Answer:
The RSTAB 9 solver automatically selects the best strategy and tries to solve all nonlinearities at once. If that fails, the nonlinearities are solved one by one. Nonlinearities of hinges and supports are considered in the same way.
In RFEM 6, it is necessary to make the corresponding settings in the "Edit Static Analysis Settings" dialog box in the "Reactivation" tab; see the image.
