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Seismic Retrofit and Repair of Circular Bridge Columns with Advanced Composite Materials

Experimental studies on seismic retrofit and repair of typical circular bridge columns with poor lap splice details utilizing prefabricated glass fiber reinforced polymer (FRP) composite jackets and epoxy are presented in this paper. A total of seven tests on three 1/2-scale model columns were conducted. One column was tested under “as-built” condition and the other two columns were retrofitted with prefabricated composite individual and continuous jackets respectively. The jackets were applied in the potential plastic hinge region of the column to increase its lateral confinement. Brittle failure was observed in the “as-built” model column due to the bond deterioration of lap spliced longitudinal reinforcement. This brittle failure was prevented in the retrofitted columns. The repairing of failed “as-built” column by injecting epoxy into damaged plastic region resulted in significant stiffening of the portion and increase of capacity and ductility. The second repair of the specimen using both epoxy injection and prefabricated composite jacketing effectively improved its behavior further. The results of this study indicated that dramatic improvement in ductility and energy absorption capacity of columns can be achieved using these retrofit and repair methods.