Design and seismic performance of precast segmental bridge columns repaired with UHPC jacket after earthquake-induced damage

Precast Segment Bridge Columns (PSBCs), which attract more attention owing to the merits of faster construction rate and higher construction quality compared with monolithic columns, are prone to serious damage under a severe earthquake. Seismic performance improvement and rehabilitation of earthquake-damaged PSBCs are significant to promote applications in seismic-prone areas. Ultra-high performance concrete (UHPC) jackets, which are promising in the field of rapid retrofit of civil structures, were used to retrofit damaged PSBCs in this study. To investigate the seismic design method and performance of repaired PSBCs using UHPC jackets, a 1/10scale earthquake-induced damaged PSBC was retrofitted based on a proposed reinforcement design method, and tested under vertical loading and incremental lateral cyclic loading. The failure mode, hysteresis curve, residual displacement, and energy dissipation capacity of the repaired column were compared with those of the original column. In addition, based on a verified 3D finite element model by the test, a parameter analysis was conducted to explore the effect of the height and wall thickness of the UHPC jacket on the seismic behavior of the repaired PSBCs. The results indicated that the earthquake-damaged PSBC repaired with the UHPC jacket had an equivalent initial stiffness, 18.9% higher energy dissipating ability at 4.0% drift ratio and 16.2% larger strength compared with the undamaged column. The numerical simulation showed that the height and thickness of the UHPC jacket had an influence on the failure location and strength of the repaired PSBCs. Besides, the design method for the damaged precast column reinforced with the UHPC was confirmed by the test and finite element model, and it could be applied to the retrofit design of the damaged precast segment column.