DELETE MEMBER COMMAND

Question

I am trying to simulate a demolition sequence for a large hangar. The demolition sequence will involve removing steel members in a particular sequence. I have to monitor the stresses in the members to remain at the end of each stage of the removal. Here are the issues I am facing with the STAAD Pro model for this: 
 - I cannot use the INACTIVE MEMBER command to remove the members that are demolished because the joints that are no longer connected (once I make the member inactive) generates the warning messages that joints are not connected. Also, the output shows instabilities at these unconnected joints. 
 - I cannot use the DELETE MEMBER command because it has to be provided immediately after the MEMB INCIDENCE command. If I place it after the change command, it gives me a error message. I really do not understand the purpose of this command at all. If I have to place it immediately after MEMB INCIDENCE definition, why bother modeling the members? 
 
 Any thought on how I can develop this model to simulate the progression of the demolition?

Sye · Answer

Here are the options 
 You may use the INACTIVE command as needed and just ignore the warnings as you know that there are nodes which are not connected to the structure. 
 You may save the model by a different name and remove the demolished members from that one and re-analyze it. So essentially you will have the first analysis with the full model and then separate analysis models for each subsequent stage. 
 DELETE member cannot be used for a scenario where you start with the full model and deactivate members in installments. DELETE member is typically used when you need to model the entire structure for completeness of the model but do not need to consider some of these for analysis purpose. For example some non- structural components like ladders, handrails, architectural elements, attachments etc.