Seismic performance of precast concrete superposed shear walls with CFST end columns subjected to cyclic loading

With the widespread use of precast concrete (PC) structures in regions of seismic hazard, the seismic performance of PC structural members, including the PC superposed shear walls, has been a major concern of engineers and researchers. In this study, a modified design of PC superposed shear walls called Precast Concrete Superposed Shear Walls with CFST End Columns (or PCSSWEC) has been proposed. The PCSSWEC is expected to have favorable seismic performance while gaining advantages in construction industrialization. Since little research on the seismic performance of similar designed shear walls has been done, a full-scale specimen that followed the PCSSWEC concept was built and evaluated through a pseudo-static test. The test investigation gave a preliminary perception of the hysteretic behavior of PCSSWEC, which reflected a favorable seismic performance (in terms of failure mode, lateral load-bearing and deformation capacity, stiffness and strength degradation, ductility and energy dissipation capacity). The CFST end columns and the superposed wall panel were able to work together as expected throughout the loading process. As an extension of the test investigation, the finite element models of PCSSWEC were developed and validated by test results. The influence of three major design parameters (i.e., axial compression ratio or ACR, shear span ratio or SPR, and thickness of steel tubes) was specified according to simulated results. The PCSSWEC exhibited considerable ductility and deformability even under a large ACR or with a small SPR, and the reasonable thickness of steel tubes should be in a range of 3.5-5.0 mm.