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 ravail= 4.05 - 0.26 - 0.10
= 3.69 psi
Two times pressure load = 2(1.1) = 2.2 psi
3.69 >/= 2.2 psi
Since the maximum response of an element is twice the
blast load, this section is O.K.
(6)
Calculate new section properties.
new A = 401 + 96 x 1
= 497 in2
new yt = 6.85 + 1.0 - 96(7.35)/497
= 6.43 in
new Ig = 20985 + 401(1.42)2 + 96(1)3/12 +
96(5.93)2
= 25180 in4
d = 7.85 + 14.15
= 22.0 in
pp = 4 x 0.153/(96 x 22.0)
= 0.000290
(7)
Calculate fps.
fps = fpu [1- [gammap (pp fpu)]
K1
f'dc
[gamma]p = 0.40
K1
= 0.85 - 0.05 (6250 - 4000)/1000
= 0.7375
fps = 270,000 [1 - 0.40 (.000290 x 270,000/6250)]
.7375
= 268,167 psi
(8)
Calculate moment capacity of beam in loading phase.
Apsfps
a=
.85f'dc b
=
0.612(268,167)
.85(6250)96
=
0.32 in
c = a/K1
= 0.32/0.7375
= 0.43 in < 3.0 in thick flange
2.08-260
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