ASCE-7 Wind Load Cases
ASCE-7 Wind Load Cases
(OP)
For determining roof pressures for MWFRS in Design Load Cases 3 & 4 (Fig. 6-9 p. 54), are the roof loads additive for the different wind directions i.e. 0.75Px + 0.75Py for the roof as well as the walls?






RE: ASCE-7 Wind Load Cases
RE: ASCE-7 Wind Load Cases
Regards,
chichuck
RE: ASCE-7 Wind Load Cases
I think that we are saying the same thing. The diagonal wind was the problem with the Citicorp building for the bracing and shear walls. It is my understanding that these are for wall loads, not roof uplift
RE: ASCE-7 Wind Load Cases
RE: ASCE-7 Wind Load Cases
You have a very valid concern especially for pre-engineered light buildings.I believe based on the wind testing studies I have seen regarding "Quartering Winds" at say 30 to 60 degrees in the corner of the building, it is definitely occuring at the immediate areas of the roof in both directions. To quantify it, the suction/uplift forces on the roof perimeter strip edges in both directions can easily exceed a Cp coefficient of negative 4 and get quick spikes as high as negative 10 or 20. Its referred to as "Conical Vortices" on the roof. A great book for you to get is "Wind Loading on Structures" by Holmes. Its on page 172 and 173. As I see it, C&C loading issue for sure, MWFRS probably so in your case. Good Luck.