Development of a Generalized Slenderness-Based Resistance Method for the Design of High-Strength Steel Hollow Section Beam-Columns

The significant increase in the use of high-strength steel has led to a renewed interest in the strength and stability design criteria for hollow sections, owing to the fact that the majority of the resulting cross-sections and beam-columns are to be classified as slender. This paper illustrates a novel approach for the design of slender hollow section members loaded in compression and general bending about both main axes. It introduces a "Generalized Slenderness-based Resistance Method" (GSRM), which was developed over the course of an extensive, multinational and EU-funded research project - HOLLOSSTAB (2016-2019). The GSRM further generalizes the advanced cross-sectional definitions of local and global slenderness used in established strength design methods such as the Direct Strength Method, the Continuous Strength Method and the Overall Interaction Concept, leading to a definition of slenderness that accounts for the overall load case as well as for the elastic buckling strength. This generalized definition of slenderness is used as the basis for the derivation of new design formulae and calibration coefficients for the studied cases, which very closely follow the underlying mechanics while remaining easily handleable. The presented study also includes an analysis of the underlying level of reliability of the GSRM and a representation of its advantages over conventional design methods for slender hollow-section beam-columns. The result of the HOLLOSSTAB project is thus a set of novel design formulae that can be used in combination with bespoke software tools to efficiently and safely determine the ultimate strength of high-strength steel hollow sections.

View content