Seismic performance of repaired hollow-bridge piers

To develop an effective repair technique for rapid bridge restoration after an earthquake, four hollow bridge columns were cyclically loaded to failure, repaired and retested. The repair process includes using dog-bone shape bars to replace the fractured longitudinal bars in plastic hinges and using FRP (Fiber Reinforced Plastic) wraps to enhance the deformation capacity of columns. The repair aims to restore seismic capacity in terms of strength and ductility. Test results indicate that the fractured longitudinal bars can be completely repaired and the deformation capacities of the columns were enhanced by FRP wraps. However, due to concrete deterioration and the buckling of the longitudinal bars in the inner layer of the hollow sections, the test results also indicate the repaired column strengths are less than anticipated.