Section classification (ULS) (Composite beams: EC4 Eurocode)
Tekla Structural Designer classifies the section in accordance with the requirements of EC3, 5.5.2 except where specifically modified by those of EC4.
A composite section is classified according to the highest (least favorable) class of its steel elements in compression. The compression flange and the web are therefore both classified and the least favorable is taken as that for the whole section.
Flanges of any class that are fully attached to a concrete flange are assumed to be Class 1. The requirements for maximum stud spacing according to clause 6.6.5.5 (2) are checked and you are warned if these are not satisfied.
There are a small number of sections which fail to meet Class 2 at the composite stage. Although EC4 covers the design of such members they are not allowed in this release ofTekla Structural Designer.