Seismic Ch12 weight
Seismic Ch12 weight
(OP)
Is there not an inherent contradiction within ASCE 7 in that to calculate ELFs you use a seismic weight with only 25% of LL but then when you combine load factors you use up to 0.75LL for allowable stress design. So you are combining ELFs based on 0.25LL with gravity loads of 0.75LL?






RE: Seismic Ch12 weight
Regards,
M.S. Genidy, PE
Structural Soft, LLC
RE: Seismic Ch12 weight
RE: Seismic Ch12 weight
RE: Seismic Ch12 weight
DaveAtkins
RE: Seismic Ch12 weight
A 3'-0" tall stack of paper would shift all over the place.
RE: Seismic Ch12 weight
Also, whenever the snow load exceeds 30 psf, then a 25% factor, or whatever the local building official dictates, is added.
Mike McCann
MMC Engineering
RE: Seismic Ch12 weight
DaveAtkins and StructuralCA, I see what you were trying to say and that might be the case for designing individual members but for say footing design the same is true of the large tributary area for gravity loads as for earthquake loads. There are LL reduction factors for gravity loads of course to cover this but they would never get you down to 25%LL.
Msquared, thanks for that. Is that common practice or is it in the code?
RE: Seismic Ch12 weight
RE: Seismic Ch12 weight
Mike McCann
MMC Engineering
RE: Seismic Ch12 weight
RE: Seismic Ch12 weight
Mike McCann
MMC Engineering