Wind loads on Diaphragms
Wind loads on Diaphragms
(OP)
Hi all, We usually use earthquake loads to design buildings against lateral loads because it yields a greater force compared to wind. I usually apply the earthquake load per storey on the floor diaphragm's center of mass + accidental eccentricity. Now going to wind loads, I have read that wind loads are usually applied on the perimeter walls of the building so I assume if the walls are non structural (ie brick) the loads would be applied on the exterior columns of the moment frames as a Uniformly distributed load (based on tributary area of each column). Please correct me if I am wrong about this.
My main question on this is can i treat the wind load as point load acting on the floor diaphragm on every storey (similar to wind loads) if yes, where would the load act on the diaphragm? on the center of rigidity? the geometric center on the face where the wind is acting (average of center of the leeward wall and windward wall)? center of mass?
My main question on this is can i treat the wind load as point load acting on the floor diaphragm on every storey (similar to wind loads) if yes, where would the load act on the diaphragm? on the center of rigidity? the geometric center on the face where the wind is acting (average of center of the leeward wall and windward wall)? center of mass?






RE: Wind loads on Diaphragms
RE: Wind loads on Diaphragms
For example - you might have exterior walls comprised of vertical studs. The studs span from floor to floor.
So as the load is applied to the wall, the 1/2 story of wind load is delivered to the diaphragm along the diaphragm width....both windward and leeward sides.
The codes distinguish between windward and leeward applied winds so these would be applied on either side (near side and far side) of the floor....1/2 wind from each adjacent half story.
The wind then essentially becomes a uniform load along the diaphragm which will "span" from brace line to brace line.
This would follow for other similar exterior wall systems that span vertically.
Other exterior walls (such as for industrial type buildings) may have horizontal girts that span from column to column. Just follow the load path as the wind is applied to the exterior envelope.
RE: Wind loads on Diaphragms
Mike McCann
MMC Engineering
RE: Wind loads on Diaphragms
RE: Wind loads on Diaphragms
RE: Wind loads on Diaphragms
But for the commercial office building - rigid and small diaphragm - the point load application would be fine for the overall lateral force system.
RE: Wind loads on Diaphragms
The conclusion I've got from the comments here is that the point load method is only applicable for rigid and small diaphragms. My follow up question to this is how can you determine if you have a rigid or flexible diaphragm? I have always thought that using RC slab equates to a rigid diaphragm.
RE: Wind loads on Diaphragms