Effect of moment gradients on stainless steel sections under combined bending moment, shear force and axial load

To address the limited research on the effect of moment gradients on the resistance of stainless steel members subjected to combined bending moment, shear force and axial load, this paper presents a comprehensive numerical study on austenitic, duplex and ferritic stainless steel I-sections, RHS and SHS. Advanced finite element models were developed and rigorously validated against available experimental results. On the basis of the validated models, an extensive parametric study was conducted to investigate the effects of stainless steel grade, loading conditions, cross-sectional thickness, aspect ratio, slenderness, moment gradient ratio and axial load ratio on the load-bearing capacity of stainless steel members. The results reveal that the presence of local moment gradients markedly enhances the load-carrying capacity of stainless steel members, particularly for sections with stiffeners. The applicability of the current Eurocode design provisions was evaluated using the numerical database. Consequently, a modified design approach incorporating a strength enhancement parameter to account for the beneficial influence of moment gradients was proposed. Reliability assessment in accordance with EN 1990 demonstrates that the proposed design equations achieve improved accuracy and consistency while satisfying the Eurocode safety requirements, offering a refined design framework for stainless steel members under combined loading. • Finite element models of welded and cold-formed stainless steel sections under combined loading were established. • Parametric analysis was conducted to generate a large pool of dataset with a total of 6933 cases. • Effect of moment gradients on stainless steel sections under combined loading was investigated. • The design framework in current Eurocodes was assessed. • New approaches accounting for the effect of moment gradients were proposed.