Seismic resilience analysis of self-centering prestressed concrete frames with generalized flag-shaped hysteretic behavior

To increase the stiffness and energy dissipation of conventional self-centering concrete joints, this paper proposes a self-centering prestressed concrete frame with a generalized flag-shaped hysteretic behavior (GFS-SCPC). First, the working mechanism of the GFS-SCPC joint is clarified, and the key parameters affecting the generalized flag-shaped hysteresis are proposed: the second stiffness ksθ and the energy dissipation ratio βE. Subsequently, the three-dimensional self-centering prestressed concrete frame with flag-shaped hysteretic behavior (FS-SCPC) and GFS-SCPC frames are established, and the time history analysis and incremental dynamic analysis (IDA) method are carried out to compare their seismic performances. Finally, according to the FEMA P-58 specification, the resilience indexes of the frames with different hysteretic parameters are evaluated to clarify the influence of ksθ and βE. The results show that the energy dissipation capacity of the GFS-SCPC frame increases with larger second stiffness ksθ and the energy dissipation ratio βE. The increase of ksθ effectively controls the maximum drift angle and acceleration response of the GFS-SCPC frame, which would reduce the vulnerability of the structure. The main structure of the GFS-SCPC frame remains undamaged after the earthquake, and the loss mainly comes from the damage of the acceleration-sensitive non-structural components of the upper floors. The increase of ksθ can effectively reduce the damage degree of non-structural components and further reduce the resilience indexes, including casualties, repair time and repair cost, while the increase of βE alone does not significantly improve the resilience indexes. Therefore, the proposed GFS-SCPC frame with larger second stiffness has better seismic resilience performance.