# RF-CONCRETE Surfaces – Online Manual Version 5

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## RF-CONCRETE Surfaces – Online Manual Version 5

In RFEM, we can define the various loadings in individual load cases (LC). These load cases can be superimposed into load combinations (CO) and result combinations (RC). The differences between these types of combinations is described in the chapters 5.5 and 5.6 of the RFEM manual.

While load cases and load combinations respectively yield only one set of internal forces, up to 16 sets of internal forces can be created 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), only the axial forces nx, ny, and nxy are obtained in the surfaces.

Their combination yields six sets of internal forces, with one of these axial forces respectively showing its maximum or minimum value.

• For the model type 2D - XY (uZ / φX / φY) (plate), the maximum and minimum values of the moments mx, my, and mxy and the shear forces vx and vy are determined.

Ten sets of internal forces are thus obtained.

• The model type 3D contains all 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 processes the internal forces of the selected load cases and load combinations one by one. 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 a loading. The program determines the greatest loading among all reinforcement directions. If the resistance is different for the individual reinforcement directions, the program searches for the reinforcement direction that yields the largest quotient from loading over resistance.