Lateral Building Stability under Wind Loads

[tdawgye]

Hi There,

When designing a whole building for lateral stability against wind loads, do you consider the height of the building under wind loading as the full height or full height minus half of the first story?

Thanks.

 

[phamENG]

Full height, but distribute the loading according to the tributary area of the framing/diaphragms. So in a steel framed building with light gauge studs, the lower half of the first floor would react into the slab or foundation wall, depending on the detailing. If the first floor is a slab on grade, that load generally isn't resisted by the MWFRS. If you have a basement, crawl, or if the structure is elevated, then the first floor would likely need to be a diaphragm and would distribute into the MWFRS. In a structure with girts rather than studs, like a PEMB, all of the load goes to the columns/bents and has to be resisted by the MWFRS.

So in short...it depends.