Diaphragm Question

[strguy11]

I have a building with precast concrete walls with metal deck (untopped) roof diaphragm. I have calculated to be flexible.

My questions is that the discussion in the code of rigid/flexible and whether to include torsional effects only appears in the seismic parts of the code. For wind design, can you always consider the diaphragm flexible, and only perform a tributary beam loading analysis to find loads to the shearwalls? And if so, can this be done for the wind loads, even if it would be considered rigid for seismic?

 

[Lion06]

I don't think so. I'm sure others can comment further, but if you have a rigid diaphragm and a center of rigidity that favors one side because of a much longer wall, there will be torsional effects on the building. I don't see how you can just ignore it.
Additionally, ASCE 7 requires the torsional wind load checks (I believe this comes from quartering winds).

 

[Taro]

What building code are you using? The code should tell you how to apply torsional wind loads. For ASCE 7-05, see section 6.5.12.3. Buildings two stories or less with flexible diaphragms need not consider torsional wind load.