How are the signs of the member internal forces, for example the moments, defined in RFEM/RSTAB?
The bending moment My is positive if tensile stresses occur at the positive member face (in direction of the z-axis).
Mz is positive if compressive stresses occur at the positive member face (in direction of the y-axis).
The sign definition for torsional moments, axial forces, and shear forces conforms to the usual conventions:
These internal forces are positive if at the positive face they act in the positive direction.