Software implementation of section class and resistance calculation for general loading case

In this paper, the problems arising in implementation of the cross-section class and resistance according to Eurocode, especially for classes 1 and 2 of the steel sections, are presented for general loading case. As Eurocode assumes full plastification of the section, regardless of corresponding strain in the material, it is inevitable to find the position of the plastic neutral axis for ultimate limit state of the section. But, for this purpose, one cannot use the Eurocode’s expressions for section resistance. Moreover, solution and strategies used in the steel design module of the Matrix 3D are presented in the paper.