Strengthening of Concrete Beams Using Innovative Ductile Fiber-Reinforced Polymer Fabric

An innovative, uniaxial ductile fiber-reinforced polymer (FRP) fabric for strengthening structures is described. The fabric is a hybrid of 2 types of carbon fibers and 1 type of glass fiber, and has been designed to provide a pseudo-ductile behavior with a low yield-equivalent strain value in tension. The effectiveness and ductility of the developed fabric was studied by strengthening and testing 8 concrete beams under flexural load. Similar beams strengthened with currently available uniaxial carbon fiber sheets, fabrics, and plates were also tested to compare their behavior with those strengthened with the developed fabric. This fabric has been designed so that it has the potential to yield simultaneously with the steel reinforcement of strengthened beams and hence, a ductile plateau similar to that of nonstrengthened beams can be achieved. The beams strengthened with the newly developed fabric exhibited higher yield loads and achieved higher ductility indices than those strengthened with the currently available carbon fiber strengthening systems. The fabric shows a more effective contribution to the strengthening mechanism.