Numerical investigation on out-of-plane behavior of unilateral stainless steel double-steel-plate composite shear walls

In the design of the double-steel-plate composite shear wall for the nuclear reactor pool, as one side of the wall is in contact with water, a unilateral stainless steel plate is utilized to realize an integrated design of structural loadbearing and waterproofing. However, the out-of-plane mechanical behavior of unilateral stainless steel doubleplate composite shear walls (USCWs) remains unexplored. To address this gap, this study employs finite element analysis, validated by prior scaled model tests, to investigate the impact of asymmetric strength and stiffness on the out-of-plane mechanical behavior, which is triggered by the distinct steel plates on either side. The analysis evaluates shear walls with different configurations, including low-alloy double-steel-plate walls and unilateral stainless steel walls designed with either equal thickness or equal strength. The results demonstrate that increasing the steel ratio effectively enhances the lateral stiffness and ultimate load-bearing capacity in all configurations. Specifically, at a 2 % steel ratio, USCWs with equal-thickness design achieve a 15 % higher negative load-bearing capacity compared to alternative configurations. Furthermore, when the capacity disparity between the steel plates on two sides exceeds 30 % of the stronger plate, the difference in bidirectional loadcarrying capacity will surpass 20 %, which significantly impairs the cyclic loading performance. These findings provide critical insights into the structural optimization and practical application of USCWs under dynamic loading conditions, offering guidance for their design in nuclear engineering and other high-demand environments.