I ’-—* ——'- "" "'

 

 

 

 

«a
it? A STRUCTURAL ANALYSIS OF THE
‘ MICHIGAN STATE COLLEGE
LIBRARY BUILDING: II
,   THESIS IIIII IIII mm III B. s.
i _ ' - W. B. Edwards
.. “' * , 1931
:- ;. 3,

 

 

 

 

 

 

 

 

' A - — - ~~ -‘ — r ‘ _ - ‘_ _ ‘b - 2"-” ‘

 

 

PLACE IN RETURN BOX to remove this checkout from your record.
TO AVOID FINES return on or before date due.

 

DATE DUE DATE DUE DATE DUE

 

 

 

 

 

 

 

 

 

 

MSU Is An Affirmative Action/Equal Opportunity Institution

 

A Structural Analysis of

The Michigan State College Library Building

A Thesis Submitted to

The Faculty of
NICUIGAN STATE COLLEGE
of

AGRICULmURE AND APPLIED SCIENCE

By
W. B. Edwards
hhula-um

Candidate for the Degree of

bachelor of Science

June 1931

ACKNOWLEDGMENT

The writer of this thesis wishes to acknowledge the
assistance given him by Mr. C. L. Allen and Mr. C. L. Miller
of the Civil Engineering department, also the cooperation
of the Bowd-Munson Co. of Lansing, in furnishing detail

plans of the steel and reinforced concrete used in the

building.

w. B. E.

\h’
c

C?
01
FL

BIBLIOGRAPHY -

"Roofs & Bridges" - Merriman & Jacoby

"Graphic Statics" - Malcolm

"Structural Theory" - Sutherland & Bowman

"Theory of Structures" - Spofford

"Reinforced Concrete Construction" - Hool, Vol. I & II
Building Code - City of Lansing

A. I. S. C. Handbook

Carnegie Pocket Companion

INTRODUCTION

This thesis, "A Structural Analysis of the Hichigan
State College Library Building", is presented as a practical
problem on one phase of Civil Engineering; namely, Struc-
tural Engineering.

The building under consideration is located on the cam-
pus of the Michigan State College opposite the Engineering
Building. It was erected in 1922 by the State of Michigan;
Bowd-Munson a Co. of Lansing, being the architects.

The building is of brick and reinforced concrete con-
struction with a slate roof supported on steel trusses. In
general, the buildings may be divided into three parts: the
west ell, housing the book stacks; the east ell, housing the
Magazine Room, the seminars, and the College Museum; and the
main part of the building in which is located the graduate
study, the assigned reading room, and the main study hall.

The building may also be classified, for the purpose of
analysis, into the roof system, the floor system, the walls

and columns, and the footings.

PART I

The roof system is composed of four parts, the truss-

supported roofs over the east and west ells and the main sec-

tion of the building and the reinforced concrete slab roof

over the art gallery and main hall.
The first roof to be considered is the roof over the

main part of the building. It is composed of slate roofing

nailed to wooden sheathing which is SUpported directly upon

the purlins, 8" @ ll.25# channels, which are in turn support-
ed upon the modified Fink roof trusses shown in Fig. 1 at all
panel points with the exception of the end panel points just

above the reactions, the roof at the end resting directly

upon the wall of the building. The size of the members in

the roof truss, with other data concerning the trusses is
found in table 1 on the following page.

The loads upon the roof trusses may be divided into two
classes, the dead and the live. The dead load is composed of
the weight of the truss itself supported from the panel points
on the upper chord of the truss and the weights of the roof
covering and purlins on the upper chord and the weight of the

suspended ceiling on the lower chord which is also considered

as acting at the panel points. The live load may consist of

aany of several combinations of loadings acting at the panel
IDOints on the upper chord, the combination producing the
glusatest stress in each member being used in figuring the
f1—ber stress in that particular member. These different com-
biJnations of live loads are as follows: (1) snow over the en-

ticre roof, (2) wind on one side and snow on the opposite side,

 

 

 

 

 

 

 

 

 

 

TABLE 1
MAIN ROOF TRUSS DATA

MEMBER ANGLES WT/FT.
BS & B,S, 2-5x5%x5/16 17.4
CU & c,U, 2-5x5%x5/16 17.4
Dw & D,w, 2-5x5%x5/16 17.4
EY & E,Y, 2-5x5%x5/16 17.4
SR & 3,3, 2-4x5 x5/15 14.4
TQ & T,Q, 2-4x5x5/18 14.4
VP & V,P, 2-4x5x5/16 14.4
20 a 2,0, 2-4x5x5/18 14.4
ST & s,T, 1-2%X2x% 5.62
TU & T,U, 2-2%x2x% 7.24
UV & U,v, 2-2%x2x% 7.24
vx & v,x, 2-2%x2x% 7.24
xw & x,w, 2-2%X2x% 7.24
WY & v,y, 2-2%x2x% 7.24
xz a X,z, 2-2%x2%x% 8.2
YZ a Y'Z, 2-2%z?%x% 8.2
zz, 1-2%X2x% 3.62
Total weight

2374#

LENGTH

VI
7c
7t
71
4I
4t
9!
5r
4r
5!
91

10'
91
51
gr
gr

17'

AREA (in2)

5.12
5.12
5.12
5.12
4.18
4.18
4.18-
4.18
1.05
7.24
2.12
2.12
2.12
2.12
2.38
2.58

1.06

 

and (3) wind on one side and ice over the whole roof.

The dead load on the main truss is computed as follows:
the total weight of the truss itself as taken from table 1 is
2474 pounds, which, when distributed equally over the upper
chord, produces a load of 264 pounds at each of the inter-
mediate panel points and 152 pounds at each of the end panel
points; the weight of the roof covering is equal to the area
of the roof supported by the truss times the weight of a unit
area of the roof, the area being 586 square foot per side per
truss, and the weight being 11.25 pounds per square foot and
the sheathing 4.00. This makes the total weight of the roof
covering 4542.5 pounds, which, when divided equally among
the panels, produces a load of 960 pounds at each of the in-
termediate panel points, and a load of 480 pounds acting dir-
ectly upon the wall at each end. The dead load caused by the
purlins at each panel point is obtained by multiplying the
distance between trusses (13 feet) by the weight per foot of
the purlins (11.5 pounds) and is equal to 150 pounds per panel
point. The weight of the suspended ceiling on the lower chord
is taken as 10 pounds per square foot producing a load of 130
pounds per foot upon the chord of the truss. This is divided
proportionately amoung the various panels as is shown in the
load schedule in table 2.

In considering the live load, the snow load is taken as
10 pounds per square footl, and the ice load is taken as the

same, While the wind load is considered as being 20 pounds

 

1. "Theory of Structures" - Spofford

per square foot on vertical surface2 and the component nor-
mal to the surface is figured. by the formula Pu = R! 2%; .
These live loads are also shown in tabular form in table 2.

All stresses in the members of the main truss were
found by graphical methods, the stress in the ambiguous mem-
.bers wx and w,x, being found by the method as described in
Art. 25 of Part II of "Roofs & Bridges" by Merriman a Jacoby.
These stresses are found in table 5, and the graphic solutions
are found in Figs. 2, 3, and 4.

The Fink roof truss which is used on the east ell is
shown in Fig. 5 and the size of the members is shown in table
4. The method of computing the loads on the truss being the
same as that used on the main truss, the distance between
trusses being 16.53 feet, and the roof area per truss being
405 square feet. The loads on the east e11 trusses are shown
in table 5 and the stresses are shown in table 6 with the
graphical solutions in Figs. 6, 7, 8, and 9.

The third part of the roof system, the roof over the west
ell, is somewhat different than the others in that the truss
used to support the roof is statically indeterminate under
unsymmetrical loading such as snow 6r wind on one side. This
makes necessary certain assumptions in the computation of the
stresses, these assumptions being explained in the discussion
of the computation of the stresses produced by the unsymmetrical

loading.

The data regarding the members of this truss is found in

‘

2. Building Code - City of Lansing.

     

 

 

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EAST ELL - DEAD LOAD
SCALE I"=Iooo*

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EAST EL.
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PEACTIONS

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SCALE I”: :000“

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EAST ELL - SNOW ON EIGHT

SCALE - 11500“

 

TABLE 2

LOADS ON MAIN TRUSS

LOAD DEAD SNOW 0R ICE WIND
AB 150
BC 1580 970 1550
CD , 1380 970 1550
DE . 1:590 970 1550
EE' 1580 9V0 775
E'D' 1580 970
D'C' 1580 970
C'B' 1580 970
B'A' 130
AR 500
HQ 600
QP 900
P0 990
00' 780
O'P' 990
P'Q' 900
Q'R' 600
R'A' 300
Left Reaction 8140 5595 5050
Right Reaction 8140 3595 2400

Note:- All loads vertical except wind which is normal
to the roof surface

TABLE 5

STRESSES IN MAIN TRUSS NENBEFS

.MEMBER DEAD ICE 0N WIND MAX.
' STRESS WHOLE ROOF .
BS 15550 C 5900 C 4460 25690
CU 11940 C 5550 C '4460 21750
DW 10120 C 4750 C 4460 C 19550
EY 9550 C 4160 C 4460 C 17950
R3 10820 T 4850 T 5200 T 20870
QT 10640 T 4850 T 5200 T 20690
PV 9050 T 4140 T 5850 T 17040
OZ 6120 T 2750 T 1170 T 10040
ST 640 T 0 0 640
TU 1470 C 810 C 1550 C 5850
UV 2210 T 700 T 1520 T 4250
VX 2970 C 1590 C 1550 C 6110
XW 960 T 710 T 1520 T 2990
WY 1150 C 810 C 1550 C 5510
YZ 4580 T 2050 T 5950 T 10560
X2 5580 T 1540 T 2590 7510
ZZ' 780 T 0 0 780
X'Z' 5580 T 1540 T 0 4920
Y'Z' 4580 T 2050 T 0 6610
WVY' 1150 C 810 C 0 1960
X'W' 960 T 710 T 0 1670
V'X' 2970 C 1590 C 0 4560

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TABLE

DEAD

STRESS

2210
1470
640
6120
9050
10640
10820
9550
10120

11940

B

*3

v3

0 c: C) .3 a

(cont)

ICE 0N
WHOLE ROOF

700
810
0
2750
4140

4850

T
C

000081—3813

VII N D

0

0

0
1170
1170
1170
1170
5500
5500
500

5500

r—3

0 O C) 9—3 3-3 *3

0

MAX.

2910
2280
640
10040
14560
16660
16840
16790
18170
20570

22550

Maximum Compressive Stress is 4640 pounds per square

Maximum Tensile Stress is

5000 pounds per square

(DP—3

1-3

00005353538

inch

inch

MEMBER

BQ &
CS
DT

QK

2° 8° 2° 2°

C:
L?”
h—‘D
93

ST

311
U)
R°R° 898°

TU

Y0

‘ YN

YZ

YX

XW

TABLE 4

EAST ELL TRUSS DATA

ANGLES

2-4x5x5/16
2-4x5x5/16
2-4x5x5/16

2-5x5x5/8

2-5x5x5/8

Total weight

WT/FT
14.4
14.4
14.4
25.0
25.0

25.0

5.62
7.24
7.24
8.2

7.24

1200#

LENGTH
7' 11%"

7' 11%"

7' 114"

5' 8%"

5' 8%"

5' 7-5/16"
4' 5-5/16"
6' 6"

8' 10-5/8"
15' 6-9/16"
14' 6"

AREA (ing)

4.18
4.18
4.18
6.72
6.72
6.72
1.06
2.12
2.12
2.58

1.06

TABLE 5

LOADS 0N EAST ELL

LOAD DEAD SNOW 0R ICE SNOW 0N RIGHT WIND
AB 100
BC 1150 675 1550
CD 1150 \ 675 1550
DE 1150 675 558 675
EF 1150 675 675
RC 1150 675 675
GR 100
AK 470
KL 940
LM 940
MN 940
N0 940
OF 940
PH 470
Left React. 5795 1688 506.5 1540
Right React. 5795 1688 1181.5 1850
Note: - All loads vertical except wind which is normal

to the roof surface.

TABLE 6

STRESSES IN EAST ELL TRUSS MEMBERS
MEMBER DEAD SNOW ICE ON WIND MAX.
STRESS ON RT. WHOLE 0N LEFT
BH 9590 C 925 C 5110 C 2250 C 14750 C
CS 7450 C 925 C 2490 C 1850 C 11770 C
DT 7450 C 925 C 2490 C 5150 C 15090 C
KQ 6700 T 670 T 2260 T 2840 T 11800 T
LR 6700 T 670 T 2260 T 2840 T 11800 T
MU 5650 T 585 T 1200 T 500 T 4150 T
QR 940 T 0 0 0 940 T
RS 1550 C 0 500 C 1400 C 5450 C
ST 1150 C O 675 C 1900 C 5725 C
TU 4560 T 150 T 1550 T 5590 T 9500 T
UV 940 T 0 0 0 940 T
VW 4560 T 1500 T 1550 T 200 T 6510 T
WX 1150 C 675 C 675 C 0 1825 0
XY 1550 C 500 C 500 C 0 2050 C
YZ 940 T O O 0 940 T
NV 5650 T 585 T 1200 T 500 T 5150 T
CY 6700 T 1525 T 2260 T 580 T 9540 T
P2 6700 T 1525 T 2260 T 580 T 9540 T
EW 7450 C 1500 C 2490 C 2190 C 12150 C
F1 7450 C 1500 C 2490 C 2190 C 12150 C
02 9590 C 2125 C 5110 C 2190 C 14690 C

is 5550 pounds/sq. inch

Maximum compressive stress
1750 pounds/sq. inch

Maximum tensile stress is

A. . "l. ‘ .I I
‘

 

.15 50>, - 353 L8»

 

 

 

 

 

table 7 and the loads on the truss are found in table 8.
The dead stress in the members of the truss have been
computed by the method of joints, these computations being

shown in the following paragraphs.

 

 

5898.5
St ess - _ r
5 r (BR) .70., 559095 c
95
H t 898 5#
S e S :3) o
A I" 8 (AH) T
. 3995 EM: 0
5898.5(9.91) - 1559.4 (4.95) - 7.01 8(CNT 0
’5“ s - 44004‘ c
6 (CK)
A, R _ I:
5 1559-4 (-.90) 7.01 3(HK) o
H 3(HK)= 1100# c
13900
A530
2M=0

= #
S(KN) 779.7 T

 

-——i

3900

MENBER
BH & GS
CK & FP
DM 5 EM
HK & PS
KN & NP
MN

HNS-A

TABL 7

L13

WEST ELL TRUSS DATA

ANGLES
2 - 4x5x5/16
2 - 4x5x5/16
2 - 4x5x5/16
2 - 5x5x5/16
2 - 5x5x5/16
2 - 5x5x5/16
18" - 20" G

Total weight

wr./FT.

14.4
14.4
14.4
12.2
12.2

2.2

*-

1159.41#

LENGTH

71-
7:-
7!-
7t-
91-
9!-

291-

1/8"
1/8"
1/8"
1/8"
11"
ll"

9"

* Weight of Girder beam considered elsewhere

AREA (ind)

4.18
4.18
4.18
5.56
5.56

5.56

TABLE 8

LOADS ON WEST ELL

LOAD DEAD SNOW 0R ICE SNOW 0N RT. WIND
BC 1560 1080 2160
CD 1560 1080 2160
DE 1560 1080 540 1080
EF 1560 1080 1080
F0 1560 1080 1080
GA 95
AB 95
Left Reaction 5995 2700 810 V 1550
H 1915
Right Reaction 5995 2700 1890 V 5825
. H 1915

Note:- All loads vertical except wind which is normal
to the roof surface.

 

 

2M=0
c 1559.4 (9.91+4.95) = 9.915 s 7
K N # (ILN)
” §Fv=o
f A

S(DM)==5898.5 - 2(1559.4) €‘.707'= 110d# 0

K ._ , .. g #

 

The stresses in the members on the opposite side of the
truss are the same as those already computed.

The stresses for ice or snow over the entire roof are
shown in Fig. 11 and are included in the table on stresses in
West ell members, Table 9.

From this point on the truss becomes statically indeter-
minate if the entire truss is considered as a unit with reac-
tions at each end of the supporting girder beam, but if the
Upper portion of the truss is considered as being SUpported
by the girder beam with reactions at the four points where
the truss is fastened to the girder H, N, S, A, the stresses
for conditions of unsymmetrical loading may be readily computed.
Following is the solution for snow on the right side of the
truss. The loads as given in Table 8 are DE =540#, EF & FG==

1080#. These loads are considered as being transmitted to

 

 

 

/:\

 

3

\VEST ELL- ICE ON \VHOLE IZCQDF‘
SCALE- \”= 1000‘

the beam along the most direct route causing reactions on the
beam, reading from left to right, of 0, 270, 1890, and 540
pounds, respectively. With this assumption the stresses may
be readily figured by the method of joints.

Since the left reaction is zero, it is apparent that the

stress in members BH, HA, HK, and CK must also be zero.

=540 -.‘- .707 =750# c

 

 

S<se>
#
=7 .70 '-'-‘ ,
A
[080 J40
F S 1080 760#
p G (PS) ‘ .707 X '5' C
5
6'40
0 E S 540 - 580
M (DM) I 2(,'70'7) C
SUN?) = 540 =380# C

s = 270*"
(KM) C

 

 

3(MN)==580 X .707 = 270# T

 

=(3
S(CK) .
mo
E #
S = 3» + . , = 3,
M ,F (NP) 1030 707 x580 1 50 C
N’
‘p

 

Considering the reactions as concentrated loads upon the
beam, the reactions upon the walls may be determined by the
equation 2M: 0.

(270)1 + (1890)2 + (540)5 = 5 R

(right)

a #
R<right) 1890

The other condition of unsymmetrical loading is that of
the wind on the left side of the roof. The wind load as com-
puted by the formula in the discussion of the main truss is
20 pounds per square foot normal to the surface which is at
an angle of 450 with the horizontal. The panel loads as given
in table 8 are 2160# at the top panel point. The reactions
here are considered in the same manner as were the reactions
for the unbalanced snow load, that is, there are assumed to
be four reactions instead of the customary two end reactions.
Since the loads are normal to the surface there will be both
horizontal and vertical components to the reactions on the
beam, the horizontal components being considered as produc-
ing shear in the rivets which fasten the truss to the girder
beam, there being fourteen rivets at each end joint and twelve
at each intermediate joint. The reactions on the girder beam
are taken as follows: left - zero, second - vertical 5060#,

#; third - vertical negative 1550# (acting down)

horizontal 1550
horizontal zero; right - vertical 2295#, horizontal 2295#.
With these assumptions it is very easy to compute the stresses
in the members using the method of joints. The stresses com-
puted in this manner are shown with the other stresses in
west ell members in table 9.

One further assumption is made in the computation on
this truss, that is that the horizontal components of the re-
actions on the girder are transmitted equally to the support-

ing walls causing a horizontal component of 1915# on each

wall. The vertical components of the reactions are:

TABLE 9

STRESSES IN WEST ELL TRUSS MEMBERS

MEMBER DEAD SNOW ICE 0N WIND 0N MAX.
STRESS ON RT. WHOLE LEFT
BR 5520 C 0 5810 C 0 9550 C
CK 4400 C O 5050 C O 7450 C
DM 1100 C 580 750 C O 1850 0
HA 5900 T 0 2750 T 0 6650 T
NA 5120 T 0 2180 T O 5500 T
HK 1100 C O 750 C 2160 C 4010 C
KN 780 T 270 540 T 1550 C 1520 T
1020 0*
EN 2540 C 270 1650 C 1550 C 5520 C
ND 780 T 1550 540 T 1550 T 2850 T
570 C*
PS 1100 C 760 750 C 0 1860 0*
SA 5900 T 540 2750 T 0 6650 T
NE 1100 C 580 750 C 1080 C 2950 C
PF 4400 C 0 5050 C 5240 C 10690 0
SC 5520 C 760 5810 C 5240 C 12570 C

* Maximum produced with snow on one side

Maximum compressive stress is 5000 pounds/square inch

Maximum tensile

stress is

800 pounds/square inch

left - 1530# and right - 2295#.

The fourth and last section of the roof system is the
flat slab roof over the art gallery and main stairway. Since
data concerning the placing of steel in this slab was not a-
vailable, the only computations made were the values of the
reactions upon the wall. The slab is a 4" slab covered with
cinders and roofing material. It is 28' wide and is supported

# I-beams spaced 15 feet apart. The total weight

on eight 9" -21
of the roof including a dead load of 55 pounds and a snow load
of 10 pounds, is 65 pounds per square foot.. Considering a
section of the slab one foot wide as a continuous beam over
the eight supports the loads per foot upon the supporting I-
beams are as follows:

Supports No. 1 & 8 555 pounds per foot

Supports No. 2 & 7 960 pounds per foot

Supports No. 5 & 6 786 pounds per foot

Supports No. 4 & 5 855 pounds per foot

The above loads, together with the weight of the I-beams

produce the following reactions upon the supports:

On each end of the 1 st & 8 th beams 4,950 pounds
2 nd & 7 th beams 15,750 pounds
5 rd & 6 th beams 11,500 pounds

4 th & 5 th beams 12,250 pounds

PART II '

After considering the roof system, the next part of the
building to be considered will be the floors. All of the
floors in the building, with the exception of those of paten-
ted construction used in the book stacks, are of reinforced
concrete. The important slabs are of the steel pan type of
construction, the slabs being 2" thick and the joists varying
from a" to 14".

The first slab to be considered will be the one in the
attic of the west e11. This slab is of type "X" and has a
Span of 14' from girder to girder. It is 6" thick and is re-
inforced with 5/8" round bars 8" c.c. The dead load per
square foot is 1 x 1 x s x 150, or 75 pounds. The live load
as taken from the Lansing Building Code is 20 pounds per
square foot, making a total load of 95 pounds per square foot.

M = 1/8 w12 =-. 1/8 x 95 x (14)2=2550'# = 27,960"#
.4602
12 x 6
J' *o884 " ; k = .355
f8" 27960
.4602 x 6 x .884

AS= .5068 x 12/8 =.4602 ; p -.-.

 

= .0064

==ll,400 pounds per square inch

 

2 .0064
fC == (11’423; x - = 412 pounds per square inch

 

The reactions on the walls, exclusive of the weights of
the girders are % x 95 x 14 x 54 22,600#, acting at each end
of each girder, and an equal weight uniformly distributed over

each of the end walls. Each of the two southermost girders

weighs 5920 pounds, 1960 pounds being carried by each support,
while the remaining girders weigh 5220 pounds, 1610 pounds
acting at each support.

The only other slabs at the same elevation as the above
are two small slabs in alcoves off of the attic. Wtese slabs
are 6' long and 10' wide and 4" thick, having 5/8" round bars
6" 0.0. The dead load is 50 pounds per square foot and the
live load is 20 pounds per square foot, making a total load
of 70 pounds per square foot.

"'
M = 1/8 x '70 x 56=.)15'# = 5780 #

 

AS: 2 x .1104 = .2202 ; p =.2208/48 =.0045
j = .897 k =.505
f 5 5780
s ~~ = 4770 pounds per square inch

.2208 X 4 x .897

2 x 4770 x .0045
f0 = 505 =:l41 pounds per square inch

 

The total weight distributed over each of the supporting
walls is 70 x 5 x 10, or 2100 pounds.

The remaining floors slabs have been checked by finding
the safe load as given in tables taken from the Concrete De-
signer's Nanual by 8001 and Whitney. These results are found
in table 10 on the following page.

The last point for consideration under the general class-
ification of floors will be a typical stair slab used in the
main stairs. The slab considered is the one leading from the
first floor to the landing. This is a 7" slab, 17' long, hav-

in

ing ‘ square bars, %" c.c. and 1/4" round bars, 12" c.c.,

making a steel area of .594 square inches. The live load to

SLAB

W

(IQ

TABLE 10

FLOOR SLABS

LOCATION

Middle 5 Seminars and
Conference Rooms
N & S Seminars

E

up

of Delivery Room

N 1/5 of w 5; s 1/5 of w 4

of Delivery Room

Middle 1/5 of w 4 of
Delivery Room

SW & SE corner of Main
Reading Room

NW & NE corner of Kain
Reading Room

S center section of
Main Reading Room

N center section of
Kain Reading Room

Art Gallery
East end of hall
Coat Rooms (lst. floor)

Assigned Readings and
Graduate Study

Hall
N. Vestibule

Library Offices -
Catalogue Room

Corridor

(cont)

SAFE LOAD
#/sq. ft.

112
95
101

162

164

155

150

150
101
162
164

(64)
(48)
(4O)

(55)

(125)

(105)

(78)

(75)

(100)
(40)
(125)

(105)

(78)
(75)

(100)

(40)

(186)

AREA
39

496
496

512

96

144

1008

527

182
1162
70
496

1008

01
(0
<1

182

884

155

ft.

TOTAL LOAD
PER SLAB

55,600
46,100
51,600

9,150

25,500

21,500

154,000

58,500

27,500
117,500
11,540
51,500

154,000
52,500

27,500

99,200

56,900

SLAB

TABLE 10

LOCATION

N & S Assigned Reading
Periodicals (e. ell)
Periodicals(0ther than s)

Supplies (Basement)

ACloset

Corridor

Staff Room and
Receiving Room

Storage - south part
Storage - north part

Bindery - Janitors room
Rest room (mid)

Bindery - Rest room

N 4 S sections
Fan Room S. Section
Basement

Fan Room Cent. Section
Fan Room - N. Section

Air Chamber

Safe Live Load in Parenthesis

(cont)

SAFE LOAD
#/sq. ft.
95 (48)
95 (48)
105 (57)
204 (104)
241 (186)
101 (40)
164 (103)
155 (78)
95 (48)
95 (48)
188 (112)
188 (112)
578 (502)
178 (126)

AREA
sq ft.
496
496

527

256

810

TOTAL LOAD

PER SLAB

46,100
46,100
55,500
54,200

56,900

89,200
81,500

154,000

46,100

46,100

96,400
96,400
96,800

144,400

be used is taken as 100 pounds per square foot.
"-
M‘= 1/10 wl2 = 1/10 x 187.5 x (17)2 =.542079‘ =-6504o #

‘ 65040

_ 4— =.l7,750 pounds per square inch
3 .594 x .885 x 7

(18,000 allowable)

 

f =. 2 X 17750 X .594 =. 642 pounds per square inch

C 0551 X 94
(650 allowable)

 

PART III

The last parts of the building to be analyzed in this
thesis are the columns, the bearing walls and footings.
Since a number of the columns, walls and footings are of the
same type, only one of each will be considered here.

The column to be considered is one of the columns sup-
porting the roof of the west ell and the attic floor in the
west e11. This column is 45'-4" long and has a cross-sec-
tional area of 720 square inches. As the column is a por-
tion of the west wall of the building, there is ample sup-
port to prevent buckling, thus compressive area will be the
limiting factor in the design of the column; and since a
steel plate is used to spread the load over the t0p of the
column the allowable stress will be somewhat above the 500
pounds per square inch as recommended by the Joint Committee
for plain concrete columns made of 2000 pound concrete.

The maximum load upon the column is somewhat under
56,000 pounds, (55,080), but to allow for the weight of the
parapet wall and the end reactions of the roof, this value
will be taken, giving a unit stress of 56000/720, or 50

pounds per square inch.

It would seem that the size of the column was determined
by artistic considerations rather than by the stress in the

member.

The wall to be considered is the east wall of the west
ell. This wall is 17" thick, and the maximum load per foot

of wall is the reaction of the roof truss and floor girder

in the attic; the load being 56,000 pounds plus 8500 pounds
which is the weight of one foot of the wall itself. The

load is transmitted to the wall by means of a plate 12" x 14",
therefore the effective area considered will be 168 square
inches. The unit stress will be 44500/168, or 265 pounds per
square inch.

The first footing checked will be one of the footings
under the book stacks. One cubic foot of books weigh approx-
imately 64 pounds. In computing the weight supported by the
footings under the stacks, a value of 70 pounds will be taken
to allow for the weight of the stacks and other loads support-
ed by them.

The total load upon each book-stack footing is 12 x 2 x 42
x 70, or 70560 pounds.

The area of the base of the footing is 28 square feet,
making the total load equal to 2520 pounds per square foot,
this being less than the allowable under the most adverse con-
ditions.

The other footing checked is the footing under the wall
column discussed previously. The externally applied load is
56000 pounds, which with the load of 50000 pounds exerted by
the column itself, applies a total load of 66000 pounds. The
area of the footing is 9.72 square feet, making the load per
square foot equal to 6800 pounds, this load being allowable
under good conditions.

While there are other parts of the construction which

might be included in this problem, those presented are typical

examples and are all that could be done in the time allotted

with the data available.

F I N I S

 

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