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Column design in moment frames (for cladding spanning vertically vs horizontally)

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Samwise Gamgee

Structural
Joined
Oct 7, 2021
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118
Location
US
I have a system with moment frames and the analytical software I used adds wind load based on the wall exposure heights. However the actual condition I have is the walls are spanning horizontally. Per what I analyzed (in the screenshots below) , the columns will see an additional moment I need to account for if they are spanning horizontally. I put together some calcs and noticed that if I account for an additional 13% in the DCR for the columns, it should work. As long as my column DCR's have an additional 13%, it should be adequate right ? Or do I need to consider anything else I am missing?


1_ez34lc.png



2_f7rjxf.png
 
If your model has a rigid diaphragm, the lateral loads will be shared equally by the three frames. But since the cladding spans horizontally, the center frame will actually see twice as much lateral load as the outside frames.

I recommend modelling it correctly.

DaveAtkins
 
I would encourage you to find a way to manually load the frames in a way that is consistent with the building you are modeling. Using a %increase is not only tedious but its not accurate.
 
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