1 FAILURE CHARACTERISTICS OF REINFORCED CONCRETE BEAMS REPAIRED WITH CFRP COMPOSITES

The flexural performance of reinforced concrete beams with externally bonded carbon fiber reinforced polymer (CFRP) fabrics were studied in terms of fabric length and thickness. The internal steel reinforcement ratio and preloading on the behavior of the strengthened beams are discussed. It was found that attaching of CFRP system to the tension surface of either pre-cracked or un-cracked beams improve the load-carrying capacity and stiffness of the flexural beams while unexpected failure modes, such as the peeling of concrete cover and the debonding between the CFRP fabric and concrete still occur. The causes and mechanisms involved in these types of failure modes are investigated. The ultimate strains of the steel reinforcement at failure were on the average about 2.5 times that of yield strain for steel. Therefore, despite the eventual peeling of the concrete cover and debonding of the fabric, the retrofitted beams have capability for considerable deflections