Seismic performance of repaired RC columns

Abstract

Steel or fibre-reinforced polymer (FRP) composite jackets have been utilised in retrofitting reinforced concrete (RC) bridge columns and have shown to be effective in enhancing seismic performance of the structures. However, to date, only a few researches have been conducted on the behavioural characteristics of the repaired RC columns using steel or FRP jackets. In the present paper, the comparative performance of repaired RC columns using steel and CFRP jackets is presented. Also, the effect of transverse reinforcement ratio on the behaviour of the steel and the CFRP repairing is investigated. Monotonic and cyclic load tests are conducted on nine RC column specimens with different repairing strategies and transverse reinforcement ratios to compare the ultimate and the hysteretic behaviours. From the tests, it is observed that both steel and CFRP jacket repairing can significantly increase the ductility and the ultimate capacity of damaged columns. Notably, the steel jacket repaired columns show better energy dissipation capacity than the CFRP jacket repaired columns for columns with lower transverse reinforcement ratio. It is also observed that the location of plastic hinge region goes up as the transverse reinforcement ratio of RC columns increases.