What is the best way to model a wall that spans multiple stories (i.e. no intermediate diaphragm) for purposes of lateral analysis? I have a building with four different roof heights, so I have four separate stories in my model. When I go to the RAM Frame module, I receive a warning dialog:
"Some mass has been detected on one or more stories that is not associated with any diaphragms.
It will be ignored in Analysis unless it is combined with one or more diaphragms.
See the Loads - Masses command."
This mass is obviously the self weight of the walls. If I only had two roofs, I could use the "Combine To" option in the Diaphragm Masses dialog. Since I have four roofs, on Level 1 for example, I need to split the unassociated mass on that level between the other three diaphragms. Even if I could figure out how to do that, I think I would still have issues with wind loading. Any advise on this other than creating four separate files would be much appreciated!
