Experimental and theoretical investigations of post-tensioned precast reinforced concrete bridge pier with external replaceable energy dissipaters

This study presents a post-tensioned (PT) precast reinforced-concrete bridge pier with external replaceable energy dissipaters (PRCB-EREDs). The EREDs provide both bending resistance and energy dissipation (ED) capacity, and the unbonded PT strands enable prefabricated construction and self-centering capabilities. This study introduces the construction, assembly process, and post-earthquake repair technology of the PRCB-EREDs. Subsequently, parametric quasi-static tests were performed by altering parameters, such as the initial PT force and the size of core energy dissipation steel plate in the ERED (ERED-CEDP). The test results indicated that the precast pier column remained essentially elastic, with damage localized within the ERED-CEDP, exhibiting good deformation and ED capabilities. The hysteresis curve of the specimen was full and stable, and the curves before and after repair were essentially identical, confirming the feasibility of the repair. With an increase in the initial PT force, both the stiffness and bearing capacity were improved, and better self-restoration effects were achieved. For test conditions with the same ERED-CEDP thicknesses but different initial PT forces, the ED capacities were almost the same. Finally, the load-resisting mechanism of the PRCB-ERED piers was analyzed and theoretical model of hysteretic behavior was proposed and verified.