Shear resistance of perforated QN1803 high-strength stainless steel plate girders through experimental testing and numerical analysis

QN1803, a high-strength stainless steel, has been developed by steel industry recently. Its tensile yield strength can be approximately 40% (or more) higher than that of the commonly-used EN1.4301, while its cost is 20% lower due to its reduced nickel content. One obvious application for QN1803 is in plate girders, where web perforations are often required to accommodate building services. However, no research work has been reported in the literature that investigates the reduced shear buckling capacity of QN1803 plate girders as a result of web perforations. This issue is addressed herein. An experimental program comprising six plate girder tests is conducted in this study. Three different hole ratios were considered: 0.2, 0.4 and 0.6. The depths of web were selected as 700 mm and 500 mm, while the thickness of web was fixed as 4.0mm. The initial geometric imperfections were determined from three-dimensional (3D) scanning prior to the plate girder tests. Finite element (FE) models incorporating the material non-linearity and initial geometric imperfections were then developed and validated against the experimental results. A parametric analysis including 62 FE models was performed to examine the influences of the critical parameters on the shear buckling capacity of such perforated members. The results suggest that for those members with a hole diameter - web height ratio of 0.6, the shear buckling capacity was reduced by 56% on average due to the web perforation. The design rules for determining the shear buckling capacity of stainless steel plate girders as specified in Eurocodes (EN 1993-1-4+A1) (2015) and American Specification (ANSI/AISC 370-21) (2021) were evaluated. Upon comparison, it was demonstrated that both EN 1993-1-4+A1 (2015) and ANSI/AISC 370-21 (2021) cannot provide accurate and safe predictions for determining the shear buckling capacity of such members.