Hello,
I found a problem when I have to analyze a structure in two different situation. One with equipment in operation and another one with equipment empty. For eatrhquake I used "Response spectra". It is knows that response spectra use only the mases defined in first seismic load case. Why it is not posible to use "Change" comand like we used for let say similar situation, like for example we did when we change the support, or activate/inactivate some members or for IBC Earthquake loads. No everybody work for earthquake with "IBC".
2. It not possible to perform p-delta analysis when we used earthquake loads generated by "Response spectra" because "reponse spectra" loads can't be combined using repeat loads requested by p-delta analysys.
Thank you for posting your ideas. We would request that each one is posted as a separate idea so that if any one is included in STAAD.Pro, you will get notified.
Your first idea is essentially suggesting that we provide a method for supporting multiple mass models for dynamic analysis has already been posted. See the idea, https://bentleysystems1.aha.io/ideas/ideas/SP-I-156 . Perhaps you can vote to support that idea.
The second idea is perhaps the idea you can be supporting here which is to extend the response spectrum analysis method to include the secondary effects which I think is a reasonable suggestion. Is there a way that you would suggest is the method that the secondary affects are accounted for?