Abstract:

The seismic performance evaluation and retrofit process are very important in damaged bridges. If the result is not appropriate, then retrofit process are required. In this paper, to validate the seismic performance of retrofitted bridge experimentally, an experimental study was conducted to verify the application and efficiency of the jacket retrofit method to ensure seismic performance of damaged reinforcement concrete (RC) bridge piers. A total of 4 RC bridge piers was made and then 3 piers were pre-loaded under the range of service load to be damaged. These piers were retrofitted and repaired using a carbon fiber reinforced polymer (CFRP), steel plate, and fiber steel composite (FSC) plates. These retrofitted and repaired piers were subjected to monotonic loading. Hysteresis and ultimate behaviors of the 3 RC piers were evaluated and compared with those of 1 non-damaged pier (standard specimen). As a test result, the retrofitted and repaired RC bridge piers applied by the jacket retrofit method were ensured under the targeted displacement ductility and ultimate load. The ultimate load and displacement ductility of the pier retrofitted and repaired by FSC plate were higher than those of other piers by CFRP and steel plates and also the pier by FSC plate showed better energy dissipation capacity than others. Generally, RC bridge pier retrofitted and repaired with the jacket retrofit method has low ductility but it was found that the pier retrofitted and repaired by FSC plate combined with CFRP and steel wire had overcome effectively this disadvantage through ductility evaluation based on the concept of energy numerically. This experiment showed that one could improve the safety margin and targeted ductility by repairing the cracks, spalls, etc. of the damaged RC bridge piers appropriately and then retrofitting them with the high ductile materials. The responses of existing damage bridges are compared with those of retrofitted bridge by jacket method for earthquake of target level, and also seismic performances are evaluated. By the test and analysis results it can be concluded that the proposed seismic retrofit method was found to be valid.

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