RISA 3D CMU Load Bearing Wall

[Nameless_One]

Does anyone have any experience using RISA 3D to analyze load bearing CMU walls? I am trying to get loading transferred from a steel framed roof into modeled CMU walls. It seems that even though the nodes for the steel members are positioned on the top of the CMU wall, the program is not recognizing that the beams are bearing on the wall. Is this something RISA 3D has the capabilities to analyze?

 

[JoshPlumSE]

I don't think this is a masonry question, so much as it is a question about the way beam elements connect to wall panel elements and transfer force into those elements.

Obviously, there are a number of ways of verifying that the load path is working correctly in the model. Some suggestions:
1) Do the shear and moment diagrams of the beams look correct?
2) If you amplify the deflection diagrams so that the deflection is easy to see, does it look like the load is transferring correctly.

I don't think RISA gives you the ability to easily investigate the force diagrams of masonry walls.... like it would for a beam or column element. Hence my suggestions above. Frequently, when load is not transferring correctly, there is a modeling problem of some sort. You might have joints that fall just short of the wall. Or, you might have instabilities in your model that are getting "fixed" by the program.

 

[dold]

You can view the wall panel force/stress contours. If your beams are at the very top of the wall, check to make sure there is not a boundary condition at the top of the wall that restrains the top of the wall panel for Y-direction translation? RISA definitely has this capability. I suspect a modeling error of some sort. The detail report for the wall panel will show axial, shear, and moment diagrams for the entire wall panel (or region, if you have multiple regions for a single wall panel).