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 K*lx/rx = 0.75(17 x 12)/5.25 = 29.1
K*ly/ry = 0.75(17 x 12)/1.54 = 99.4
Fa = 13.10 ksi for K*ly/ry = 99 and Fy = 36 ksi
Fa = (1.1)(13.10) = 14.41 for Fdy = 39.6 ksi
Mmx = [1.07 - (*l/ry)(Fdy)1/2/3160]Mpx < /= Mpx
= [1.07 - (204/1.54)(39.6)1/2/3,160]169.0
= 136.2 < 169.0 ft-k
F'ex = 12[pi]2E/23(K*lb/rx)2
= 12[pi]2(29,000)/23(29.1)2 = 176.3 ksi
Pex = 23AF'ex/12 = 23(10.3)(176.3)/12 = 3,481 k
Pp = FdyA = 39.6(10.3) = 408 k
Pu = 1.7AFa = 1.7(10.3)(14.41) = 252 k
Cmx = .85 (Section 1.6.1, AISC Specification).
(6) P/Pu + Cmx Mx /(1 - P/Pex )Mmx
+ Cmy My/(1 - P/Pey)Mmy < /= 1
= 53.5/252 + 0.85(115)/(1 - 53.5/3,481)136.2
= 0.212 + 0.729 = 0.941 < 1
O.K.
P/Pp + Mx /1.18Mpx + My /1.18Mpy < /= 1
= 53.5/408 + 115/1.18(169)
= 0.131 X 0.577 = 0.708 < 1
O.K.
d.
Design of Single-Story Rigid Frames for Pressure-Time Loading.
Problem:
Design a single-story, multi-bay rigid frame subjected to a
pressure-time loading.
Given:
(1) Pressure-time loading.
(2) Design criteria.
(3) Structural configuration.
(4) Properties of steel.
2.08-184
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