Seismic performance and design approach of unbonded post-tensioned precast sandwich wall structures with friction devices

Abstract

The unbonded post-tensioned (PT) precast sandwich wall structure with friction devices is a combination of the precast sandwich wall structure with friction devices and with PT tendons. The friction devices provide the energy dissipation capability and PT tendons provide the self-centering capability. The mechanical behavior of unbonded PT precast sandwich wall structures with friction devices are investigated theoretically and experimentally. The experimental results verify the effective of the theoretical analysis on predicting the hysteretic responses. It is shown that the structures with rigid joints dissipate energy through plastic damage, and the structures are destroyed finally with the bottom concrete crush; the structures with friction devices have lower stiffness and moment capacity than that of structures with rigid joints, but the friction devices can effectively protect the main concrete walls from damage; additional PT tendons can improve the self-centering capabilities of structures with friction devices. In addition, the multi-layer shell and truss element are adopted to simulate the sandwich wall and the friction devices in finite element analysis (FEA) model. The simplified procedures are proposed to simplify the smooth experimental hysteresis curves into idealized flag-shape curves. The effectiveness of the numerical and simplified results is experimentally verified. Finally, the performance-based design approach suitable for unbonded PT precast sandwich wall structure with friction devices is proposed and confirmed by dynamic time-history analysis.