The continuous strength method for the design of high strength steel tubular sections in bending

Abstract

The continuous strength method (CSM) adopts base curves which relate the deformation capacity to its overall cross-section slenderness to take into account the element interaction and employs elastic, linear hardening material models to exploit the strength enhancement from strain hardening. This paper extends the CSM for structural design of hot-finished and cold-formed high strength steel tubular sections under bending. Results of 146 tests in the literature were compiled and a parametric study on 660 high strength steel tubular beams was conducted using validated finite element models. Base curves and resistance functions were proposed for non-slender and slender high strength steel circular hollow sections (CHS), elliptical hollow sections (EHS), square hollow sections (SHS) and rectangular hollow sections (RHS). Bi-linear and tri-linear material models were adopted for cold-formed and hot-finished steel tubular sections, respectively. Experimental and numerical results of 806 tubular beams were used to assess the proposed CSM, the direct strength method (DSM) and codified design methods. The resistance prediction of the proposed CSM is more accurate and less scattered.