Hello, When running the shear wall module. There is one section cut that pops up with -nan(ind). What would cause this problem and what are possible solutions. Thanks.
Rerun the Ram Frame analysis for all load cases and check that you get a stable analysis (check deflected shape or reactions for example).
I reran Frame, the deflected shapes looks okay at this level. The forces at the Wall above and below look okay
Its Standard analysis and version 17.01.01.05. I uploaded the file"CHS PH Lateral Members 12.02.20"
A very strange case indeed. The problem is isolated to one (or a few?) sections, but most are fine. A new section cut a few inches below also has some "not a number" (nan) errors.
On a hunch, I went back to Ram Frame and turned off the rigid link that might be created between beams and walls, but this did not make any difference. This is still a good think to review, in case you don't actually want these rigid links.
There is a lateral beam framing into this wall at the level in Question (Beam 9, Lvl 4), and the diaphragm is semi-rigid so there are a lot of nodes involved. I will try some other tests.
If I convert that beam (#9, lvl 4) into a gravity beam (and a few supported members) then the problem goes away. I'm not exactly sure why the original configuration lead to a problem, but I have a theory that having a lateral, fixed-ended beam supported on the face of a wall without consideration of wall out-of-plane stiffness leads to some sort of instability and the wall forces in that level are junk as a result. The same junk demand forces are also apparent in the Ram Frame - Shear Wall Forces module by the way, and they are particular to the gravity load cases.
Here's my end model framing:
And the criteria I used in case it matters.
Answer Verified By: Timothy Schuster
Thank you for your help. I made the changes and I can now see results in the section cuts. By making beam 9 gravity, I wont be able to design it in RAM? I will need to do a hand calc since its transferring load from a two way slab?
You can still design gravity beams in Ram Steel or Concrete. If that section really needs to be a lateral frame then there is probably another work-around.