Evaluation of a Full-Scale Friction Spring-Based Self-Centering Damper Considering Cumulative Seismic Demand

Abstract

Various self-centering (SC) structural systems have been developed and proven effective in ensuring structural resiliency over the last few decades. However, information on cumulative seismic demand for SC structural systems under seismic excitations, especially under mainshock–aftershock sequences and long-duration ground motions, is very limited. In this paper, the recommended design and fabrication processes for friction spring-based SC dampers are first presented. Accordingly, a 6-story braced frame equipped with the SC dampers is designed. A typical full-scale SC damper is subsequently manufactured and tested. To satisfy the codified requirement for practical application, two loading protocols are adopted to investigate the hysteretic and fatigue performance of the damper. The test results show that the damper has very stable flag-shaped hysteretic behavior and maintains excellent SC capability and moderate energy dissipation under multiple rounds of loading. In particular, the behavior of the damper is stable under 30 cycles of constant amplitude loading without visible degradation. After the experimental study, an accumulative seismic demand index is developed, followed by a system-level analysis performed on the considered structure under mainshock–aftershock and long duration earthquake excitations. It was found that the cumulative seismic capacity of the SC damper surpasses the corresponding cumulative seismic demand under the considered multiple earthquake excitations, and therefore no fatigue failure of the damper is expected.