Civil Engineering Reference
In-Depth Information
c
w
=
ω+α
0.036
20.038
0.038
+
)
=
)
+ 0.72
= 0.092
(
(
2
ω+
0.85
×
0.85
⎛
⎞
⎛
⎜
⎞
⎟
P
u
A
st
f
y
c
w
M
n
=
0.5A
st
f
y
w
1
⎜
+
⎟
1
−
⎝
⎠
219
3.84
⎛
⎜
⎞
⎟
(
)
=
0.5
×
3.84
×
60
×
96 1
+
1
−
0.093 / 12
=
1633ft
−
kips
×
60
(
)
= 1469ft − kips < M
u
= 1712ft − kips N.G.
φ
M
n
=
0.9 1633
No. 4 @ 10 in. is not adequate for moment strength in the E-W direction at the first story level.
Try No. 5 @ 10 in.:
A
st
=
2
×
0.39
×
8
=
6.2in.
2
6.2
96
60
4
=
⎛
⎞
ω=
⎜
⎟
0.061
×
16
c
w
=
0.061
+
0.036
)
+ 0.72
= 0.114
(
2 0.061
219
6.2
⎛
⎞
(
)
M
n
=
0.5
×
6.2
×
60
×
96 1
⎜
+
⎟
1
−
0.014
/12
=
2094ft
−
kips
×
60
(
)
= 1885ft − kips > M
u
= 1712ft − kips O.K.
φ
M
n
=
0.9 2094
(b) For 2-8 ft wall segments at 2nd floor level:
P
u
= 171 kips
M
u
= 1016 ft-kips
3.84in.
2
A
st
=
Check No. 4 @ 10 in.:
ω=
0.038
171
α=
4
=
0.028
96
×
16
×
c
w
=
0.028
20.038
0.038
+
)
+ 0.72
= 0.082
(
171
3.84
⎛
⎜
⎞
⎟
(
)
M
n
=
0.5
×
3.84
×
60
×
96 1
+
1
−
0.082
/12
=
1474ft
−
kips
×
60
(
)
= 1327ft − kips > M
u
= 1016ft − kips O.K.
φ
M
n
=
0.9 1474
No. 4 @ 10 in. (required shear reinforcement) is adequate for moment strength above the first floor.
(c) For 2-8 ft wall segments at 3rd floor level:
P
u
= 128 kips
M
u
= 580 ft-kips
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