Seismic Performance Investigation And Seismic Resilience Assessment Of Self-centering Prestressed Concrete Frame With Upper-bottom Friction Damper

Seismic resilient structure,which is a fundamental part of resilience cities,plays an essential role on improving the resiliency of urban and rural infrastructure.The self-centering prestressed concrete（SCPC）frame with enhanced performance characteristics,such as high construction assembly efficiency,small residual deformation and favourable resilience,has been developed as an important seismic resilient structure.With the concept of self-centering and friction energy dissipation,a SCPC frame with upper-bottom friction damper was proposed in this dissertation.This dissertation focused on the seismic performance and seismic resilience of the SCPC frame through experimental analysis and numerical simulation.The main research contents are as follows.（1）Meeting the demands of precast concrete frames with different spans,upper-bottom friction damper self-centering prestressed concrete beam-column connection（UBFD-SCPC）and upper-bottom friction damper self-centering prestressed concrete beam-column connection with hidden corbel（HC-UBFD-SCPC）were proposed.The configuration and working mechanism of the two connections were introduced.The theoretical deductions of gap-opening moment and second stiffness were given.The numerical model of the connections was simulated by Open Sees,and the influence mechanism of design parameter on the mechanical performance of the connection was studied.（2）SCPC frames with hidden corbel and upper-bottom friction dampers were proposed.A half-scale one-story one-bay SCPC frame specimen was designed and fabricated.Six low cyclic loading tests were performed to investigate the seismic performance of the SCPC frame.The influence of two key design parameters（initial PT forces and friction forces）on the hysteretic performance of the system,such as the stiffness,self-centering capability,energy dissipation capacity and bearing capacity was studied.The results indicated that the SCPC frame has desirable self-centering and energy dissipation capabilities.（3）Performance-based seismic design methods were adopted to design a six-story,fourbay SCPC moment frame to evaluate the seismic performance of the multi-story SCPC frame.Based on the numerical model of beam-column connection,a multi-story SCPC frame benchmark model was established.The nonlinear time history analysis was carried out under design-based earthquake levels（DBE）and maximum critical earthquake levels（MCE）and compared with RC frame.The results showed the residual displacement of SCPC frames was effectively controlled under maximum critical earthquake levels（MCE）and the resilience of the structure was improved.（4）On the basis of the benchmark model,a series of parameterized models was simulated with the second stiffness and energy consumption ratio as the key parameters,and the interstory drift,residual drift,peak floor acceleration,and peak floor velocity were counted.The influence of different parameters on the seismic performance of self-centering frames was investigated.Based on the incremental dynamic analysis method,the fragility curves of different performance level for parameterized models were derived,providing a basis for the seismic resilience assessment of the structures.（5）Based on the FEMA P-58,using the structural analysis results and fragility curves during the nonlinear time history analysis,the building performance models of the SCPC frame and RC frame were established.The comparative evaluation of the performance assessment of the SCPC frame and RC frame under design-based earthquake levels（DBE）and maximum critical earthquake levels（MCE）showed that the SCPC frame guaranteed low damage to the structural components due to its small residual displacement.Compared with the RC frames,the repair cost and repair time of the SCPC frame have been reduced,and the seismic resilience of structure has been improved.