RISA Diaphragm Shear Forces 1

[Ruben71]

Does anyone have a simple method to calculate diaphragm shear forces using RISA? For example, a two story building with masonry shear walls, steel framing and concrete filled metal floor deck. RISA will calculate loading to shear walls but not directly output the shear forces in the deck which are needed to determine fastener size/spacing for metal deck. I've considered using the base shear reactions divided by the length of the wall. In general this works but can be overly conservative at times. Any help will be appreciated.

 

[JoshPlumSE]

Ruben -

Is this when using the rigid diaphragm option in RISA-3D? Is so, then there is not a direct way to get these forces. I tend to look at the shear force that gets into the wall at this location and divide it by the length of the drag line leading to the wall.

Another option is to get rid of the rigid membrane diaprhagm. Instead, use plate elements. That's a lot of extra modeling effort and may not be worth it. But, it is the only way to directly get diarphagm forces out of the analysis.