CSM proposal for predicting buckling resistance of stainless steel CHS beam-columns

Abstract

Stainless steel is increasingly being utilized to enhance the sustainability and long-term performance of structures owing to its exceptional corrosion resistance and excellent material propreties. However, most global design standards incorporate cross-section classification into the design procedures, limiting the load-bearing capacity of sections to the 0.2 % proof stress. This approach prevents the full utilization of the significant strain hardening capacity of stainless steel, leading to overly conservative predictions. Therefore, there is a real need to develop a more advanced analytical design approach. This study presents the first systematic extension of the Continuous Strength Method to stainless steel circular hollow sections under combined axial compression and bending, addressing a key gap in current design guidance. For this purpose, a finite element model is developed and used to conduct a parametric study for assessing the proposed CSM approach. The existing interaction factors are evaluated, and a revised interaction factor is proposed based on the findings. A comparative analysis with design rules given Eurocode 3 is presented. The results demonstrate that implementing the proposed CSM method with the revised interaction factor leads to more accurate resistance predictions for stainless steel CHS under combined axial compression and bending. Finally, the safety of the proposed CSM method is evaluated through a reliability analysis.