Shear strength of strengthened RC beams with FRPs in shear

We propose a predictive model for shear strength of RC beams strengthened by fiber material. It consists of a plasticity model for web crushing, a truss model for diagonal tension, and a simple flexural theory based on the ultimate strength method. To analyze the shear-strengthening effect of the fiber, the model considers the interfacial shear-bonding stress between base concrete and the fiber. This reflects that the primary cause of shear failure in strengthened RC beams is rapid loss of load capacity due to separation of the strengthening fibers from the base material. The predictive model can estimate load capacities of each failure mode, and is compared to tested specimen data including extreme load failure. The analysis matches well with the experiments concerning load capacity and failure mode. Also, the experimental results of other published data are compared to the predictive model to evaluate its application. The results show that the predictive model has good adaptability and high accuracy.