

Renovation projects are characterized by their complex nature due to the presence of
external constraints and unforeseen conditions that impact the production of various
construction activities. This impact could be on the cost, time, quality and/or safety of the
activity’s production (Krizek et al. 1996, Mitropoulos 2002, Wayne et al. 198 8).

Based on the understanding assimilated from the interviews and literature review,
this research has developed a graphical illustration, shown in Figure 4.3, of the complex
state of renovation projects interfacing with the reviewed state-of—the-art construction
performance assessment systems.

Overall, Figure 4.3 demonstrates the intricacies involved in production
assessment of a construction activity in renovation projects. Figure 4.3 shows some of the

essential attributes of production management systems for renovation projects, as

mentioned in section 4.3. These essential attributes are: the constraints, their project

115

conditions, critical activities, broad performance categories of state-of-the-art
construction performance measurement systems and their performance indicators.

Through Figure 4.3, this research attempts to illustrate that in renovation projects,
the production of a construction activity as it relates to the estimated time, cost, quality,
and safety, could be impacted by multiple constraints and their various project conditions,
and not merely labor, material and equipment availability, which are traditionally
considered for project planning and controlling processes. Those construction activities,
which are typically impacted by these constraints, collectively define critical activities.
For instance, all activities pertaining to demolition process in renovation projects such as
concrete drilling and sawing, drywall cutting, ceiling uncovering, and dismantling of
mechanical ducts, would fall under the “Selective Demolition” critical activity.

The literature and interviews state that there are numerous project conditions that
generate constraints in a renovation project (Krizek et a1. 1996, Mitropoulos 2002,
Wayne et al. 1988). A thorough investigation of these project conditions would lead to
better identification and assessment of constraints and therefore, a better production
management of renovation projects. In addition, these project conditions need to be
investigated in order to assess the impact of constraints on the production of critical
activities. Therefore, this research assumes that these project conditions could define the
performance indicators for production management of renovation projects because these
project conditions would identify the ability of a construction crew for completing a
production assignment within budget, on time and at desired quality. Thus, in Figure 4.3

shows these project conditions as performance indicators for each constraint.

116

Figure 4.3 clearly shows that a performance indicator of any constraint could have
multiple impacts on the production of various critical activities with respect to their
estimated cost, time, quality, and safety performance. In other words, any critical
activity’s production could be impacted by multiple performance indicators of numerous
constraints. This impact can only be quantified and planned when all these essential
attributes are linked in a systematic process of production planning, execution, and
performance assessment.

On the contrary, from the interviews of contractors and subcontractors and the
literature review of state-of—the-art construction performance measurement systems, this
research concluded that these systems do not incorporate the constraints, project
conditions, and critical activities of renovation projects in their performance
measurement processes. Past researchers have also concluded that state-of-the-art
performance measurement systems have not been able to identify a definitive set of
performance indicators which assess the true performance of construction projects
(Krizek et.al. 1996, Costa 2006).

Therefore, state-of-the-art performance measurement systems could prove to be
incomplete in their effective application to production management in renovation
projects. This research has also observed this ineffectiveness of state-of-the-art
performance measurement systems in the performance indicators proposed by these
systems, which do not account for the constraints of renovation projects as shown in
Figure 4.3. In addition, the interviews of contractors and subcontractors revealed that
current practice do not consider coping with the constraints as a critical success factor for

performance assessment of renovation projects.

117

For a renovation project, the lack of identification of constraints and their
assessment in production planning and assessment processes could lead to budget and
schedule failures, and could incapacitate project teams in identifying real causes of
underperformance. If a project were running over budget or behind schedule, it would
become extremely difficult to ascertain which constraints have caused these impacts in
which critical activities.

Although the performance indicators of state-of-the-art performance measurement
systems are incomplete for renovation projects, but this research has analyzed the
feasibility of using their measurement methods for the performance indicators of
renovation projects in planning and assessing the production. This analysis has further
lead to the development of both objective and subjective measurement methods for
performance indicators of constraints of renovation projects. For instance, performance
indicator of “cycle time”, as suggested by Alarcon et al. (2000), could assess the schedule
impact of project condition of “limited site access” that generates “physical constraint”,
as it involves limited movement of crews, labor and equipment. Similarly, other
performance indicators of state-of-the-art performance measurement systems have been
analyzed for their appropriate application to assess the constraints’ schedule impacts on

production of renovation projects.

118

PERFORMANCE
INDICATORS

 

Space Limitations for construction
Space Limitations for Material Storage —

Space Limitations for newly designed
Equipment/material

 

 

Limited capacity of downstream system
Non-disruption to Existing Utilities
Impact of existing utilities and structural
systems on the design of new systems

 

Noise Control
Dust Control
Vibration Control
Debris Control
Odor Control

Non-availaibilty of As-built Drawings
Presence of Hazardous Materials
Presence of Unforeseen Conditions

 

 

 

 

 

Timing Limitations of Owner's Operations-
Relocation of Owner to/from Swing Space —

CONSTRAINTS
OF RENOVATION

PROJECTS

Physical

Utility

Pollution

Uncertainty

 

Owner Furnished F _ 'r
Removal & Reinstallation of Owner's

 

 

Furniture
Multiple Inspections by End Users ——

Conditions with current codes

Impact on Crew Productivities

oordination

 

CRITICAL
ACTIVITIES

Development
of Plans &
S ecs.

Site
Investigation

Site
Lo istics Plan

Temporary
Construction

Selective
Demolition

Mobilize &
Demobilize

M.E.P
Rou h- ins

azar ous
Material
Abatement

Demolition

Waste
Management

 

 

Users & Public

Regulatory
Non conformance of Existing Materials/
Work Restructuring/Sequencing of Trades Schedule
Safety
Traffic

Movement Limitation of Crews
Movement Limitations of Materials
& Equipment

aterla
Equiment
Procurement

Figure 4.3 Interface between Renovation Projects
and State-of-the-art Performance Measurement Systems

119

 

CRITICAL BROAD STATE-OF-THE-ART
ACTIVITIES PERFORMANCE PERFORMANCE

CATEGORIES INDICATORS

Development
of Plans &

Specs.
\ Cost of

 

 

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120

The complexities of renovation projects contribute to the need for developing a
simplified and methodical process of production planning and assessment that takes into
consideration the essential attributes, discussed above. In order to fulfill this need, this
research has developed a framework for production management of renovation projects.
This framework establishes appropriate links between essential attributes for their
effective application in production planning, execution, and assessment process of
renovation projects. The framework provides a template to contractors for incorporating
their subjective assessment of essential attributes as they relate to specific project

conditions.

4.5 Introduction to the Production Management Framework for Renovation
Projects

Prior to discussing the framework for production management of renovation
projects, there is a need to reiterate the definition of “production management” for
renovation projects as stated in this research. In industrial engineering, production
management refers to planning , executing, and controlling the production assignments
on day-to-day basis that are established based on the analysis of constraints prevailing in
site conditions, prerequisite work, and resource availability (Ballard 2000). Numerous
studies have concluded that the constraints in renovation projects by their complex
nature, negatively impact the production of construction activities leading to schedule and
cost overruns ((Mitropoulos et al.2002, McKim et al. 2000, Krizek et a1. 1996). Those
construction activities that frequently encounter these constraints during their execution

contribute most to the production performance and, hence, are termed critical activities.

121

Therefore, this research posits that the process of planning, executing, and controlling the
production of critical activities based on the analysis of constraints for the purpose of
completing the production assignments within budget, on schedule and of desired quality,
defines production management in renovation projects.

Hence, a framework for production management of renovation projects should
primarily originate from those essential attributes, which characterize the complexities of
renovation projects. Constraints and critical activities represent the leading essential
attributes that should drive the framework development and identify other essential
attributes such as performance factors of each constraint, their measurement methods, etc.

At a broad level, this framework proposes two major processes: production
planning, and production performance assessment. Both these processes are linked in a
cyclic process to obtain the feedback from production performance assessment and apply
it in future production planning processes for continuously improving the schedule
performance of renovation projects.

By linking the essential attributes stated in section 4.3, this framework presents a
high level process of planning and assessing the production performance at the
construction activity level of renovation projects based on the analysis of prevailing
constraints. This high level process, at a micro level suggests a number of steps required
to be performed by the contractors for production planning and assessment. These
suggested steps also represent the development stages of framework, as they correspond
to the chronological sequence of how this research developed the framework from
essential attributes identified in literature and interviews. The following section briefly

states these development stages of this framework.

122

4.6 Stages in Framework Development

Section 4.4 emphasized that it is imperative to identify relationships between essential

attributes and link them in a methodical process for their effective application in

production management of renovation projects. In the previous section, the process of

production management for renovation projects was defined, which underscored the

importance of constraints and critical processes in building this process. This section

states the chronological stages in development of the framework undertaken by this

research for defining possible interactions between essential attributes and developing

production planning and performance assessment methods for renovation. projects. These

stages are:

1. Identification of constraints and critical activities

2. Mapping the interdependency relationships between constraints and reduce the
number of constraints- optional step

3. Mapping the impact levels of constraints on the estimated production schedule of
critical activities

4. Identification of weighted impacts of constraints on the production schedule of
critical activities

5. Quantification of additional production duration of critical activities based on
project conditions

6. Prepare lookahead schedule of production assignments

7. Match production assignments and resource capacities

8. Preparation of execution plan for each critical activity

9. Production performance assessment

123

10. Production failure analysis

Figure 4.4 shows the developed framework that involves all of the above mentioned
stages. As stated before, the stages shown in Figure 4.4 represent the steps proposed by
the fi'amework that should be performed in production management of renovation
projects. These steps have been synthesized from the analysis of the literature of
renovation projects and production management, which provided the basis for developing
the framework. Before proceeding to define how each step should be performed, an
explanation of why each step is required would provide the reader with the significance
of each step in the overall framework for production management of renovation projects.

The first step in production planning is to identify possible constraints and critical
activities in the scope of work by reviewing the project conditions. The constraints
prevailing in renovation projects and the critical activities that are impacted by these
constraints form the primary essential attributes that impact the production performance
of renovation projects.

While impacting the production of critical activities, the constraints of renovation
projects may exhibit varying degree of dependency levels within themselves. Any
constraint may be weakly dependent on one constraint, strongly dependent on two
constraints while absolutely dependent on all others. Therefore, for the second step, a
correlation analysis is required to be performed among the constraints. This would help in
understanding the contribution of each constraint towards other constraints. This analysis
would eventually help in accurately planning the production of construction activities in

the presence of absolutely dependent or strongly dependent constraints.

124

Step-2 has been specified as optional because its main purpose in the framework
is to limit the number of constraints and simplify the procedures in steps 3, 4 and 5.
Skipping this step might have a slight impact on the estimation of production in step-5,
which is explained further in the demonstration of framework. Therefore, after
identification of constraints and critical activities in step-1, a decision node is placed, as
shown in Figure 4.4 to either proceed through step-2 or go directly to step-3.

Similar to the previous step, in step 3, a correlation analysis is required between
constraints and their impacts on different critical activities. These relationships would
help in understanding the impact levels of each constraint on the increase or decrease of
the estimated production performance in all critical activities. It is important to analyze
this impact on the production of each critical activity as it relates to estimated cost, time,
quality, and safety performance. This analysis would enable project teams to understand
the dynamic nature of how each constraint changes with each critical activity so that they
would be better able to plan the production accordingly.

The purpose of step-3 is to map the impact levels of constraints on the production
of critical activities while the purpose of step-4 is to establish hierarchy of constraints
based on the mapped impact levels. As explained in step-3, each constraint has different
impact levels on the production of different critical activities, it becomes imperative to
obtain the relative importance of constraints for each critical activity. The hierarchy
would be established through Analytical Hierarchy Process (AHP) in step-4.

The production planning of any critical activity would entail estimating the
impacts of constraints on its estimated budget, schedule and quality. For quantifying

these impacts of constraints, assessment of project conditions that generate these

125

constraints should be done. Therefore, defining the assessment methods of project
conditions of each constraint, through step-5, is one of the major stages in this framework
because these assessment methods would facilitate production planning.

Step-5 represents a major milestone in production planning as it has a dual
function in the overall framework. The first function entails the assessment of project
conditions of each constraint and estimating their impact on production schedule of
critical activities. The second function is to normalize this impact by capturing the data
from previous steps (correlation analysis and AHP) and use it in estimating the
production duration of a critical activity.

Step-6 entails entering the production assignments of critical activities in a
lookahead schedule for the upcoming 3 to 6 weeks. Only those assignments are to be
entered in the lookahead schedule for which all the constraints have been addressed or
removed.

Step-7 involves balancing the production duration and scope of work with the
available resources based on the analysis of broad external constraints, which are
maximum buffer, pre-requisite work and given directives. The revised production
duration would represent the performance that any activity ‘can’ achieve under the
impacts of the constraints. Communication of this production estimate to the construction
crew prior to activity execution becomes an important step. However, simply
communicating the production estimate would not enable the crew in achieving it.
Therefore, step-8 involves preparing an activity execution plan, which in addition to

production estimate, includes preparing a daily production schedule that lays out the

126

production assignments of crews based on the analysis of constraints and associated
project conditions.

Step-9 is required to determine the production efficiency of the crew, which
captures how well the crew performed under the presence of the constraints. Therefore,
assessment of production performance should be done after activity execution in the
presence of constraints and comparing it with the estimated production. Based on
production performance assessment, if the actual production does not meet the estimated
production, a production failure analysis is required in the last step (step-10) to
understand the cause of underperformance and apply the learning to future constraints
analysis.

Overall, this framework is developed per the literature review and interview
responses of contractors and subcontractors. Steps 1 through 10 of the developed
framework are shown in Figure 4.4. While performing some of these steps, the
fi'amework suggests incorporating query nodes (Query node-1, 2 &3) which are
explained in the detailed discussion of those steps. The following section discusses in

detail steps 1 through 10 of the framework.

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4.6.1 Step-l Identify Constraints and Critical Activities

The first step in planning the production of any activity should be to review all pertinent
project conditions that might impact the production of various construction activities.
These project conditions could be specified in the contract between owner and contractor
and/or could be informally communicated to the contractor prior to start the work. As
stated by the literature of renovation projects, these project conditions generate various
constraints that adversely impact the construction activities. Therefore, as an outcome of
the project conditions review, all the constraints should be identified that could be
encountered during construction.

Having identified the constraints, all construction activities should be reviewed to
identify those the production of which will be impacted by the constraints. These
activities are termed critical activities, as their production planning requires a thorough
consideration of potential constraints upfront, in order to avoid the cost and schedule
overruns. Although, the constraints and critical activities are very project specific, but for
the explanation of the framework from steps 2 through 10, the constraints and critical

activities have been assumed based on the literature review.

4.6.2 Step-2 Interdependency Relationships between Constraints- Correlation
Matrix 1a (CM-1a)

The correlation analysis in step-3 and AHP calculations in step-4 for all
constraints could prove to be complex and time consuming. In such case, the synergies
between constraints should be explored which might reduce the number of constraints in
steps 3 and 4. For example, if there are 20 constraints present for any construction

activity, it would be wise to limit this number prior to conducting their correlation

132

analysis with critical processes and AHP calculations by identifying interdependency
relationships between these 20 constraints.

Therefore, prior to mapping production impacts of each constraint in different
critical activities in step-3, this framework recommends investigating the
interdependency levels between all constraints impacting the production. This analysis
helps in understanding the contribution of each constraint towards generating other
constraints. For instance, if physical constraint is absolutely dependent on coordination
constraint, then the impact due to coordination constraint on the production of critical
activities would not be solely an outcome of its associated project conditions, but an
indirect impact of project conditions of physical constraints also. Therefore, each
constraint exhibits a specific dependency level on the existence of other constraints.
These dependency levels could be absolute, strong, moderate, slight or none.

Correlation analysis has been adopted as a tool in the form of a matrix to check
the interdependency levels between constraints. This matrix is termed as Correlation
Matrix-1a (CM-1a). As stated before, performing this analysis has been specified as an
optional step in the framework, which would be guided by a decision node, as shown in
Figure 4.2, of whether to go through step-2.

Table 4.1 shows an example of CM-la for a selective demolition activity where
each constraint is mapped against all other constraints. In this matrix, each cell (aij) is
referred by its relative row number (i) and column number (j). In the assignment of
column and row numbers, the left most column and the top most row are ignored, as they

list all the constraints from top to down and left to right respectively.

133

In this matrix, each cell (aij) represents the dependency level of “column”
constraint on the “row” constraint. For instance, in Table 4.1, cell an represents that
utility constraint is slightly dependent on physical constraint. In another example, the cell
a36 represents that schedule constraint is absolutely dependent on pollution constraint. As
can be seen from Table 4.1, a typical correlation matrix-1a uses five dependency levels,
which are; absolute (A), strong (S), moderate (M), slight (SL), and none (N).

Therefore, in order to complete and read this matrix, one should follow each
column constraint at one time moving from left to rights, and analyze its dependency
level on all row constraints. For instance, in Table 4.1, the user would start filling this
matrix from the first column constraint at the left i.e. physical constraint and analyze its
dependency on all row constraints moving down from physical to regulatory constraint. It
should be noted that in each cell (aij), the dependency level is to be assigned with the
assumption that only ith row constraint and jth constraint are present.

The dependency levels in this matrix have been assigned numerical figures from 1
to 9, which represent the percentage of a column constraint being dependent on row
constraint, in the presence of only these two constraints. These numbers would not be
employed for performing any quantitative assessment, but they would facilitate in making
qualitative judgments of the level of dependencies between constraints. For instance, if
physical and coordination are the only constraints present, it would be simple to identify
whether one constraint is 30%, 50%, 70%, 90% or 0% dependent on the other constraint
as compared to whether the dependency is slight, moderate, strong, absolute or

negligible.

134

A negative sign prior to the dependency level indicates a reverse dependency of
row constraint on column constraint. For instance, for cell (13), the negative sign before
‘M’ indicates that instead of pollution constraint (column) being moderately dependent
on physical constraint (row), physical constraint (row) is moderately dependent on
pollution constraint (column).

Therefore, relating the numerical figures and dependency signs to Table 4.1, it
could be seen that the first column constraint i.e. physical depends 50% on pollution,
90% on coordination, and 0% on regulatory constraint. The negative signs before
dependency levels on other row constraints depict that these row constraints are
dependent on physical constraint. Thus, utility constraint depends 30%, uncertainty
constraint depends 50%, schedule constraint depends 70%, safety constraint depends
70%, and traffic constraint depends 50% on the physical constraint. Similarly, other

dependency levels can be interpreted by observing their signs and numerical assessment.

135

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136

4.6.2.1 Constraint Reduction Process

As stated above, the purpose of identifying dependency relationships between
constraints is to limit the complexities involved in correlation analysis in step-3 and AHP
calculations in step-4, by reducing the number of constraints. If a column constraint is
absolutely dependent on the row constraint, this means that only column constraint could
be considered in step-3 and 4, as the column constraint would represent the row
constraint. Based on the project conditions, the absolute interdependency relationships
could also extend beyond two constraints, which would significantly decrease the number
of constraints in subsequent phases.

Based on CM-la exemplified above, Table 4.2 shows that 5 constraints could be
eliminated from further steps due to their absolute dependencies on 3 other constraints.
Therefore, for performing further steps of the framework, only 4 constraints could be
considered instead of 9.

Table 4.2 Constraint Reduction using CM-la

 

 

 

 

 

 

 

Constraint to be Removed Representative Constraint
Physical Coordination
Pollution Coordination
Schedule Pollution

Safety Utility
Regulatory Uncertainty

 

 

137

 

4.6.3 Step-3 Impact levels of Constraints on Estimated Production Schedule of

Critical Activities- Correlation Matrix 1 (CM-1)

Afier obtaining the interdependency levels between constraints, dependencies between
the constraints and the estimated production of critical activities would be mapped. This
analysis would help in understanding the level of impact that any constraint could have
on the estimated production of a critical activity. Similar to CM-la, a correlation matrix
(CM-1) would be prepared between constraints and critical activities to map the impact
levels. It is important to map the impacts of constraints on the cost, time and quality of
the production critical activities. Therefore, the estimated production of critical activities
would be categorized under budgetary, schedule and quality performance and for each

category, a separate correlation matrix would be developed against the constraints.

However, this research focuses on identifying only the schedule impacts on the
production of critical activities. Therefore, only one type of correlation analysis regarding

the schedule impacts would be discussed for the remainder of this thesis.

Table 4.3 shows an example of Correlation Matrix 1 (CM-1) between constraints
and critical activities with respect to the impact levels of constraints on production
schedule of critical activities. This matrix is constructed on a structure similar to CM-la
except in this case, each constraint is mapped against all critical activities in a matrix
form. Each cell (aij) represents the level of impact that the constraint in ith row has on the
production schedule of critical activity in jth column. The impact levels have been
categorized under 5 types; absolute (A), strong (S), medimn (M), slight (SL), and none

(N). These impact levels represent the contribution of constraints in increasing the

138

production schedule of critical activities. For instance, in Table 4.3, cell a35 represents
that pollution constraint has a strong impact on the production schedule of the selective
demolition critical activity. This means that assuming only pollution constraint being
present for a selective demolition activity, 70% of its additional duration will be due to
the pollution constraint. In another case, cell a37 represents that pollution constraint has a

moderate impact on the production schedule of MEP rough-in critical activity.

Similar to CM-la, this matrix should also be completed and read from lefi to
right, considering each critical activity in jth column at one time. While considering a
critical activity in jth column, the impact levels of all row constraints on its production
schedule should be mapped, moving from top to down. For instance, in Table 4.3, the
completion of the correlation matrix should begin from the left most critical activity in
the first column i.e. development of plans and specifications. While considering this
critical activity, the impact levels of all constraints, from physical to regulatory, on its
production schedule should be mapped. Once all the constraints’ impact levels have been
mapped, the next column should be considered in the same manner. As the impact levels
in this case cannot be reversed, only positive sign should be assigned to all the impact

levels mapped.

Table 4.3 shows the first approach of constructing a correlation matrix-1 for all
the 9 constraints being considered independently. These 9 constraints could have been
reduced to 4 based on the constraint reduction process discussed above. Mapping the
impact levels of only 4 constraints as representatives of 5 other constraints would become

much simpler compared to the process presented in Table 4.3.

139

This alternative approach of mapping the impacts of only representative
constraints, in correlation matrix (CM-l) is presented in Table 4.4. The matrix structure
of alternative approach is similar to that of first approach shown in Table 4.3, except that
in this case, only representative constraints along with those which are not absolutely

dependent on any other constraints are to be mapped against each critical activity.

In this case, it can be seen that the impact levels of representative constraints have
been increased as compared to their individual impact levels as mapped in the previous
CM-l, as was shown in Table 4.3. This is due to the fact that a representative constraint
now characterizes the impact of its dependent constraint also, which should be more than

its individual impact.

The correlation matrix-1 between constraints and critical processes is followed by
Analytical Hierarchy Process (AHP) to establish the hierarchy of constraints in impacting
production of critical processes. Thus, knowing the information in CM-l, either through

approach 1 or 2, would facilitate conducting AHP as explained in the next section.

140

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4.6.4 Step-4 Identification of Weighted Impacts of Constraints on the Production

Schedule of Critical Activities- Using AHP

In order to better estimate the production schedule of a critical activity in the presence of
various constraints, it becomes essential to identify the relative weight at which each
constraint impacts the production schedule of critical activities. Assigning suitable
weights to each constraint through the quantitative technique of Analytical Hierarchy

Process (AHP) was selected to establish the hierarchy amongst constraints.

In order to conduct AHP, a pair-wise comparison matrix is prepared with all
constraints being individually placed in rows and columns. Each cell (aij) represents the
importance of its relative row constraint (ith row) over its column constraint 0‘“ column)
in impacting the production schedule of a critical activity. The AHP uses a scale of 1 to 9
to reflect the importance level that an i‘11 row constraint has over the jth column constraint.

The 9 importance levels are shown in Table 4.5.

Table 4.5 Scale of Importance Levels in AHP (Saaty 1980)

 

 

 

 

 

 

 

 

 

 

 

Scale Definition {Importance of row constraint
over column constraint}

11 Equal Importance
3 Weakly more
5 Moderately more
7 Strongly more
9 Absolutely more

1/3 Weakly less

1/5 Moderately less

1/7 Strongly less

1/9 Absolutely less

 

 

142

 

In each cell of the pair-wise comparison matrix of AHP for all constraints, the
assignment of importance level should be referenced to Table 4.5. In addition, this
assignment should also be facilitated by the impact levels of constraints mapped in CM-l ,
as was shown in Table 4.3 and 4.4. For this purpose, this research has mapped the AHP

importance levels to the corresponding impact levels of CM-l , as shown in Table 4.6.

Table 4.6 has two major columns. The left column shows the impact levels of
CM-l for any two constraints with all the possibilities of different combinations.
Constraint 1 of CM-l, in the left column, represents the ith row constraint being
compared to jth column constraint in AHP, which is Constraint 2 of CM-l. The
comparison between any two constraints in the pair-wise comparison matrix of AHP
should first refer their impact levels on the production schedule of critical activities in
CM-l, and then assign the corresponding importance scale of AHP, shown in the right
column of Table 4.6. Therefore, the overall purpose of using CM-l is to facilitate the
assignment of importance levels in AHP’s pair-wise comparison matrix and to avoid any
subjectivity in evaluator’s judgments by providing additional data in the form of

correlation matrix.

An example of the pair-wise comparison matrix of AHP for all constraints is
shown in Table 4.7 that has assigned the importance level of ith row constraint over the
jth column constraint in impacting the production schedule of a selective demolition
activity. In order to provide the reader a clearer understanding of how to use Table 4.6 for
completing Table 4.7, two example cases are illustrated. In the first case, if physical and
pollution constraints are being compared in the pair-wise comparison matrix, their impact

levels on the production schedule of selective demolition activity should be first referred.

143

With reference to the impact levels of constraints mapped in CM-l, shown in Table 4.4, it
could be seen that both physical and pollution constraints have a ‘strong’ impact on the
production schedule of selective demolition activity. Therefore, in the left column of
Table 4.6, if physical constraint represents Constraint 1 and pollution constraint
represents Constraint 2, then the pair wise comparison between these two constraints will
result in equal importance (a “1” in this case). This “1” should be placed in cell an, of the
pair-wise comparison matrix shown in Table 4.7. It should be noted that the numbering of
rows and columns does not include the left most column and the top most row as they

only list all the constraints.

In the second case example, if physical constraint and safety constraint are being
compared in AHP, then with reference to CM-l, shown in Table 4.4, it could be seen that
physical constraint strongly impacts the production schedule of selective demolition
activity but safety constraint has a moderate impact. Therefore, according to Table 4.6,
the pair-wise comparison between physical (Constraint 1) and safety constraint
(Constraint 2) should assign a weakly favored scale to physical constraint over safety
constraint (a “3” in this case). This “3” should be placed in cell an of the pair-wise
comparison matrix shown in Table 4.7. Similarly, all other cells of the pair-wise

comparison matrix, shown in Table 4.7, could be filled.

Using AHP method and Table 4.6, Table 4.8 is produced for the example, which
shows the relative weights of constraints in impacting the production schedule for any

task belonging to the ‘selective demolition’ critical activity.

144

Table 4.6 Mapping of AHP and Correlation Matrix-1 Scales (Modified from Saaty 1980)

 

 

 

 

 

 

 

 

 

 

 

Correlation Matrix Scale (CM 1) AHP
Constraint 1 Constraint 2 Definition Scale
{Importance of row
constraint (1) over
column constraint
(2)}
N N Equal Importance 1
SL SL
M M
S S
A A
SL N Weakly more 3
M SL
S M
A S
M N Moderately more 5
S SL
A M
S N Strongly more 7
A SL
A N Absolutely more 9
N SL Weakly less 1/3
SL M
M S
S A
N M Moderately less 1/5
SL S
M A
N S Strongly less 1/7
SL A
N A Absolutely less 1/9

 

 

 

145

 

As per Table 4.8, utility and uncertainty constraints have the most impact on
production schedule of selective demolition activity. This means that while planning the
duration for any activity of selective demolition, all project conditions related to utility
and uncertainty constraints must be identified, assessed, and given the highest priority for
their additional duration, otherwise, the actual duration would exceed than what is
planned. This is not to say that project conditions of all other constraints should be
ignored, they are still required to be considered for additional duration but it will be
normalized with lesser priority scale. The assessment of project conditions is explained

later in detail in Section 4.6.4.

In order to provide the reader an understanding of how to conduct AHP and
calculate relative weights through it, a typical process is discussed in the appendix section
(Appendix-2). Therefore, the reader is directed to Appendix-2 for further explanation of

AHP.

The AHP process should be repeated for obtaining the hierarchy of constraints in
impacting the production schedule of each critical activity. In addition, for obtaining the
hierarchy of constraints in impacting the cost and quality of production of critical
activities, AHP process should be conducted separately for cost and quality, based on
their respective CM-l matrices. However, this research focuses only on the schedule

impacts that constraints have on the production of critical activities.

As stated before, the constraints interdependency relationships would facilitate in
limiting the calculations of AHP. If the optional matrix of CM-l based on the reduced

number of constraints, shown in Table 4.4, is used then, as an alternative to conducting

146

AHP calculations of 9 constraints, only 4 constraints could be considered, as
representatives of the 5 other constraints. Table 4.9 and 4.10 show the pair-wise
comparison matrix of these 4 constraints and their final weights, respectively. As
expected, it could be observed that the weightage of representative constraints in Table

4.10 have increased from that calculated in Table 4.8.

147

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4.6.5 Step-5 Quantification of Additional Production Duration of Critical Activities
based on Project Conditions- Constraint Assessment Matrix (CAM)

The objective of obtaining relative weight of constraints is to better assess the impact of
constraints and estimate the production duration of critical activities. After ascertaining
the relative weights of all constraints in impacting the production schedule of each
critical activity, the production time can be planned through a process of constraint
assessment.

Constraint assessment process primarily involves planning the additional duration
of critical activities after assessing project conditions, and applying the established
hierarchy of constraints to their relevant project conditions. Therefore, for planning the
additional duration of critical activities, the following two factors should be considered:

1. Hierarchy of constraints in impacting estimated duration of critical processes
2. Assessment of project conditions of all constraints for estimating the required
additional duration of critical activities

Constraint assessment process should be conducted separately for each critical
activity involved in the scope of work. This process of planning additional duration of
each critical activity is to be conducted through Constraint Assessment Matrix (CAM).
For any critical activity, CAM incorporates all constraints, their project conditions as
performance indicators, assessment methods of project conditions, additional duration
required due to each project condition, and the normalized additional duration based on

constraint weight.

149

An example of CAM for a construction activity of ‘selective demolition’ is shown
in Table 4.11. The assessment of project conditions in Table 4.11 are for illustrations
only and do not relate to any real renovation project.

It should be noted that in Table 4.11, CAM lists all project conditions and
constraints, irrespective of the type of critical activity being considered. This has been
done to avoid project team’s unawareness of the impact of any project condition while
planning the additional duration of a critical activity. Therefore, even if the assessment of
a project condition reveals a 0 day impact, it should be documented for ascertaining the

quantified impact of each constraint, and analyzing delay causes after activity execution.

This research has identified the project conditions, shown in Table 4.11, from the
literature review and interview data. Therefore, the list of project conditions shown in

Table 4.11 is not exhaustive.

For each identified project condition, this research has developed assessment
methods to estimate the additional duration from the literature review of state-of-the-art
performance measurement systems and construction production management. The
assessment of each project condition requires project team’s knowledge and previous
experience of performing construction activities in similar project condition. In addition,
the assignment of quantitative scale values to qualitative project conditions necessitates
project teams’ expert judgment based on the site conditions and nature of project

conditions.

The additional duration due to any project condition of a constraint is estimated

based on its developed quantitative or qualitative assessment method depending on the

150

nature of project condition. For instance in the example shown in Table 4.11, the
additional duration required due to the project condition of “off-site storage space” can be

quantitatively assessed as:

Additional duration = Cycle time to install the material on site / cycle time to deliver the
material from off-site storage space to construction site (time lapse between material

procurement and material installation

or
1- wait time of crew for receiving the material on site/ cycle time to install the material

on site

In this example, the additional duration results in a 0 day duration based on the

assumption that off site storage space is not required.

In another case example of quantitative assessment, shown in Table 4.11, the additional
duration due to project condition of “noise, dust, debris, vibration, and odor control” can

be assessed as:

Additional duration = (Time for enclosing construction zone + time for installing
peripheral sound & vibration insulation + time for installing negative air machines + any
other time for pollution control activities+ non-work period specified by owner due to

pollution problems)

The qualitative assessment applies to those project conditions which are subjected to

evaluator’s judgment and prior experience. For instance, for the example shown in Table

151

4.11, the additional duration due to the project condition of “space limitation of on-site

storage space” can be qualitatively assessed with a reference quantitative scale as:

Available space Additional duration (% of original duration)
0 More than required 0

- Required 0 to 10

° Limited 10 to 20

- Very limited more than 20

Based on the assumption that the on-site storage space is bit less than what is
required, the additional duration will be increased by 5 % of the original duration.
Therefore, as shown in Table 4.11, 0.5 day comes out as the additional duration, as the
original duration was 10 days.

After estimating the additional duration due to all project conditions, the total
additional duration due to all project conditions of each constraint should be added, and
then normalized by multiplying it with the constraint’s relative weight obtained through
AHP. The normalization process gives the minimum impact that a constraint will have on
the production duration. Therefore, the normalized additional duration represents the
quantified contribution of a particular constraint at a minimum level, in impacting the
production schedule of a critical activity.

For instance, in the example shown in Table 4.11, the total additional duration due
to utility constraint is 4 days, which represents the maximum impact of utility constraint
on the schedule of selective demolition activity. Based on the relative weight of 0.253 for
utility constraint, which is obtained from AHP (Table 4.9), in impacting the schedule, the

total additional duration should be normalized to ascertain the least additional duration

152

due to utility constraint, which must be included in the production schedule of selective
demolition. The normalized additional duration due to utility constraint is:
Normalized additional duration due to utility constraint = 4 x 0.253 = 1.012 days

Therefore, the additional duration due to the project conditions of each constraint
should be normalized according to the relative importance of that constraint in impacting
production schedule, obtained from AHP.

The summation of normalized additional duration gives the minimum additional
duration (ADmin) required for any critical activity. However, the summation of additional
duration due to project conditions of all constraints without their normalization, gives a
maximum additional duration (ADmax) required for any critical activity.

N
ADmin = 2(additional duration due to project conditions of each constraint) x W
i=1

N
ADmax == 2(additional duration due to project conditions of each constraint)

i=1

Where,

N= Number of constraints
W = Relative weights of constraints for impacting production schedule of critical process
With reference to the example in Table 4.11,
ADmin = (4 x 0.253) + (1 x 0.114) + (1.25 x 0.142) + (4 x 0.253) + (0.5 x 0.051) + (O
x 0.024) + (0.5 x 0.024) + (0.67 x 0.114) + (0 x 0.051) = 2.393
= 3 days (approx.)

ADmax=4+l +1.25 +4+0.5 +0+0.5 +0.67+0= 11.92 = 12 days (approx.)

153

Therefore, the constraint assessment process results into a range of additional duration,
having a minimum and maximum value. An estimated additional duration (BAD) is a
middle value of its range, as shown in equation.

BAD = {(ADmin) + (ADmax)} / 2
The Revised Production Duration (RPD) for any critical activity, based on the assessment

of constraints would be:

RPD = Original duration (without consideration of constraints) + EAD

For the example shown in Table 4.11, the BAD and RPD are:
EAD = 3 + 12 / 2 = 7.5 = 8 days (approx.)

RPD=10+8=18days

The RPD will serve as a benchmark for critical activities against which the production

performance will be evaluated after the execution.

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The constraint assessment matrix shown in Table 4.11 is based on the independent
impacts of constraints mapped in CM-l (Table 4.3) and their relative weights calculated
in AHP for all 9 constraints. For the alternative approach in which the number of
constraints was reduced to 4 due to their interdependencies a different method for

constraint assessment should be followed.

Table 4.12 shows the alternative CAM which is based on the same structure of the
previous CAM in Table 4.11, but due to the interdependencies, the framework
recommends two major deviations which are:

1. Normalizing the estimated additional duration due to each constraint should be
based on their relative weights obtained from the constraint reduction process
(CM-1a, Table 4.1), and the AHP using the reduced number of constraints (Table
4.10).

2. The constraints which were observed to be absolutely dependent on others will
have the total additional duration due to their project conditions, added to the
additional duration due to their representative constraints.

The purpose of including these deviations during the constraint assessment process is to
preserve the consideration of those constraints which were removed from AHP and CM-
1. For instance, in Table 4.1, physical constraint was observed to be absolutely dependent
on the coordination constraint for the example activity of selective demolition and
therefore, was removed from CM-l (Table 4.4) and AHP calculations (Table 4.10). The
removal of physical constraint from AHP makes its relative weight to be 0 for the
constraint assessment process. However, 0 relative weight does not imply that the

additional duration due to project conditions of physical constraints would also be 0.

161

As shown in Table 4.12, the additional duration due to physical constraint is 1 day
for the selective demolition activity. Normalizing this duration based on 0 relative weight
will again result in 0 additional days and the impact of physical constraint will not be
considered in planning the additional duration of selective demolition activity. Therefore,
in order to reflect the impact of physical constraint and maintain its consideration, this 1
day should be added to the additional duration due its representative constraint i.e.
coordination.

Based on the above mentioned deviations, Table 4.12 shows an example of
constraint assessment process for a selective demolition activity, in which the dependent
constraints have been assigned a relative weight of 0, while all other constraints’
weightage have been obtained from AHP conducted in Table 4.10.

In this case, the assessment methods for project conditions are similar to those in
the first approach. The alternative CAM incorporates an additional section after each
constraint’s assessment for identifying if the constraint is a representative one or being
represented by other constraint. In the first case, the additional duration due to
represented constraints should be added to its additional duration while in the latter case,
the additional duration due to its project conditions should be added to its representative
constraint. For instance, in Table 4.12, as schedule constraint is represented by the
pollution constraint, the total additional duration due to schedule constraint (0.67 day) has
been added to the total additional duration due to the pollution constraint. In other case,
as physical constraint is represented by coordination constraint, the additional duration
due to physical constraint (1 day) has been added to the additional duration due to

coordination constraint. In order to avoid any repetition or error, once the additional

162

duration of represented constraint has been added to its representative constraint, the
additional duration due to the former should become 0. This can be seen with utility and
physical constraint in Table 4.12.

After adding the total additional duration due to the project conditions of each
constraint including its represented constraints, the overall method of normalization of
additional duration also differs from what is discussed in the first approach. The
normalization of all represented constraints results a 0 day additional duration due to their
0 relative weights which means that the additional duration due to the represented
constraints would be normalized with the relative weight of its representative constraint,
as are the cases with utility and physical constraints in Table 4.12.

Therefore, this approach of constraint assessment process also results into a range of
additional duration, having a minimum and maximum value. An estimated additional
duration (BAD) is a middle value of its range, as shown in equation.

EAD = {(ADmin) + (ADmax)} / 2
The Revised Production Duration (RPD) for any critical activity, based on the alternative
approach of constraint assessment would be:

RPD = Original duration (without consideration of constraints) + EAD
For the example shown in Table 4.12, the EAD and RPD are:

EAD = 4 + 12 / 2 = 8 days (approx.)

RPD=10+8=18days
It could be seen that the maximum value of additional duration (ADmax) is not changed
from approach 1 to 2, as the assessment methods of project conditions are same in both

approaches and ADM,x is just the summation of additional duration without their

163

normalization. The difference of 0.5 day is encountered in ADmm values due to the change
in normalization method with the additional duration due to represented constraints being
normalized according to the relative weights of their representative constraints. The
differences between the results of both approaches have been discussed later in the

demonstration section.

Similarly, Estimated Additional Cost (EAC) can be ascertained for a critical
activity, where the assessment of project conditions would involve estimating the
additional cost required. In such case, the relative weights of constraints would also

change for impacting the production cost of critical activities.

164

 

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175

4.6.6 Step-6 Enter and Move Production Assignments in Lookahead Schedule

As a part of the lookahead process, the Last Planner System TM (LPS) of production
control suggests preparing a lookahead schedule of the upcoming work for the next 3 to
12 weeks for the purpose of controlling the flow of work between trades (Ballard 2000).
The appropriate size of lookahead window is the function of project characteristics and
lead times for material, information, labor and equipments (Ballard 2000, Howell et al.

2002)

Having reviewed the complexities of renovation projects from both literature and
interviews, this research recommends incorporating a lookahead schedule as an integral
part of the production management framework. This framework employs the lookahead
schedule for its intended objective as suggested by Ballard (2000), of producing a
“phase” schedule of those activities that “can” be performed based on the state of the
system (constraint analysis) rather than what “should” be performed as per the CPM. The
lookahead schedule would assure a reliable workflow between trades and reinforce the
constraint assessment before executing any activity. Therefore, while preparing the
lookahead schedule, a general rule is that only those activities or assignments for which
the constraints have been removed or addressed, through CAM, should be allowed to

enter and move in a lookahead schedule.

The fulfillment of this rule would be facilitated by a query node (Query Node-1)
in the framework. Prior to revising the production duration of critical activities based on
the Constraint Assessment Matrix (CAM), query node-1 assures that in the CAM, all the

pertinent constraints are addressed with the assessment of their project conditions to

176

identify additional duration. Figure 4.5 shows the location of query node-1 in the
framework. If the answer to the query is “no”, the framework suggests to go backward to
conduct CAM again considering all constraints and their project conditions. In case of a
“yes” answer, one should follow the next step of revising the production duration of
critical activities and entering them into the lookahead schedule. Therefore, query node-1
reinforces the consideration of all constraints upfiont rather than reacting to them later on

which could adversely affect the production schedule.

In the lookahead schedule, the activities would begin to advance forward week by
week as their preceding activities are selected for further steps of the framework. During
this time, if any activity for which a new constraint is generated, would not be allowed to
move forward but would be directed to go backward to the CAM for assessing the impact

of constraints and revising its production duration.

177

From AHP (Step-4)

 

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Figure 4.5 Function of Query Node-1 in the Framework

4.6.7 Step-7 Match Production Assignments and Resource Capacities

As discussed in Chapter 2, the Activity Definition Model (ADM) of the Last Planner
System TM explodes each activity to analyze the three broad constraints for its execution
which are; perquisite work, required resources, and directives. As the name suggests,
prerequisite work represents the base or structure which should be in place before

executing the activity. Resources could be labor, tools, equipment and/or space while

178

directives dictate the production of activity against which its performance is assessed

(Ballard 2000).

As the framework covers the assessment of internal constraints generated from
project conditions of renovation projects, it also becomes essential to investigate the
external constraints which are required to execute the production assignments critical
activities within their estimated duration. Having only considered the internal constraints
in production planning could have adverse impacts on production performance.
Therefore, this research adopts the ADM for analyzing production assignments of
renovation projects from the perspectives of four broad external constraints, including the
three stated above and the fourth one is maximum time buffer available for executing the
activity. The maximum time buffer for any activity is the difference between its
maximum additional duration and estimated additional duration, as calculated from the

constraint assessment matrix.

Maximum Time buffer = AD max - EAD

For instance, the maximum time buffer for the example selective demolition activity, as

calculated from its CAM, shown in Table 4.12, is:

Maximum time buffer = 12 — 8 = 4 days

The amount of duration over and above the additional duration, estimated on the
basis of constraint assessment, during which any activity should be completed represents

the maximum time buffer for that activity. As the amount and availability of time buffer

179

for any activity could affect the assignment of resources, it represents one of the four

major constraints in ADM for renovation projects.

Figure 4.6 shows the ADM in the developed fi'amework, which suggests that once
an activity is selected for its execution from the lookahead schedule, it should be
exploded to analyze the four broad constraints based on which, the production capacities
of the available resources should be compared with the scope of work required to be
completed in its revised production duration. This means either adjusting the resources
according to the production duration or production duration according to the available
resources or both. This balance between production duration and available resources,
based on the analysis of external constraints would result in a workable production

assignment.

4.6.8 Step-8 Activity Execution Plan

After estimating the revised production duration of critical activities and balancing it with
the available resources, their execution plan would be developed by using the constraint
assessment matrix that would provide guidance for their execution. Table 4.13 shows an
example of an Activity Execution Plan (AEP) for a selective demolition activity that
stipulates the planned resources, revised production duration, estimated work quantity,

planned buffer, and prerequisite work.

Development of this plan before activity execution represents a proactive

approach of planning the production in the presence of constraints, both internal and

180

external. This plan would also involve the daily production schedule that will direct the
contractor in executing daily construction activities based on the revised production
duration estimated from constraint assessment process. The daily production schedule
would drive the contractor for establishing daily production assignments for crews,
keeping in mind the constraints, so that the activity could be finished within its revised
production duration. Therefore, a major significance to the contractor for creating this
plan is to prepare for all possible constraints, and release only those assignments for
production for which the line of attack of each constraint has been worked out and could
be finished within their revised duration, even if the resources to perform the task and its

prerequisite work are available.

Although, AEP shows a maximum time buffer available for an activity, but its
end date is still constrained by the start date of next immediate activity. Thus, the use of
buffer is discouraged, unless any deviations in production assignments are encountered
due to unforeseen conditions because employing the time buffer would effect the start

date of next immediate activity.

181

 

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4.6.8.1 Quality Criteria for Activity Execution Plan — Query Node 2

During the initial application of the last planner system, Ballard and Howell (1997) found
that approximately 50% of the planned assignments were completed by the crews. It was
concluded that this was an outcome of an inadequate work selection fiom the lookahead
schedule, which also gets affected by the dynamics and uncertainties of the production
systems. The lack of consideration of the quality of work being selected adversely
affected the reliability of the work flow. It became apparent that the quality of production
assignments should be assessed before selecting for execution. Therefore, as a possible
solution, quality criteria were proposed for assessing the assignments. The quality criteria

has five dimensions; definition, soundness, sequence, size, and learning.

“Definition” means whether the assignment explains in detail the type and amount
of materials to be collected, required coordination with other trades so that it can be made
ready, and it is possible to verify and conclude the completion of the assignment.
“Soundness” determines the feasibility of the assignment in terms of its pre-requisite
work and available resources. “Sequence” assesses the internal logic of the work from the
standpoints of constructability, customer requirements and overall project goals. “Size”
reviews whether the right amount of work is selected as per the productive capability of
crews and could be completed within the planned time frame. The last criterion,
“learning”, focuses on assessing whether the incomplete assignments are being tracked

with their causes.

This research has captured from the literature review of renovation projects that

uncertainty and dynamism form their primary characteristics that affect production

183

(Krizek et al. 1996, Mitropoulos 2002, Wayne et a1. 1988). These projects constantly
exhibit changing conditions, which could affect the reliability of workflow in their
production systems, even if the internal and external constraints have been assessed prior
to entering the assignments in lookahead schedule, and their execution plans have been
developed. As a result, in renovation projects, it becomes imperative for the last planner
to assess the quality of each Activity Execution Plan (AEP) developed in the previous
step of the framework, and to verify that the performance of AEP meets the required
quality criteria. The framework suggests employing the quality criteria of Last Planner
System TM including five dimensions, as proposed by Ballard and Howell. As all the five
dimensions of quality criteria are subjective in nature, their assessment could be done on

qualitative basis.

Therefore, as shown in Figure 4.6, for the purpose of improving the reliability of
workflow in renovation projects, this framework proposes a query node (Query Node-2)
after preparing the AEP that checks whether the plan meets the required quality criteria.
Being a qualitative assessment, the decision at this query node is a function of
evaluator’s/last planner’s past experience and knowledge in managing production of
renovation projects. If the answer to the query node is “no”, it means that either one or
more quality dimensions of the AEP i.e. definition, soundness, sequence, size, and
learning, does not satisfy the minimum requirements and the plan will not be released for
execution. In such case, as the Figure 4.4 depicts, the AEP should be sent backwards to
revisit its activity definition model for adequately matching the production assignment
and resource capacities. In the other case, the AEP should be forwarded to the backlog of

workable plans.

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4.6.8.2 Enter Activity Execution Plan in Workable Backlog

The workable backlog forms a part of the last planner system, as suggested by Ballard
and Howell (1997), where its objective is to maintain a backlog of sound assignments
that can be made ready for execution. Having assessed the quality of assignments, the
workable backlog assures that the assignments in workable backlog are realistic and
workable. The workable backlog is usually made for the upcoming assignments of 2

weeks (Ballard 2000, Howell et a1. 2002).

Therefore, once the quality of the Activity Execution Plan (AEP) is verified in the
previous step of the framework (if the answer is “yes” in query node-2), it should be
placed in a backlog of assignments, which the crew knows can be done in their estimated
production duration. Figure 4.6 shows the location of workable backlog in the
framework. This framework suggests that the size of workable backlog could be a
function of project characteristics and duration, as renovation projects could have short
durations also. Any AEP that forms a part of workable backlog provides assurance that
all the potential constraints, both internal and external, have been addressed and the
quality performance of the plan has been assessed from the five dimensions mentioned
above. Thus, any critical activity whose AEP is in the workable backlog can be made

ready to be performed by the crew.

4.6.9 Step-9 Production Performance Evaluation

After the activity execution, its production performance would be evaluated by

comparing the actual duration and revised production duration, as shown in Figure 4.7.

186

At the production level, the performance evaluation includes measuring the consistency
of work-flow between hand-offs. In this context, flow and quality of work delivered
between the trades are required to be measured after activity execution. Therefore, the
percentage of quality work delivered to the next trade and the percentage of planned
buffer used should also be measured. The production performance of any critical activity,
say selective demolition, would be expressed by the Activity Production Factor (APF),

explained as follows:

Activity Production Factor (APF) Selective demolition =

(Revised production duration/ Actual duration) + (% of quality work delivered to the next

trade/ 100) + (1- % of buffer) } / 3 equation 4.1

The three components of APF are shown in Figure 4.7. A desired value of APF for any
activity would always remain 1. As per the equation 4.1, an APF value of 1 means that
the activity finished within the revised production duration delivering 100% of quality
work to the next trade, and without using any percentage of time buffer initially planned.
In a renovation project, although, achieving an APF value of 1 could be a utopian
situation, but comparing APF with its desired value of 1 could determine the level of
underperformance in the production efficiency of a crew and apply the learning in further
activities. Therefore, the comparison between desired and actual values of APF would

provide a stretch goal to work towards continuous performance improvement.

187

—-- - -- ——- From- Perform Activity
Actual Duration '
of Activity '7 7

 

z’" “—7 —_" A # ‘# 7 - 1 - i — A J“— )- —_ i —_ i 1 IT“? ”—fi -—_“1
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, ‘ * Production I I

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of buffer .‘ V—v 91 -u—i Production Performance Assessment 1‘“? a
l l
1
1
1

 

How much %

[of quality work was, ~17 -~4 T0- Query Node 3
delivered '

 

Figure 4.7 Components of Production Performance

In order to release any work to the next trade, it is essential to verify that the
production performance of the completed work at least meets the minimum criterion in
regard to its APF value. Otherwise, the quality defects of the delivered work could get
unnoticed by the next crew and the delivered work would also affect the production of
the next activity, as it might first required to be reworked before the next crew begins to
work. This would impact the reliability of the work flow and generate more waste in the
production of next activities. Therefore, instead of delivering a defected work between
trades, it should be corrected at its source and then moving it further.

The fi'amework suggests a query node (Query Node-3) after the production
performance assessment to verify whether it meets the minimum criterion before
releasing it to the next trade. As shown in Figure 4.8, if the answer to the query node is
“no”, production failure analysis should be conducted and simultaneously, the work

should be redone, if needed. If the answer is “yes”, the work would be released to the

next trade, but the production failure analysis still needs to be conducted to improve the

188

production efficiency further. The process of how to conduct production failure analysis

is explained in the next section.

4.6.10 Step-10 Production Failure Analysis

A comparative analysis of Activity Production Factor (APF) of a critical activity with its
desired value of 1 could estimate the underperformance level of the activity and identify
those constraints that impacted the activity’s production. This process of ascertaining the
production underperformance levels along with their causes has been termed as
production failure analysis for this research. For instance, if APF of a critical activity
comes out as 0.7, this means that the crew fell approximately 30% short of completing
their production assignments within the estimated production duration, and of desired
quality. The 30% production failure could be attributed to either single or multiple
constraints.

In order to ascertain which constraints have resulted in production failure or poor
quality, the actual crew production should be documented on a daily basis against the
production schedule of Activity Execution Plan (AEP). Table 4.14 shows an example of
actual daily production of a demolition crew against the production schedule of its AEP.
The documentation of actual daily production would lead to a better understanding of
which project conditions have affected the production that were not accounted for in the
constraint assessment matrix.

For instance, in the example shown in Table 4.14, the comparison between
planned production and actual production documented for date “10-19-07” illustrates that

the temporary walls could not be uninstalled because of public traffic near construction

189

zone. This means that “traffic” constraint was either not properly assessed or ignored
during the constraint assessment process of production planning. It could also be
concluded that the weighted impact of traffic constraint on the production schedule of the
exemplified activity of “selective demolition of interior walls” was not established
through AHP of constraints and/or correlation matrix.

Therefore, the overall objective of conducting production failure analysis is to
direct better judgments for the assessment of constraints in future production planning for
similar activities. Thus, in Figure 4.6, the production failure analysis is preceded by a
feedback loop to the constraint assessment matrix that maintains a continuous learning
after each activity execution from its failure analysis, by improving the identification and

assessment of constraints.

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4.6.11 Summary of Developed Framework for Renovation Projects

The production management framework is developed from the literature review of state-
of—the-art performance measurement systems, renovation projects’ complexities, and
production management of construction processes. By linking the essential attributes of
production performance management in renovation projects, this framework presents a
detailed process of planning and assessing the production performance at the activity
level of renovation projects.

In addition to the literature review, the production management framework
incorporates the inputs for the essential attributes from the interview responses. For
instance, the interviewees were asked to identify project conditions of renovation projects
and critical construction activities. This response has facilitated in identifying any
additional constraint, project condition, and critical activities to be incorporated in the
essential attributes of the framework that could be applied to steps 1 through 5.

The production management process suggested by the framework is broadly
divided in two phases: production planning and production performance assessment.
Production planning of any construction activity involves constraint assessment based on
the hierarchy of constraints for that activity, while production performance assessment
involves assessing the production factor of critical activity based on its actual duration,
percentage of quality work delivered, and percentage of buffer used.

The following section presents a detailed demonstration of the developed

framework with an example of a construction activity in a renovation project.

193

4.7 Demonstration of the Framework

This demonstration example is hypothetical and has been assumed to be a part of interior
remodeling of an institutional building. The scope of work involves replacing 3500 sqfi
suspended ceiling assembly for an elevator lobby of an institutional building per a new
design. Under a negotiated contract, the contractor is required to replace existing ceiling
panels, cross tees, wire hangers, and wall moldings with newly designed ceiling
suspension system. If the existing structure does not have enough capacity to support new
design, the contractor would be required to work on its structural improvement.

The work is located in the elevator lobby of the building’s fourth floor. A
hypothetical plan of the lobby is shown in Figure 4.9. The lobby opens up into an
auditorium, opposite to the elevators. The fire exit stair is located on one side of the
elevator while on other side, faculty offices are located.

Prior to starting the work, the contractor has been asked to notify the owner of an
appropriate duration of the work as per the project conditions (stated in the contract) and

a list of special measures, furnished by the facilities management department.

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4.7.1 Scope of work and required Resources
Table 4.15 summarizes the major portions of work along with the required crew sizes and
their daily output. The contractor has referred to the Means Building Construction Cost

Data 2005 for obtaining the standard crew sizes and their daily outputs.

Table 4.15 Scope of Work and Required Resources

 

Scope of Work Crew Daily Output

 

1. Selective demolition of 2 laborers 720 sqft
ceiling panels on
suspension system,

including system

 

2. Installation of new

ceiling suspension system

 

 

 

 

 

a. Hanging wire, 12 ga., 4’ l carpenter 6500 sqfi
long

b. Carrier channels for 1 carpenter 460 sqft
ceilings with recessed

lighting fixtures

c. Install 2’x2’ grid panels, 1 carpenter 650 sqft
9/ 16” T bar

3. In case of asbestos 1 asbestos foreman 3500 sqft
presence, demolition of 7 asbestos workers

ceiling suspension system
in asbestos contaminated

area

 

 

 

196

 

4.7.2 Estimated Duration of Work

Initially, assuming that there are no constraints present, the contractor would calculate the
total duration of ceiling replacement activity based on the crew sizes and their daily
outputs mentioned above. The total duration of work would include:

1. Duration of selective demolition

Total quantity of work/7203qfi = 3500/ 720 sqfi = 5 days
2. Installation duration of new suspended ceiling system:

The contractor would use two carpenters for installing the new system, except for
hanging wires. For a crew of two carpenters, assuming that the crew productivity will be

decreased by 10%, the duration of installation activity will be:

Hanging wires- 3500/6500 sqft = 1 day

Carrier channels for ceilings- 3500 / (460x 2 — 10% of 460 x2) sqfi = 5 days
2’x2’ grid panels, 9/16” T bar- 3500 / (650x 2 — 10% of 650 x2) sqfi = 3 days
The total duration for installation of new ceiling suspension system = 9 days

In case the contractor encounters asbestos during ceiling demolition, asbestos abatement
crew would be used instead of two laborers and the duration of selective demolition of
ceiling suspension system will be 7 days ( 5 + 35005qfi/21005qfi per day). So the total

duration of work including demolition and installing new ceiling will be 16 days.

4.7.3 Assessment of Project Conditions & Identification of constraints
Before notifying the owner of the duration of this work as estimated above, the
contractor, on a project level, should assess the project conditions and special measures

for identifying potential constraints to be encountered during the replacement of the

197

ceiling system. Table 4.16 briefly summarizes project conditions and states the

constraints generated due to those conditions.

Table 4.16 Example Project Conditions and Constraints Generated

 

Project Conditions

Constraints

 

The work cannot take place from Noon to 8 on Monday through
Wednesday due to continuous class schedule conflicts in the
auditorium. For other weekdays, the contractor would have to take

extra care during class times.

-Coordination
-Schedule
- Physical

- Pollution

 

The contractor should coordinate the ceiling replacement activity
with an owner furnished sculpture to be installed in the middle of the
lobby.

- Coordination

- Physical

 

The faculty offices located next to the lifts imposes additional risk of
disrupting construction operations, and being disrupted due to
construction operations fiom 9am to 5pm during weekdays. The

contractor should take adequate measures for minimizing both.

-Coordination

 

The contractor cannot take over the entire lobby at one time, for
maintaining the students and faculty movement. The work should be
done in incremental phases and the contractor must always leave a 6
ft. wide continuous passageway to allow for the movement of

physically challenged individuals.

- Physical

 

There are no service elevators in the building and the contractor

cannot use public elevators for carrying materials and equipment.

-Traffic

 

 

For maintaining the continuous operations of the building, the
contractor cannot remove the suspended fixtures that include lights,
diffusers, and fire sprinklers during weekdays from 7am to 8pm.
During nights and weekends, when the diffuser is removed, open
ducts should be covered securely for preventing any dust or debris in

the air flow system.

 

-Utility

- Coordination

 

198

 

Table 4.16 (cont’d)

 

 

 

 

 

 

 

 

As the work is located in a lift lobby of an operational building, -Physical
storage space is not available for material or equipment. -Traffic

The original building was constructed in 1960, so the contractor -Uncertainty
might encounter asbestos after uncovering the ceiling.

After removing the ceiling, the contractor would check the structural -Regu1atory
specifications of the joists with current building standards.

The contractor should conduct a thorough site investigation before -Schedule
starting the work for developing an appropriate logistics plan. -Coordination
The flooring needs to be covered temporarily to avoid any possible -Coordination
damages due to erecting of scaffolds.

The contractor should incrementally remove the floor-mounted - Coordination
fumiture and reinstall them once the work is complete.

The contractor cannot block the fire exit and auditorium exits during - Physical
building operational time. - Traffic

 

 

4.8 Steps Suggested by the Framework

As suggested by the developed framework, the following section describes a step by step
procedure for production planning and assessment for the demonstrated ceiling
replacement work. The demonstration explains both approaches for production planning;
one considering each constraint independently without considering dependency

relationships between constraints, and the other considering the dependency relationships

and limiting the number of constraints in fiirther steps.

Figure 4.10 shows both approaches of demonstration in the framework. The
decision of “no” at the decision node results in the first approach, while the “yes”

decision resulted in the alternative approach of going through dependency relationships

and constraints reduction process.

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4.8.1 Step-1 Identification of Constraints & Critical Activities

The project conditions listed in Table 4.16 will result in the following constraints;
physical, utility, pollution, uncertainty, coordination, schedule, safety, traffic, and
regulatory. These constraints will impact the estimated duration of the major portions of
work, as the constraints will be encountered during their execution. These major portions
are the following critical activities; selective demolition of existing ceiling system, and

installation of ceiling suspension system.

4.8.2 Step-2 Mapping the Interdependency Relationships between Constraints
As step 2 is an optional step, the first approach does not consider this step and works

directly from step 3.

4.8.3 Step-3 Mapping the Impact Levels of Constraints on Estimated Production
Schedule of Critical Activities

The level of impact that each of these constraints will have on the estimated duration of
critical processes will be different. These different impact levels are required to be
mapped through correlation analysis. As stated before, this research considers five levels
of impact that a constraint could have on the duration of critical process: absolute, strong,
moderate, slight, and no impact. The correlation matrix (CM-1), shown in Table 4.17
maps the impact levels of each constraint on the estimated duration of each critical

process as per the project conditions.

201

Table 4.17 Correlation Matrix-1

Ceiling Ceiling suspension
onstraints removal Installation

1
llution

Schedule

A

A

M
N

A

S
SL
SL
S

oderate
o

 

4.8.4 Step-4 Identification of Weighted Impacts of Constraints on the Production
Schedule of Critical Activities

After obtaining the impact levels of constraints, their relative weights would be
established to understand their overall contribution to increased duration of the critical
activities. As the framework suggests, the hierarchy will be established through the
quantitative technique of Analytical Hierarchy Process (AHP). The AHP is required to be
performed for each critical activity involved in the scope of work because as per the
project conditions and correlation analysis, the contribution of constraints will change for
each critical activity. For instance, per the correlation analysis, the physical constraint has
a moderate and strong impact on the estimated duration of “selective demolition” and
“installation of ceiling system” activities respectively. Consequently, the hierarchy of
physical constraint for increasing the duration of “selective demolition” will be different

in case of “suspended ceiling installation”.

202

In the pair wise comparison of any two constraints in AHP, the assignment of relative

importance will be guided by the correlation matrix-1, as shown in Table 4.18.

Table 4.18 Mapping of AHP and Correlation Matrix-l Scales

 

 

 

 

 

 

 

 

 

 

 

 

Correlation Matrix Scale (CM 1) AHP
Constraint 1 Constraint 2 Definition Scale
{Importance of row
constraint (1) over
column constraint
(2)}
N N Equal Importance 1
SL SL
M M
S S
A A
SL N Weakly more 3
M SL
8 M
A S
M N Moderately more 5
S SL
A M
S N Strongly more 7
A SL
A N Absolutely more 9
N SL Weakly less 1/3
SL M
M S
S A
N M Moderately less 1/5
SL S
M A
N S Strongly less 1/7
SL A
N A Absolutely less 1/9

 

203

 

4.8.4.1 AHP for Selective Demolition of Ceiling System

Table 4.19 shows the AHP’s pair-wise comparison matrix of constraints for impacting
the estimated duration of selective demolition process. Each cell represents the
importance of a row constraint over column constraint. The importance scale for each
row constraint has been filled on the basis of the correlation matrix and Table 4.18. For
instance, physical constraint moderately impacts the estimated duration of selective
demolition while utility constraint strongly impacts its estimated duration. Therefore,
while comparing the importance of physical constraint over utility constraint, as per
Table 4.18, a scale of 1/3 (weakly less important) has been assigned to physical

constraint. Similarly, all other pair-wise comparison cells have been completed.

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Table 4.22 shows the final relative weights of constraints in impacting the duration of
selective demolition activity. However, there is a need to check the degree of consistency
in contractor’s judgments of pair-wise comparison. Saaty (1980) stated that perfect
consistency is impossible to achieve, but, a low consistency will result in inconsistent
results and therefore, all pair-wise judgments should be re-evaluated. Therefore, Saaty
(1980) proposed Consistency Ratio (CR) as a measure of consistency used in AHP. If the
value of consistency ratio exceeds 0.1, it signifies inconsistent judgments of the decision-
maker (contractor) in pair-wise comparison, which need to be revised (N assar 2005). The
value of CR depends on the value of Consistency Index (CI) which is defined as:
CI=Xmax—n/(n-l)
n = number of items being compared
9» max = maximum eigenvalue of the normalized comparison matrix
There are 3 steps to calculate 2» max;

1. In the pair-wise comparison matrix, multiply each column with the corresponding

final weight.

2. Divide the sum of rows with the corresponding final weights.

3. Compute the average of values from step 2 and denote it by k max,
The value of CR = Consistency Index (CI) / Random Index (RI)
Random index is the value of consistency index of a randomly generated pair-wise
comparison matrix for ‘n’ number of items. Based on the “11” value, the value of random

index should be obtained from Table 4.23 (N assar 2005).

207

Table 4.23 Random Index Values (Nassar 2005)

0171 121314 15 16 l7 319
[R1 [0 [0 I058 [0.9 [1.12 [1.24J132 11.41 [1.45 |

 

 

4.8.4.2 Consistency Measurement for AHP of Selective Demolition
Table 4.24 shows how to calculate the maximum eigenvalue of the normalized

comparison matrix 0» mm) for selective demolition activity.

Table 4.24 Multiplication of Pair-wise Comparison Matrix with Final Weights

'Physical '. ‘. j... . Regulatory E :
Physical ' . . . 1 . . . . . 5 0.078
Utility . 3 7 0.172
Pollution , ,. * 3 7 0.172
in,“ = Uncertainty - 1 5 X 0.078
Coordination 5 9 0.333
Schedule > I 5 0.078
Safety ., 1/3 3 0.035
Traffic 1 U3 3 0.035
Regulatory 1/5 I _ 0.019 __

 

 

 

 

From Table 4.24, 7» max = 9.321

CI = 9.321— 9 / (9 -1) = 0.0401

Value of RI is = 1.45 (for n= 9, from Table 4.23)

CR = 0.0401 / 1.45 = 0.028

The CR value of 0.028 (less than 0.1) signifies that the consistency in the pair-wise
comparison of constraints for the selective demolition activity was high and therefore,

there is no need to re-evaluate pair-wise judgments.

208

4.8.4.3 AHP for Installation of Ceiling Suspension System

Similar to the AHP of selective demolition, the pair-wise comparison matrix for
installation of ceiling suspension system, shown in Table 4.25, has been completed up on
the basis of Table 4.18 and the correlation analysis.

Table 4.28 shows the final weights of constraints in impacting the duration of ceiling

suspension system installation.

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4.8.4.4 Consistency Measurement for AHP of Installation of Ceiling Suspension
System
Table 4.29 shows how to calculate the maximum eigenvalue of the normalized

comparison matrix (7. max) for the activity of installation of ceiling suspension system.

Table 4.29 Multiplication of Pair-wise Comparison Matrix with Final Weights

Physical . . . . . Regulatory : :
Physical 1 . . . . . 3 0.221
Utility 1 . . . . . 3 0.221
Pollution 1/5 . . . . . 1/3 0.055
In,“ = Uncertainty 1/9 . . . . . 1/7 X 0.016
Coordination l . . . . . 3 0.221
Schedule 1/3 . . . . . 1 0.104
Safety In . . . . . 1/5 0.029
Traflie 1/7 , . . . . 1/5 0.029
Regulatory 1/3 . . . . . 1 _ 0.104 I

 

 

 

 

From Table 4.29, 9» max = 9.370

CI = 9.370 — 9 / (9 -1) = 0.0462

Value of R1 is = 1.45 (for n= 9, fiom Table 4.23)

CR = 0.0462/ 1.45 = 0.032

The CR value of 0.032 (less than 0.1) signifies that the consistency in the pair-wise
comparison of constraints for the activity of installation of ceiling suspension system was

high and therefore, there is no need to re-evaluate pair-wise judgments.

212

4.8.5 Step-5 Quantification of Additional Production Duration of Critical Activities
based on Project Conditions— Constraint Assessment Matrix (CAM)
As stated before, constraint assessment process primarily involves planning the additional
duration of critical activities after assessing project conditions, and applying the
established hierarchy of constraints to the additional duration based on assessment of
project conditions. The major factors that should be considered for planning the
additional duration of selective demolition activity, and installation of ceiling suspension
system activity, are:
1. Weighted impacts of constraints on the production duration of critical activities
2. Assessment of project conditions of all constraints for estimating the required
additional duration of critical activity

Table 4.30 shows the constraint assessment matrix (CAM) for selective
demolition activity. The assessment of each project condition for the selective demolition
activity has resulted in greater than or equal to 0 day additional duration. As suggested by
the framework, the total additional duration due to project conditions of each constraint is
added, and then multiplied by the constraint’s relative weight obtained through AHP.
Therefore, the additional duration due to the project conditions of each constraint is
normalized according to the relative importance of that constraint in impacting
production duration of selective demolition activity.

For each project condition whose assessment resulted in additional duration of
greater than 0 day, an explanation of assessment is provided in the right most column,
which provides information about the data relating to that condition. For the given

demonstration example, these explanations can be seen in Table 4.30 & 4.31, which have

213

 

been assumed for each critical activity. For obtaining a better understanding of the
assessment method of project conditions and the additional duration based on the
assessment, the reader of this thesis is suggested to go through their explanations of
assessment. This framework suggests completing this column of assessment explanation,
in order to document and employ them further in production planning of construction
activities under similar project conditions.

It could be seen in Table 4.30 that amongst all the constraints, coordination
constraint results in the highest value of additional duration of 2.5 days without its
normalization. This is in complement with the weighted impacts of constraints
established from AHP, as coordination constraint has the highest weighted impact of
0.333 on the production duration of selective demolition activity. Similarly, regulatory
constraint results in the least additional duration of 0 day without its normalization, and it
has the least weighted impact of 0.019 on the production duration of selective demolition
activity. Therefore, the weighted impacts of constraints, as established through AHP, are
the functions of the amount of additional duration resulted due to the assessment of their

project conditions.

4.8.5.1 Query Node-1

Assuming that all the constraints have been addressed for both critical activities,
the answer to the query node-1 will be “yes” and the production duration of critical
activities will be revised as follows.

The summation of normalized additional duration due to all constraints gives the

minimum additional duration (ADM-n) required for selective demolition activity.

214

However, the summation of additional duration due to project conditions of all
constraints without their normalization, gives the maximum additional duration (ADmax)
required for this activity, as shown below.

N
ADmin = 2(additional duration due to project conditions of each constraint) x W
i=1

N
ADM,x = 2(additional duration due to project conditions of each constraint)
i=1

Where,

N= Number of constraints

W = Relative weights of constraints for impacting production schedule of critical process

From Table 4.30,

ADmin (selective demolition) = (1 x 0.172) + (0.5 x 0.078) + (1.25 x 0.172) + (0.5 x
0.078) + (2.5 x 0.333) + (0 x 0.019) + (0.625 x 0.035) +
(0.5 x 0.078) + (0 x 0.035) = 1.358

= 2 days (approx.)

ADmax (selective demolition) = 1 + 0.5 + 1.25 + 0.5 + 2.5 + 0 + 0.625 + 0.5 + 0 = 6.875

= 7 days (approx.)
Therefore, the constraint assessment matrix shown in Table 4.30 has resulted into a range
of additional duration having a minimum and maximum value. The estimated additional

duration (BAD) would be a middle value of its range.

EAD = {(ADmm) + (ADm,,)} / 2 = (2 + 7) /2 = 4.5 or 5 days

215

The Revised Production Duration (RPD) for selective demolition activity, based on the
assessment of constraints would be:
RPD = Estimated duration (without consideration of constraints) + BAD

= 5 + 5 = 10 days

Similarly, for the installation of ceiling suspension system activity, Table 4.31
shows the CAM that lists the same project conditions and constraints, but the additional
duration resulted due to each project condition and the weighted impacts of constraints
have changed per the nature of critical activity.

For instance, the additional duration due to utility constraint for the activity of
selective demolition per Table 4.30 is 1 day and its weighted impact is 0.172. But, for the
installation of ceiling suspension system activity per Table 4.31, the additional duration
due to utility constraint is 2.9 days and its weighted impact is 0.221. The change in
additional duration and hierarchies are direct outcome of the nature of project conditions
and the critical activity itself, as the constraints’ impacts differ for each critical activity.
From Table 4.31,

ADmin (installation) = (2.9 x 0.221) + (2.85 x 0.221) + (1.25 x 0.055) + (O x 0.016) + (3 x
0.221) + (2 x 0.104) + (0.625 x 0.029) + (1.9 x 0.104) + (0 x 0.029)
= 2.424
= 3 days (approx.)
ADmax (selective demolition) = 2.9 + 2.85 + 1.25 + 0 + 3 + 2 + 0.625 + 1.9 + 0 = 14.525
= 15 days (approx.)
The estimated additional duration (EAD) would be a middle value of its range.

BAD = {(ADmm) + (AD...,,.)} / 2 = (3 + 15) /2 = 9 days

216

The Revised Production Duration (RPD) for installation of ceiling suspension system,

based on the assessment of constraints would be:

RPD = Estimated duration (without consideration of constraints) + OAD
=9+9=18mws

For the reader’s better understanding of the demonstration, the framework is reproduced

in Figure 4.9 which shows steps 1 through 10 of the demonstration including the query

nodes.

217

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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4.8.6 Alternate Approach to Production Planning using Dependency Relationships
between Constraints- Approach 2

As the framework suggests, an alternate approach to limit AHP calculations can be used.
This approach involves a correlation analysis carried out to ascertain the interdependency
levels between constraints. This approach would lead to limited number of constraints
which would simplify the correlation analysis of CM-l and AHP calculations, as
compared to previous approach. However, the accuracy of determining the additional
duration based on a limited number of constraints may result in error. This is considered
and explained in the current demonstration example.

The interdependency levels between constraints should be mapped for each critical
activity of the demonstration example, i.e., selective demolition of ceiling suspension,
and installation of new ceiling suspension system. The following section illustrates this
alternate method of production planning from steps 2 through 5 of the framework. These
4 steps have been explained again but considering the dependency relationships between
constraints, as in the first approach, these 4 steps did not consider dependency
relationships between constraints. From steps 6 through 10, as the procedure suggested
by the framework is same, therefore, steps 6 through 10 have been explained once,
considering the dependency relationships between constraints. To reiterate, the first five
steps suggested by the framework are:

1. Identification of constraints and critical activities

2. Mapping the interdependency relationships between constraints and reduce the

number of constraints- optional step

230

3. Mapping the impact levels of constraints on estimated production schedule of
critical activities

4. Identification of weighted impacts of constraints on the production schedule of
critical activities

5. Quantification of additional production duration of critical activities based on

project conditions

4.8.7 Step-1 Identification of Constraints and Critical Activities
As this step is common for both approaches, the constraints and critical processes would

remain same, as identified in section 4.8.1

4.8.8 Step-2 Mapping the Interdependency Relationships between Constraints

For the selective demolition activity, Table 4.32 shows the correlation analysis
through the correlation matrix-la (CM-1a) for selective demolition activity, which maps
the dependency level of each column constraint (ith.) on all row (ith.) constraints. The
dependency levels, shown below, are absolute, strong, moderate, slight, and none. Each
cell (36) in this matrix represents the dependency level of the jth. column constraint on
the ith. row constraint. For instance, cell a23 in the CM-la shown in Table 4.32, shows
that pollution constraint is moderately dependent on the utility constraint. A negative sign
prior to the dependency level indicates a reverse dependency of row constraint on column
constraint. For instance, for cell an, the negative sign before ‘M’ indicates that instead of
utility constraint (column) being moderately dependent on physical constraint (row),

physical constraint (row) is moderately dependent on utility constraint (column).

231

In order to provide the reader a clearer understanding of the correlation matrix
(CM-la) between constraints, as shown in Table 4.32, for the selective demolition
activity, the following section discusses dependencies of first column constraint

(physical) on all row constraints.

4.8.8.1 Dependency level of Physical constraint (first column) on all other
constraints (rows) for Selective Demolition Activity
1. Utility constraint- Moderate dependency

Due to the presence of existing services above ceiling, the physical space required
to remove existing hanging wires and channels, will not be adequate, and due to this
limited space, the risk of disrupting utilities increases while replacing the ceiling
assembly, even if the task does not require any shuts down of services. Therefore,
physical constraint is moderately dependent on utility constraint.
2. Pollution control- Strong dependency

The ceiling demolition activity needs to be executed in a temporary enclosure to
avoid the transmission of dust, debris, noise, and odor being generated, to other areas.
Thus, given that the activity is to be done in incremental phases while not blocking any
fire exits, auditorium entry, and maintaining at least 6’ wide passageway implies that
erection of temporary enclosure for controlling pollution would impose a strong physical
constraint on the contractor.
3. Uncertainty constraint- Slight dependency

The limitation of physical space for construction does not necessarily mean that

there are possibilities of encountering unforeseen conditions, but simultaneously it could

232

have a slight relationship with the execution of construction in a limited space. For
instance, the loading capacity per unit area of the floor might not allow all the trades to
work at the same time, in the temporary enclosure.
4. Coordination constraint- Strong dependency

Due to the existing operations of the building, the contractor cannot take over the
entire lobby at one time. This imposes a strong physical constraint for carrying out
phased demolition.
5. Schedule constraint- No dependency

The time buffers, or any non-work period would not impact the physical space
required for demolition activity. However, the productivity of crews might be strongly
affected due to phased construction in limited space. Therefore, physical constraint is not
dependent on schedule constraint but, due to the productivity loss, schedule constraint is
moderately dependent on physical constraint.
6. Safety constraint — Moderate dependency

In this operational building, the contractor bears the risk of injuring any visitor,
and the contractor would have to incorporate all tools, material, and equipment within the
temporary enclosure. This further limits the available space for construction.
7. Traffic constraint- Strong dependency

Due to limited physical space, the maneuvering and shifting of scaffold from one
location to another in conjunction with the building users’ continuous movement in the
lift lobby would require more time than estimated.

8. Regulatory constraint- No dependency

233

In the given case, the building codes do not seem to impact physical space
required for construction, material storage or site access.

Similarly, for installation of ceiling suspension system activity, Table 4.33 shows
the correlation analysis through CM-la, which maps the dependency level of each
column constraint on all row constraints. It could be seen that due to the change in the
scope of work and project conditions, the dependency levels mapped in Table 4.32 for the
selective demolition activity have been changed in Table 4.33 for the installation activity.

For instance, in Table 4.33, in the cell am, the dependency level of schedule
constraint on the physical constraint has changed from “moderate” to “absolute”. This is
due to the fact that the installation activity requires transitory storage and handling of new
materials in the temporary enclosures of all five phases, limiting the physical space
available to crew which will eventually affect its productivity. In addition, due to the
limited physical space for material storage in the elevator lobby, all material will be
stored on the ground floor. In the absence of a service elevator, this will increase the
cycle time to get the material to the fourth floor through the staircase, which might

increase the wait time of the labor for installing new material.

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4.8.9 Reduction of Number of Constraints Based on Interdependency Levels-
Constraints Reduction Process

After conducting correlation analysis between constraints for both critical activities, the
dependency levels should be reviewed to identify maximum degree of relationships
(absolute dependency) between constraints. Based on maximum degree of relationship,
all those column constraints having absolute dependency over other row constraints could
be removed from further CM-l analysis and AHP calculations. If a column constraint has
an absolute dependency on row constraint, it could be represented by the row constraint
CM-l analysis and AHP calculations. For instance, in Table 4.32, utility constraint is
absolutely dependent on coordination constraint for the ceiling demolition activity, which
leads to the consideration of coordination constraint, as a representative of utility
constraint, in CM-l and AHP. Therefore, utility constraint would not be considered for
obtaining the hierarchy of constraints in impacting the duration of ceiling demolition
activity, as the weightage of coordination constraint would be inclusive of the weight of
utility constraint.

Using the correlation matrix-1a shown in Table 4.32 for the selective demolition activity,
Table 4.34 was constructed. Table 4.34 shows that 4 constraints could be eliminated from
further steps due to their absolute dependencies on 3 other constraints. Therefore, for
performing further steps of the framework, only 5 constraints could be considered instead

of 9.

236

Similarly, using the CM-la shown in Table 4.33 for installation of ceiling suspension

system, Table 4.35 was derived. Table 4.35 shows that 5 constraints could be removed

further.

Table 4.34 Constraint Reduction for Selective Demolition

 

Constraint to be Removed

Representative Constraint

 

 

 

 

 

Utility Coordination

Schedule Coordination
Safety Pollution

Regulatory Uncertainty

 

 

Table 4.35 Constraint Reduction for Ceiling Installation

 

Constraint to be Removed

Representative Constraint

 

 

 

 

 

 

Utility Coordination

Schedule Coordination
Safety Physical
Traffic Physical

Regulatory Uncertainty

 

 

 

 

 

4.8.10 Step-3 Mapping the Impact Levels of Reduced Number of Constraints on
Estimated Production Duration of Selective Demolition

This section reiterates the correlation analysis between constraints and their impact on the
duration of critical activities, based on the correlation analysis conducted in the first
approach. Table 4.36 shows this analysis through CM-l for the selective demolition
activity. It should be noted that those constraints, which are representing other constraints
in this matrix, have increased their impact levels because of the additional impact of their

dependent constraints, as compared to their individual impacts in CM-l, shown in Table

237

4.17. Table 4.17 has been recreated below for an easier comparison between the impact

levels of constraint in this Table and Table 4.36.

Table 4.17 Correlation Matrix-l for Approach-1

Demolition- Ceiling Ceiling suspension
onstraints removal Installation

Schedule

lute
Moderate '
. = N

 

Table 4.36 Correlation Matrix-l for Selective Demolition based on Reduced Number of

 

 

 

 

 

 

 

 

Constraints

Critical Processes
Demolition- Ceiling

Constraints assembly removal
Physical M
Pollution S
Uncertainty S
Coordination A
Traffic SL
Egend

 

Absolute impact =A, Strong impact = S
Moderate impact = M, Slight impact = SL
No impact = N

 

 

 

 

 

Similarly, Table 4.37 shows the correlation analysis between constraints and their impact

on the duration of installation of ceiling suspension system, based on the correlation

238

analysis conducted in CM-la, Table 4.33. As stated before, it should be noted that those
constraints, which are representing other constraints in CM—2, have increased their impact
levels because of the additional impact of their dependent constraints, as compared to

their individual impacts in CM-l shown in Table 4.17.

Table 4.37 Correlation Matrix-1 for Ceiling Installation

 

 

 

 

 

 

 

 

 

 

 

 

Critical Processes

Ceiling suspension
Constraints system Installation
Plysical A
Pollution S
Uncertainty M
Coordination A
Legend
Absolute impact =A Strongirnpact = S
Moderate impact = M Slight Impact = SL
No impact = N

 

4.8.11 Step-4 Identification of Weighted Impacts of Reduced Number of Constraints
on the Production Schedule of Critical Activities
The weighted impacts of reduced number of constraints, obtained from CM-la, on the
production duration of selective demolition activity, should be established using AHP in
the similar manner as represented in the first approach (section 4.8.4). It should be noted
that after having conducted the correlation analysis through CM-la, only limited number
of constraints including the representative ones would be considered in AHP.

As stated before, the pair-wise comparison matrix of constraints should be filled
with reference to CM-l conducted in Table 4.36 and 4.37, and the integrated scale of

AHP and CM-l shown in Table 4.18.

239

Tables 4.38 through 4.40 show the AHP calculations for obtaining the relative

importance of 5 constraints in impacting the production schedule of selective demolition.

Table 4.38 Pair-wise Comparison Matrix

  

 

"J-‘Physioale-iiPIsiluiiénIf ' " __ .__f fjfj
Physical”'_",__ _. 1 1/3. 1/5 3
Poirot-ion ' 3 1 1 1/3 5
[A] = Uncertainty 3 l I 1/3 5
Cooricirim ' 5 3 3 1 7
Tan-to 1/3 1/5 1/5 1/7 1

 

Table 4.39 Pair-wise Comparison Matrix (Decimal Form)

   

 

physicail’oltutmn . . " *
0.333
I
[A] = 1
3
0.200
Table 4.40 Normalization Matrix
[A1 =

 

 

Table 4.41 Final weights

[W]: Physical Pollution Uncertainty Coordination Traflic
0.088 0.202 0.202 0.464 0.043

240

Table 4.41 shows the final weights of constraints in impacting the production schedule of

selective demolition of ceiling suspension system.

Similarly, Tables 4.42 through 4.44 show the AHP calculations for obtaining the

relative importance of 4 constraints in impacting the production schedule of installation

of ceiling suspension system.

[A] =

 

[A] =

 

[A] =

 

Table 4.42 Pair-wise Comparison Matrix

" Physical Pollution“. -' ~ Confirm on
Physical .“~‘::»_'.-." 1
Pollution a 1/3 1 1/3
Unoemunty , 1/5 1/3 1/5
Coordination: ,. - l 3 l

 

Table 4.43 Pair-wise Comparison Matrix (Decimal Form)

. 7 Physical-3 Pound-In"), -UI'Ifomai'myj: ; cam-110311011;
Physical , .p . , 3 l
Pollutior‘rf _ 0.333 1 3 0.333
Uncertainty 0.200 0.333 1 0.200
coordination 1 3 5 1

Table 4.44 Normalization Matrix
T-Physioal. t-Pollution ' . ~2g.eoordixiatiori-
Physical 0.395 0.409 0.357 0.395
Pollution , . 0.131 0.136 0.214 0.131
Uncertainty 0.079 0.045 0.071 0.079
Coordination 0.395 0.409 0.357 0.395

241

Table 4.45 Final weights

Physical Pollution Uncertainty Coordination
[W]= 0.389 0.153 0.068 0.389

Table 4.45 shows the final weights of constraints in impacting the production schedule of

installation of ceiling suspension system.

4.8.11.1 Consistency Measurement for AHP of Selective Demolition
Table 4.46 shows how to calculate the maximum eigenvalue of the normalized
comparison matrix (9» max ) for selective demolition activity.

For reader’s reference, Table 4.23 of random index values is recreated below.

Table 4.46 Multiplication of Pair-wise Comparison Matrix with Final Weights

 

 

 

 

 

 

‘ ’ Physical '. . . Trafic'
| Physical l . . . 3 0.088
Pollution ' " 3 5 0.202
2. m, = Uncertainty _ 3 . . . 5 X 0202
Coordination 5 7 0.464
Traffic -. ' 1/3 1 0.043
Table 4.23 Random Index Values (Nassar 2005)
N 1 2 3 4 5 6 7 8 9
RI 0 0 0.58 0.9 1.12 1.24 1.32 1.41 1.45

 

 

 

 

 

 

 

 

 

 

 

 

From Table 4.46, )- max = 5.129

or: 5.129 — 5 / (5 -1) = 0.032

242

Value ole is = 1.12 (for n= 5, from Table 4.23)

CR = 0.032 / 1.12 = 0.029

The CR value of 0.029 (less than 0.1) signifies that the consistency in the pair-wise
comparison of constraints for the selective demolition activity was high and therefore,

there is no need to re-evaluate pair-wise judgments.

4.8.11.2 Consistency Measurement for AHP of Installation of Ceiling Suspension
System

Table 4.47 shows how to calculate the maximum eigenvalue of the normalized
comparison matrix (2» max) for installation of ceiling suspension system.

Table 4.47 Multiplication of Pair-wise Comparison Matrix with Final Weights

 

 

Physical . . . Coordination
Physical 1 . . 1 0389
Pollution 1/3 . . 1/3 0.153
3...,“ = Uncertainty 1/5 . . 1/5 X 0.068
Coordination 5 . . 1 0.389

 

 

 

From Table 4.47, k max = 4.043

CI = 4.043 — 4 / (4 -1) = 0.014

Value of RI is = 0.9 (for n= 4, from Table 4.23)

CR = 0.014/ 0.9 = 0.016

The CR value of 0.016 (less than 0.1) signifies that the consistency in the pair-wise
comparison of constraints for the activity of installation of ceiling suspension system was

high and therefore, there is no need to re-evaluate pair-wise judgments.

243

4.8.12 Step-5 Quantification of Additional Production Duration of Critical Activities
based on Project Conditions- Constraint Assessment Matrix (CAM)
Similar to the constraint assessment matrix (CAM) demonstrated for all the constraints in
section 4.8.5, this section also involves assessing the project conditions of all constraints
for estimating the additional duration of critical activities. As stated in the framework
discussion, there are two main deviations in the CAM of second approach, which are:
1. Normalizing the estimated additional duration based on the relative weights of
constraints, obtained from CM-la and constraint removal process.
2. Those constraints which were observed to be absolutely dependent on others, the
estimated additional duration due to their project conditions should be added to
the additional duration due to their representative constraints.
Based on these deviations, Tables 4.48 and 4.49 show the CAM for selective demolition
and ceiling installation activity, respectively, in which the dependent constraints have
been assigned a relative weight of 0 and all other constraints’ weightages have been
obtained from AHP conducted in the previous step. In these constraint assessment
matrices shown in Tables 4.48 and 4.49, the calculations for obtaining additional duration
are similar to those conducted in the first approach.
4.8.12.1 Query Node-1

Assuming that all the constraints have been addressed for both critical activities,
the answer to the query node-1 would be “yes” and the production duration of critical
activities would be revised as follows.

From Table 4.48,

ADmin (selective demolition) = (0.5 x 0.088) + (1.25 x 0.202) + (0.5 x 0.202) + (4 x

244

 

 

0.464) + (0.625 x 0.043) = 2.28

= 3 days (approx.)
ADmax (selective demolition) = 0.5 + 1.25 + 0.5 + 4 + 0.625 = 6.875

= 7 days (approx.)
Therefore, the constraint assessment matrix shown in Table 4.48 has resulted into a range
of additional duration for selective demolition activity, having a minimum and maximum
value. An estimated additional duration (EAD) would be a middle value of its range.

BAD = {(ADmIn) + (ADmax)} / 2 = (3 + 7) /2 = 5 days
The Revised Production Duration (RPD) for selective demolition activity, based on the
assessment of reduced number of constraints would be:
RPD = Estimated duration (without consideration of constraints) + EAD
= 5 + 5 = 10 days
Similarly, from Table 4.49 for ceiling installation activity,
ADmin (installation) = (3.47 x 0.389) + (1.25 x 0.153) + (2 x 0.068) + (5.9 x 0.389)
= 3.972 = 4 days (approx.)

ADmax (installation) = 3.47 + 1.25 + 2 + 5.9 = 14.525

= 15 days (approx.)
An estimated additional duration (EAD) would be a middle value of its range.

EAD = {(ADmin) + (AD-n30} /2 = (4 + 15) /2 = 9.5 or 10 days

The Revised Production Duration (RPD) for installation of ceiling suspension system,
based on the assessment of reduced number of constraints would be:
RPD = Estimated duration (without consideration of constraints) + EAD

=9+10=19days

245

It could be seen that in the second approach, while calculating the ADmin and ADM,x for
both critical activities, only reduced nrunber of constraints are considered, involving
those, which are either representatives of other constraints or which are not absolutely

dependent on any other constraint.

246

 

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4.8.13 Comparison between Approach 1 and 2
Both approaches have resulted in similar value of the maximum additional duration for
both critical activities. However, second approach results in a greater value of minimum
additional duration as compared to the first one. For instance, approach-1 resulted in
minimum additional duration of 2 days for selective demolition activity, while approach-
2 resulted in 3 days of minimum additional duration. Similarly, for ceiling installation
activity, approach-l resulted in 4 minimum additional days, while approach-2 resulted in
3 days. These differences of 1 and 2 days indicate that the incorporation of constraints
interdependencies in the constraint assessment process will result in more additional
duration to critical activities. The correlation analysis between constraints provides a
more comprehensive method for planning the additional duration. Therefore, approach-2
should be preferable over approach-l.

For the remaining steps of demonstration (fi'om steps 6 through 10), the additional
duration resulted from approach-2 is considered as the one that the contractor will plan
for. In addition, for the purpose of avoiding any complexities in the reader’s

understanding, only selective demolition activity is considered for the following steps.

4.8.14 Step-6 Enter and Move Production Assignments in Lookahead Schedule

The lookahead schedule would be prepared by the contractor afier assessing the impacts
of constraints and revising the duration of critical activities. Therefore, this schedule
would maintain a reliable workflow between trades, as all the constraints’ impacts have

been considered.

266

Table 4.50 shows the lookahead schedule for the first three weeks of the
demonstration example. This table is created on the template of lookahead schedule as
suggested by Ballard (2000) in the explanation of the Last Planner System. In the
lookahead schedule, the critical activities are broken down further to define their sub-
activities on day-to-day level, and the sub-activities of each week would be advanced

forward as they are being considered for further steps of the framework.

Table 4.50 Example of Lookahead Schedule for the Demonstration

 

9/3/2007 9I1 0I2007 9/1 7/2007

 

 

 

Activity MTWTFSS MTWTFSS MTWTFSS

 

Demolition Crew
(Selective Demolition)

 

Site Investigation X

 

Work on Phase-1 X X X

 

Work on Phase-2 X X

 

Remove and reinstall
fixtures X

 

Work on Phase-3 X

 

><><

Work on Phase-4

 

XX

Work on Phase-5

 

 

 

Ceiling Installation
Crew (Installation)

 

Work on Phase-l X X X X X

 

Work on Phase-2 X X X X

 

 

 

 

 

 

4.8.15 Step-7 Match Production Assignments and Resource Capacities

In this step, the four external constraints would be analyzed with regard to the scope of
work of each critical activity and its revised production duration (RPD) in order to create
a balance between the RPD and available resources. The external constraints are;

prerequisite work, available resources, directives, and maximum time buffer. Each

267

activity would be selected from the lookahead schedule for the analysis of its external
constraints, as the work proceeds on site.

This research assumes that the prerequisite work and planned resources (2
laborers) are available for the selective demolition activity. In addition, for executing the
activity, clear directives in terms of project conditions and specifications are provided in
the contract and design drawings. From the constraint assessment matrix of selective

demolition activity (Table 4.48), the maximum time buffer available is as follows.

Maximum Time buffer = AD max - EAD = 7 — 5 = 2 days (From Table 4.48)

As the available buffer is 20% of the production duration (10 days) of selective
demolition activity, this constraint would not require any additional resources to expedite

the activity.

Based on the review of external constraints, it is assumed that there would be no
need to adjust either resources or production duration of selective demolition activity, and

its execution plan could be constructed in the next step.

4.8.16 Step-8 Activity Execution Plan

The contractor would prepare an Activity Execution Plan (AEP) after estimating the
revised production duration of each critical activity and balancing it with the review of
external constraints. As suggested by the framework, the AEP would stipulate the
planned resources, revised production duration, estimated work quantity, maximum time

buffer, and prerequisite work.

268

Table 4.51 shows the AEP for selective demolition of ceiling system that the
contractor would prepare before starting demolition activity as a proactive measure of
planning its production in the presence of constraints. This plan reflects the production
schedule that lists the crew production assignments on daily basis that were established
on the basis of constraint analysis and revised production duration. By keeping track of
daily production assignments, the contractor could minimize the wait time between the

selective demolition and installation activities.

This plan would be directly communicated with the demolition crew on daily
basis in order to make it aware of the production assignments, which are to be completed
on the current day, and which are expected to complete on the next day. Thus, this
activity execution plan would provide guidance for executing the selective demolition

activity by planning and controlling daily production assignments.

4.8.16.1 Query Node-2

It is assumed that the developed AEP for selective demolition activity meets the
quality criteria of definition, soundness, sequence, and size. Being the first activity, the
fifih criterion of “learning” does not apply to it. Therefore, at the query node-2 of the
framework, the contractor would answer “yes”, and the selective demolition activity

would be performed on site.

269

Table 4.51 Activity Execution Plan for Selective Demolition Activity

 

 

 

ctlvity Selective Demolition of Ceiling System
Preguisite Work None

 

Planned Resources

1 Foreman, 2Labors

 

Estimated Quantity

3500 sqft (5 Phases)

 

Critical Activity

Selective Demolition

 

Optimum Schedule

0903-07 to 09-12-07

 

Optimum Production Duration

10 Days

 

Maximum Buffer

2 Days (tiII 09-14-07)

 

Instaflafian of Ceiling Suspension System scheduled to be started

 

 

Next Activity on 09-13-07
[Eroductlon Schedule _
Days Production Assignment

 

09-03-07 - Monday

The crew forman will conduct a thorough site investigation and an
inspection might be conducted by the Hazardous material
abatement team.

 

09-04-07 - Tuesday

Floor mounted fixtures will be uninstalled and stored on the
ground floor.Crew will install temporary walls around Phase-1 and
work on demolition tilI Noon.

 

09-05—07 - Wednesday

Work on demolition of Phase-1 ti—II Noon.

 

 

09—06-07 - Thursday

Finish Phase-1 demolition and uninstall temporary walls around
Phase-1 and re-install around Phase-2 and start demolition of
Phase-2.

 

09-07-07 - Friday

Finish demolition of Phase-2.

 

|09-08-07 - Saturday

Remove and reinstall fixtures for all Phases from 1 to 5 .

 

I09-09-07 - Sunday

Install temporary walls around Phase-3 and start demolition.

 

09-10-07 - Monday

Finish demolition of Phase-3, uninstall temporary walls and
reinstall around Phase-4 till Noon.

 

09-11-07 - Tuesday

Finish Phase-4 demolition and uninstall temporary walls around
Phase-4 and re-install around Phase-5 and work on demolition of
Phase-5 till Noon.

 

 

09-12-07 - Wednesday

 

Finish Phase -5 demolition and uninstall temporary walls

 

 

270

4.8.17 Step-9 Production Performance Evaluation
After executing the work on site, the contractor would evaluate the production
performance of each critical activity by comparing its actual and revised production
duration. As suggested by the framework, the production evaluation should also include
the quality of workflow between hand-offs and the utilization of planned buffer.
Assuming that the selective demolition activity was completed in 11 days, it has
used 50% of its maximum time buffer (2 days). However, the demolition was done
consistently with drawings and specifications, without any reworks. Therefore, the
quality of work delivered to ceiling installation crew was 100%. The production
performance of selective demolition activity would be evaluated in terms of its

production factor, as shown below.

Activity Production Factor (APF) Selective demolition = (Revised production duration/ Actual
duration) + (% of quality work delivered to the next trade/ 100) + (1- % of buffer) } / 3

= [(10 days /11 days) + (100/100) + (1-05)] /3 = 0.803

As the quality of work of selective demolition activity was 100%, it could be handed off
to the ceiling installation crew without any rework.
Similarly, production performance of ceiling installation activity could be

evaluated. The maximum planned buffer for this activity was:

Maximum Time buffer = AD max - EAD = 15 — 10 = 5 days (From Table 4.49)

271

Assuming that ceiling installation was completed in 21 days, its activity production factor
would be:
Activity Production Factor (APF) Ceiling installation = (Revised production duration/ Actual
duration) + (% of quality work delivered to the next trade/100) + (1- % of buffer) } / 3
= [(19 days /21 days) + (90/100) + (1-2/5)] /3 = 0.801
Although, the ceiling installation activity used 10% less amount of maximum time buffer
as compared to selective demolition activity, but given that 10% of the installed ceiling
system was found to be unacceptable on inspection, its activity production factor resulted
as similar to that of selective demolition activity.
4.8.17.1 Query Node-3

Based on the assumption that the planned minimum performance criterion for the
selective demolition activity was 0.9 APF, the contractor would conduct a production
failure analysis after answering “no” at the query node-3 of the framework, and
simultaneously release the work to the next trade without any rework. It is assumed that
the criterion of achieving 0.9 APF was decided based on the subjective judgment of the
contractor per its past experience of performing demolition activities under similar

project conditions.

4.8.18 Step-10 Production Failure Analysis

Based on the values of APFs of critical activities, the contractor would conduct a
production failure analysis to understand the causes of production delay and apply it in
future constraint assessment processes. In comparing the actual APFs of critical activities

with the desired APF value of 1, it could be observed that both crews fell approximately

272

20% short of completing their production assignments within revised duration and of
desired quality. The 20% production failure could be attributed to either single or
multiple constraints. If the contractor had documented actual crew productions against
the production schedule of AEP on daily basis, the causes of production delay or poor
quality could be explored. Therefore, one of the methods of performing production
failure analysis could be to document daily production and compare and analyze it
against the production schedule.

Table 4.52 shows the actual daily production of demolition crew against the
production schedule of its AEP. The daily production documentation shows that the
demolition crew took more time than estimated in uninstalling the floor mounted fixtures
in the lift lobby, and transporting them to the storage room located on ground floor. The
labor foreman reported that the immense student and faculty traffic in the stairways, due
to the continuous class schedule, resulted in decreased crew productivity.

In addition, it was reported that the production of Phase-3, being located next to
the auditorium was not appropriately planned in consideration with the class schedules in
auditorium. As the crew could not block the auditorium exits till Noon, the crew had to
uninstall the temporary walls and re-install them around Phase-4.

The actual production documentation justifies that the contractor did not give
much importance to coordination and traffic constraints while planning the production of
selective demolition activity. The contractor should have strategically located all the

phases, not only in floor plan but also according to the class schedule and public traffic.

273

 

      

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274

4.9 Framework Verification

The verification of the developed framework for production management of renovation
projects forms the last phase of this research. The purpose of conducting verification was
to understand the usefulness, and identify the limitations and improvement areas of the

framework for its appropriate application to renovation projects.

4.9.1 Verification Procedure

The verification of the developed framework was conducted by obtaining construction
professionals’ views regarding the proposed production planning and assessment
methods. The researcher selected a project engineer, a superintendent, and a project
manager as interviewees from a mid-size construction company. This company primarily
works as a general contractor, and had completed over $3 billion worth of projects with
an average annual volume $130 million. The company had experience in institutional,
health care, commercial, and hospitality sectors, both for new construction and
renovation work. The interviewed project manager and superintendent had an average
experience of 7 to 9 years of working on renovation projects, while the project engineer
had 2 years of experience in new construction projects.

The verification process was conducted in a group session involving all
interviewees. Interview questions for verification were not drafted, as an Open-ended
discussion was essential for reaching on consensus regarding the improvement areas and
usefulness of the framework. In order to explain the framework to the interviewees, the
researcher first presented its demonstration, discussing each suggested step in detail. All

the matrices and quantitative calculations such as RPD, APF etc. were explained with

275

hypothetical facts and figures. The demonstration was similar to what has been presented
in Phase-4 of this research. Based on the demonstration of framework, the interviewees
were asked to provide their feedback in a formal discussion. Overall, the verification

process was completed in a 4 hours session.

4.9.2 Verification Findings
The interviewees acknowledged that the developed framework involves a comprehensive
process of production planning, execution, and assessment and it can be used as a vital
tool by construction professionals for managing renovation projects. However, the
interviewees found the fi'amework to be time consuming, as it involves numerous steps,
which could limit its application in managing smaller renovation projects. In addition, in
smaller projects, the indirect cost associated with implementing the framework could
increase the overall budget of the contractor. Therefore, the interviewees suggested that
for smaller projects, a miniature or a compact form of the framework should be
developed by combining some of the time consuming steps. Nonetheless, for larger
projects, the interviewees agreed that the number of steps as suggested by the developed
framework should be undertaken, as the constraints and project conditions become
significant and may have a considerable impact on the project cost, time, and quality.
Therefore, the time spent in implementing the fi'amework steps and its associated indirect
cost could be offset in larger renovation projects by improving the production
performance of construction crews and completing the project on time and within budget.
Another major observation found in the verification was that the implementation

of the framework requires a close coordination of all trade subcontractors for performing

276

most of the suggested steps. For instance, while filling out correlation matrix-1 (CM 1),
in order to identify the impact level of “coordination” constraint on the schedule of an
activity involving mechanical system replacement, a proper communication and feedback
is required from the HVAC, plumbing, electrical, and fire-protection subcontractors. This
coordination can become an arduous task for a project manager or a project engineer
working for the general contractor who is conducting the framework steps, as
subcontractors might not be available through out the required steps or may not show
interests. Therefore, the interviewees suggested that the process of fi'amework
implementation should be formalized by including it in the subcontract conditions of
major trade contractors such as HV AC, plumbing, electrical etc., which would make the
framework application more effective by involving major subcontractors during the
construction process.

At the micro level, the interviewees also recommended on the qualitative
measurement methods of the project conditions of constraints, as proposed by the
framework. According to the interviewees, the assessment of project conditions is
function of the experience and judgment of the evaluator, and thus the measurement
methods would change from person to person and project to project. Therefore, in case of
qualitative assessment of project conditions, it would become difficult to strictly follow a
definitive set of measurement methods as suggested by the fi'amework. However, the
interviewees agreed that irrespective of the measurement methods, the project conditions
should be measured in order to ascertain the additional duration of critical activities due

to the impact of constraints generated from them. Thus, the interviewees consented on the

277

overall process of assessing project conditions in the “constraint assessment matrix”
(CAM) of the framework.

At the macro level of the framework, the interviewees commented on managing
the cost aspect of production assignments also, in addition to their schedule. The
interviewees stated that in most of the cases of renovation projects, as the owner’s budget
is limited, production performance of crews should be assessed from the perspective of
budget management also. This should entail assessing the impact of constraints on the
cost of production assignments for preparing an accurate cost estimate for renovation
projects so that the cost impacts can be planned for. As stated by the interviewees, time
and cost should go hand in hand when managing daily production in the presence of
constraints. Therefore, the budget and schedule of production assignments should be
planned simultaneously by thorough consideration of constraints and the production
performance of construction crews should be assessed accordingly. Thus, the
interviewees suggested using an integrated approach where the framework can be used to
manage time and cost impacts of constraints on the production assignments.

Overall, the interviewees stated that the developed framework covered most of the
essential attributes of a production management system for renovation projects and the
exemplified constraints, their project conditions, and critical activities were encountered
in actual practice also. Having reviewed the framework demonstration, the interviewees
stated that a separate production management system should be in place for renovation
projects, as they involve greater complexities, risk and uncertainty, as compared to new

construction projects. In regard of this view, the interviewees stated that the developed

278

framework presented a detailed approach to renovation project management as it suggests

a systematic method for production planning, execution and assessment.

4.10 Chapter Summary

This chapter discusses the interview procedure including the interview questions, data
collection process, and synthesis of the collected data. Further, a stepwise development of
the framework for production management of renovation projects is discussed. This
chapter brings forward the significance of essential attributes identified from literature
review in formulating the construct of the framework. This chapter also explains how the
framework adopted some of the components of the Last Planner System TM of production

control for production planning in renovation projects.

Further, a detailed demonstration of the developed framework with an example of
a suspended ceiling replacement work in an operational institution is discussed. Having
explained each step of the framework with hypothetical facts and figures, the
demonstration example provides guidance for how to apply the suggested steps of the
framework to production planning, execution, and control in renovation projects. The
demonstration illustrated the use of quantitative tools such as AHP and correlation
analysis for production planning, as suggested by the framework. In the demonstration, it
was found that the consideration of dependency relationships between constraints,
through approach-2 in production planning provided a better estimate of production

duration of critical activities.

279

Overall, the demonstration exemplified that the developed framework could be
employed in renovation projects, given the fact that the subjective assessments of
constraints and their project conditions in CM-l, CM-la, and CAM are based on
evaluator’s prior knowledge and experience in managing renovation projects. However,
considering that renovation projects exhibit constantly changing conditions, the overall
process suggested by the framework should be constantly updated for each critical
activity. Although, the demonstration example was completely hypothetical, but it can be
observed that the framework resulted in a production schedule, which “can” be
implemented based on a thorough analysis and assessment of constraints with regard to
the project conditions and scope of work, rather than what “should” be done as per the
initial estimate of work duration based on the Means Building Construction Cost Data

2005.

As the final phase of this research, the chapter explains how the researcher
conducted the verification process of the framework through a second round of interview,
and discusses the findings regarding framework’s limitations and usefulness for its

application to renovation projects.

280

CHAPTER-5

SUMMARY AND CONCLUSIONS

281

5.1 Introduction

As a concluding part of this thesis, chapter-5 provides an overview of this research and its
major findings along with a brief discussion of how the goals and objectives were
accomplished. This chapter also discusses the limitations of this research and other future

research based on those limitations.

5.2 Research Overview

This research provided a framework for production management of renovation
projects which was constructed based on the literature review and verified through
interviews of contractors. To reiterate, the last four chapters are briefly discussed below
explaining how this framework was constructed.

Chapter 1 presented the current problems of renovation projects that lead to
schedule and cost ovemms, and discussed the need for their production management in
addition to the traditional performance measurement. Based on the need statement, this
chapter stated the overall goal and objectives of this research along with its scope, and the
potential benefits that might be achieved with the research goal accomplishment. In
addition, chapter 1 defined what production management meant in the context of
renovation projects for this research.

Chapter 2 provided a detailed account to some of the past researches in the field
of state-of-the-art construction performance measurement systems, renovation projects,
and production management. In this chapter, the research has extensively reviewed
performance indicators and measurement methods of state-of-the-art performance

measurement systems for their application to production management of renovation

282

projects. Production management methods such as Last Planner System prevalent in the
construction industry are also discussed for their significance in the developed
framework. From the literature of renovation projects, chapter-2 provided an insight to
some of the constraints encountered in renovation projects that mostly inhibit the
schedule and budget performance. These constraints were identified by past researches
that focused on renovation projects. Overall, chapter 2 provided the essential attributes
from literature review which were used in the development of a framework for
production management of renovation projects.

Chapter 3 explained a five phased methodology that was adopted to accomplish
the research goal and objectives based on the literature review and contractors’ and
subcontractors’ interviews. Each phase was discussed in detail to explain what was done,
and how did it contribute to achieving the research objectives. This chapter also
underscored the need for reviewing literature in the categories of state-of-the-art
construction performance measurement systems, renovation projects, and production
management. The procedure adopted for conducting contractors’ and subcontractors’
interviews is also discussed.

Chapter 4 represented the main contribution of this research as it documented and
discussed the data collected from interviews of contractors and subcontractors, and
conducted its analysis in context of the framework. Therefore, chapter 2 and the initial
part of chapter 4 were instrumental in achieving the first objective, which was to
document state-of-the-art construction performance measurement systems and production

management practices for renovation projects.

283

In addition, chapter 4 explained a stepwise development of a fi'amework for
production management of renovation projects. A thorough discussion of how to conduct
each step suggested by the framework is presented in this chapter. In order to provide a
better understanding of the framework, this chapter presented its detailed demonstration
with a hypothetical example of a construction activity of renovation project. In the end,
this chapter discussed the procedure adopted for verification of the developed framework
through second round of interview with contractors, and its results.

Building upon the understanding gained in the last four chapters, chapter-5 draws
major conclusions based on the key observations found in the literature review and the
interviews. Prior to discussing the conclusions, the fulfillment of research goal and

objectives is discussed.

5.3 Research Goal and Objectives
The overall goal of this research was to develop a framework for production management
of renovation projects. In order to achieve this goal, two objectives were proposed in
chapter 1, which are:
1. Document state-of-the-art construction performance measurement systems and
production management practices for renovation projects.
2. Develop a framework for planning, execution and performance assessment of
production operations of renovation projects.
Objective 1 was partly achieved by reviewing the literature of state-of-the-art
construction performance measurement systems, renovation projects, and production

management, and partly by conducting interviews of contractors and subcontractors for

284

identifying their production management practices in renovation projects. Both literature
review and interviews provided the essential attributes that were considered for
developing a framework for production management of renovation projects. Some of
these essential attributes are; constraints, critical activities, performance indicators,
measurement methods, performance categories, performance failure analysis etc.

Based on these essential attributes, the research drafted interview questions to be
asked from contractors and subcontractors. The interview responses facilitated in
identifying any additional essential attributes of production management currently in
practice for renovation projects. Therefore, this research documented the state-of-the-art
performance measurement systems and production management practices in terms of
literature review, in chapter 2, and interview data analysis in chapter 4.

In order to attain objective 2, based on the literature review, the essential attributes
were analyzed to identify appropriate links between them so that they result in a
comprehensive process of production planning, execution, and assessment for renovation
projects that could be implemented through a framework. The primary essential attributes
in developing this framework were the constraints and critical activities of renovation
projects, which were mostly identified in the literature review, and the interviews, to
some extent. The developed framework suggested a number steps to be performed in
renovation projects, where the first few steps required analyzing the project conditions
and their resultant constraints for production planning and execution, while others
entailed production control technique including production performance assessment and

production failure analysis.

285

Quantitative techniques such as AHP and correlation analysis were applied to the
framework so that the impact of constraints on the critical activities could be quantified
and therefore, planned for. Although, this research focused only on the schedule impacts
for limiting the complexity levels of the thesis, the framework could be further adopted
and modified for identifying the budget and quality impacts also.

Therefore, objective 2 was achieved by developing a framework from essential
attributes identified from the first objective, and demonstrating it with a hypothetical
example of construction activity in a renovation project. The demonstration played a
major role in achieving this objective as it exemplified each step of the framework with
theoretical facts and figures, and provided clear directions for conducting each step,
which could be applied to different construction activities under varying project

conditions of renovation projects.

5.4 Conclusions and Inferences

This section discusses the conclusions drawn from the literature review, interviews of
contractors and subcontractors, and the feedback obtained on the developed framework of
production management for renovation projects. The literature of renovation projects and
the interviews emphasized the significance of constraints in the growing
underperformance of renovation projects, as compared to new construction. Most of the
project conditions and constraints stated in literature that lead to budget and schedule
overruns were also reported by the interviewees to be encountered in actual practice.
These potential constraints of renovation projects involve uncertainty, dynamic nature,

physical space, coordination with owner’s operations, traffic, and safety which impact

286

time, cost and quality performance. Therefore, they require a thorough consideration
before planning crew assignments. As the state-of-the-art construction performance
measurement systems mainly focus on assessing performance of construction projects in
three categories of cost, time, and quality, it becomes imperative to investigate the
impacts of constraints on the cost, time, and quality performance of renovation projects.

Although, the reviewed performance measurement systems proposed different
sets of performance indicators for assessing the performance in the three categories
mentioned above, but a consensus has not been arrived at the most appropriate set of
performance indicators that define the actual performance of construction projects and
identify the sources of inefficiencies. In addition, some of the reviewed researches
focused on developing different performance measurement methods but each of them had
certain limitations and the most suitable performance measurement methods have not
been concluded.

In addition, the reviewed state-of-the-art performance measurement systems do
not involve the assessment methods for the constraints and/or project conditions
encountered in renovation projects. Consequently, state-of-the-systems will find limited
application in assessing the performance of renovation projects at the activity level.
Therefore, to assess the performance of renovation projects, an appropriate set of
performance indicators need to be investigated that can assess the impact of constraints
on the cost, time, and quality of construction activities.

Despite the complex, uncertain, and dynamic nature of renovation projects, unlike
new construction, the interviews of contractors and subcontractors revealed that there are

no perceived differences in performance assessment methods for new construction and

287

renovation projects. The critical success factors, measurement methods, and their
hierarchies were reported to be same in the interviews for both new construction and
renovation projects. Due to the uncertainty and other numerous constraints involved in
renovation projects, the literature of production management underscores the importance
of production planning and performance assessment through the use of operational level
indicators such as percentage of plan completed (PPC). However, the critical success
factors reported in the interviews were on a very broad level of the project such as
quality, under budget, repeat business, and client satisfaction. None of the respondents
reported a success factor or performance indicator for renovation projects that deal with
the production level. Moreover, the respondents did not state constraint management as a
critical success factor for renovation projects.

As the increasing cost and schedule overruns of renovation projects is an
aftermath of constraints’ impacts on the construction activities, performance
measurement of renovation projects should be handled at the activity level where the
constraints generate their impacts. Performance planning and assessment at the activity
level will identify the causes of inefficiencies at their sources and improve the
performance at project level. Therefore, production planning should be undertaken by
analyzing all constraints in establishing suitable crew assignments and the performance
should be assessed by using operational level indicators. Nonetheless, this research
concluded that currently, the analysis of project conditions and constraints of renovation
projects is done in an informal basis. There is a lack of formalized and documented

procedure for assessing the constraints in production planning of renovation projects.

288

This is also exemplified by the fact the researcher did not obtain a documented process
map of establishing crew assignments from any of the interviewees.

The data collected from interviews and literature review underscored the need for
developing a formalized process of production planning and assessment of renovation
projects. This process should consider the impact of constraints on the production of
construction activities in the categories of their cost, time, and quality. In this view, the
developed framework presented one of the processes for production management of
renovation projects by suggesting a number of steps to be undertaken. Due to time
limitations for conducting this research, as the developed framework focused on
assessing only the schedule impacts of constraints, the verification process concluded that

their cost impacts on the production should also be incorporated.

5.5 Research Benefits and Contribution

As identified by previous researchers, performance in renovation projects is
typically lower than new construction projects due to the challenges and risks imposed by
various constraints inherent in project conditions (McKim et al. 2000, Attalla et a1. 2003).
This research has developed methods to quantify the impacts of these constraints on
production schedule of construction activities, which can be employed by project teams
in planning for these constraints, and improve the schedule performance of renovation
projects.

As there has been a lack of research in production management of renovation
projects, this research contributes to their construction management practices by

delivering a framework for improving their schedule performance. This framework can

289

be adopted as a measurement tool by construction professionals for self-assessment, for
meeting owners’ requirements, and improving production planning techniques. It can be
employed by end-users or owners for evaluating the production performance of
contractors in renovation projects. The framework can also aid contractors in assessing
the production performance of subcontractors.

In addition to the framework’s application to production management in new
renovation projects, the developed framework can be used to review the health of an
ongoing renovation project by evaluating its production performance and assessing the
effectiveness of production planning techniques being undertaken. This can be achieved
by measuring the Activity Production Factor (APF) of various critical activities in an
ongoing project and comparing it with what the project teams desired to be.

This research presents a new and comprehensive approach for production
planning of renovation projects that involves unique methods to arrive at the Revised
Production Duration (RPD) of critical activities after assessment of possible constraints.
In addition, the research proposes a thorough assessment method of production
performance through the Activity Production Factor (APF). The APF incorporates usage
of production level performance indicators such as the percentage of quality work
delivered to the next trade, and the usage of planned buffer. As the reviewed state-of-the-
art construction performance measurement systems do not suggest any production
performance indicators specifically for renovation projects, the APF surfaces as a major
contribution of the framework in production performance assessment. In addition, the

proposed qualitative and quantitative assessment methods of project conditions of

290

constraints can assist state-of-the-art performance measurement systems to develop
performance indicators for assessing production performance in renovation projects.

Another significant contribution of this thesis is the way researcher investigated
the application of state-of-the-art construction performance measurement systems to
renovation projects by constructing a graphical interface between their essential
attributes. Similar investigation has not been covered by the reviewed literature for the
performance measurement of renovation projects. The constructed interface can be
adopted as a potential research area to conduct further analysis for better application of
state-of-the-art performance measurement systems to renovation projects for assessing
and improving their cost, time, quality, and safety performance.

With the growing underperformance of renovation projects, this research can be
employed in an outreach effort to engage contractors and other construction professionals
in collaborative work sessions for disseminating efficient production planning and
assessment techniques for renovation projects. On an educational front, this outreach
effort would drive construction organizations to share best practices and different ideas
regarding production planning of renovation projects, and develop better methods to cope
with the encountered constraints. The developed fiamework can serve as a common
platform in these collaborative sessions where construction professionals can explore
firrther research areas in production management of renovation projects for improving
their performance levels.

This research will primarily benefit public owners and governmental agencies due
to their major involvement in renovation of institutional and commercial buildings

(B eatham et al. 2003, Attalla et al. 2003). The framework will facilitate owners’

291

understanding of production management systems of contractors, and would equip the
owners in acquainting themselves with the metrics for evaluating contractors’ production
performance or verifying the performance measurement methods implemented by

contractors in renovation projects.

5.6 Future Areas of Research
Building upon the findings from the framework verification, this research proposes two
areas that can be investigated in production management of renovation projects making
the framework more applicable.

As observed in the verification, further research is required for assessing the cost
and quality impact of constraints on the production of renovation projects. The developed
framework could be modified to incorporate the production planning, execution, and
assessment methods focusing on the cost and quality of production also. This will lead to
a better cost estimate at the activity level and identify the indirect and direct costs
associated with the coping of constraints in renovation projects. This will involve
investigating the assessment methods of project conditions of constraints for estimating
the additional cost involved in completing an activity at the desired quality in the
presence of constraints. For instance, for the demonstration example discussed in
Chapter-4, the developed framework could be modified to plan the direct and indirect
cost involved in completing the demonstrated activity under the specified project
conditions and constraints. Accordingly, research is required to develop assessment
methods for measuring production performance of crew from the cost and quality

standpoints. In addition, the interdependencies between constraints in impacting cost and

292

quality of construction activities should be explored which will lead to identifying the
constraints’ hierarchies in impacting the cost and quality of different activities.

As a second potential area of research, a simulated approach could be investigated
for the developed framework that can reduce the time consumed in performing the
suggested steps. This will involve modeling all the suggested steps of the framework by
developing a template that would require variables of constraints depending on the
project conditions. These variables will involve the constraints’ interdependencies,
constraints’ hierarchies in impacting the cost, time, and quality, and the assessment
methods of project conditions for estimating the schedule and cost of the production. By
changing the variables for different critical activities, the simulation model would make
predictions regarding the additional duration and cost associated with coping of
constraints that will facilitate in production planning. The simulation could be done on

stroboscope software or as a mote Carlo simulation model.

5.7 Chapter Summary

This chapter concludes this research by discussing how the research goal and objectives
were achieved, summarizing what was done in the previous chapters, and presenting the
final conclusions of the thesis. The chapter also suggests two major areas for fiirther

investigation in production management of renovation projects.

293

APPENDICES

294

APPENDIX-l
INTERVIEW RESPONSES

Contractors' Responses
(Abdelhamid et al. 2007)

 

No.

 

Questions

1

Responses

 

Vendor Performance Assessment Questions

VP2 Define in your own terms project succes
(critical success factors), i.e. what is

successful project to
Is this same for renovation projects?

you

rorta eprOJe . ntrme . wner
satisfaction 4. Vendor satisfaction
Yes

 

When it meets and exceeds all of client's
expectations. Profit is not the main aim of the
firm

Yes, both are client driven.

 

When the end user is happy, the company
makes profit and no one gets hurt.

Yes (it is more invasive when owner is
occupying the premises)

 

For a successful project we consider following
factors fulfilled: A Happy Owner, future work,
On schedule, Good relationships. Make profit.
Good quality product. Add value to the life of
entity, negotiate more work.

Yes

 

A successful project is which is done on time.
its on budget (which makes owner happy),
should have a good profit margin

Yes.

 

 

Schedule completion, Within Budget, Owner
completely satisfied with process and product.
Yes

 

VP3

 

How should each of these critical succes
factors be measured

Is this same for renovation projects?

1. Profit - By money made, measured through
cost accounting. Usually. the company profit

and overhead should be 2% for major projects
which is accrued . 2. Time- by dates specified
on schedule 3. 8. 4 Owner vendor staisfaction-

by communication
Yes, but the performance is measured to a

lesser extent due to more unknowns that
affect the production. For instance, there are
lesser fixed dates in the schedule. The
contractor carries contingency for his use but
the contingency is generally higher for
renovation projects as compared to new
construction.

 

If the firm is able to build lasting relationships;
repeat business is the key.
Yes

 

 

Ask feedback from end user. We have a ISO-
certified customer satisfaction survey form.
Yes

 

 

295

 

APPENDIX-l (cont'd)

 

We measure it through reputation in the
market. customer feedback survey, repeat
business is a huge measure.

Yes

 

All need equal attention.
Yes

 

We interview the owner at the end. For longer
projects we interview them every 6 months.
Yes

 

VP4I

 

Do critical success factors remaln constant for Yes
all project types Yes
Is this same for renovation projects? :93

es

 

Yes, for projects over $100K. factors are
critically looked at.
Yes

 

Yes
Yes

 

Yes
Yes

 

Yes
Yes

 

 

VP11

Do you use the same evaluation form for
renovation projects? Explain why or why not.

Yes we use the same evaluation because the
criteria don't change.

 

Yes, but only for projects above $100K.

 

Yes

 

VP17

 

form should be filled more often than new

Do you think that for renovation projects the

We do it at the end, we don't do mid-stream
review.

 

construction projects? Explain why or why not

No. because we get feedback informally from
the user during the job.

 

No, we treat them the same way.

 

 

VP3

 

If you develop a form, what factors would you
look to evaluate?
Is this same for renovation projects?

Change order rate, -R-l'=-l rate. Meeting
attendance, working style of personnel, safety
etc.

 

Yes

 

Quality, Safety records. Interaction w/ owner,
timeliness, attentiveness and responsiveness

 

Yes

money, whether their submittals are approved
quickly, work is done on time. We would use it

 

 

Yes

 

RP1 I

 

Renovation Pro|ects Questions

For your key trade, does your organization
have a formal process for planning day-to-day
construction activities and establishing crew
assignments on renovation projects? If yes,
can we obtain a copy of that? If no, can you
descrlbe the informal process in your own
words?

The VP in charge of field operations assigns
crews or self performed work through
communication with superintendent. It is hard
to forecast the required manpower in
renovation projects on daily basis.

 

 

Yes we have it. But since it is proprietary, we
cant share it with you.

 

 

296

APPENDIX-l (cont'd)

 

No there is no formal process. One person
schedules the crew on a daily basis.

 

Yes. a copy is provided for your reference.
The VP of filed operations assigns crew to
superintendent and the superintendent
assigns crew to tasks. This process happens
in every Thursday meeting.

 

We have no formal process. The foreman is
responsible for assigning tasks to the crew
everyday. Even the truck drivers are made
responsible for all the tools at site.

 

Yes, if it is a big even like hoisting equipment.
But we don’t have it for daily activity.

 

RPZ

What project conditions do you experience In
renovation projects that impact the estimated
budget, schedule, and quality the most?

Inadequate design. Concealed conditions,
Poor as-built drawings

 

Unforeseen conditions, Presence of Haardous
materials, Suitability of infrastructure to
accommodate project requirements.
Dimensional analysis of design (proper survey
is a must before design as it causes maximurr
roblems).

 

Differing site conditions, often the site doesn't
match the construction documents supplied to
us.

 

Unforeseen Conditions, Design-Build method
works really well for us in renovation projects.

 

Irregularities in plans, specs, omissions.
if the facility is occupied by the owner, that

causes more time. Unknowns on the site also
cause delay.

 

RP3

How and when do you identify/address these
project conditlons as they relate to daily crew
assignments?

We try to identify as early as possible and planr
for them. We use the lessons learned from
previous renovation projects. We
communicate with the superintendent and
identify important details.

 

As soon as they come up.

 

Make adjustments as needed, shift work as
needed between projects. (Shifting of man
power)

 

We address these issues daily, but if the
performance is scheduled for following week
then we assign it every Thursday.

 

The foreman contacts the Project Manager if
necessary.

 

Plan as best as we can. Do it hands on

 

 

RP4

 

Is the crew foreman responsible for addressing Primarily, the foreman or superintendent and

these project conditions? lf not. who Is?

then the Project manager gets alerted.

 

Superintendent is responsible for assessing
the conditions and giving constructable
solutions.

 

Yes, we have a working foreman, or
sometimes the PM.

 

Yes, he does it on thursdays for the coming
week

 

The foreman is responsible.

 

 

 

297

APPENDIX-1 (cont'd)

 

Yes, they have certain responsibility to get it
done, but if those conditions entail change in
cost, schedule then the responsibility go to P“

 

IRP5

 

 

Which construction processes (e.g., mobilize,
demobilize, demolition, hazardous material

abatement, demolition waste management etc.)
impact the schedule performance of renovatior
projects the most?

Hazardous material abatement, Demolition,

Duct-workz Flooring, Finishes etc.

abatement, 2. Managing unforeseen
conditions. Mobilization and demobilization
are treated as part of usual mangement.

 

Hazardous material abatement that is not

 

azardous Material Abatement, ln MSU
arkigq is a mblem

 

emobilization due to 'ob disru fion at site.

 

emomron,Uemo rrza Ion. aza ous
material abatement is usually well planned so

 

 

that is not a problem.

 

298

APPENDIX-1 (cont'd)

Subcontractors' Responses
(Abdelhamid et al. 2007)

 

No. Questions 1 Responses

 

 

Vendor Performance Assessment Questions

 

VP2 Define in your own terms project success - INS I09 rojects 0" “"19me
(critical success factors), i.e. what is aand 3-HaDPY owners

 

successful project to you? Yes .

Is this same for renovation projects? That the owner should be happy, prOject
completed in time, make profit
Yes

 

customer satisfaction, profit, learning from
project, better relationship.
Yes

 

The critical success factors for any job would
be a good Profit margin, high level of owner
satisfaction. no repair calls, lack of warranty
issues.

Yes

 

VP3 How should each of these critical success Measurement of on-time and within budget is

factors be measured? pretty black and white, but customer

is this same for renovation projects? satisfaction is diffiCUlt to measure which I am

not sure of. We might have done some phone
surveys in the past.

Yes

 

For owner satisfaction talk personally to the
client; and money
Yes

 

By conducting surveys with CM, 6.0.
Yes

 

Repeat business, relationship with owner
yes

 

VP4 Do critical success factors remain constant for Yes
all project types? Yes

 

lls this same for renovation projects? \Y/es
es

 

Yes
Yes

 

Yes
Yes

 

 

VP32 If you develop a form, what factors would you
look to evaluate? 1. Met Schedule, 2. Being a WBE itself, we

Is this same for renovation projects? would also look for a vendor which is minority
company (MBE & WBE), 3. Quality of work, 4.
Responsiveness, and 5. Value added.

Yes

 

That the material is delivered on time.
competitive pricing, and quality.
Yes

 

Quality, Cost, and Delivery time. Will obtain
feedback from personnel
Yes

 

Quality of work, Size of contractor
(manpower), Type of work
Yes

 

 

 

 

299

APPENDIX-l (cont'd)

a formal process for planning day-to-day
construction activities and establishing crew
assignments on renovation projects? If yes,
can we obtain a copy of that? If no, can you
describe the informal process in your own
words?

Renovation Projects Questions

For your key trade, does your organization have There is not a formal process. We conduct

 

 

evaluations on project basis such as type and
size. Evaluations are conducted on daily basis
which includes; what areas are we working on
and other trades working on to avoid any
clash.

 

No formal process in place. Foreman
meetings take place to assign projects to
personnel, ordering of materials, procurement
of projects.

 

we only have an informal process in place, too
much formal is a waste of time. We use daily
log reports which are required by the CM at
times.

 

Yes we do have formal process for planning
but that is not on a day to day basis, but
atleast 3 days in advance. The PM discusses
with suprintendent and foreman to assign crew
and coordinates so that material and
equipment reach on site before labor.

 

What project conditions do you experience in
renovation projects that impact the estimated
budget. schedule, and quality the most?

IRP3 lHow and when do you identify/address these

project conditions as they relate to daily crew
assignments?

   
 
   

  

1.Unforeseen conditions. 2. concealed things
or something embedded such as above ceiling
or in the walls, and 3. in monor works, to make
something look good or of better quality so
that it does not look out of place (aesthetics
maintenance
The location of the project creates difficult
situation like ground floor or the 10th storey.
For example in a swimming pool project, to
re ir leaks concrete slab is cut u .
Undoing of the old installations which effects
ets schedules.

Unknown items mostly impact the project.
We address these conditions daily (first thing
in the morning). As these projects are very
dynamic. we handle them as the changes
occur.

 

   

 
   

   
     

 

According to the qualifications of the guy who
ou are sendin to work.

React accordingly to the situation on a daily
basis. Wait for an answer from owner through
RF l.

The foreman writes the RFls to NE to
communicate project conditions or we often do
it ourselves.

  
 
   
   

  

 

 

 

is the crew foreman responsible for addressing
these project conditions? If not. who Is?

 

Primarily, yes, the foreman is responsible. but
it’s a team effort also.
Yes

 

 

Yes

 

 

 

Yes, the foreman is responsible

 

300

 

APPENDIX—l (cont'd)

 

RPS

 

Which construction processes (e.g., mobilize,
demobilize, demolition, hazardous material
abatement, demolition waste management etc.)
impact the schedule performance of renovation
projects the most?

1. Demolition, 2. Hazardous materials
abatement, and 3. Taking care of not to

damage existing things.
e time bereen demolition and mobrlrzalron

create an impact, getting the right tools to right
people is troublesome. Also anything outside
the normalfloject scope has an impact.

 

azardous material abatement, identifying it
prior to construction.

 

 

abatement

 

 

301

APPENDIX 2

Analytical Hierarchy Process

Analytical Hierarchy Process (AHP) is a proven decision making technique, developed
by Thomas Saaty in 1980 for setting priorities of multiple objectives in a hierarchical
structure. AHP facilitates assessment, prioritization, and selection of multiple objectives
for different alternatives by providing their overall ranking. It reduces complex decisions
to a series of pair wise comparisons that synthesize the ranking of multiple objectives.
Being recognized as an appropriate technique for making complex decisions in teams,
AHP incorporates both subjective and objective assessment of each criterion, and checks
the consistency throughout the assessment (Saaty 1980, Nassar 2005).

An example of a typical AHP application process is explained below. This example does
not relate to any real project and all the judgments are assumed for the purpose of
explaining each step of AHP.

Assume that there are five objectives of a construction project which are required to be
ranked in their contribution to overall project performance. These five objectives are:
Objective 1 (0]) = on time

Objective 2 (02) = within budget

Objective 3 (03) = desired quality

Objective 4 (04) = safety

Objective 5 (05) = functionality

A pair wise comparison matrix of five rows (I]-5) and five columns 01-5) is formed for the
four objectives, where the number in each cell (aij) represents the relative importance of

the row objective (0,) over the column objective (Oj). The number in each cell is

302

assigned based on the importance scales of AHP developed by Saaty (1980). The

importance scale is shown in Table l. The pair wise comparison matrix of five objectives

is shown in Table 2 where each cell (aij) represents the importance of row objective over

column objective. For instance, the assignment of “1/3” to cell an represents that

“objective 1” is weakly less important than “objective 2”. Similarly, the assignment of

“5” to cell as represents that “objective 2” is moderately more important than “objective

5”. It should be noted that in the pair wise comparison matrix, the left most column and

‘6'?’

the top most row that list the objectives are excluded from 1 to 5 numbering of 1 rows

6"9’

and j columns.

Table 1 Scale of Importance Levels in AHP (Saaty 1980)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Scale Definitionflmportance of row constraint
over column constraint}
1 Equal Importance
3 Weakly more
5 Moderately more
7 Strongly more
9 Absolutely more
1/3 Weakly less
1/5 Moderately less
1/7 Strongly less
1/9 Absolutely less
Table 2 Pair-wise Comparison Matrix
or 02 03 04 05 _
01 1 1/3 1/3 1/5 3
02 3 r 1 1/3 5
[A] = 03 3 r 1 1/3 5
04 5 3 3 I 7
05 1/3 1/5 1/5 1/7 1
...J

 

 

 

303

 

The pair-wise comparison matrix shown in Table 1 is converted to its decimal form as

shown in Table 3 where the fractions are converted to their decimal forms.

Table 3 Pair-wise Comparison Matrix (Decimal Form)

r__
or 02 03 .04 , 05*
01 1 0.333 0.333 0.200 3
02 3 1 1 0.333 5
[A] = 03 3 1 1 0.333 5
04 5 3 3 1 7
05 0.333 0.200 0.200 0.142 1

 

The next step is to normalize the pair wise matrix shown in Table 3 by normalizing the
weight assigned to each cell. The formula for normalizing the weights is; compute the
sum of each column and then divide the scale assignment in each cell by that sum. The
normalization matrix is shown in Table 4.

For instance, in Table 4, the value of cell an is normalized as:

1/ (1+3+3+5+0.333) = 0.081

Similarly, for cell an, the normalized value is calculated as:

0.333/ (0.333+1+1+3+0.200) = 0.060

Table 4 Normalization Matrix

01 02 03 04 05
01 0.081 0.060 0.060 0.100 0.143
02 0.243 0.181 0.181 0.166 0.238
[A] = 03 0.243 0.18] 0.181 0.166 0.238
04 0.405 0.542 0.542 0.498 0.333
05 0.027 0.036 0.036 0.071 0.048

 

304

Once the normalization matrix is prepared, the final weights of objectives are obtained by
averaging the sum of each row. For instance, the final weight of “objective 1” is
calculated as:

(0.081+0.060+0.060+0.l00+0.143)/5 = 0.088

Similarly, final weights of other objectives are calculated. The final weights are shown in

Table 5.

Table 5 Final Weights

[W]= or 02 03 04 05
0.088 0.202 0.202 0.464 0.043

Table 5 shows the final relative weights of five objectives in contribution to the overall
project performance. However, there is a need to check the degree of consistency in
evaluators’ judgments of pair-wise comparison. Saaty (1980) stated that perfect
consistency is impossible to achieve, but, a low consistency will result in inconsistent
results and therefore, all pair-wise judgments should be re-evaluated. Therefore, Saaty
(1980) proposed Consistency Ratio (CR) as a measure of consistency used in AHP. If the
value of consistency ratio exceeds 0.1, it signifies inconsistent judgments of the decision-
maker (contractor) in pair-wise comparison, which need to be revised (Nassar 2005). The
value of CR depends on the value of Consistency Index (CI) which is defined as:

CI = k max —n / (n-l)

n = number of items being compared

k max = maximum eigenvalue of the normalized comparison matrix

There are 3 steps to calculate 7» max;

305

 

1. In the pair-wise comparison matrix, multiply each column with the corresponding
final weight.
2. Divide the sum of rows with the corresponding final weights.
3. Compute the average of values from step 2 and denote it by it max,
The value of CR = Consistency Index (CI) / Random Index (RI)
Random index is the value of consistency index of a randomly generated pair-wise
comparison matrix for ‘n’ number of items. Based on the “11” value, the value of random

index should be obtained fi'om Table 6 (Nassar 2005).

Table 6 Random Index Values (Nassar 2005)

N 3 4 5 6 7 8 9
RI 0 0 0.58 0.9 1.12 1.24 1.32 1.41 1.45

 

—s
N

 

 

 

 

 

 

 

 

 

 

 

 

 

Table 7 shows how to calculate the maximum eigenvalue of the normalized comparison

matrix (2. max ) for five objectives.

Table 7 Multiplication of Pair-wise Comparison Matrix with Final Weights

 

 

 

 

 

 

V or 02 I: :
01".} 1 3 0.088
02 . _~ 3 5 0.202
km“ = 03 , 3 5 X 0.202
04- 5 7 0.464
05 1/3 1 __ 0.043 _

 

From Table 7, k max = 5.129
CI = 5.129 — 5 / (5 -1) = 0.032

Value of R1 is = 1.12 (for n= 5, from Table 6)

306

CR = 0.032/1.12 = 0.029

The CR value of 0.029 (less than 0.1) signifies that the consistency in the pair-wise
comparison of five objectives for project performance was high and therefore, there is no
need to re-evaluate pair-wise judgments.

Thus, the final hierarchy of five objectives in contributing to the overall project
performance, as obtained through the AHP is:

Objective 4 = Safety = 0.464

Objective 2 = Within budget = 0.202

Objective 3 = Desired quality = 0.202

Objective 1 = On time = 0.088

Objective 5 = Functionality = 0.043

307

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308

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