Civil Engineering Reference
In-Depth Information
2.
Is it a slender column?
9
u
12
12
11.25 ft
Max
k
u
4
to be a short column
22 for nonsway frames.
k
u
r
(1.95)(12
11.25)
0.3
12
73.12
22
It is a slender column
3.
Consider the loading case U
1.2D
1.6L
(
See Figure 11.10
).
a.
Are column moments
ACI minimum?
e
min
0.6
0.03
12
0.96 in.
M
2,min
(66)(0.96)
63.36 in.- k
5.28 ft- k
173.5 ft- k
(see Figure 11.10)
OK
b.
Compute the magnification factor
ns
:
E
c
57,000
4000
3,605,000 psi
3605 ksi
(1.2)(1)
(1.2)(1)
(1.6)(2)
d
0.273
(0.4)(3605)(1210)
1
0.273
EI
1.37
10
6
k-in.
2
Figure 11.10
