Karamba3D does cross section design by going through the list of cross sections in a group of cross sections called a family. It starts at the first entry and proceeds to the next until a cross section is found that is sufficient for the given cross section forces of an element.
The calculation of the utilization of a beam is done using the procedure described in EN 1993-1-1 i.e. Eurocode (EC) 3 . It takes account of buckling and lateral torsional buckling. The superposition of different cross section forces works according to procedure 2 (see annex B of EC 3). The values , and are limited to 0.9. The “Utilization”-component’s “Details”-output returns a listing of intermediate values from the calculation according to EC3 (see section 3.6.6). For a detailed comparison of the steel design procedures implemented in Karamba3D and Dlubal's RFEM see .