ASCE 7 MWFRS Wind Load Case 3

[eng003]

I am working on a design spreadsheet for lateral wind design of one and two story structures. The structures will all all have wood roof and/or floor diaphragms (flexible). Walls will either be frame or masonry. For these type of strucutres ASCE 7 notes you only have to evaluate CASE 1 & 3 of the MWFRS load cases. I am trying to see the need in my case for evalutaing case 3 which applies 75% of each orthogonal load at once. The 100% load case 1 in each orthogonal direction will analyze the max shear in your shearwalls. The only way I can see where you might be interested in load case 3 would be if you wanted to evaluate the shear in plane of a shearwall in combination flexure of the wall from out of plane pressures or if you wanted to evaluate a tangential stress on a diaphragm contributed by components from both orthogonal directions. I have not seen any design examples and guidelines get this critical in their analysis for small wood frame and masonry structures. Any thoughts?

 

[wannabeSE]

Case 3 may govern the design of boundary elements at the intersection of orthogonal walls.