Seismic behavior of earthquake-damaged hybrid connections reinforced with replaceable energy-dissipating elements

In recent years, self-centering post-tensioned concrete structures have received extensive research attention owing to their excellent seismic performance and post-earthquake functional recoverability. This study entailed the development of a novel repair method for earthquake-damaged unbonded post-tensioned hybrid connections (PTHCs) by using a novel energy-dissipating device to improve seismic resilience. To investigate the effectiveness of the repair method, four connections with different degrees of seismic damage were repaired using different repair methods, and quasi-static experiments were then conducted. The test variables included the position of the glass fiber-reinforced polymer (GFRP) arrangement, connection method of energy-dissipating devices, number of replaceable energy-dissipating elements (REDEs) of the damper, and initial prestressing force of post-tensioned (PT) strands. The experimental results indicate that the proposed repair methods can recover the lost capacities of PTHCs, and the mechanical properties of the reinforced self-centering precast connections (RSCPCs) can even be restored by replacing the REDEs under a second rare earthquake. The proposed energy-dissipating device facilitates increase or decrease of the REDEs to meet the energy dissipation and stiffness targets of the component for different levels of earthquake damage. The calculation results based on the recovery force model were in good agreement with the test results, showing that the proposed model could reasonably predict the hysteresis behavior of the RSCPCs.