Self-centering companion spines with friction spring dampers: Validation test and direct displacement-based design

Abstract

Abstract This paper aims to propose self-centering companion spines with friction spring dampers (denoted as SCS) for obtaining better post-earthquake resilience in steel building structures. Two typical configurations of SCSs in buildings were first introduced. The SCS mainly consists of two rigid spines (RSs) and many friction spring dampers (FSDs). The two RSs have adequate strength and stiffness to create uniform inter-story drift distribution in SCS. The FSDs are the lateral force-resistant and energy-absorbing components and provide self-centering capacity for SCS. Some validation tests were further performed to investigate the hysteretic behavior of the developed SCS. Two different loading protocols were adopted in the experiments to test the stability of SCS subjected to different loading histories. 6% was set as the maximum loading roof drift to indicate the superior deformability of SCS. Moreover, three repeated loadings were performed for each loading protocol to study the behavior of SCS under aftershocks or multiple earthquakes. The experimental results show that the developed SCS can obtain stable and convincing self-centering hysteretic responses under repeated loading with different loading protocols, and no strength or stiffness deterioration can be found. These observations confirm that SCS is fully recoverable after earthquakes and has the potential to be used as a resilient seismic-resistant system in the building located in seismic regions. Lastly, the direct displacement-based design (DDBD) method was developed for SCS. A three-story SCS was designed on the basis of the proposed DDBD method. Nonlinear static and dynamic analyses were performed to validate the efficiency of the proposed DDBD procedure. The numerical results show that the designed SCS can show the anticipated nonlinear behavior and obtain the expected performance target.