Before calculating a result combination, I get a message saying that the addition of load cases is not allowed due to failing objects. What does it mean?

Answer

Result Combinations in which load cases are superimposed with '+' can lead to falsified results in connection with non-linear objects (tension or compression members, failure of supports, etc.).

Example: A tension member is subjected to compression in a load case and therefore fails. The member results are indicated as zero in this load case. However, in another load case, this tension member can be under tension, thus remaining in the structure and adopting the internal forces. When adding the results of these load cases in a result combination, two different static systems would be superimposed. This could be problematic.

Therefore, in the case of nonlinear objects in the model, you should rather use load combinations.

Keywords

Warning Addition Load case Load combination Result combination Failure Tension member Compression member Support Foundation Invalid addition

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