Two-Way Slab

l1 = 22 ft. (centerline span)

width, in 54 32.5 43 32.5 54 l2 = 18 ft. (transverse span)
c1 = 15 in. column
dimension
c2 = 15 in.
s
t= 6 in. (slab thk.)
ds = 4.75 in. (slab "d")
ln = 20.75 ft. (clear span)
bw = 15 in. (beam web width)
Exterior Span Moments (ft-k) Interior Span (ft-k) h= 20 in. (beam depth)
% of Mo from Table 16.2 16.00 57.00 70.00 65.0 35.0 beff = 43 in.
Total Moment at ….(ft-k) 48.36 172.29 211.58 196.47 105.79 y = 7.4872 in.
Column Strip Moment 42.24 138.61 170.22 158.07 85.11 Ig = 15781 in4
Beam portion 35.90 117.82 144.69 134.36 72.35 Is = 3888 in4
Column Strip slab 6.34 20.79 25.53 23.71 12.77 db = 17.5 in. (beam "d")
Middle Strip Moment 6.13 33.67 41.35 38.40 20.68 f'c = 3 ksi
beam Rn=Mu/fbd2 104.20 119.29 419.96 389.97 73.25 fy = 60 ksi
r 0.00177 0.00204 0.00770 0.00709 0.00124 m= 23.53
As =rbd, in2 0.47 1.53 2.02 1.86 0.93 wD = 100 psf
Col Strip slab Rn = 57.60 189.03 232.14 215.56 116.07 wL = 120 psf
r 0.00097 0.00328 0.00406 0.00376 0.00198 wu = 312 psf
As - in2 half on each side
of beam in col. strip slab 0.702 1.012 1.255 1.161 0.702 Mol = 302.3 ft-k

bt = 1.62 not more than 2.5

Mid Strip slab Rn = 33.52 184.26 226.28 210.12 113.14 af1 = 4.06
r 0.00056 0.00319 0.00396 0.00366 0.00193
As - in (half in each
2

middle Strip) 1.167 1.637 2.029 1.877 1.167

af1l2/l1 = 1.00
T & S % 0.0018
Edge Span
124.5 l1 = 18 ft. (centerline span)
29 71.5 39 l2 = 22 ft. (transverse span)
c1 = 15 in.
20 c2 = 15 in.
t= 6 in. (slab thk.)
15 ds = 4.75 in. (slab "d" using #4 bars)
ln = 16.75 ft.
bw = 15 in.
m 17.65 17.65 17.65 17.65 17.65 h= 20 in.
f'c 4 4 4 4 4 beff = 29 in.
fy 60 60 60 60 60 y = 8.4688 in. from top
Exterior Span Moments (ft-k) Interior Span (ft-k) Ig = 13468 in4 (beam)
% of Mo from Table 16.2 26.00 52.00 70.00 65.0 35.0 Is = in4 (slab)
Total Moment at ….(ft-k) 33.07 66.14 89.04 82.68 44.52 db = 17.5 in. (beam "d")
Column Strip Moment 26.29 45.20 60.84 56.50 30.42 f'c = 4 ksi
Beam portion 22.34 38.42 51.72 48.02 25.86 fy = 60 ksi
Column Strip slab 3.94 6.78 9.13 8.47 4.56 m= 17.65
Middle Strip Moment 6.79 20.95 28.20 26.18 14.10 wD = 100 psf
beam Rn=Mu/fbd 2
64.85 57.68 150.11 139.39 38.82 wL = 120 psf
r 0.00109 0.00097 0.00256 0.00237 0.00065 wu = 312 psf
As =rbd, in2 0.29 0.49 0.67 0.62 0.33 Mol = 127.2 ft-k
Col Strip slab Rn = 32.59 56.04 75.43 70.04 37.72 bt = 1.62 not more than 2.5
r 0.00055 0.00094 0.00127 0.00118 0.00063 af1 = 3.32
As - in half on each side
2

of beam in col. strip slab 0.772 0.772 0.772 0.772 0.772 af1l2/l1 = 1.0000

T&S% 0.0018
Mid Strip slab Rn = 102.83 317.38 427.24 396.73 213.62
 r 0.00174 0.00556 0.00764 0.00705 0.00368
As - in2 (half in each
middle Strip) 0.42 1.03 1.41 1.31 0.68
d" using #4 bars)
Flat Plate
1/2 middle strip column strip 1/2 middle strip
60 120 60

Exterior Span Moments (ft-k) Interior Span (ft-k)

26.00 52.00 70.00 65.0 35.0

Total Moment at ….(ft-k) 119.91 239.82 322.84 299.78 161.42

Column Strip Moment 118.94 143.89 242.13 224.83 96.85
Rn=Mu/fbd2 = 167.78 202.99 341.56 317.16 136.62
r 0.00290 0.00353 0.00614 0.00566 0.00234
As 3.08 3.76 6.53 6.03 2.49
Middle Strip Moment 0.97 95.93 80.71 74.94 64.57
Rn=Mu/fbd2 1.37 135.32 113.85 105.72 91.08
r 0.00002 0.00232 0.00194 0.00180 0.00155
As 2.16 2.47 2.16 2.16 2.16
 l1 = 24 ft. (centerline span)
l2 = 20 ft. (transverse span)
c1 = 15 in. exterior column
c2 = dimensions
15 in.
c1 = 20 in. interior column
c2 = dimensions
20 in.
t= 10 in. (slab thk.)
ln = 22.96 ft. (clear span)
f'c = 3 ksi
gc = 145 pcf
l= 1
fy = 60 ksi

bar dia. = 0.75 in. direction of l1

bar dia. = 0.75 in. direction of l2

ds1 = 8.875 in. (slab "d") direction of l1

m = fy/.85f'c 23.53
wD = 60 psf
wS = 125
wL = 80 psf
wu = 350 psf
Mol = 461.2 ft-k
bt = 0.081
af1 = 0
af1l2/l1 = 0.00
Torsional Constant C and b1
x y
15 20
C = (1 - 0.63 x/y)(x3y/3) = 11868.75
6 14
C= 735.84
0.0 0.0
C= 0.00 12605 = SC
l2 (ft) t (in)
18 6
Is = l2 t3/12 = 3888 in4
bt = C/2Is = 1.621
 x y

in4 y

x
Interior Beam (flange on both sides)
bE
bE = 43 in. bE/bW = 2.8667
bW = 15 in.
t= 6 in. t/h = 0.3
h= 20 in.
l2 = 22 ft
k = 1.5781
Ib = 15781 in4
Is = 4752 in4
af1 = 3.3209

bW

Edge Beam
bE

bE = 29 in. bE/bW = 1.9333

bW = 15 in.
t= 6 in. t/h = 0.3
h= 20 in.
l2 = 22 ft
k = 1.3468
Ib = 13468 in4
Is = 2511 in4
af1 = 5.3635
bW
bE

bW

bE