PREDICTION OF DEBONDING FAILURE IN FRP STRENGTHENED RC BEAMS

摘要

The Performance of FRP strengthened RC beams may always be compromised by debonding failure. Concrete cover debonding (CCD) and Intermediate flexural crack-induced debonding (IFCD) are the two most common debonding failure modes in FRP strengthened RC beams. Based on fracture theory a new prediction model of CCD is presented. The FRP strain at CCD failure only relates to these factors: mode I fracture energy of concrete, ratio of beam width and FRP width, thickness and elastic modulus of FRP, anchorage length of FRP, crack spacing of the strengthened beam. A new prediction model of IFCD is also presented with the influences of restraint stress and crack spacing on debonding load taken into account. The two models are then calibrated with test data from literatures and found outperform other existing models.