Cyclic behaviour of earthquake- and corrosion-damaged RC columns

An experimental study was undertaken to investigate the cyclic behaviour of earthquake- and corrosion-damaged rectangular reinforced concrete (RC) columns. Nine un-corroded columns and nine columns corroded using an external current method were tested to evaluate the effects of reinforcement corrosion level, initial earthquake damage degree (EDD), retrofit method and loading pattern on their cyclic behaviour. The test results indicate that reinforcement corrosion deteriorated the cyclic behaviour of RC columns in terms of strength, ductility, low-cycle fatigue life, secant stiffness and cumulative energy dissipation capacity, while retrofitting with carbon fibre reinforced polymer wraps and high-strength grout greatly improved the cyclic behaviour of both the un-corroded and corroded columns. For columns with an initial EDD of less than about 30%, regardless of whether they were first corroded or not, their strength, fatigue life and cumulative energy dissipation capacity after retrofit were fully restored to the levels prior to earthquake damage, whereas the level of improvement in the initial secant stiffness of damaged columns after retrofit was affected by the reinforcement corrosion level and the initial EDD. The influence of loading pattern on the cumulative energy dissipation capacity of un-corroded and corroded columns was also studied.