RF-/C-ZU-T allows you to avoid complex buckling analyses, especially for welded sections with thin plates: Failure due to buckling of the cross-section parts can be excluded by the fulfilled (c/t) design.
If the design with RF-/C-ZU-T is not fulfilled, you can try to perform the design according to DIN 18800, Part 3, with RF-/FE-LTB by determining the exact plate buckling stresses.
