Question:
My model in RFEM 6 is unstable. How can I fix it?
Answer:
There can be many reasons for unstable structural systems. The best way to determine the reason for this message is to use the Structure Stability add-on. This add-on allows you to calculate your structure without loading, and thus to perform an instability analysis using the mode shape.
Therefore, you can display the unstable shape of your structure.
As you can see in our example, the upper steel beams are subjected to lateral deflection.
Upon closer inspection of our modeling, we recognize that we have unconsciously created a hinge chain from couplings of the Rigid-Hinge type. If we remove this hinge chain, we can calculate the load case.