Torsional Repair of Severely Damaged Column Using Carbon Fiber-Reinforced Polymer

Although a limited number of studies have been conducted on the use of externally bonded composites for torsional retrofit or strengthening of reinforced concrete (RC) members, very few are available on torsional repair. This paper evaluates a method for repairing severely damaged RC columns subjected to torsional moment using externally bonded carbon fiber-reinforced polymer (CFRP) composites. A half-scale RC column that was previously tested to failure under constant axial load and cyclic torsional moment was repaired with externally bonded CFRP using a rapid methodology. CFRP sheets with fibers oriented in both the transverse and longitudinal directions were applied to restore the strength and ductility of the damaged column to its original condition. This study demonstrates that this method can be used to restore the torsional performance of severely damaged RC columns. Contributions of the transverse and longitudinal CFRP sheets to the torsional resistance are evaluated, and repair design for torsional moment using this method is discussed.