Problem 2.25
Load Symbol Given Value (psf)
(acting downward)dead load D 10 weight of ice Di 0 earthquake load E 2 load due to fluids F 0 flood loads Fa 0 load due to sub-surface pressure H 0 live load L 0 roof live load Lr 20 rain load R 30 snow load S 35 self-straining force T 0 wind load W 18 wind-on-ice Wi 0
ASCE 7 LRFD Load Combination Possible Values (psf) Largest Value (psf) 1 1.4(D + F) 14 14 2 1.2(D + F + T) + 1.6(L + H) + 0.5(Lr or S or R) 22 or 29.5 or 27 29.5 3 1.2D + 1.6(Lr or S or R) + (L or 0.8W) 58.4 or 82.4 or 74.4 82.4 4 1.2D + 1.6W + L + 0.5(Lr or S or R) 50.8 or 58.3 or 55.8 58.3 5 1.2D + 1.0E + L + 0.2S 21 21 6 0.9D + 1.6 W + 1.6 H --A --A 7 0.9D + 1.0E + 1.6 H --A --A A Combinations 6 and 7 are not applicable because W and E are acting in the same direction (downward) as D. See highlighted paragraph in ASCE 7 section C2.3.
Note a small difference in IBC, where f1 = 1 or 0.5 and f2 = 0.7 or 0.2. See 1605.2.1 for details.
IBC LRFD Load Combination 16-1 1.4(D + F) 16-2 1.2(D + F + T) + 1.6(L + H) + 0.5(Lr or S or R) 16-3 1.2D + 1.6(Lr or S or R) + (f1L or 0.8W) 16-4 1.2D + 1.6W + f1L + 0.5(Lr or S or R) 16-5 1.2D + 1.0E + f1L + f2S 16-6 0.9D + 1.6 W + 1.6 H 16-7 0.9D + 1.0E + 1.6 H