https://communities.bentley.com/products/ram-staad/f/ram-staad-forum/241854/ram-frame-unstable-structureI have a 6-story BRB model that runs fine. As soon as I add a seventh story (diaphragm is different than stories below), I get an unstable structure detected. The node for which the instability is found occurs in the middle of the diaphragm. I have columnen-USTelligent Community 12https://communities.bentley.com/thread/754258?ContentTypeID=1Tue, 21 Feb 2023 17:21:36 GMT6dad98f5-dbc9-4c4d-a9ba-e9da8dc6aa8e:23baac2f-80c6-4231-bfd3-1e28d4014259Seth Guthrie<p>BRB can be excluded from the gravity analysis like tension-only braces. This can lead to an unstable structure for gravity loads. If you want to keep them for lateral loads only, then a secondary form of stability (i.e. a fixed column base or foundation spring) can resolve things. See: <a href="/products/ram-staad/w/structural_analysis_and_design__wiki/3058/ram-frame---tension-only-faq">RAM Frame - Tension Only [FAQ]</a></p><div style="clear:both;"></div>