RISA 3D v14 Lateral Load Distribution
RISA 3D v14 Lateral Load Distribution
(OP)
I am using RISA 3D v14 and I do not have RISA Floor. I am modeling a somewhat complicated two-story structure (high-end residence) composed of steel posts, steel beams, CFS floor joists, and CFS shear walls. I can design the CFS floor joists and CFS shear walls easily enough using catalogs. Therefore, I am not planning on modeling the CFS floor joists, but I do want to model the walls so I can have the model determine the distribution of lateral forces to the shear walls. However, if I don't model a diaphragm (using plates), it seems like I can't use RISA's auto-generated wind load and seismic load generator since how will the program know how to accurately distribute the lateral loads to the walls without a diaphragm?
I may be answering my own question, but if I don't model a diaphragm (since RISA 3D can't model flexible diaphragms, unless I define a plate properly), will I need to manually input all of the lateral loads (and load combinations) versus having the program auto-generate them?
Thanks!
I may be answering my own question, but if I don't model a diaphragm (since RISA 3D can't model flexible diaphragms, unless I define a plate properly), will I need to manually input all of the lateral loads (and load combinations) versus having the program auto-generate them?
Thanks!





RE: RISA 3D v14 Lateral Load Distribution
Therefore, you will likely need to manually enter in your wind and seismic loads. Though you could apply these to a semi-rigid diaphragm made out of plate elements and let the program distribute them to the appropriate shear walls based on relative rigidities.
For seismic, you might have some luck with a response spectra analysis. But, generally my experience is that most engineers will avoided this unless it is required by code or they have a particular interest or career focus on structural dynamics.
RE: RISA 3D v14 Lateral Load Distribution
So just to confirm: with a RISA-3D only model, if I model my diaphragm using plates to approximate the semi-rigid/flexible behavior, can I still utilize the auto generated wind loading to distribute the wind loads to the shear walls in my model?
RE: RISA 3D v14 Lateral Load Distribution