Local stability of laser-welded stainless steel I-sections in bending

Design guidance for stainless steel structures has become more comprehensive and widely available in recent years. This, coupled with a growing range of structural products and increasing emphasis being placed on sustainable and durable infrastructure, has resulted in greater use of stainless steel in construction. A recent addition to the range of structural stainless steel products is that of laser-welded sections. Owing to the high precision and low heat input of the fabrication process, the resulting sections have smaller heat affected zones, lower thermal distortions and lower residual stresses than would typically arise from traditional welding processes. There currently exists very limited experimental data on laser-welded stainless steel members and their design is not covered by current design standards. The focus of this study is therefore to investigate the cross-sectional behaviour of laser-welded stainless steel I-sections in bending. The present paper describes a series of laboratory tests performed on laser-welded stainless steel I-sections, including tensile coupon tests, initial geometric imperfection measurements and in-plane bending tests. Results of the bending tests are used to validate finite element (FE) models, which are subsequently employed for parametric investigations. The obtained experimental and FE results are used to assess the applicability of the existing design provisions of EN 1993-1-4, AISC Design Guide 27 and the continuous strength method (CSM) to laser-welded stainless steel sections. It was found that the scope of application of these existing design provisions may be safely extended to laser-welded sections.