Seismic behaviour of double skin composite shear walls with overlapped headed studs

This paper proposes a type of double skin composite (DSC) shear walls with boundary columns to make solutions to improve ductility of high-rise buildings. In this DSC shear wall system, overlapped headed studs were used to achieve composite action between the steel face plate and concrete core. Seven DSC shear walls were tested under combined axial compressive force and horizontal cyclic loads to evaluate the seismic behaviours of this DSC shear wall. Key parameters in this test program include height of overlapped headed studs, axial force ratio, introducing steel tubes in boundary columns, and aspect ratio of the DSC shear wall. The test results exhibited that the tested seven specimens failed in flexure mode characterized by local buckling of steel face plate, tensile fracture of steel boundary column, and concrete crushing. Test results also show that using higher headed studs in DSC shear walls improved their deformation capacity and energy dissipation capacity. Increasing axial force on the DSC shear walls did not compromise their energy dissipation capacities but slightly reduced their ductility. Introducing steel tube in the DSC shear walls significantly improved the ultimate resistance, ductility, and energy dissipation of the DSC shear walls. Decreasing the aspect ratio from 2.0 to 1.0 nearly doubles the ultimate resistance and energy dissipation capacity of the DSC shear walls. Theoretical models were also developed to predict the ultimate load carrying capacity of the DSC shear walls under horizontal loads. The validations of the predictions by the developed analytical models against 14 test results confirm the accuracy of the developed theoretical models.