Debonding mechanisms in continuous RC beams externally strengthened with FRP

One of the biggest challenges in structural engineering nowadays is strengthening, upgrading and retrofitting of existing structures. The use of fibre reinforced polymers (FRPs) bonded to the tension face of the structural member is an attractive technique in this field of application. The strengthening of reinforced concrete (RC) structures by means of externally bonded reinforcement (EBR) is achieved by gluing FRP reinforcement to the concrete substrate. For the efficient utilization of the FRP EBR systems, an effective stress transfer is required between the FRP and the concrete. The paper will discuss the bond behaviour between the FRP and the concrete in the case of flexural strengthening of continuous beams. With respect to this type of beams, few research has been reported. At the Magnel Laboratory currently a test program on flexural strengthening of 2-span continuous beams is ongoing.