Effect of the strengthening patterns on the flexural performance of RC continuous beams using FRP reinforcements

Statically indeterminate RC elements such as continuous beams are the most widely used structural form. Their flexural behavior and failure modes are considerably different from those of simply supported ones. The use of FRPs for flexural strengthening and retrofitting continuous RC beams has hardly been studied. Therefore, this paper compares the impacts of NSM-FRP and EB-FRP systems in two-span beams. The overall experimental program of this study consisted of fourteen large-scale bending tests. The performance of each strengthening system is presented and discussed in terms of failure mode, yielding and load-carrying capacities, ductility, and energy absorption capacities, FRP debonding strain, and serviceability state. The experimental results showed that the failure mode is mainly dependent on the type, length, and position of the FRPs, however, a general improvement in the flexural performance of strengthened beams was observed. The NSM technique allows the FRP tensile strength to be better exploited than the EB technique.