Load Combinations
Load Combinations
(OP)
I'm confused with the load combination's. The minimum live load is 20 psf. If designing a roof and taking a reduction due to area I get a roof Lr =12 psf. I have a snow load of 15.4 psf, DL = 20 psf, and WL = 15 psf.
In the load combination's is there still a LL or is the Lr the only live load?
D + .75W + .75L? +.75(Lr or SL)
In the load combination's is there still a LL or is the Lr the only live load?
D + .75W + .75L? +.75(Lr or SL)





RE: Load Combinations
Note that for low slope roofs your tributary reduction down to 12 psf may not apply because you are subject to minimum uniform loads, typically equal to ground snow load, and/or rain on snow loads of 5 psf.
Design for the larger of the appropriately adjusted live load or the snow load.
RE: Load Combinations
Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask
RE: Load Combinations