Civil Engineering Reference
In-Depth Information
Computing Magnified Moment
M
c
M
c
M
2
ns
s
M
2
s
(ACI Equation 10-16)
97.5
(1.80)(90)
259.5 ft- k
Is M
c
minimum value permitted in ACI Section 10.12.3.2?
M
2,min
P
u
(0.6
0.03
h
)
(ACI Equation 10-14)
(544)(0.6
0.03
18)
620.2 in.- k
51.7 ft- k
259.5 ft- k
Yes
Selecting Reinforcing
13
18
0.722 with reference to Figure 11.8
P
n
P
u
544
0.65
836.9 k
e
(12)(259.5)
544
5.72 in.
P
n
836.9
(4)(18
18)
0.646
K
n
c
A
g
f
P
n
e
5.72
18
R
n
h
(0.646)
0.205
c
A
g
f
By interpolation between Appendix A Graphs 3 and 4, we find
g
0.0304
A
g
g
A
g
(0.0304)(18
18)
9.85 in.
2
Use 8 #10 Bars (10.12 in.
2
)
11.10
ANALYSIS OF SWAY FRAMES
The frame of Figure 11.9 is assumed to be unbraced in the plane of the frame. It supports
a uniform gravity load
w
u
and a short-term concentrated lateral load
P
u
. As a result, it is
Figure 11.9
