Debonding failures in RC beams and slabs strengthened with FRP plates

Strengthening of reinforced concrete (RC) structures by the external bonding of advanced fibre-reinforced polymer (FRP) composites has become very popular around the world over the past decade due to the well-known advantages of FRP composites over other materials, including their high strength-to-weight ratio and good corrosion resistance. This thesis presents an in-depth study into debonding failures in RC beams/slabs strengthened by a bonded tension face FRP plate (i.e. FRP-plated RC beams/slabs).; Following an introduction to the subject and a review of existing research, the thesis presents an extensive experimental investigation into the bond behaviour between externally bonded FRP and concrete. Seventy-two pull tests were conducted on FRP-to-concrete bonded joints using a simple set-up. The test results confirm the reliability of both the test method and Chen and Teng's bond strength model. Furthermore, the interfacial parameters of these specimens were identified to establish bond-slip curves. A comparison of the pull test results and the analytical solution for the full-range behaviour of bonded joints confirms the feasibility of this approach of identifying interfacial parameters.; Debonding failures in FRP-plated RC beams and slabs may be induced by intermediate flexural or flexural-shear cracks (i.e. IC debonding). The results of twenty-two tests on FRP-plated RC slabs are presented. Through these test results, the failure process and the failure mechanism are carefully examined. The present results together with results from existing studies are then used to assess the accuracy of existing strength models and to develop a new, more reliable strength model for IC debonding failures.; Debonding is also likely to occur at a plate end (i.e. plate end debonding). The results of twenty-one tests on plate end debonding are presented to gain an improved understanding of the failure process. These test results together with existing test results are then used to develop a new, more accurate plate end debonding strength model, as the existing models are found to be inadequate. The new model takes into account the shear-bending interaction at the plate end.