This two‐part article gives an overview of the developments of the structural member verification in prEN 1993‐1‐1:2020 “Eurocode 3: Design of steel structures – part 1‐1: General rules and rules for buildings”, one of the second generation of Eurocodes. These developments were undertaken by Working Group 1 (WG1) of Subcommittee CEN/TC250/SC3 and by Project Team 1 (SC3.PT1) responsible for drafting the new version of EN 1993‐1‐1. In the past, WG1 collected many topics needing improvement, and the systematic review conducted every five years also yielded topics needing further development. Based on this, the current version of EN 1993‐1‐1 has been developed into a new draft version prEN 1993‐1‐1:2020 enhancing “ease of use”. The technical content of this new draft was laid down at the end of 2019. Many improvements to design rules have been established with respect to structural analysis, resistance of cross‐sections and stability of members. This two‐part article focuses on member stability design rules and deals with the basis for the calibration of partial factors, the introduction of more economic design rules for semi‐compact sections, methods for structural analysis in relation to the appropriate member stability design rules, new design rules for lateral torsional buckling plus other developments and innovations. This first part of the article primarily serves to explain the general background to the European Commission Mandate M/515 that led to the further evolution of the Eurocodes and to illustrate the developments in prEN1993‐1‐1:2020 that pertain to new material grades, partial factors, cross‐sectional classification and structural analysis. These form the necessary background to the changes to member buckling design rules, which are treated more specifically in the second part.

Extended version of the Tomáš Vraný SDSS Award 2019The method of the equivalent compression flange simplifies the verification of lateral torsional buckling of steel beams to flexural buckling of an equivalent part of the cross‐section that is in compression. The current simplified method is based on outdated normative rules and the design results may be both, uneconomic and non‐conservative. To remedy these shortcomings, the simplified method is modified based on the basic structural behaviour of steel beams taking into account the effects of material, cross‐sectional geometry and residual stresses. This paper presents a comprehensive experimental study on the lateral torsional buckling behaviour and residual stresses of welded doubly‐ and mono‐symmetric I‐shaped steel beams. Moreover, an improved simplified method of the equivalent compression flange is proposed for design purposes.

This two‐part article gives an overview of the developments of the structural member verification in prEN 1993‐1‐1:2020 ”Eurocode 3: Design of steel structures – part 1‐1: General rules and rules for buildings“, one of the second generation of Eurocodes. These developments were undertaken by Working Group 1 (WG1) of Subcommittee CEN/TC250/SC3 and by Project Team 1 (SC3.PT1) responsible for drafting the new version of EN 1993‐1‐1. In the past, WG1 collected many topics needing improvement, and the systematic review conducted every five years also yielded topics needing further development. Based on this, the current version of EN 1993‐1‐1 has been developed into a new draft version prEN 1993‐1‐1:2020 enhancing ”ease of use“. The technical content of this new draft was laid down at the end of 2019. Many improvements to design rules have been established with respect to structural analysis, resistance of cross‐sections and stability of members. This two‐part article focuses on member stability design rules and deals with the basis for the calibration of partial factors, the introduction of more economic design rules for semi‐compact sections, methods for structural analysis in relation to the appropriate member stability design rules, new design rules for lateral torsional buckling plus other developments and innovations. This second part of the article is dedicated to illustrating the most relevant changes to member buckling design rules.

This article presents new equations for the design shear resistance of headed studs in solid concrete slabs and new reduction factors that consider the influence of profiled steel sheeting with ribs transverse to the supporting beam. Comparisons with push‐out test results show that the current reduction factor k_t in Eurocode 4 does not take sufficiently into account parameters such as geometry or position of the headed stud in the rib. Therefore, the mean shear test results are overestimated by the current equations. When introducing the new approach for the design resistance of headed studs, the main focus is on the description of the basic procedure for the development of the new approach and on the comparison with values in the existing code. Comparisons with push‐out test results from a recent European project have shown the good quality of the new approach.