I have set up a RISA 3d model using plates in lieu of the diaphragm feature with the intent of coming up with the shear forces. I'm using precast members and am trying to come up with the necessary forces that the connections tying them together need to be designed for. I'm still fairly new to RISA, having mostly used it for shear walls with openings, and all of the precast jobs I have done thus far were simple enough that coming up with shear/chord forces by hand was relatively easy. The asymmetrical layout and openings in the diaphragm made things fairly difficult for this one, which is why I decided to try doing it with RISA. There are Plate Stresses, Plate Forces and Plate Corner Forces. I'm trying to figure out whats the simplest way from these to get the forces I'm resisting. At this point I'm reasonably certain the model is correct, I'm just still having trouble deciphering my shear forces. I have several ideas that I'm puzzling my way through, but am hoping someone with more experience can give me some guidance.

Any suggestions would be greatly appreciated.

Thanks!