RAM Frame - Unstable Structure Detected Instability Found At Rigid Diaphragmhttps://communities.bentley.com/products/ram-staad/f/ram-staad-forum/246194/ram-frame---unstable-structure-detected-instability-found-at-rigid-diaphragmI am modeling a 5 story steel moment frame. One of my diaphragms is failing with P-Delta. I have went through the trouble shooting process of turning off P-Delta and running dead load, which is running fine. I can run wind and seismic without P-Deltaen-USTelligent Community 12RE: RAM Frame - Unstable Structure Detected Instability Found At Rigid Diaphragmhttps://communities.bentley.com/thread/768664?ContentTypeID=1Tue, 06 Jun 2023 16:35:12 GMT6dad98f5-dbc9-4c4d-a9ba-e9da8dc6aa8e:bcd82da9-657e-477d-bd84-ebca8a6f0f2eSeth Guthrie<p>The diaphragms of that level have a flimsy lateral system, especially in torsion I suspect. When we do our stiffness reduction it goes to zero.&nbsp; If you can&#39;t justify lumping the masses to another level then you are probably stuck with using B1 and B2 factors in the design in lieu of P-Delta, or adding additional lateral stiffness.&nbsp;</p><div style="clear:both;"></div>