Background: Conventional friction dampers, despite their adequate energy dissipation capacity, can limit the seismic resilience of structures due to the residual deformations they induce. To address this limitation, this study proposes incorporating self-centering capability into a double-level friction damper with the aim of reducing residual drift and improving seismic performance, thereby facilitating the restoration of structural serviceability after an earthquake.
Methods: To evaluate the effectiveness of the self-centering double-level friction damper, its performance was numerically compared with those of the conventional single-level friction damper without self-centering capability and the self-centering single-level friction damper. For this purpose, three-dimensional 6-, 12-, and 18-story steel special moment-resisting frames equipped with each of the three damper types were designed in accordance with code provisions using the Application Programming Interface (API) of ETABS. Nonlinear time-history analyses were then conducted in OpenSeesPy using a set of earthquake records at two hazard levels: the Maximum Considered Earthquake (MCE) and the Design Basis Earthquake (DBE).
Results: The results showed that, although the conventional single-level friction damper exhibited mean acceleration responses that were 32.7% and 22.6% lower than those of the self-centering double-level and self-centering single-level friction dampers, respectively, its mean residual drift responses were 342.7% and 416.3% higher, respectively. More importantly, the proposed self-centering double-level friction damper exhibited performance comparable to that of the self-centering single-level friction damper, while requiring approximately half the self-centering force to achieve a similar self-centering capability. The reduction in the required self-centering force makes the double-level friction damper a highly suitable option for use in prestressed structures to provide self-centering behavior.
Conclusion: Overall, self-centering friction dampers provide superior seismic performance compared with friction dampers without self-centering capability and can improve the seismic resilience of structures by substantially reducing residual drift. The findings highlight the importance of employing self-centering systems to enhance structural safety and maintain serviceability following an earthquake.