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RAM Frame - Unstable Structure Detected Instability Found At Rigid Diaphragm

Tom Yanovich — Tue, 06 Jun 2023 13:40:18 GMT

I 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-Delta as well but when I turn it on, my diaphragm is unstable for dead load only (and the other load cases). I have checked the modeler and I have no integrity/data check warnings or errors. I also sized up my steel to ensure it was rigid enough. Are there any other solutions that would point to this issue? I circled the diaphragm in question in the last picture. The other diaphragms shown are not on the same level/story.

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Thu, 29 Dec 2022 04:01:44 GMT

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RAM Concept Self-Weight

Tom Yanovich — Thu, 29 Dec 2022 15:01:04 GMT

When importing a RAM SS file into Concept - does it also important the self weight from RAM SS if it is turned on? I know concept calculates the self weight of the slab/beams automatically - but I am getting significantly higher shear reactions at my columns. I performed a hand check and they should be in half. I am unsure if the self dead is being accounted for twice?