Answer:
According to EN 1992‑1‑1, Clause 9.3.1, the minimum reinforcement for ensuring ductile behavior of the structural component is to be placed in the main span direction of the plate. In RF‑CONCRETE Surfaces, the "Reinforcement direction with the main tension force in the considered element" option is selected by default. This means that for each element, the program searches for the greatest tension force for each reinforcement direction and for the top surface (-z) and the bottom surface (+z). If the greatest tension force has been found for the individual element, the minimum reinforcement is applied there. If you want to arrange the minimum reinforcement in the principal stress direction for biaxially stressed slabs only, you can specifically control this. To do this, open the "Settings of Min. Reinforcement for Ductile Properties" dialog box. If you select "Define", you can specifically set in which direction and on which side of the structural component the minimum reinforcement should be arranged.
