Effect of surrounding frame members on the buckling behavior of steel shear walls restrained by stiffeners

Numerous studies have addressed the influence of the surrounding frame members on the in‐plane properties of steel shear walls with stiffeners. However, the effect of the out‐of‐plane stiffness on the buckling strength of stiffening plates has not been elucidated. Herein, the influence of surrounding frame members on the buckling behavior of steel shear walls reinforced by cross stiffeners was investigated. A calculation formula for the elastic buckling strength of the stiffened plate was proposed by eigenvalue analysis. In addition, the relationship between the buckling strength and out‐of‐plane stiffness of the surrounding frame members was revealed and a calculation formula for the buckling strength considering the out‐of‐plane stiffness was put forward. Finally, through experimental tests and large deformation analysis, the effect of vertical frame members on the elasto‐plastic property of the stiffened plate was shown. The results obtained are as follows. This study proposes an elastic buckling strength calculation formula for a stiffened plate by correcting the elastic buckling strength calculation formula of an orthotropic plate using the ratio between the torsional rigidity of an actual stiffened plate and that of the plate regarded as anisotropic. The rate of decrease in elastic buckling strength of the stiffened plate due to the out‐of‐plane stiffness of the surrounding frame member can be evaluated by the flexural rigidity ratio between the surrounding member and the stiffened plate. The rate of decrease in elastic buckling strength of stiffened plates due to the out‐of‐plane stiffness of the left and right surrounding vertical frame members with different bending stiffnesses and intermediate vertical frame members can be evaluated by the buckling stress ratio determined from the out‐of‐plane stiffness of the surrounding vertical frame members. It is possible to obtain a stable behavior even if the out‐of‐plane stiffness of the surrounding member is relatively small, if the elastic buckling strength is higher than the shear yield strength of the stiffened plate. It was confirmed that the effect of the end constraint condition on the elasto‐plastic behavior of a stiffened plate was negligible. The results obtained in this study can facilitate the construction of novel earthquake‐resistant steel shear walls. In this study, a method was proposed for estimating the elastic buckling strength of stiffened plates by treating steel shear walls with cros