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Due to the relatively low damping and sharp stiffness change, friction-based self-centering dampers are less effective in controlling peak interstory drift (PID) and peak floor acceleration (PFA). To address these concerns, at least partially, this paper leverages the two activation plateaus and proposes two types of double-stage friction-based self-centering dampers. The double-stage behavior provides enhanced stiffness and energy dissipation in the second stage. As the kernel elements, the grooved friction plates or disc spring stacks are elaborately designed to realize two activation points. The configurations and working mechanisms of the dampers are described first, followed by the derivations of their analytical equations governing the force–displacement relationships. Proof-of-concept tests are conducted on two reduced-scale specimens to experimentally examine their hysteretic behaviors. The experimental observations and data meet expectations and validate the analytical equations. At the system level, a steel-braced frame is selected as the example structure for demonstrating the seismic control characteristics of the double-stage friction-based self-centering dampers, through comprehensive comparisons against the companion single-stage self-centering dampers, under earthquakes associated with three seismic hazard levels. The comparison results indicate that the double-stage friction-based self-centering dampers have superior PFA control effect under all hazard levels and better PID control effect under the maximum considered earthquake hazard level.
Liu et al. (Wed,) studied this question.