Hello there,
I am trying to analyse a structure which is incrementally subjected to dead loads using the inactive members / change commands so I can simulate the sequence of construction. There are several issues regarding this and very little to no help online.
1. I am using plate elements in the model and even though there is a "INACTIVE ELEMENTS" command in the manual this does NOT seem to be working. I have ended up using the "INACTIVE MEMBERS" command for both members and elements. I think this is working but it seems strange since there already is a command assigned for that purpose.
2. I get some random warnings about the stiffness of the joints (usually the first ones) which are immediately activated in the next part of the analysis. A typical warning message is copied here: " *WARNING- ZERO STIFFNESS IN DIRECTION 1 AT JOINT 1003 EQN.NO. 5773 "
3. During each step of the analysis, the first row of the immediate (above) inactive elements are always over-stressed even thought that they are defined as INACTIVE for that specific analysis run. There seems to be a mixup causing them to pick up stresses from load cases that induce loading to the active elements below.
Has anyone used STAAD for multiple analysis for this purpose before? Have you ever come across any of these issues? I would really appreciate your help.
Regards,
Christos