2.6.5 Governing Effects of Actions
Governing Effects of Actions
In RFEM, we can define the various loadings in individual load cases (LC). Load cases can be superimposed in load combinations (CO) as well as result combinations (RC). The differences between both types of combinations is described in chapters 5.5 and 5.6 of the RFEM manual.
While load cases and load combinations yield only one set of internal forces respectively, there can be up to 16 sets of internal forces in a result combination, depending on the type of model:
- For the model types 2D - XZ (uX / uZ / φY) and 2D - XY (uX /uY / φZ) (wall), we obtain only the axial forces nx, ny, and nxy in the surfaces.
Their combination yields six sets of internal forces, of which one of these axial forces shows its maximum or minimum value, respectively.
- For the model type 2D - XY (uZ / φX / φY) (plate), the maximum and minimum values of the moments mx, my, and mxy, as well as the shear forces vx and vy are determined.
Thus, we obtain ten sets of internal forces.
- The model type 3D contains all the axial forces, moments, and shear forces mentioned above and therefore yields 16 sets of internal forces.
The analysis core for the serviceability limit state designs proceeds with the internal forces of the selected load cases and load combinations sequentially, that is, row by row. The same is true for the sets of internal forces of a result combination. This shows that the design of a result combination is much more time-consuming.
In most checks for the individual reinforcement directions, the internal forces or sets of internal forces result in an action-effect. The program determines the greatest action-effect of all reinforcement directions. If the resistance for the individual reinforcement directions is different, the program searches for the reinforcement direction that yields the largest quotient from action-effect over resistance.