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• ### Why is the bending moment characteristic in the oblique bar different to my hand calculation? Normally there should be no bending moments.

FAQ 002681 EN-US Results RFEM RSTAB

The reason for the occurrence of a bending moment in the oblique and straight bar is that the middle post has a certain flexibility due to its finite rigidity. Thus, compression takes place at the middle support, so that the deformation of the middle support also affects the right-hand latch. Because the right-hand latch is additionally held on a movable support, a forced moment arises at this point.

The calculation by means of RFEM results in minimum bending moments, which however are not taken into account in the manual calculation.
• ### In the design of a classic rigid end plate joint, the moments about the major axis (y‑axis) are only considered. If the moments are entered about the minor axis, the resulting tensile forces are not taken into account in the design. Am I correct?

FAQ 002513 EN-US Add-on Modules Eurocode 3

Designs in our module RF-/JOINTS Steel - Rigid are based on the assumptions and regulations of the standard EN 1993‑1‑8. Here, bending from the main beam plane is not considered.

In RFEM, it is possible to model any rigid joint. All internal forces can then be taken into account.

• ### In my L-section, there is no My or Mz moment when rotating the member by 45°. What is the reason?

FAQ 001101 EN-US Calculation RFEM RSTAB

In the case of unsymmetric cross-sections (angles, Z-sections), main axes are inclined. The main axis angle α describes the location of the main axes relative to the standard main axis system: this is the angle between the axis y and the axis u. It is defined as positive if clockwise.

If a bending moment at an unsymmetric cross-section is determined, the designation of the bending moment changes to Mu and Mv. These moments also relate to the main axes of the cross-section. If the axes u or v run parallel to the load direction, the corresponding internal force Mu or Mv is omitted.

The position of member axes can be activated in the Display naigator under "Member Axis Systems u,v,w."

• ### How are the signs of the member moments defined?

FAQ 000303 EN-US Calculation RFEM RSTAB

The bending moment My is positive if tensile stresses occur at the positive member face (in the direction of the z axis). Mz is positive if compressive stresses occur at the positive member face (in the direction of the y axis).

The sign definition for torsional moments, axial forces, and shear forces conforms to the usual conventions: the internal forces are positive if they act in the positive direction at the positive face.