In a load case of my model, I obtain compressive forces in a cable, which is impossible.
What is the explanation for this and what can I do?
Compressive forces in cables or tension members can result if the number of iterations is not sufficient for this analysis so that the system did not converge.
You can specify the number of iterations in the "Global Calculation Parameters" of the "Calculation Parameters" dialog box (from RSTAB 8 in the figure).
Specify, for example, 100 as the maximum number of iterations.
This does not mean that all iterations will be run. Depending on the structural system, the calculation often converges much earlier.
If compressive forces are shown after all, check the settings in the "Reactivation of Failing Members" section of the "Global Calculation Parameters" dialog box.
If the option "Assign reduced stiffness to failing members" is selected, small compressive forces can result.
If this is not justifiable, select the option "Failing members to be removed individually during successive iterations."