Seismic performance assessment of metal-friction hybrid damper linked steel frame considering extremely rare earthquakes

In this paper, a new metal-friction hybrid damper linked steel frame (HDSF) system is proposed for seismic resilient application considering extremely rare earthquakes (EREs), through developing a metal-friction hybrid damper (MFHD) as the primary fuse. The configuration and working mechanism of the HDSF is detailed. The two-level yielding and failure self-protection behaviors of the MFHD are investigated by cyclic loading tests, and a theoretical hysteretic model is derived to simulate its cyclic behavior. Subsequently, a seismic resilient design procedure that can simultaneously capture the performance objective of service level earthquakes, design-based earthquakes, maximum considered earthquakes and EREs is presented and employed to design a 9story HDSF. To examine the seismic performance and resilience of the designed HDSF, a reliable numerical model is built for performing nonlinear dynamic analysis under the four seismic levels. The results show that the developed MFHD has stable hysteretic loops and its friction force is recommended as 1.2 times of the metallic damper's yielding strength to ensure desirable hysteretic performance and failure self-protection. The design targets for roof drift ratio, base shear and inter-story drift ratio of the designed HDSF are achieved, whilst the anticipated performance objectives and predefined yielding mechanism under the four seismic levels are successfully accomplished. Moreover, the small residual inter-story drift ratio responses of the designed HDSF further demonstrate the effectiveness of the proposed HDSF system as a seismic resilient structural system against EREs.