THE NEW EDITION OF EUROCODE 3-1-1. Considerations on the evolution of cross-section classification

The introduction of the semi-probabilistic limit state design approach has brought significant improvement in structural engineering, which involved also the steel constructions. In particular, both the previous and the new edition of Eurocode 3 (EC3) address several aspects that were previously overlooked by the allowable stress design. One of the most critical aspects is the classification of cross-sections, which directly influences the choice of analysis methods and, consequently, of the verification procedures. The latest edition of EC3 introduces specific improvements to the formulas used to determine cross-section classification; thus, the purpose of this article is to analyse the impact of these changes, with a particular focus on the hot-rolled IPE, HEA, HEB, and HEM profiles, which are widely used in constructions. Additionally, a critical evaluation on the classification methodology, that has been adopted in routine steel structures design for the past two decades, is herein proposed.