Flexural performance of RC beams strengthened by bonded CFRP laminates under monotonic and cyclic loads

RC beams, strengthened by external bonded FRP reinforcement, often fail by one of several possible debonding modes. Although many experimental studies have been performed to assess the exural behavior and failure modes of FRP-strengthened RC beams under monotonic loads, the exural performance of these elements under cyclic loads have rarely been examined. The present paper illustrates the results of an experimental study aimed at better understanding of the structural behavior and debonding failure mechanisms of FRP-strengthened RC beams under monotonic and cyclic loads. This experimental research program is made of exural tests carried out on eight RC beam specimens with dimensions of 150 mm width, 200 mm height, and 1800 mm length, externally strengthened with CFRP laminates and tested under monotonic and cyclic loadings. Three specimens were considered as control specimens. The remaining ve specimens were strengthened in exure by CFRP laminates. This program investigated the structural behavior and debonding failure trends in the FRP-strengthened beams. Results of this investigation are presented in the form of load-de ection curves and FRP strain proles.