Hysteretic and seismic performance of disc spring-based self-centering viscous dampers for improved seismic resilience

This study presents an innovative self-centering viscous damper with flag-shaped hysteretic behavior to address critical issues in the current self-centering bracing system and enhance its structural resilience against earth-quakes. First, the basic configuration, working principle, and simplified physical model are described in detail. Then a comprehensive experimental study is conducted on large-scale damper specimens with different design parameters. The damper exhibits a typical flag-shaped hysteretic behavior, and disc springs combined in parallel can significantly increase the load-bearing capacity and the second stiffness of the damper. Subsequently, a numerical modeling technique is developed to capture the complex nonlinear behavior of the proposed damper accurately. Finally, the study is further extended to a structure-level analysis to investigate the influence of key brace-design parameters on the overall response of the structure along with its collapse fragility. It is found that the rational design of the self-centering viscous damper can effectively suppress the peak inter-story drift, re-sidual inter-story drift, and peak absolute floor acceleration of the structure, thereby achieving a favorable trade-off in the design outcome. Additionally, reducing the self-centering ratio and increasing the loading stiffness ratio are effective measures to improve the collapse resistance of such structures.