Behaviour and design of stainless steel slender cross-sections subjected to combined loading

•Behaviour of slender stainless steel RHS are numerically examined under compression plus bending.•Current design codes produce conservative predictions for combined loading.•CSM linear interaction equation performs well for uniaxial eccentric loading.•Nonlinear moment curves make CSM linear equations conservative under biaxial bending.•Nonlinear CSM formulation is proposed for biaxial interaction in slender sections.

The Continuous Strength Method (CSM) is a recently developed strain based design technique that produces accurate predictions for cross-section resistances for stocky sections against individual and combined actions. This paper numerically investigates the behaviour slender stainless steel cross-sections subjected to combined loading i.e. compression plus bending. Generated numerical results and available test results were used to develop CSM formulations to tackle the conservatism shown by the current international codes in predicting resistances of slender sections. Keeping the basic design philosophy in line with the current CSM design technique, interaction equations are re-calibrated herein for slender stainless steel hollow sections.