Live Load Reduction per area
Live Load Reduction per area
(OP)
Case 1: Suppose we have a beam with tributary area of 300 sq. ft. and roof live load can be reduced to 0.9 x L (10% reduction).
Case 2: Now suppose we add a second (continuous), equal span so that we have 2 spans of 300 sq. ft. tributary area each for a total of 600 sq. ft.
Now, it is clear that the beams in both cases should be designed with roof live load reduced 10%, but what about the design loads for the center supporting post?
Should the live load acting on the post be reduced for:
A) Trib area = 600 sq. ft.
B) Trib area = 300 x 1.13 = 338 sq. ft. (based on the actual reaction at the center support, i.e., the wl x 1.125 reaction at the center support of a 2-span continuous beam equally loaded both spans)
Case 2: Now suppose we add a second (continuous), equal span so that we have 2 spans of 300 sq. ft. tributary area each for a total of 600 sq. ft.
Now, it is clear that the beams in both cases should be designed with roof live load reduced 10%, but what about the design loads for the center supporting post?
Should the live load acting on the post be reduced for:
A) Trib area = 600 sq. ft.
B) Trib area = 300 x 1.13 = 338 sq. ft. (based on the actual reaction at the center support, i.e., the wl x 1.125 reaction at the center support of a 2-span continuous beam equally loaded both spans)






RE: Live Load Reduction per area
Mike McCann
MMC Engineering
http://mmcengineering.tripod.com
RE: Live Load Reduction per area
BA
RE: Live Load Reduction per area
RE: Live Load Reduction per area
Snow load S is not allowed to be reduced for area in the IBC. That makes sense. I never did reduce snow load...it has been a few years since I had a snow load project.
Actually, my OP asks the same question regarding reducible floor loads.
RE: Live Load Reduction per area
In lower floors, though, it can be reduced.
Mike McCann
MMC Engineering
http://mmcengineering.tripod.com
RE: Live Load Reduction per area