Ultimate shear strength of steel plate shear walls with edge-stiffened openings

Steel Plate Shear Walls (SPSWs) are widely used as efficient lateral load–resisting systems; however, the presence of web openings required for architectural and service demands disrupts the diagonal tension field and reduces shear capacity. While previous studies have proposed strength-reduction factors for perforated SPSWs, the explicit contribution of stiffeners installed along the opening edges has not been adequately quantified. This study presents a combined analytical and numerical investigation on the effect of edge stiffeners on the ultimate shear strength of SPSWs with rectangular and circular openings. A simplified analytical formulation is based on tension field theory, and an effective width reduction approach is developed and extended to incorporate the contribution of edge stiffeners. The proposed method is validated using nonlinear Finite Element (FE) models verified against experimental results. A comprehensive parametric study is conducted to evaluate the influence of opening size, opening location, infill plate thickness, boundary element stiffness, and stiffener dimensions. The results indicate that increasing opening size significantly reduces shear capacity, while edge stiffeners partially restore strength by improving stress redistribution and stabilizing tension field action. The proposed analytical model predicts the ultimate shear strength with good agreement with the FE results, demonstrating its accuracy and suitability for practical design applications.