Civil Engineering Reference
In-Depth Information
12" x 12"
column
7-#4T
3'-3"
Column strip—10'-0"
(13-#4T)
Figure 4-20 Bar Layout Detail for 13-#4 Top Bars at Exterior Columns
8. Check slab shear strength at edge column for gravity load shear and moment transfer (see Fig. 4-21).
(a) Direct shear from gravity loads:
10.5'
live load reduction:
K
LL
A
T
(2 panels) = 24
20
2 = 960 sq ft
L = 50(0.25 + 15/
) = 36.7 psf
960
1
.32
'
q
u
= 1.2(142) + 1.6(36.7) = 229 psf
V
u
= 0.229[(24)(10.5) - (1.32)(1.65)] = 57.2 kips
(b) Moment transfer from gravity loads:
Critical section
When slab moments are determined using the approximate
moment coefficients, the special provisions of ACI 13.6.3.6
apply for moment transfer between slab and an edge column.
The fraction of unbalanced moment transferred by eccentricity
of shear (ACI 11.11.7.1) must be based on 0.3 M
o
.
Slab
edge
9 in. slab (d = 7.75 in.)
Figure 4-21 Critical Section
for Edge Column
(c) Combined shear stress at inside face of critical transfer
section:
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