Civil Engineering Reference
In-Depth Information
Design for flexure:
Check moment strength for required vertical shear reinforcement No. 4 @ 9 in
ρ
˜
= 0.2/(9
8) = 0.0028.
For 1-20 ft-8 in. wall segment at first floor level:
Consider
P
u
= 279 kips
M
u
= 7839 ft-kips
˜
w
= 248 in.
h
= 8 in.
For No.4 @ 9 in.:
A
st
= 0.0028
20.67(12)(8) = 5.5 in.
2
5.5
248
60
4
=
⎛
⎜
⎞
⎟
ω=
0.042
×
8
279
α=
4
=
0.035
248
×
8
×
c
w
=
0.042
+
0.035
)
+ 0.72
= 0.095
(
2 0.042
279
5.5
⎛
⎜
⎞
⎟
(
)
M
n
=
0.5
×
5.5
×
60
×
248 1
+
1
−
0.095 / 12
=
5699 ft
−
kips
×
60
(
)
= 5129 ft − kips < M
u
= 7839 ft − kips.
φ
M
n
=
0.9 5699
Use No. 6 @ 6 in spacing
ρ
= 0.44/(6X12) = 0.0065
A
st
= 0.0065
20.67(12)(8) = 12.81 in.
2
⎛
⎜
12.81
248
⎞
⎟
60
4
=
ω=
0.097
×
8
279
α=
4
=
0.035
248
×
8
×
c
w
=
0.035
+
0.097
)
+ 0.72
= 0.144
(
2 0.097
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