The generalized slenderness-based resistance method for the design of SHS and RHS

Selected, extended paper from the SDSS 2019 special session ECCS/TC8 - Structural Stability
The cross-sectional strength of square (SHS) and rectangular (RHS) hollow sections loaded in compression and various degrees of uniaxial or biaxial bending are governed by local instabilities in the elastic or plastic range. Common design checks for cross-sectional strength, e.g. those found in the Eurocodes, regularly penalize these sections through a conservative omission of various mechanical effects and a categorization of cross-sections into distinct classes with corresponding, markedly different, design rules. This leads to discontinuities and inaccuracies in the strength representation. Such conservatism is particularly detrimental to the introduction of high-strength steel hollow sections, which often fall into the semi-compact and slender cross-section classes for which local buckling is more relevant. This paper discusses the results of extensive research work carried out during the RFCS research project HOLLOSSTAB. In this project, new design rules were developed for the cross-sectional and member design checks of hollow sections with various shapes and slenderness ratios, termed the “Generalized Slenderness-based Resistance Method - GSRM”. This paper summarizes the experimental and numerical campaign carried out within HOLLOSSTAB and describes the new GSRM design rules and their background for the case of the cross-sectional strength of SHS and RHS.