Floor Slab Adequacy Check
103.125
Length of Slab[short Direction] 20 feet.
Length of Slab[Long Direction] 20.5 feet.
Thickness Of Slab 6.25 in.
Length of Column Strip [Long Direction] 123 in.
Length of Middle Strip [Long Direction] 123 in.
Length of Column Strip [Short Direction] 120 in.
Length of Middle Strip [Short Direction] 120 in.
Edge Beam Depth 24 in.
Interior Beam Depth 24 in.
Edge Beam Width 12 in.
Interior Beam Width 12 in.
S.W.of Slab 78.125 Lb.
Floor Finish 25
Live Load 125 lb.
F'c 4003 psi.
fy 72500 psi.
Ec 3606348.15291037 psi.
Unit wt of concrete 150 pcf.
Step-01: Factored Load Calculation
qu=1.4 DL+1.7LL 356.875 psf. Fig: Typical Exterior pannel.
Say-
STep-02:Moment of Inertia Calculation
For the edge Beam I=b*h3/12*1.5 20736 in4.
For the interior Beam I=b*h3/12*2 27648 in4.
For the Slab Strip L1 19.5 ft.
Slab edge width 10.75 ft. L2 19 ft.
for 10.75 ft edge width I= 2624.5
for 20 ft width I= 4882.8 in4.
for 20.5 ft width I= 5004.9 in4.
αf
For,Edge Beam β
αf 7.9
For, two 20.5 ft Long beam
αf 5.7
For, two 20. ft Long beam
αf 5.5
Average Value αfm 6.4 234 0.8 0.3625 36 9.225
The Ratio of Long span & Short span, β 1.025
234 1.1625 45.225
Step-03: Thickness Of Slab
6.015 in.
Adequate. 6.014925 in
Provided= 6.25 in.
Step-04: Moment Calculation.[Short Direction]
Total Static Moment 330 k-ft.
Negative Design Moment,Mn 215 k-ft.
Positive Design Moment,Mp 116 k-ft.
Column Strip Width 10 ft.
L2/L1 1.025
6
From Eqn.7.9 .indicate 70 percent of negative 150 k-ft.
momenttaken buy column strip =
which 85% taken beam= 128
15% taken slab= 23
The Remaining 64.38 is alotted the slab middle strip. 64 k-ft.
Graph A.4 Also indicate that 70 percent of the 81 k-ft.
positive moment taken by column strip=
Which 85% taken beam= 69 k-ft. 70%
15% taken slab= 12 k-ft.
The Remaining 34.66 is alotted the slab middle strip. 35 k-ft.
Total Static Moment 160 k-ft. 34.66383
Negative Design Moment,Mn 104 k-ft.
Positive Design Moment,Mp 56 k-ft.
8
From Graph,A.4.indicate 70 percent of negative 73 k-ft.
momenttaken buy column strip =
which 85% taken beam= 62 k-ft.
15% taken slab= 11 k-ft.
The Remaining 31.23 is alotted the slab middle strip. 31 k-ft.
From Eqn.7.9 Also indicate that 70 percent of the 39 k-ft.
positive moment taken by column strip=
Which 85% taken beam= 33 k-ft.
15% taken slab= 6 k-ft.
The Remaining 16.81 is alotted the slab middle strip. 17
Beam Moment Column Strip Middle Strip
Interior Slab Beam Strip- 20 ft Span. Slab Moment Slab Moment
Negative Moment 128 23 64
Positive Moment 69 12 35
Exterior Slab Beam Strip- 20 ft Span.
Negative Moment 62 73 31
Positive Moment 33 39 17
Total Static Moment 339.3 k-ft.
10593 c= Hand Calculation
L2/L1 0.975609756097561
5.52420526829268
βt 1.0847232
From Eqn.7.9-Indicate column strip will take 92
percent of exterior nagative moment, 88 persent of
positive moment and 88 percent of interior
nagative moment.
As before Column Line Beam will account 85
percent of the column strip moment ,the Result o
applying these moment ratio are follows=
Beam Moment Column Strip Middle Strip
Slab Moment Slab Moment
Exterior Negative Moment for 20.5 ft span 42 7 4
Positive Moment for 20.5 ft span 145 26 23
interior negative moment for 20.5 ft span 178 31 28
Step-5: Slab Reinforcement calculation.
1 2 3 4 5 6 7 8 9
MuX12/b, Req. As, Provided.
20.5 ft.span, Location Mu'=k-ft. b,in. d,in. p
Ft-kips/ft. in2 As, in2
Exterior Negative 7 108 5.25 0.83230388 0.0021 1.22 5.83
Two Half Column Strip Positive 26 108 5.25 2.83616592 0.0021 1.22 3.88
interior negative 31 108 5.25 3.48301078 0.0021 1.22 5.83 p 0.135
Exterior Negative 4 120 5.25 0.4342455 0.0021 1.35 5.83
Middle Strip
Positive 23 120 5.25 2.32049939 0.0021 1.35 3.88 0.025714
interior negative 28 120 5.25 2.84973609 0.0021 1.35 5.83 0.002143
20 ft.Span.
Exterior Half-Column Strip. Negative 73 54 5.25 16.1924201 0.0021 0.61 5.83
Positive 39 54 5.25 8.71899546 0.0021 0.61 3.88
Middle Strip Negative 64 126 5.25 6.13142857 0.0021 1.42 5.83
Positive 35 126 5.25 3.30095238 0.0021 1.42 3.88 18.11142
0.327817 0.193412 0.806588
Interior Half-Column Strip. Negative 11.27 54 5.25 2.50349857 0.0021 0.61 2.91 14172.3 11431.21
Positive 6.07 54 5.25 1.34803769 0.0021 0.61 1.94
2.27464426471637 in
d= 2.27464426471637 in. OK p 0.0181
Step-6: Shear Check
Vu= 2.9528125 kips.
5.97894562193034 Kips. Ok.
63.26927 12
94.9039
5978.946
The Values of Moment of Inertia 5.978946
Short Direction Long Direction
IFrame 37537 in4 37333 in4
Icol 32112 in4 31931 in4
Imiddle 2563.47 in4 2442 in4 103.125
Deflection of Floor in Span Short Direction
0.011 in.
0.00835792071499751 in.
0.0563757133884929
So,
0.00835792071499751 in.
0.0563757133884929 in.
Deflection of Floor in Span Long Direction 103.25
0.013 in.
From ,The Moment Analysis , it was Found that the (0.92+0.88/2+0.88)*.5
column strip take 92 percent of the exterior negative =0.89
moment and 88 percent of the positive moment &
88 percent interior negative moment ,the average
Lateral Distribution foactor for column strip is=
0.0135273812282735
0.176880757575758
Mo= 108477.03125
108.47703125 k-ft.
we found 11 percent of the static moment 11.9324734375 k-ft.
the equvelent column stiffness as ,169E 609472837.841852
0.00023 red.
0.0070725 in
0.0205998812282735 in.
0.0634482133884929 in.
0.0769755946167664 in.
0.153951189233533 in.
0.093190792514245 in.
0.5125 in.
0.247141981747778 in.
Limit= 0.51 ok
