Seismic Evaluation of Repaired and Retrofitted Circular Bridge Piers of Low-Strength Concrete

An experimental investigation was carried out to study the effect of retrofitting on change in dynamic properties of 1/4 scaled damaged and undamaged bridge piers of low-strength concrete. Response of three bridge piers, subjected to cyclic lateral loads and free vibration tests under constant axial loading, was evaluated. One of the piers was tested twice: firstly, it was tested up to damaged state, and then it was repaired with single layer of carbon fiber-reinforced polymer (CFRP). This repaired column was then subjected to the same type of loading as the original one. Third pier was retrofitted in undamaged state with single layer of CFRP. It was observed that ductility of retrofitted column at 2% drift level was 39% higher than that of original column. However, ductility of repaired column was improved to original level. Cumulative energy dissipation capacity of retrofitted column was also improved up to 39.38%, whereas energy dissipation capacity of damaged retrofitted was recovered to original state. After subsequent cycles, improvement in energy dissipation capacity was 25.8 and 18% in retrofitted and repaired columns, respectively.