Experimental Study on the Seismic Mechanism of Full-scale Specimens of Superimposed Slab Shear Walls with Innovative Construction Details

The seismic performance of precast reinforced concrete structures has long been a source of concern that impedes their use in seismic regions and high-rise buildings. To further optimize the reinforcement configuration and enhance the seismic performance of the superimposed slab shear wall structures, this research proposed a superimposed slab shear wall with innovative construction details. Five innovative superimposed slab shear walls and one cast-in-place concrete shear wall were designed and tested under low cycle lateral load. The effect of axial compression was considered during tests and analyses as well. In this paper, the seismic performance, including failure mode, hysteretic behavior, load-bearing capacity, lateral stiffness degradation, energy dissipation, and seismic ductility was investigated and analyzed. The experimental results showed that five innovative superimposed slab shear walls and one cast-in-place concrete shear wall exhibited a similar failure mode of flexural-shear failure, and a large area of concrete was damaged and crushed at the shear wall corner. However, the area of crushing concrete in the cast-in-place concrete shear wall was relatively small. And the area of crushing concrete in the superimposed slab shear walls increased with the axial compression ratio. For the superimposed slab shear walls, the development of concrete cracks decreased gradually with the enlargement in the axial compression ratio, while the length of the cracks increased in this respect. The results indicated that innovative superimposed slab shear walls had a higher strength capacity and lower lateral-resistant stiffness than the cast-in-place concrete shear wall. With the enlargement in the axial compression ratio, the peak strength capacity of the superimposed slab shear wall increased obviously, while it degraded rapidly after the peak load. It is suggested that the contribution of axial compression to the shear resist capacity of the inclined section should not be considered in practical design. Meanwhile, the ductility coefficients of the six specimens were larger than 2.2, which was in accordance with the seismic requirements. This investigation could provide effective experimental data for future structural seismic performance evaluations and applications of precast superimposed slab shear wall structures.