Experimental study on shear strengthening of R.C. beams using FRP repair techniques

摘要

This paper presents results of an extensive experimental investigation of strengthening of reinforced concrete beams pre-damaged in shear using fiber reinforced polymer repair techniques.Typically carbon or glass fiber sheets externally bonded to the bottom and sides of RC beams were used for the shear strengthening of RC beams. Another technique, previously studied by the author, is to strengthen RC beams in shear by drilling holes through the depth of the beams and then embedding FRP rods in these holes. In this paper a comparison of these two techniques in strengthening and repairing RC beams is presented. Six beams were tested; a control beam without strengthening, two beams strengthened using externally bonded CFRP (Carbon Fiber Reinforced Polymer) sheets and two beams strengthened using embedded CFRP rods. For each technique, one specimen was preloaded beyond the formation of the first crack before strengthening, while the other was not preloaded in order to study the effects of preloading. The last specimen was the control specimen which was retrofitted after being loaded to failure in shear then retested again after repair. Research findings have shown the use of FRP sheets for strengthening damaged reinforced concrete beams is an efficient technique that can maintain structural integrity and enhance the behavior of such beams.