Seismic Performance Analysis of Squat Symmetric Shear Walls: Based on Different Reinforcement Ratios

To tackle the safety performance concerns of Squat shear walls in nuclear island structures (which serve as shields for powerhouses) under seismic action, this research endeavors to explore the seismic performance of such shear walls with different reinforcement ratios. Pseudo-static loading tests were carried out on 6 shear wall specimens, which were divided into 3 groups (with different reinforcement ratios). The focus was on analyzing the specimens’ failure process, load-deformation hysteretic curves, shear strength, ductility, strain, and other crucial parameters. The experimental findings demonstrate that all specimens underwent shear failure, which was characterized by the compression of web concrete. A higher reinforcement ratio can alleviate the buckling extent of structural steel. Specifically, an elevated horizontally distributed steel ratio notably enhances the ductility and energy dissipation capacity of the specimens, thereby effectively improving the yield load, stiffness, and ductility of squat shear walls. Nevertheless, its influence on cumulative energy dissipation and crack development is limited. Based on the analysis of the specimens’ failure modes, hysteretic curves, skeleton curves, energy dissipation, and stiffness degradation laws, finite-element numerical analysis was carried out on selected specimens. Comparison with the experimental results showed a good consistency between the two. Ultimately, the influence of the reinforcement ratio on the seismic performance of the shear walls was ascertained, and the research on the variation rules of the seismic performance parameters of squat shear walls was completed after verification through finite-element modeling. Based on this, a nonlinear fitting approach was employed to construct a regression prediction model for the seismic performance of shear walls in the Hainan Changjiang Multipurpose Modular Small Reactor Technology Demonstration Project. Typical squat shear walls were chosen for seismic response analysis, and the corresponding outcomes were acquired. Finally, a series of seismic vulnerability curves for nuclear island shear walls with varying guarantee rates were formulated for verification.