Experimental and numerical study on seismic behavior of SSC slab-RC wall joints in NPP

A new type of single steel-plate concrete slab-reinforced concrete wall joint (SSCSWJ) is proposed to enhance the seismic performance of slab-wall joints (SWJs) in nuclear power plants (NPPs). Based on a typical side SWJ in NPPs, three 1:3 reduced scale SWJ specimens were designed and fabricated: one reinforced concrete slab-wall joint (RCSWJ) specimen as a reference, and two SSCSWJ specimens (SSCSWJ1, SSCSWJ2). Low cyclic loading tests were conducted to evaluate and compare the seismic performance of the three specimens. A finite element model (FEM) was developed and validated against the experimental results. Subsequently, a parametric analysis was performed on SSCSWJ1 to investigate the influence of critical design parameters. Test results indicate that, compared with RCSWJ, both SSCSWJ1 and SSCSWJ2 exhibit enhanced bearing capacity, ductility, and energy dissipation, and also have the potential to improve construction efficiency. The parametric study further reveals that increasing the slab reinforcement ratio effectively enhances both the initial stiffness and bearing capacity of SSCSWJ1. Within the studied parameter range, increasing the steel-plate thickness improves the initial stiffness and has minimal influence on bearing capacity, whereas T-section steel spacing and concrete grade exert relatively limited effects on both.