Moment Frames: Wind Drift at COM? 1

[JC20]

I apologize about the simplicity of this question. Here in CA we're not used to wind drift governing design. We are working on a moment frame building in a low seismic area so wind loads are higher. We are limiting wind drift to h/400. My boss says to just check wind drift at center of mass. This doesn't make sense to me since wind is determined by exposure, not rigidity or weight. Do you typically check wind drift/displacement at center of mass or at extreme ends of the building. Thanks for your help!

 

[DaveAtkins]

Wind drift is typically checked at the moment frames themselves, because diaphragm deflection is generally small. If diaphragm deflection will be large, that should be considered as well.

DaveAtkins

 

[jike]

I would check deflections at the ends or corners of buildings. Depending upon the arrangement of bracing, you might see more movement at the corners due to torsion than you see at the center of mass. You are looking for the largest movement not an average movement. It is these large movements that can crack brick, pull flashing loose, etc.