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THE DESIGN.AND CONSTRUCTION
of the
LOGAN STREET VIADUCT, LANSING;MICHIGAN

Submitted to
Michigan State College
as a

Thesis for the Degree of Civil Engineer
by

1'""
Collins Thornton

Spring 1933

TABLE OF CONTENTS

Page

General Information ..... . ............ . 1
Location, Contractors, City Engineers
and Officials, Cost Data, etc.

Preliminary Design.... ... ......... ... 5
Authority for, Surveys, Estimates,
Bond Issue.

General Design Data....................
Composite Design, Controlling
Features.

........ 11

”Ch Desj—SnOOOOeooooooeooeo00.000000000000000.0 1)
Arch Analysis, Slab and Column
Design, Tee-Beams, Influence Lines.

Viaduct Beam and Girder Design................. 31
Steel Beams, Reinforced Concrete
Beams, Retaining Wall, Street
Intersections and Factory Outlet,

Railing and Lamp Post Design.

Construction, Fall-of 1923..................... 42
Contractors Plan, Temporary Foot
Bridge, Trestle, Columns, Footings,
Honeycomb,Concrete Design, Equipment.

Construction of River Foundations.............. 50
South Abutment, SOuth Pier,
North Pier, Horth Abutment,
South Pier Cofferdam COllapse.................. 54
Construction of Cofferdam,
Rebuilding Cofferdam.
Removal of Old FOundations.................... 58
Viaduct Superetructure Construction...... .... 59

Arch Ribs and Superstructure.................. 53

Concrete Protection............. ..... ......... 63

HAPS CR DRAWIHqS
Page
City of Lansing, Hichigan, Iap..................... 2
Sketch of Beam And Girder Section..................14
Earth SOunding Chart.............................. 22

North Abutment CPOSS Seetiongooeooeoe0.0.0.0000... 29

The Design and Construction of the
Legan Street Viaduct

The contract for the erection of the Logan Street
Viaduct was awarded October 8,1928, and the viaduct
was accepted by the City of Lansing, June 30,1930, as
a completed structure. The cost to the city was about
$400,000.00 . The Folwell Engineering Co. of Chicago,
Ill. was the general contractor. Mr. E. Sebern was
general superintendent and in active charge of the
work for the Folwell Co.

The viaduct Was designed by the bridge department
of the City of Lansing, Michigan. Mr. R.F.Rey being
Bridge Engineer and Collins Thornton, his assistant.
mr. E.G.Eddy was City Engineer and Mr. laird J. Troyer
the Mayor, at that time. The Bridge Committee of the
City Council consisted of Mr. F.S.Vandervoort, chairman,
mr. Geo. Hagamier, and mr. Wm. MCComb.

The construction Was supervised by the City of
Lansing, which was represented by the Bridge Engineers.
All work, materials, and workmanship, were performed
in accordance with the COntract and Specifications
of the Logan Street Viaduct.

In order to designate the location of the project
in the mind of the reader, the following sketch is

presented.

 

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By means of this sketch, the setting of the preposed
structure can be visualized. The importance of the
crossingfinghe inadequacy of the existing structure to
present day traffic were principli factors in the
promotion of the improvement. As can be seen, Logan
Street is a North and South street in the City of
Lansing, Michigan, ten blocks West of the Capitol. It
extends North to the Grand River, where a prOposed
bridge would connect it to U.S. 16. To the South of the
city it becomes State Trunk No. 9 and is the paved road
to Eaton Rapids and Albion. Three quarters of a mile
South of the Capitol it crosses the Grand River, the
Grand Trunk R.R. main lines and sidings, and the Michigan
Central R.R. switches to the Oldsmobile plant. Previous
to 1928, a steel Pratt truss, erected in 1858, served
the public. The steel was in fair condition but was
designed for lighter traffic than that to which it was
being subjected. Eoreover, the maintenance costs were
increasing, the planking in the roadway not being able
to withstand inceaming traffic vibration. In 1926, a
five ton load limit was imposed upon it.

Bordering the river on the North, lie the main
tracks of the Grand Trunk R.R. Just to the N.E. of this
is the huge plant of the Oldsmobile Co., which is served
by four Grand Trunk sidings and three Nichigan Central
sWitchesQ This aggregation of railroad switches and main
lines, which are in almost constant use when the Oldsmobile
Co. is running at peak production, caused a serious traffn:

impediment. Not only this but the situation is dangerous,

the bottle neck bridge and steep grade to the North

having caused several accidents, a number of which were
fatal. The last one in 1926, when four persons were
instantly killed by a fast Grand Trunk flier, so aroused
public sentiment that the elimination of the grade crossing
was demanded. Nevertheless, the problem of convincing the
city council of the necessity was not so easy, but the
following excerpt from the council proceedings are self
explanatory.

Excerpt- City Council Proceedings

October 17, 1927
Public Improvement, Resolution No. 1
by Ald. F.S.Vandervoort

"It is hereby determined to be a public necessity
and a necessary public improvment to separate the grades
and build a bridge over the Grand River and the Grand
Trunk R.R. on Logan Street, City of Lansing, and to be
paid for by the city at large, be it"

"Resolved,- That the City Engineer be and hereby
13.}. directed to estimate kind and quantity of materials
to be used therefor, and estimate in detail the probable
expense of such work, and of all materials and labor to be
used therein, and to cause to be prepared the necessary
plans and specifications for such work, and to report to the
City Council as soon as possible, the expense to be paid
from the contingent fund?

This resolution authorized the City Engineer to
proceed with a preliminary survey for the purpose of
determining the type of structure and probable expense

to the city, and incidently, the economic need of a new

Among the first steps, was the location survey and

mapping the details of the area concerned. By inspection
of the profile, it is easy to discern that a viaduct
spanning the railroads and river is the most apprOpriate.
The greatest difficulty in this plan was that of providing
outlets for the Olds motor Works and the Lansing Municipal
Power Plant. Consultation with the Lansing Board of Water
and Light showed a plan involving the construction of
another bridge, the Island Avenue Bridge, to be the most
feasible. This, because it made the plant more accesible
to the downtown area and at a very nominal increase in cost,
also, it was desirable that they have an outlet during the
construction of the viaduct. The cost arrangement Was a
fifty-fifty preposition, and was erected at a cost of
$75,000.00, of this, $25,000.00 of the city at large's shame
was to be paid from the funds for the viaduct, it bemng
considered incidental and necessary to its construction.
$12,500.00 was paid from the contingent fund, and the
Board of Water and Light furnished the remainder. This
bridge was built during the summer of 1928 and the roadway
was ready for use Dec.1,1928; The outlet for the Olds
Motor Works was provided for by the construction of a new
drive, paralleling the new viaduct and on city prOperty,
connecting the old outlet with Olds Avenue on the North.

The desirabilmy of a new structure is evidenced by
the promptness in which the officials of the Old: cOOperated
enabling a tentative agreement to be signed by I.J.Reutter,
President of the Oldsmobile Co., Oct.31,1927, providing

for the new outlet and waiving damages.

Before consulting either of the railroads, it was
decided upon to go ahead with the preliminarmes and have
a clear cut,workable plan or plans when the time came to
consult with them, it being realized, that while the
railroads have capable engineering organizations, it is
usually necessary for the public authorities to take the
initiative. With this in mind, several plans were prepared
and consideded.

Late in 1927, the railroad officials were consulted
and after several conferences and much correspondence
between the parties, tentative agreements were signed with
the Grand Trunk R.R. on Nov. 16,1927, and as their share,
agreeing to pay $80,000.00, and the Michigan Central
Jan. 16,1928, in which they agreed to pay the sum of $20,000CW
and to lower their tracks to elevation 144.00 feet, an
average of five feet at their own expense.

This form of agreement, commonly called the "Lump Sum
Agreement”, was based upon the preliminary estimate of cost.
These agreements are representative of a fifty-fifty
division of costs as per the Public Acts of 1893, Act 92,
as amended, which is a part of the Compiled Railroad Laws:

PrOperty damage was limited to those lots fronting
on Logan between Olds Ave. and Albert St., and was settled
by the agreement to build new sidewalks at the preperty
lines abbutting and at the new elevations at the cities
expense.

In order to make a fairly accurate estimate of the
probable cost, it was necessary to decide on the details
of the prOposed structure. For instance, although the clear-

ances over the railroads is standardized at 22 feet over

main lines and from 18 to 21 feet over switches and sidings,
it was necessary that the general city plan of grade
separations be thonmughly considered. In 1923, the City of
Lansing employed as engineer, Harland Bartholmew of St. Louis
no. to make a city plan for the City of Lansing and in it

he recommends an underpass at Washington Ave. separating it
from the Grand Trunk R.R., this being not quite a mile from
the preposed structure at Logan St. In his survey, however,
he did not establish definite controlling grades but
established a general plan and probable system of grade
separation. After due consideration, it was found that even a
considerable elevation of the tracks would not materially
affect the grade at Logan Street.

The general profile was determined by using a 22 foot
clearance over the Grand Trunk main lines and it was found
that a five percent grade would meet Moores River Drive
nicely. The Michigan Central insisted on a 21 ft. clearance
over its switch tracks, and in order to limit the maximum
grade to 5.5%, it would be necessary to raise the intersectioi
at Albert St. This would be a place for the excess dirt
from the excavations and was adOpted.

The entire portion of the viaduct north of the river
was planned and estimated as concrete beam and girder,
resting upon concrete columns as being the most fitting and
economical type of structure. However, it must be understood
that these plans were only tentative.

Because of the position and size, the river crossing
cannot be of the same type of construction. The old steel

bridge was 203 ft. long, but the banks were curved to the

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old abutments and the proper span Was about 240-250 feet,

and as the water elevation was maintained at elevation 127.00
feet by the dam belonging to the Lansing Municipal Power Plan;
it was planndd to widen the river to the width required by
this elevation.This elimated the collection of trash on

the upstream side that had made the old bridge such an
eyesore:

In considering a bridge of this size, it is necessary
that the architectural lines be pleasing to the eye and
a source of pride to the community. Economically, it may
have been cheaper to bridge the river with steel, encased
in concrete, using two or perhaps three spans, but the
depth of the beams necessary to Span these distances as
compared to the depths of the beams over the railroad were
so different as to give a very displeasing appearance. Also,
the clearance above the water on the south side would have
been very small which Was undesirable. Test borings or
earth soundings had been made and the soil conditions found
suitable for arch foundations. In view of the above, three-
arches of progressing span lengths were adepted as most
suitable and fitting in this preliminary design.

The general cross section was a roadway which could
carry four lanes of traffic, 38 ft. between the curbs. A six
foot sidewalk on the West and a two and one-half foot
sidewalk on the East, with 1ft; Bin. on either side for
cOping and handrail, giving an overall width of 49 ft. The
walk on the East was necessarily narrowed to provide for
an 18 ft. drive for the Oldsmobile Outlet on city prOperty.

By actual traffic and pedestrian count, it was found that

the foot traffic was comparatively light, and although the
designers would have liked equal width walks, they felt
Justified under the conditions in making one narrower than
the other. The handrails were to be of concrete spindles set
on a concrete plinth and surmounted by a concrete cOping. A
# in. crown and brick wearing surface were used in the
design of the roadway. The depth of the beams throughout
the viaduct were maintained constant, varying the reinforcing
steel to fit the span lengths.

From this preliminary design, quantities could be
estimated, and an aporoximate idea of the cost obtained,
but as a check, the costs of the previous bridges and viaducm
built by the city recently were tabulated. Reducing these to
costs per square foot of roadvay gives a quite accurate
method of comparison and estimate. For instance, the
Kalamazoo St. Bridge, completed in 1926, was of a similar
type and cost nearly $200,000.00, and the Saginaw St. Bridge,
completed early in 1928, cost about$S1,000.00. When reduced
to costs per square foot, we find a figure of approximately
$9.50 per square foot, and checking With the other method
and making due allowance for the deep water piers and
abutments, it is found that it will require approximately
$400,000.00 to build the structure as designed. Of this
amount, as before stated, $100,000.00 would be paid by the
two railroads, leaving $300,000.00 to be raised by the city.
On Jan. 23,1928, the city clerk of Lansing was instructed by
vote of the council to prepare the ballot for the spring
election. The form of the ballot was questioning whether or
not the city should bond itself for the sum of $300,000.00

for a period of thirty years, paying a maximum of 4 1/2%
interest.

In order to stir up public interest in the project, a
series of articles were published in the local newspapers,
describing conditions as they existed. An architectural
sketch of the prOposed structure was prepared and shown in
the papers iS the type of bridge contemplated. mayor
Troyer threw his influence behind the project, describing
it as a necessary improvement and a public necessity. Both
newspaper editors commended the project and all the civic
leaders and clubs were loud in their acclaim. Consequently
the bond issue carried by a vote of three to one.

On april 30,1928, the City Engineer was instructed by
the City Council to prepare specific and detailed plans
and specifications for the erection of a viaduct at Legan

Street.

10.

11.

Design of the Logan Street Viaduct

By the order of the City Council of Lansing April 30, igag
the bridge engineers were definitely ordered to go ahead with
the detailed design of the structure. In presenting this
design, it will be necessary to condense the material to a
considerable degree. For instance, where only span lengths
vary but the rest of the section remains the same, a typical
beam will be designed illustrating method and proceedure.
The results obtained will be tabulated so that a comprehensibli
view of the designed and viaduct is obtained. Only the design
of the viaduct as constructed willbe detaiied in this
analysis; however, its relative merits in comparison with
var‘ous other designs will be discussed.

As was mentioned before, certain controlling factors
are encountered in the design of any structure. Tabulation
of these is of first importance, and the best possible
method is by a drawing, so the drawing showing the prOposed
layout and profile was prepared. Upon examination of these
drawings, we find the following details:

1. Using 0900 as the South prOperty line of Moores

River Drive and LOgan Street, it is 22#.1 ft. to the old
bridge abutment and between the abutments is 200 feet. There
is a pier midwaywhich is built of concrete set upon a timber
cribbing. It is inadequate for the foundation of a new, wider,
and heavier structure. The removal of this pier and both
abutments shall form a part of the contract. In order to
widen the river to boundaries more nearly in conformity

with the established banks, this span was increased to
240 feet, With the face of the South Abutment at station

2+03 and the North at station 4443.

12.

2. The next controlling feature was the clearance over
the Grand Trunk main lines. These are located at station
S+58.3 south rail of the south tracks, and station 5978.5
the north rail of the north tracks. The elevation of the
center of the road at station 0+00 is 138.03 feet, station
0&66, the north side of Moores River Drive, is elevation
137.54 feet. Inoordsr to maintain the existing grade on
Moores River Drive, station 0+66 is the beginning of the
rise and consequently the P.C. (pOint of curvature) of a
vertical curve. The elevation of the south rail is 134.55 ft.
Allowing the 22foot clearance over main lines and estimating
the beam to be of probable span of 40 ft. and a depth of
24", with a slab thickness of 8" or 10", we find that the
elevation of the deck on the center line of roadway approxima-
tely elevation 159.30 ft. From elevation 137.54 at station
0‘66 to elevation 159.30 ft. at station 5458.3 is a rise of
21.76 ft. in 492.3 feet. Assuming a 100foot vertical curve,
the P.I. (point 0f intersection) would be at station 1916
leaving a distance of 442.3 feet. This gives a grade of 4.9%,
very close to the 5% grade adOpted.

3. Using the center line grade at station 5458.3 as
elevation 159.30 ft., the next controlling point is that of
providing the necessary clearance over the Michigan Central
switches. The north rail of the south tracks at station 9-00
is at elevation 147.59 ft. According to the agreement between
the Michigan Central R.R. and the City of Lansing, the
railroad would lower their tracks to elevation $44.00 ft.

Adding the required clearance of 21 feet and the 2.75 ft.

for the depth of structure, we get an elevation 0f 167.75ft.
Which is a rise of 6.45 ft. in 342 feet or approximately

13.

a 2% grade. This was later revised because of necessary
vertical curves to a 2.5% grade. ‘

4. The center line intersection of Albert Street with
Losan Street on the north end of the viaduct was originally
at elevation 154.9 at station 11930, but by raising the grade
of the intersection it Was possible to use a grade of 5.5%.

5. By certain revisions and the insertion of vertical
curves at the breaks in grades, the controlling grade was
selected. Using these grades it Was necessary thattthe design
be made to fit and correspond with precision. In several
cases the design was altered to fit as will be shown in the
railroad spans, whereby steel beams were used in the place
of reinforced concrete so as to provide the clearance
required.

It is necessary in the design of any structure that
the limiting factors be recognized, plans made to conform
with them, and then designed to fit. This will eliminate
many conflicting details that have to be ironed out later

in the design or in the construction work.

14.

 

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The Arch Design
- The general form of the superstructure is shown upon the
cross section drawing. As constructed, the arch section
consists of a 38 ft. roadway, a 7.75' walk, and a 3.25' walk,
supported by beams resting on columns, which are in turn
supported by four arch ribs. The spandrel columns are spaced
in conformity to the arch spans, so that an equal number
of columns are used in each arch Span.
The loading system used in the design is that used by
the Michigan State HighWay Bridge Department, namely that
of a system of 20 ton trucks and 15 ton trailers, so placed
as to give the maximum stress in the member concerned in.any
given section. Influence lines were used when there was any
question of arrangement, as for example, the arches. Impact
was provided for by a twenty five percent allowance. On the
sidewalks, a liveload of 100 lbs. per square foot plus one
front wheel load was used. The wearing surface wis designed
as 3" brick with 1/2" sand cushion. Both curbs were designed
as 10" and a 4" roadway crown was provided.
In designing the pavement for the arch section, the
Span lengths, as shown in the cross sestion, are of two
different dimensions, 3' and 5'. The 5' saan will govern
and is here given.
Span 5'-0"
Assume, d as 8" D.L. 150# per sq. foot
L.L. 7 ton wheel load, or 14,000 x 5/4==17,500#
Moment distribution ( O'Rourkes Empirical Formula )
E 2/3(1 - t): 2/3(5 4.25) 1: 4.156

1.793%? = 4,200 s/fl c7 Mar/2

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I: 4/3 (x M) = 7, (/.45%125)= 3.60

!—.—= 4660 ....

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The slab thus designed is in conformity with the
method recommended by the Joint Committee on Concrete
and Reinforced Concrete in the Aug. 1924, report. The
empirical distribution of loads for the slab design is given
by O'Rourke in his book on reinforced concrete design and
conforms to accepted practice.

In connection with the deck, the sidewalk must be
designed so that the reinforcing steel Will match. It is
of cantilever style, partially supported by the outside
beam. The railing weighs 550# per lineal foot, is 1' wide,
and is centered 9" from the outside edge of the walk.

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The slab and sidewalk being designed, the design of the
Tee—Beams in the arch section is next. As has been stated,
the spans vary in accordance with the arches, those over
the south arch having a span of 4.5', 7.0' over the central
arch, and 8.4' over the north arch. In the cross section,
two beams were designed, an interior,and an exteriorcor
sidewalk beam. As the typical beam design, an interior
beam of the 8.4' snan is selected and presented,

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21.

The next step is the design of the spandrel columns
over the arches. Since the beam having a seen of 8.4'

Was presented, the column for this beam is designed.

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23.

With the superstructure designed, the next step is
the arch design. In this structure, four arch ribs were
planned. With the face of the South Abutment at station
2§03 and the face of the North Abutment at station 4+4}
and governed by the 5% grade for the roadway, it is plain
that a single arch of 240 foot Span Was impossible, and that
two symmetrical arches were also unsuitable. Three equal
arches could have been used but the apnearance would not
be as satisfactory as the system used, that of three arches
of progressing Spans and rises; This conforms to the grade
closely and gives a composite structure.

As earth soundings had been made at the abutment sites,
it was known at about what depth the foundations would be
placed in order to rest the structure upon rock. The elevation
as designed called for the South Abutment foundation at
elevation 50.00 feet, the South Pier at elevation 53.00 feet,
the North Pier at elevation 96.00 feet, and the North
Abutment at elevation 100.00 feet. Going to this depth
meant the penetration of several feet of soft rock and two
feet into hard rock.

The arch piers were designed of the elastic type with
a quite heavy cross section, in order that the unbalanced
thrusts might be transmitted to the foundaticn more nearly
vertically,

As designed, the arches consist of three clear Spans,

61 feet, 76 feet, and 90 feet. The South Pier is 6 feet and
the North Pier is ? feet wide, making a total of 2&0 feet.
The elevation of the springing line is the same as the

normal water level, or elevation 127.00 feet. In each span,

four arch ribs, 7.25 feet wide and 5 feet apart are used.

24.
Each arch is a circular segment having the following
preperties,
Intradcs Fadius
61' span, Rise 11.3'
R2: (1/2 span)24 (32— rise)2
R 46.818'

75' scan, Rise 14,79'

R 96.21'

c

90' Span, Rise 16.03'
R 62.25'

The radius Of the extrados was Obtained by passing a
circle through the three points which are the assumed
thickness at the crown and at each Springing line. In order
to estimate the thickness with any degree of accuracy for the
trial analysis, the most useful aid is familiarity with the
dimensions of similar existing structures. In this bridge
the assumptions were fairly close, and with the exceptions
of the springing lines no channes were made. In each arch,
however, it Was found that the assumed size at the Springing
was too small to carry the stress placed upon it.

The final designed thicknesses at the crown and Springing

and the radius of each extrados, are,

Span Crown t Springing t Radius of Extrados
61' 1'_3" 2'-“ 1/2" 53.95!
76' 1'—5 1/2" 2'—11" 64.51'

90' 1'_8u 3I_6" 71.18.

25.

In the Open soandrel type of structure, the loads are
transmitted to the arches through the columns which definitely
fixes their point of application. In order to obtain the
loading that will produce the maximum stress in the arch or
piers and abutments, influence lines were drawn. Using this
data and the influence lines for the various loadings the
complete analysis for each arch and combination of arches
was made. The attempt to present the complete analysis will
not be made as this was the subject of a graduating thesis
in 152? by the author and is covered in full there. However,
since the thesis was presented, the analysis was checked
by the Cissell Engineering Company of Ann Arbor, Hichigan,
and approved with a few minor changes which will be noted
and explained. The steps will be shown and results obtained
through the analysis in as brief a manner as possible. The
aethod of design used is that presented by Hool in his book
"Reinforced Concrete Construction" Volume 3. Since the
construction of the viaduct a book by IcCollough of the
Oregon State Bridge Department gives a method of analysis
which is believed to be more in accordance with present day
design and construction and should be used in the place of
the method used here.

This brief of the analysis is prepared for the 90 foot
arch.

The arch, from springing line to crown, is separated
into eleven divisions having constant s/I, .nd the following
data computed, -

L of 1/2 axis 51.3'

p0 .0073:

26.

a .0122 square feet

8
na8 .193 square feet
s/I 3.7 feet

In this arch the loads are at the columns, there being
ten columns per arch and as the arches are symmetrical, unit
loads are applied at five points for 1/2 the arch. By placing
this unit load at the column points in order the thrusts and

moments at the crown are determined and are,

Unit load at L1 L2 L3 La la
Ho .070q .306 .643 1.105 1.29
V0 .0113 .0497 .121 .277 .363
Mo. .114 -.48 -.725 -.422 1.39

The moments and thrusts at each of the eleven sections are
computed with the unit lead at the five points and the
results tabulated as above.

After all points have been loaded for each section
the data for the influence lines is prepared. To do this
the thickness at each section is computed or scaled from a
large drawing. The data for the crown section is here given,

with the load at L5, L4» L3, L2, and L1. t 1.66' p0 .0073

Pt . -%°-= ‘%t K NK x' NK'
crown .645 4.10 5.29 2.30 - .97
at L4 -.257 2.25 -2.25 .3 .3
at L3 -.668 4.15 -2.70 2.30 1.50
at L2 -.933 5.50 -1.70 3.60 1.11
at L1 -.574 3.62 - .272 1.90 .131

From this data the influence line for the crown section is

drawn.

26.

a8 .0122 square feet
na8 .193 square feet
s/I 3.7 feet

In this arch the loads are at the columns, there being
ten columns per arch and as the arches are symmetrical, unit
loads are applied at five points for 1/2 the arch. By placing
this unit load at the column points in order the thrusts and

moments at the crown are determined and are,

Unit load at L1 L2 L3 L4 Lr3
HC .0700 .306 .643 1.105 1.29
vC .0113 .0497 .121 .277 .363
Me. .114 -.48 -.725 -.422 1.39

The moments and thrusts at each of the eleven sections are
computed with the unit load at the five points and the
results tabulated as above.

After all points have been loaded for each section
the data for the influence lines is prepared. To do this
the thickness at each section is computed or scaled from a
large drawing. The data for the crown section is here given,

With. the load. at; 1.1-), L4, L3, 12, 811d L1. t 1.66, p0 .0073

Pt . 35:0; 3%?) K NK :1" 1:10
crown .645 4.10 5.29 2.30 - .97
at L4 -.257 2.25 -2.25 .3 .3
at L3 -.668 4.15 -2.70 2.30 1.50
at L2 -.933 5.50 -1.70 3.60 1.11
at L1 -.574 3.62 - .272 1.90 .131

From this data the influence line for the crown section is

drawn:

Influence Lines for UK and NK' at crown section 27.

I I
~ I
“a “"'°1".\. 1/.;
j‘ ‘s : \ 1 :/ I
§ “‘ YE'7-'/
NK ' .NK'
f0 bt fc 013

From this, the unit load placed at column no. 5 produces the
maximum stress and so the dead load will remain on points 1,
2, 3, and 4, while the ccmbined live and dead loads will be
placed on column no. 5.

Dead Loads 10,690# at L1. 6.050% at L2, 4,9804 at L3,
4,370# at lg

Combined Live and Dead loads, 8,610# at L5

Unit stress

Upper fiber

-2 x .131d.l. —2 x 1.11d.l. -2 x 1.5d.1. -2 x .3d.l. q2 x
(-2.97 d.1..1.1.) a: fee 2(28,650)/1.66x144= 240 lbs. per sq.h.

compression

lower fiber
.2x.272 d.l.-2x1.70 d.1.-2x2.7 d.l.-2x2.25 d41.+2x5.29 d.1.and
1.1.‘fér2(11,068)/1.66x144=92 lbs. per sq. in. tension
Reversing the loads and loading the first four columns with
the live plus dead loads and,

the stress in the upper fiber is equal to 65 pounds per
square foot tension, and the stress in the lower fiber is
equal to 447 pounds per square foot compression.

These influence lines are drawn for each section and the

stresses due to the loading determined, and tabulated.

3“.

28.

The stresses due to temperature and to rib shortening
must next be determined for the eleven sections and tabulated.
These are computed by formula given by Hool, and only the
results of the work are given below,

Fall of temperature and rib shortening,

stress in crown section

upper fiber 137 pounds compression

lower fiber 167 pounds tension

Rise of temperature and rib shortening,

upper fiber 31 pounds tension

lower fiber 3u pounds compression.

The maximum combination of these stresses is that obtained by
using the second system of loading, combined with that due to
a rise of temperature and rib shortening and is,

upper fiber 96 pounds tension

lower fiber 484 pounds compression

The tabulated stresses show whether the designed sections
are of sufficient size to withstand the loads or not. As has
been stated, the maximum stress in this design occured at the
springing section with a compressive stress of 850 pounds
per square Inch which was resisted by the increase of the size
of the section by using a curve of short radius in meeting
the pier stem. The amount of steel was also increased at this
point by using heavy dowels and extending them well into the
arch rib.

The steel designed was provided by using 3/4" round bars
at 6" centers longitudinally, with stirrups, 3/8" rOund, at
2' centers. Under each set of columns, to distribute the
load and bond for_shear, four 3/h" round hooked rods were

placed transversely.

 

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30.

After the arch analysis is completed, the resultant
stresses are known and the foundation piers and abutments
may be designed. Inasmuch as the piers are designed as
elastic, thereby permitting the horizontal component of the
resultant to the abutments, where they must be transmitted
to the rock foundation, the vertical loading must be such as
to produce the maximum resultant. In the North Abutment design,
this was obtained by loading the north arch alone as determined
from the influence lines for maximum stress at the springing
as the thrusts produced by loading the other arches was
counteracted by the dead load of the 90' arch. The amount of
this stress at the springing being known from the analysis,
the resultant was computed and together with the dead load
of 1/2 tie span which rested upon the abutment and by assuming
several sections, the final abutment design was determined.
Similarly with the South Abutment, with the exception that
the three spans were loaded to produce maximum stresses at
the springing, which left a residual thrust to be carried by
the south abutment, the same method of design was followed.
In the pier design, the larger arch was loaded and the resul-
tant computEd. Strictly speaking, it would have been permissabke
to use a slightly smaller pier stem with a greater percentage
of steel and certain variations in the footing design so as
to cut down the concrete stresses, but ascording to general
practice in this type of design, the tendency is to be on
the safe side and to endeavor to keep the resultant within
the middle third of the footing. In order to do this the
footing was offset in each pier from the centerline of the
stem. These footings were also designed to rest upon solid

rock.

Viaduct Design 31.

A considerable portion of the viaduct design has been
discussed in the preliminaries. A complete resume' of the
design of the viaduct section will be given here.

In order to facilitate in the descriptmon, a cross
section has been drawn of a typical section. See the tracing
in pocket.

From this, it is seen that the slab span governing
remains at 5' and that the slab as designed for the arch
section holds as well for the viaduct section. In most places,
the Span lengths are determined by the location of railroad
tracks and the angle of the foundations are also determined.

From the general plan the station of the foundations, and

their angle with the centerline of the road may be tabulated.

Station Type of column Angle With roadway
4-43 Face of North Abutment 90 degrees
4-82.5 Standard go de. 35 min.
5-16 Standard 71 de. 38 min.
5-59 EXpansion 53 n 32 M
5-90 Standard 53 H 32 n
5-34 EXpansion 53 n 32 n
5-75 Standard 53 n 32 n
7-03 Standard cs "

7-40 EXpansion go a

7-77 Standard 90 H

8-1!L Standard SO "

8-51 Expansion 90 n

8-79 Standard 55 a

9-13 Standard 55 fl

9-35 ,Expansion 90 n

9-54 Standard 90 N

32.

Station Type of column Angle with roadway
9-85 Standard 115 degrees

10—20 Expansion 115 "

10-54 Standard 115 "

10-83 Expansion 115 "

11-19.5 North bridge abutment 115 degrees

From this it Can be seen that the spans vary considerably
and that the length of the beams vary in some of the spans.
The spans over the Grand Trunk R.R. were at first planned
as reinforced concrete beams but upon investigation it Was
found that as the Spans were long it w0uld be better to use
steel sections. For the remainder of the viaduct, five
interior and two exterior beams are used. These rest upon
girders supported by three columns, which in turn rest upon
concrete footings. As a speciman of the type of design used,

a steel beam and a typical concrete beam will be designed here,
In the sections over the railroads, blast plates of cast iron
were designed to be placed above the tracks as protection for
the concrete. These plates were four feet wide, one inch thick
and made in interlocking sections three feet long. BOlts

concreted in, held the plates in place.

Design of a 42' steel outside beam
In each steel section, 9 interior and 2 exterior beams

were used.

 

33.

 

 

 

 

 

 

 

 

D.L.

slab 4.75 x .75 x 15095345‘

beam 2 x 3.92 x 150 =1175#

V concrete : 1S#
I—beam -.- 175#
Railing 8 2.55035!
Total § 2 2.453%?

t‘ l_1a: ,
Moment

2
Dead Load WI /8 = 2453x42x42/8 .= 540,000 foot pounds

Uniform live load a 100x6x42x42 ,3 132,000 n a
Live load Pl/4 = 17,500x42/4 ,_. 183,500 I! a
Total Moment ._._ 72q,501 n u

Carnegie C. B. 272 27" 175# beam
M 738.750 foot pounds

maximum shear 229,500 pounds

34.
AS a typical interior reinforced concrete beam, that
having a span of 37' is here designed completely.
Negative moment at end supports,
M=w12/16 for dead load
Live Load.=7/38 of 4 trucks or .737 of 1 truck
.737x28,000 =.25,000#
.737x20,000x5/4 =18,000#

118.000 " lum‘ 1 [8.000
5. . M . fl ' c. .5- '

f: .3750" r

[a
M(truck)=(30,500x6.5 v12,500x12) .5 a 174,000 foot pounds

 

M(dead load) =1703x37x37/16 = 145,000 " "
Total moment 2319,000 " "
A8: M/fs(d-12t)==319,000x12/16000x24.75 =9.66 square inches
Bend up six 1 1/8" square bars
Investigation over support
d'/d=4/29 =.138 p': 7.62/24x29s- .0077 p: 15.18/24x29= .0218
from diagram
k = .451 J .-. .q4‘3
f8==315,000x12/15.18x.848x29 = 10,300# per square inch
fc::10,300x .461/15(1- .451) z 585# per square inch
f;=10,300x(.461-.138)/.539' -.- 6,156»? per square inch
Investigation at the center of the beam
Dead Load slab 7x150 = 1,050#

beam 2.21x2x15f‘ : 663,3“

cant. 1/3x1/3x150 = 17#

total = 1.73071“
Moment (truck):=(30,500x6.5 + 12,500x12)8 = 278,000ft.pounds

(dead load) 1,703x37x37/10 = 233,000 " "

Total fioment #511,000 " "
Shear 3:45,13o# Dead Load-129,000,231
V = 74,130#

35.
v==74,130/24x.992x29 =121¥ requires stirrups

zo =74,130/100x.892x29=-29.2"
K =1/(1-16000-15x650) = .378
As= 511,000x12/16,000x(29_4.25) = 15.5 square inches
Use 12 11/8" square bars in two rows
rs: 511,000x12/15.18x.892x29 =15,650# persquare inch
fc==15,650x.378/15(1-.378) = 586% per square inch
This works well with the steel over the supports and is
satisfactory in other respects.
Stirrups Will be spaced at 7" for 3' 3/8" round bars
9" for 3'
13" to center

The columns are of two different types, the standard
and the eXpansion type. The standard type is three foot
square, except in the steel Spans. The eXpansion type
consists of two columns, each 4' by 18" spaced 2 inches apart
for eXpansion purposes. The columns are designed to line up on
the Outside faces, and to line transversly in each bent. In
the bents forming a right angle with the road, the sides
form the same angle as does the bent. In each bent, except
the railroad steel Spans, three columns are used to the bent.
Under the steel spans, four columns are used in each bent.
The method of design is the same as that used on the arch
columns, and all columns of the same type are equally
reinforced and are sufficiently strong to carry the loads

imposed upon them:

The girder and foundations were designed by the same
methods. In the place of bending up bars for negative moment
in the girders, double reinforcement Was used. At the
expansion Joints the girders of the bent were separated by 1"
expansion felt and steel plates were set 1" apart with their
tOp edge forming the parabolic curve of the roadway crown and
set to that elevation. The foundations were designed to be
shallow as only direct bearing was transmitted to them. In
most places this was at a depth of from 6 to 10 feet and
placed them upon a gravel base. The footings were made one
foot wider than the columns and extended under the entire
bent. They were designed as three feet deep and with the
required steel necessary under the loading.

From the north bridge abutment to a point northward 150'
where the Olds outlet parallels the viaduct, it was necessary
to design a small retaining wall. The maximum height being 11'
and SIOping to 5' at the north end.

In the design of this wall the loads were considered as

surcharge being equal to 4'. The design of the 11' section,

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33.

The outlet for the Olds Totor Works was plan ed to be
built adjacent to this retaining wall on a 5.5% grade. It
was to be 19' wide, with a concrete base and brick wearing
surface. It Was reinforced with 3/4" round bars at S" c.c.
as it was in part over that area that had been excavated for
foundations,and it was not to be considered a part of the
contract for the viaduct construction.

The intersection of Hoores River Drive and Legan St. was
discussed in the preliminaries as being subject to change.
It was found in the final design that the grade of Moores
River Drive would not be materially affected, but that it
would be necessary to widen the Drive considerably. This
meant a few minor changes in the crown of the intersection.
At Albert Street it was found necessary to raise the intersection
about 5' in order to conform with the desired established
grade of the viaduct. Therefore it would be necessary to fill
the roadway for 20" from the intersection and as this was a
suitable place for the excess excavation fromthe foundations,
.it was so decided to arrange for the fill and grading of
this street to be made a part of the contract. By means of
the vertical curves the old pavement on north Logan St.
Was met very smoothly.

The wearing surface was designed as paving brick,
using a row of white brick in marking each of the four
traffic lanes. Brick was used because of the steep grades,
aSphalt having a tendency to creep and wrinkle on steep
bridge grades. Bricks are also easier to replace and have

better wearing qualities than a concrete wearing surface.

As has been stated before, one full sized and one small
sidewalk was designed for two reasons, first in order that
the required Olds Outlet might be constructed on City preperty,
and second, that as there is so little pedestrian traffic and
so much motor vehicle traffic, it was felt that, rather than
decrease the roadway width it would be better to build a
narrow sidewalk.

The handrail is of reinforced concrete plinth and c0ping
with concrete spindles spaced at about 4". Over every bent
a concrete pilaster, corresponding to the width of the bent,
is placed. In the expansion bents the 1" felt was carried up
through the pilaster. Experience shows that while the
expansion joint is supposed to be concealed, all attempts to
hide it were entirely unsatisfactory.

Concrete lamp posts were designed to be cast in place,
Spaced at about equal intervals. The city furnished the
lamp post form as well as the spindle forms. The light
wires are carried in a 2" conduit cast in the plinth.

The architectural treatment has been mentioned in
connection with the arches. Throughout the entire structure
the same thought was carried out as far as possible, that
the completed structure should be pleasing to the eye and
an asset to the city architecturally as well as economically.
Throughout the viaduct, the viaduct section beams were all
made of the same depth, breadth, and of equal number. The
lines were made as continuous as possible, for instance, the
columns all line up on the outside faces, as do the arch ribs
and spandrel columns. All columns and the girders of the bent

are of the same Width which makes a uniform line transversly.

40.

Curved brackets at the ends of the beams are used,
both for the appearance and for the extra area of concrete
available for stress in shear. Brackets are used under the
sidewalks at the pilaster points for the same reasons. The
vertical curves are carried out in detail, showing no
distinct breaks of grade. Throughout, the effect desired was
Was one of a plain, pleasing, reinforced concrete design.

In this design also simplicity in form work and identical
sections were sought in so far as possible. This held true
in the detailing of various parts as for instance, the reinfor-
ceing steel placing and Spacing.

After having completed the design, the exact quantities
of excavation, concrete, structural and reinforceing steel
were computed and placed in tabulated lists on the plans.

The total quantities are:

Excavation 10,253 cubic yards
Concrete 7,422 cubic yards
Reinforcing Steel 1,000,000 pounds
Structural Steel 233,635 pounds

The bar lists were detailed and marked with letters
and numerals indicating their place in the structure, as,
S.A.W.W.1. meaning, South Abutment Wing Wall.

The contract and Specifications were modeled on thoae
used in the state highway bridge department. The contract
calls for the erection of the Logan Street Viaduct and the
gist of it is given as follows, " Whereby the contractors
shall furnish all the necessary equipment, machinery, tools,
apparatus, and other means of construction, in order that

the work may be performed in accordance with the plans and

41.

specifications, and to furnish all materials and labor
except, cement. The work to be done under the authorized
representat’ves of the City of lansing?

The contract stated that work shall connence on Sept.
18, 1928, and be prosecuted in such a manner as to insure
completion on or before October 1, 1929. The compensation

to be paid upon completion and acceptance bf the structure

by the representatives of the city in the full amount as

3

bid. Estimates from time to time as Work progresses and
based upon 90% of the work completed will be paid. The

retained 201 retained will be paid upon final acceptance.

42.
Construction

On August 6,1528, the City Clerk was authorized to
advertise for bids for the construction of the Logan Street
Viaduct. The bids were Opened Sept.6,1928, and the low bid
Was that of the Folwell Engineering Co., one of the nineteen
bids received and was for the amount of $279,540.04. The
next low bid being that of the Stein Construction Co. of
Milwaukee and was for the amount of $280,900. Anderson and
Co. being third with a bid Of €281,300. All except three of
the bids were below $300,000.

Three alternate designs and their accompanying bids
for construction were received. TWO of these were the Luten
design and the other a design by a Detroit firm.

Cne of the Luten designs was a series of three earth fill
arches, the remaining section of the viaduct belonging to the
City Was used. The other was a structure of very similar des—
Iign to that prepared by the city. The design by the Detroit
firm used four river piers with structural steel beams Of
80' swans. Of these alternates, only one was bid at a lower
price than that bid for the City design, that one being
the earth filled arches.

After thonough investigation by the City Bridge Committee,
the bid of the Folwell Engineering Co. was accepted as being
the lowest and best bid and upon the recommendation of the
committee, the contract Was awarded Sept.10,1928 and formally
approved by the City Council after all parties had signed on
October 8,1528. The agreements between the City and the
Grand Trunk R.R., the Michigan Central R.R., and the Olds
fiotor Works were executed Cctober 25,1528.

Acetmpanying the bid as requested by the City, was a

43.

list of equipment which the contractor had available and

intended to use in the erection of the bridge. This list

follows and while more equipment Was purchased, the bulk

of the equipment used is contained in the list.

2..

[\J
I

3..

Erie steam cranes, 29 tons capacity.
Concrete mixer, 1 cubic yard capacity.
Concrete mixers, one—half yard capacity.
Concrete tower, complete With hoisting apparatus and
Spouts, height, 150'
Air compressor (large size Ingersoll—Rand)
8" Centrifugal pumps complete With electric motors
6" Centrifugal pumps complete with motors
4" Centrifugal pump complete
Barber-Greene material hoist co plete with mottrs and belt
Blaw—Knox bins and batching equipment.
- Pieces of steel sheet piling, 40' long.
McKiernan Terry Io. 7 steam hamnens
n n NO . f, n n
Upright frame band saw.
Skilsaws
Buzzsaw
Floor sanders
G.M. C. 7 Yd. truck
Ford 1 yd. trucks

temporary buildings and Office.

fiiscellaneous assortment of small tools and timbers.

44.

v“

The Folwell angineering Co. presented at the City's
request, a schedule of work and the method and manner of
proceedure. It is briefly:

1. To erect a temporary foot bridge for pedestrians.

A number of wood piling were to be driven 75' east of the
bridge and a wooden bridge erected.

2. Using the bridge as support, piling were to be driven
to act as a working trestle, later to act as arch centering
supports, and to remove the old bridge as the trestle was
built.

3. By December 1, to start excavation and set sheeting
in the South Abutment and South Pier,

h. At the same time the trestle was being built, the
excavations for the viaduct footings were to be dug, the
footings concreted, and the columns built in the entire
viaduct by December 1, and by this time formwork was to be
sufficiently advanced to permit steel placing and pouring
of the first viaduct deck section.

5. The construction was to continue through the winter
so that the viaduct section would be completed with the
exceptionof the handrail by Kay 1,1929.

6. The completion of the arches by July 1, and the
arch superstructure by August 1.

7. The entire structure to be complete by Septemberi,
1929, or a month ahead of the completion date as set by the
City in the contract.

This schedule was to be accepted as a guide to the
method of proceedure in the prosecution of the work and
was prepared by the FOlWell Co. Officials. As soon as the

contract was awarded they hired their superintendint for the

45.

for the Job, Kr. E. Sebern of Detroit, Michigan. He was not
an engineer, but had considerable eXperience in the building
line, having worked on several important projects in varying
capacities more notably, the Book Cadillac Hotel in Detroit,
as general superintendent, and for the O.W.Jenkins Co. of
Detroit on a power house project in Ohio, also as superin-
tendent, and as carpenter foreman for the Christman Co. of
Detroit, on the Fisher Building in Detroit. In his first
appearances in LanSing, he Spoke at several luncheon clubs
and promised to do better than the prepared schedule, by
having the viaduct ready for traffic by July 4,1529. Naturally
the City Bridge Committee and the engineering department were
glad to have a statement that the work would be pushed With
so much vigor and that traffic could be resumed so much
sooner than had been anticipated.

Hr. Sebern employed from 200 to 250 men and the work
followed closely on schedule. In ten days the foot bridge
was completed and the work on the trestle and viaduct progress-
ing rapidly. The first foundations dug were those at stations
5-50 and 5-90 and then the north bridge abutment and retaining
Wall. One crane was used on these foundations while the
other worked on the trestle. The viaduct footings and columns
from the North Abutment to station 5-50 were not to be
constructed at once as this would hamper the activities
on the arch construction.

As the footings were shallow for the viaduct section,

no difficulty was eXperienced and they progressed satisfactori—
ly. About the middle of October the first difficulty was

experienced. The forms for the first set of columns at

2+6.

station 6-34 were set and lined up perfectly. In bracing

the columns, Universal column clamps were used with 2x6 plank
holding the columns in their reseective positions. Before

the permit to proceed with the concreting, the superintendent
was informed that due to the shape of the columns, it was
believed that the bracing was not sufficient, and that, under
pressure the columns would tend to form a square, but he
stated that he had poured a considerable number of such
columns and that they would be all right. Concreting was
permitted, but after about two thirds had been poured, three
of the column forms broke. They failed by tending to assume

a square shape and as they were held securely at the base, the;
were badly twisted. These columns were ordered removed and
replaced With columns of true shape as designed. The remowal
of these columns was difficult because in order to save the
reinforcing steel, it was necessary to proceed with care and
even though a continuous shift with air hamders worked on it,
the concrete, which had been poured slowly, was well set up
before all had been removed. In the rebuilding of these
columns, certain of the suggestions offered by the city were
accepted for the most part and the columns were satisfactory
on the second trial. However, several were later removed for t
the same reason, and it was not until the forms were construc—
ted as the city suggested that complete‘fia‘é' obtained in their
construction. This method being that of setting the forms in
their proper positions and building the bracing square and
blocking back to the forms in the triangular Space on either

side.

i little difficulty Was encountered in the eXpansion
columns of maintaining true perpendicular eXpansion Joints,
but by filling the 2" Space betwe n the forms With dry sand
and maintaining equal heights of the concrete on either side
of the eXpansion Joint during pouring, this obstacle was
overcome.

Honeycombing was almost entirely eliminated after the
superintendent learned that the city would not tolerate it
after one complete column was ordered removed because of
an excessive amount that eXposed the reinforcing steel. The
superintendent strenously objected to removing it, as he
stated that the patch could be as strong as the rest of the
concrete, but it was felt that he had had sufficient Opportu-
ity to produce acceptable concrete, and that it was bad prac-
tice to allow patchwork as inevitably spalling results after
weathering, leaving an unsightly structure. So in the interest
0f the city and in accordance With the plans and specification:
it was ordered that any honeycombed work would not be
permitted or accepted. This proved to be a wise move, for
after that, special care was taken during concreting to
prevent the accumulation of stone pockets.

At this time, in connection with the preceeding statementg
it might be well to discuss the concrete designed and used
in this structure for it might be misunderstood and thought
that the city was unduly severe in its inSpection and control.
The contract and specifications state that the City of Lansing
Will furnish all the cement for the structure. This was
intended to eliminate any claims on the contractors part if
certain changes were made in the mix. Unden this policy, it

was to the cities advantage to produce a strong concrete

48.

with the minimum amount of cement. Although the plans were
designed using 2,000# and 2,500# concrete, the concrete
used was designed by Abram's water cement ratio for 3,000#
and 3,500# concrete. The slumps varied according to the
location and spacing of the steel, from a minimum of 4" to
a maximum of 7" which is generally considered quite workable
in a preperly designed mix. The aggregates were measured
differently, the gravel being measured by vofiume and the
sand by weight. The sand hOpper was of the scales type and
permitted rapid adjustant. For all the superstructure work
approximately 6.5 sacks of cement per yard of concrete were
used. On each pour, concrete test cylinders were made, Cured
in the same manner as the concrete they represented and
broken by the testing laboratory at Michigan State College.
Some being broken at each of 3,7, and 28 days. In the
neighborhood of 1000 test cylinders were made and tested
for accurate control of the concrete. Some of the specimans
tested represented the worst conditions encountered in the
pouring or curing. For instance, during freezing weather, if
a certain place did not recieve as much heat as the average,
a cylinder was placed there to cure and the results noted,
not as being a test of the average section but more as an
indication of the strength of the weakest spot or link in
the structure. Therefore, it is useless to tabulate the
results of these tests as they refer in part to specific
conditions and are not the indication of the average concrete
strength.

Due to the slump maintained, it was impractical to use

the spouting for any appreciable distance, as concrete

having a slump of 5" or 6" will not slide on much less than
a 45 degree angle. From the termination of the spouts it
was necessary to convey it to the destination by other
methods. In this manner the contractors cost for placing
concrete was unreasonably high. Although they had a fine
general concrete plant, the rehandling caused an increase in
cost. The plant was permanently located at about station 7-00
being in a central position for the viaduct pouring. In
order to concrete the columns and superstructure of the
arches, the concrete was mixed at the plant, hoisted to the
ton of the tower, automatically tripped and dumped to the
snouting hODoBP, there a man controlled its flow into the
soouts. This conveyed the concrete about 150' to a hOppen,
there another man controlled the flow into a minature railway
and it use tranSported from 400' to 700' into a third hOpper
and from thence to the concrete buggies and into the forms.
This was elaborate but impractical. In order to save money,
concrete handling must be contained in one or two Operations.
In the construction of other bridges, the methods used were
not as elaborate and yet produced concrete of excellent
quality and the control was just as efficient for a great
deal less money, which is the point the contractor must
watch. Of course the same methods are not always applicable
to all conditions. The concrete pours Were qaite largw and as
it Was necessary to have a large amount of aggregate on hand
to permit continuous pouring, it is understood that it
called for Special consideration.

While the concreting of the columns and footings of

the viaduct section was in progress, the temporary footbridge

50.

and trestle Was completed. About the first of December,1§28,
the South Abutment was started, the sheeting set and driven to
refusal and excavation commenced. The cofferdam was built 3’
from each face of the neat footing line which made the
cofferdam 26' x 51' as required by the plans and specifications.
The excavation proceeded at a fair rate, the material
corresponding very closely to that shown by the soundings.

The elevation of the roadway at the site cf the South

Abutment was 137.00 feet and the footing of the South

Abutment was designed to be placed at elevation 90.00 feet.

At elevation 112.00 feet, the first variation from the
material indicated was encountered. The plan showed that

sand, some clay, and hard compacted sand could be expected.
The material as eccavated proved to be a laminated, sandy
shale. It varied greatly in hardness and in places became
very soft and crumbly. This shale overlaid the hard rock

upon which the foundation was placed and is the basis of

the law suit against the city, it being the contention of the
contractor that the city engineers knew or should have known
of the existance and true nature of this material, and that

it was their intention to conceal this for the purpose of
obtaining a low bid upon the plans, and that they having

been Wilfully misled, made such low bid and that due to

the true nature of the material and of the greater difficulty
of excavation for which they were unequipped, they were forced
to make large eXpenditures in order to perform the work as
required by the city engineers. They claim as due them an
amount equal to this added expense with a fair profit and

for which amount, the city having refused to allow any such

claim, they are suing in the court Of equity for such

51.
claim as a just and reasonable reward. The city maintains
that its engineers were uninformed as to the true conditions
of the material. It matntains that from the samples obtained
by the method of sounding employed, it would have been
impossible to ascertain a difference in the material a!
actually encountered because the sample when pumped to the
surface would appear as thematerial described on the plans.
Further, that the soundings were made for the use of the city
and were not guaranteed as correct but were thought to be
so and were offered only as an aid to the bidder. However as
this lawsuit is still pending in the United States District
Court at Detroit, awaiting its turn on the court calender,
this remains a controversial subject;

In the excavation of this material, air spades were used
to good advantage. The shale was easily shelled off in layers
and loaded into boxes which were hoisted out by the crane.
The excavation of this material proceeded even more rapidly
than the previously encountered material. It was at this
elevation(112.00 feet) that the steel sheeting had stepped
penetration and in view of the character of the material, the
superintendent decided to work below the sheeting and did so,
even in the face of contrary advice from the engineers, but
in this case he was successful and the footing was poured
in a fairly dry hole on January 23,1929. The footing was
poured at the elevation planned, the rock being of suitable
hardness and free from laminationd. The rock was a hard
sedimentary limestone. Forms for the abutments took two weeks
to build, during Which time the footing was heated to a

suitable temperature. Cold weather that year made it necessary

52.°

that all materials ahould be thoroughly heated before pouring.
As the abutment consisted of about 800 cubic yards of concrete,
considerable difficulty was eXperienced in reaching this
preper temperature and so when the temperature of the concrete
fell below 60 degrees consistantly, the pour was stOpped
until the temperature of the material warranted starting again.
Thus the abutment was concreted in three pours of about equal
volumns and they were heated to a temperature of 70 degrees
for fourteen days after which time backfilling was started
and evenly distributted over the area. The sheeting was pulled
and moved to the north side of the river on about March 15,1il9.

During January, the steel sheeting was being set for
the South Pier cofferdam and after a delay of about 30 days
this was completed. This is the cofferdam that collapsed and
eSpecial care Will be taken in the description of its
construction and excavation.

In the South Abutment the cofferdam was rectangular
26' x 51' with wood walers and struts. There were six 12”x12"
transverse struts and one 12“x12" longitudinal strut with
8"x16" double walers in each set. The Spacing of the sets
varied from 10' at the tOp to 6' on the bottom, there being
five sets used. There was an Open space not timbered below
the sheeting. In the South Pier, the plan was a rectangular
cofferdam, 26' x 54.5', but in trying to close this section
it was found that five sheet piles were lacking, and in order
to avoid purchasing or renting the piling the corners were
cut on a 45 degree angle with the consent of the engineer in
charge. The tpp set of timbers was placed 1' above the

Springhng line and water surface, or at elevation 128.00 feet

53.

and the next at elevation 120.00 feet, the next at elevation
114.00 feet,another set at elevation 108.00 feet, and at the
time of the collapse, another was being set at elevation 103.0
feet. Four sets of timbers were already in place and a fifth
being placed. The following sketch gives a general idea of the

timbering used.

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The tOp set is entirely of wood, while the remaining sets
contained 12" x12" concrete struts which were to pass through

the pier and eliminate the boxing around them while concreting.

I-3

hese were held in place by cables, bolts and nailed cleats.
They appeared in every way structurally sound.

In the first attempt to denater the cofferdam it became
apparent that a leak of quite some size existed. After
driving the sheeting again and adding two more 6" pumps,
the water was gradually lowered and excavation started. The
first material was silt and debris and several large bould rs
were encountered. In removing them the cofferdam flooded.

The sheeting was again driven but ice forming on the interlock
held them Open and again made dewatering difficult. After
strug;ling for several days the water was again lowered and

the cofferdam again ready for excavation but there had been

54.

a

little progress made due to subsequent flovdixgs and acjustmen;

of timbers. The excavated material was being dumped into the

)

river on the south west corner of the cofferdam, and :s th~

(

leaks wege washing in a great deal of mater‘al, the engineer
suggested that a berm be placed around the cofferdam, but

the superintendent flatly refused to do this because of the
cost. A little money spent at this point would havr saved:
money, time, and lives as it later deveIOped. The stability
offered to a cofferdam by a berm is considerable and shOuld
not be overlooked in the work. The surface of the water was

at elevation 127.00 feet and the excavation has carried to
elevation 102.5 feet which meant a head of 24.5 feet of

rater. The material being excavated was a mixture of clay

and the shale. The sheeting had been driven to about elevation
101.00 feet and this Was the state of conditions prevailing
April 12,1529, When the cofferdam collapsed, trapping five

men and seriously injuring two others. Five minutes previous
to the collapse, nothing was noticed to indicate the impending
disaster, except that the dam was beginning to leak a little
more freely.The foreman had just called 12 or 14 men from

the bottom to put Cinders around the Outside to stOp the leak
and had it not been for this, the loss of life woul£ have.~
been much greater. The crash was almost instantaneous and

was entirely unexpected even by the men working in the

bottom as indicated by their positions when they were recover—

ed. Only one man escaped from the bottom and he was seriously

D;
(D

injured. He said that was in a different part of the
cofferdam from the rest and was carried up by the surge of

water. The other survivor was standing on the first set of

55.

timbers and was thrown high in the air and fell back into
the maize Of timbers and was permanently crippled. This
upheaval seems to be an indication Of the method Of collapse,
the timbers being broken and heaved upward and the sheeting
closing at the surface.

it the time Of the collapse, the superintendent who was
in Chicago, returned immediately and offered several theories
as to the cause of the collapse. These, )jing of a defensive
nature were later disqualified by actual findings. His
principal theory was that the excavation had reached a layer
of quic? sand and that the bottom had heaved up and disrupted
the timbering. Ohhers gave as their Opinion that the method
of cutting corners was not structually sound, while still
others said that the concrete struts gave way first, causing
the collapse. A great many other peOple eXpressed their ideas
and probably still have faith in them. Hr. Rey and the'
author of this thesis did not express or involve themselves
in any way as they only approved the methods Of construction
and were not reSponsible for the loss, as the superintendent
only presented plans for their approval and resented any
further control of their work.

A Grand Jury was called upon by the PeOple to investigate
the disaster and place the blame if any. They requested a
competant engineer to examine the plans Of the cofferdam
and to see if they were strong enough for the loads imposed.
Professor C.L.Allen of the Civil Engineering Department
of Iichigan State College made the analysis and stated that

sufficient bracing and timbering were used if prOperly

placed and fixed to withstand the pressures. After all

55.

available testimony was heard, the Grand Jury decided to
Wait until the previous level had been reached and all the
evidence then available studied.
iccordingly, a new cofferdam was constructed in the
same position as the first one. After the sheeting was set,
the task of removing the twisted cofferdam was attempted.
Host of the sheeting could not be pulled and had to be burned
off in pieces which made a slow job as only that portion above
water could be burned. Shifts worked night and day in an attemr
pt to recover the bodies as quickly as possible but progress
was necessarily slow and it was four weeks until the first
body Was recovered and six until the last corpse w-s reached.
The new cofferdam was constructed With double struts
spaced one foot apart to allow a concrete strut to be poured
between before concreting. Many more precautions were taken
in the building of the second, such as bolted x-bracing and
instead of using the cut corners, the cofferdam was made
rectangular. Also the sets were held in position by Spacers
between and bolts tying them together ridgidly. At this
time the city bridge engineer ordered a berm placed around
the cofferdam. The sheeting used in this cofferdam was the
same as that used and recently pulled from the South Abutment.
On May 25,1929, the last body was recovered and excavatiai
was ready to continue. Upon examination, it was found that
the material in the bottom at the time of the collapse was
the shale mentioned and showed no signs of upheaval. Of the
20 concrete struts used, only two were found broken. While
the sheeting was crushed completely tosether at the surface,

the general outline of the sheeting at eleVation 102.00 feet

57.

Was close to the original lines, the south wall having

shifted north about two feet and the north Wall at the corners
almost intact with a 3' or 4' curve between. The sheeting

was dragged south. Very little dirt had washed in. The Grand
Jury received this evidence but failed to place any blame for
the accident, terming it an unavoidable accident and an act

of God. In this Thesis, no attempt will be made to continue
this investigation or offer a solution, but the facts are
given the reader so that he may draw his own conclusions.

In the process of excavating from elevation 102.00 feet
to the elevation at which the footing was placed at elevation
93.1? feet, practically the same material was found at that
elevation as in the South Abutment, namely, sandy shale. The
pier was founded on the limestone rock and the forms and
concreting were simple after that.

The South Pier was completed about the middle of July,
which was considerably behind the contemplated schedule,
although Mr. Sebern assured the city that the bridge would be
completed 0% the date called for in the contract, October 1,
1929. At this time it was suSpected by the engineers that the
Job was Just a little beyond Hr. Seberns ability to handle and
the Folwell Co. was so informed but they seemed to have great
confidence in him and the protest was not pressed.

The North Abutment was being excavated atithis time, or as
the South Pier was being poured. Excavation moved along fairly
well and the materials conformed to the sounding sheet until
the shale was reached as before, but in this case the rock
at the point at which the footing was to be poured was found t>
be a wedge shaped slab, about 7' thick at the point where the

sounding had been made and vanishing completely toward the eam;

58.

This rock Was underlain with soft clay and would have been

a treacherous foundation, so the engineer ordered the conta'
ractor to go deep enough to get a suitable rock foundation.
This was found after excavating 10' of shale which was paid
for as an extra at the price bid for this depth of excavation.
Incidently, it was generally admitted by the Folwell Co.

that this excavation was the only foundation that they made
any money on, which discounts the claims made in the law suit.
The foundation was placed at elevation 50.00 feet and work
proceeded so that the abutment was completed at about the
time time that the contract called for the completion of the
bridge. In figuring the completion date when extra work is
added, the prOportion of the cost of the extra work to the
total contract was applied to the time allowance as provided
in the specifications, which added about another month, or
November 1,1929,

After the sheeting had been released in the South Pier,
it was moved to the North Pier and set. In setting this
sheeting and driving the piles slanted out of plumb and the
superintendent was so informed, but he maintained that it Was
to do any damage and did not change them at that time. After
excavating about 10 feet it Was very evident that the sheeting
would be inside of the footing line. At this, Mr. Sebern asked
the engineer to change the d sign Which he refused to do and
for this reason it cost the FolwplluCo. a lot of money to
pull and reset the sheeting and when driving again, it was
most difficult to maintain them perpendicular. It was in
December before this pier was completed, the same type of
material being excavated as before and the foating set upon

solid rock at elevation 97.00 feet which was a foot higher

than planned.

In August 1929, the removal 0f the old foundations
in the river Was finally commenced and was found more
difficult than they had anticipated. The foundations were
built upon timber cribs filled with boulders and it was almost
impossible to get a tight cofferdam around them. The old
South Abutment was removed first, the pier next and the old
North Abutment last. This was completed in January and held
up the rest of the work a month. After their removal the sub-
structure was complete and ready to receive the arches.

In describing the work on the river foundations, the desc,
ription of the work being carried on at the points has been
postponed With the idea of giving a clear picture of the
river work, Which in reality was the key to the whole structune,
For while the viaduct work presented difficulties of a kind,
it was in no manner as difficult as the river foundations.
Having disposed of this and resuming at the point where the
columns and footings of the viaduct had been poured and
certain forming had been completed by December 1928, a
brief description of the viaduct constructicn from that point
on will be given. As has been stated in the design ,
expansion joints were placed at about 105' intervals, and
the pours consisted of beams, girders, deck, and sidewalk
slabs between these joints. All the items named were
considered in the design as monolithic concrete which must
be poured without construction joints, except as specifically
provided for or permitted by the engineer in charge. This
meant that in cold weather, all material for the pour must be

on hand and.heated to the proner temperature and that the

60.

provisions for heating the concrete when poured should be
fully ttken care of.

The first section of superstructure to be formed was
that from station 6-34 to 7-40 and contained 386.1 cubic
yards of concrete and 70,000# of reinforcing steel. This
pour then included 2 girders , 2 expansion girders ,3 spans
of 7 beams each, and 106' of deck and sidewalk slabs.

The formwork was simplified as much as possible by

the preparation of beam sides and bottoms on the work
benches, as were the girder sides and bottoms. All forms
for exposed concrete were sanded, using floor sanders, and
were oiled with parafin oil. The form work progressed
rapidly in this section. The beam sides and bottoms, were
set on the true grade and then blocked up to give a construct&
ion camber and allow for settlement. As beam sides were
set to position the decks were boarded up. The falsework
consisted of upright timbers, supdorted by bases and With
longitudinal caps upon which wooden wedges were used for
blocking. The main difficulty in forming came in supporting
the curb forms to grade and line. The method employed was that
of placing stakes under it and through the deck concrete, to
be withdrawn before the concrete fully set up, but this
proved unsatisfactory as a little settlement of the forms
caused uneven lines. Later a method of cantilever support,
as suggested by the engineers was used with good success.
This method of building forms was followed throughout the
entire superstructure and worked out very well.

In placing the reinforcing steel, only method was usually

possible whereby the bars could be threaded in the stirrups.

61.

This evolved into a rule of thumb method of placing Which
the workmen easily learned and was followed throughOut the
structure. The chairs used were those manufactured by the
Universal company and were placed often enough to support
the steel to the exact gage called for in the plans. As
soon as the superintendent learned that no slipshod work
would be permitted, the steeliwas well placed.

Before pouring any concrete, the forms were thoroughly
washed with the Special object of having all construction
Joints entirely clean and all pockets free of shavings, debris
etc. When everything Was ready the approval was given and the
work allowed to proceed. In placing the concrete, the plan
followed was to work uniformly across the transverse section,
in order to evenly distribute the weight an; settlement. The d
deck was screeded to guides set by insurunent and made to
conform to the roadway grade and crown. These screed strips
were set with a construction camber also and when checked
later were found to conform closely to the desired grade. The
deck was floated to grade after screeding several times.

The surface consisted of two rubbinds With carburundum
stones and water, the first given as soon as the forms were
stripped and the next as soon as possible thereafter. All
form marks were removed in the initial rubbing, While the
second, rubbing with a finer stone, filled the small irregular’
ities and gave a smooth, white surface.

The first section of superstructure was poured December
23,1928, and was heated to 70 degrees for 14 days. The
protection used was a large circus tent which proved quite
unsuitable because in handling over form work, it was

easily snagged and torn. The heat was furnished by salamandors

with tubs of water furnishing the moisture. This was the

last section poured until Apr111525, because of the severe
cold weather and the cost of the required heating. During

the summer the remaining section of the viaduct Was

poured. This being in hot weather, Water curing was sufficient,
The viaduct section was completed nearly to schedule.

The handrail and lamp posts were constructed as close
after the completion of the viaduct as possible. The forms
for the handrail and pilasters were lined with Presdwood, a
commercial product manufactured by the Hasonite Co. which
was entirely suited to this type of work. The Spindles were
made in cast iron forms as were the lamp posts, the forms
being furnished by the city. The Spindles were cast as
separate units and were a little difficult to nah . The
concrete, in setting would shrink and tear away from the
base. This Was overcome by pouring Slowly and using a
form vibrator, Operated by electricity. The same difficulty
was encountered in the lamp posts and was overcone in the
same way, The pilasters were cast first, then the base With
the rods protruding over which was set the Spindles which
were concreted in the ceping pour. The concrete used was s
1:1:1 mix, the sand was well graded and 1/4" peastone used as
coarse aggregate. This sand grading has much to do with tho
surface finish, for if preperly graded, a very smooth, dense
surface is eXposed that needs little finishing.

The surface of the deck was floated to grade and a 1/2"
sand cushion was placed under the brick. In April 1930, the
City of Lansing paved the roadway using HetrOpolitan Paving

brick of the highest grade. Three lines of white brick

63.

were used to divide the road into four traffic lanes which
proved quite suitable. The brick were washed in with hot
asehalt whici makes a very durable paving.

In January 1930, the construction of the arch ribs began
after the completion of the river foundations. The arches
were all formed and in each set the arches were poured in
pairs, the two outside and then the two inside. The centering
remained in place for 21 days. Wooden wedges were used to bring»
the forms to the true arch curve. The arches were poured from
the south towards the north span. The concrete was deposited
simultaneously at each Springing line and worked symmetrically
to the crown. In no case was it necessary to load the crown
to prevent Springing.

After the arches were poured, the formwork for the rest
of the superstructgre Was set completely and the columns
poured and stripped of forms for examination. The cinder
concrete was poured over the crown section where it would
be impossible to remove forms. This made an ideal concrete
material, being light and easy to place.

At the end of 21 days, the centering Was struck and the
deck concrete poured in three pours over each arch, the two
end sections being cast simultaneously. Construction Joints
were placed at the third points and the concrete separated by
cepper plates which was to permit elastic movement in the
arch. The arch superstructure was completed late in March 1930,

In order to protect the concrete, a huge building was
erected over the entire area to be poured and unit steam
heaters were installed about every 50'. These were fed from

the boilers on the cranes and they kept the temperature to the

64.

required point for the required time, which was usually 7C
de3rees for 14 days. All a33re3ates were sufficiently heated
so that the concrete could be depc sited {at a Lemmw
between 60 to 75 de3rees. This protection was required on
all concrete cast during freezin3 weather. 3

The completed viaduct we s accepted by the City Of Lansing
June 30, 1930.

 

 

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