I've modeled a two story building with steel columns, beams, concrete floors and cross bracing. Static analyses, with and without static loads, run perfectly well. However, when I attempt a modal analysis, I get "Execution error no. 3060".
Any ideas as to what might cause this?
Usually it is related to ignored instabilities in model.
Correct model to get rid of instabilities.
If it is not the case please update this thread.
Possibly, you would have instability warnings first...that's because of the x bracing middle node is considered to have plane DOF but in "3D" or "Building Module" you add the out of plane displacement where the stiffness matrix becomes 0. Possible solutions...support the out of plane displacement only @ middle x node ...