Seismic behavior evaluation of precast self-centering shear walls with replaceable friction dampers through shaking table test

To improve the energy dissipation capacity and ductility of self-centering (SC) shear walls and address their lack of redundancy and poor robustness, this study proposes a novel replaceable friction damper (RFD) as an auxiliary energy dissipation element for SC shear walls and investigates the effects of various factors, such as the initial prestressing levels of post-tensioned (PT) strands, cross-sectional areas, and number and material of friction dampers, on their seismic performance. Shaking table tests were conducted on these specimens under various seismic intensities, and the displacement and acceleration time histories, hysteresis loops, skeleton curves, stiffness degradation, residual displacements, and other indices were analyzed. Moreover, the contributions of different damping mechanisms to the dynamic response were quantified. The experimental results show that these innovative walls can achieve a maximum displacement ratio of 2.16 % under rare earthquakes without significant concrete damage, such as reinforced concrete (RC) shear walls, and exhibit satisfactory energy dissipation capacity (equivalent damping coefficient of approximately 14.6 %) and lower residual displacement compared to previous quasi-static tests. The RFDs can achieve progressive activation under different levels of seismic excitation, and it is worth noting that walls with brass friction shims have higher energy dissipation efficiency than walls with carbon-carbon (C/C) composite shims. The measured viscous damping is within the range of 3.46-4.23 %, and it provides over 90 % of the total energy dissipation with hysteresis damping.