Civil Engineering Reference
In-Depth Information
The portion of the interior negative design moment allotted to the column strip, from Table
16.3, by interpolation is (0.80)(
212)
170 ft-k. This
170 ft-k is allotted 85% to the beam
(Code 13.6.5), or
145 ft-k, and 15% to the slab, or
26 ft-k. The remaining negative moment,
212
170
42 ft-k, is allotted to the middle strip.
The portion of the positive design moment to be resisted by the column strip, as per Table 16.5, is
(0.80)(157)
126 ft-k This 126 ft-k is allotted 85% to the beam, or (0.85)(126)
107 ft-k, and 15%
to the slab, or
19 ft-k. The remaining positive moment, 157
126
31 ft-k, goes to the middle strip.
The portion of the exterior negative moment allotted to the column strip is obtained by double
interpolation from Table 16.4, and is (0.86)(
79)
68 ft-k. This
68 ft-k is allotted 85% to the
beam, or
58 ft-k, and 15% to the slab, or
10 ft-k. The remaining negative moment,
11 ft-k, is
allotted to the middle strip.
A summary of the long-span moments is presented in Table 16.8.
Table 16.8
Long-Span Moments (ft-k)
Column strip moments
Middle strip
Beam
Slab
slab moments
145
26
42
Interior negative
107
19
31
Positive
58
10
11
Exterior negative
7.
Check shear strength in the slab at a distance
d
from the face of the beam. Shear is assumed
to be produced by the load on the tributary area shown in Figure 16.19, working with a 12-in.-wide
strip as shown.
3
1
d
h
cover
half bar diam.
6.00
4
4
5.00 in.
9
7.5
12
5
V
u
(0.312)
2.483 k
2483 lb
12
V
c
(0.75)(2
3000)(12)(5)
4930 lb
2483 lb
OK
Figure 16.19
