عنوان مقاله [English]
نویسندگان [English]چکیده [English]
Recent earthquakes, the severe structural damage that ensues and modifications incorporated into building codes call for retrofitting of structures more than ever. A viable method is utilizing composite Fiber Reinforced Polymer (FRP). This system was initially used to the flexural strengthening of RC beams. In this study, a RC beam, one of the primary structural elements, is investigated in a commercial finite element software, ABAQUS; ten RC beams with FRP sheets used in different shapes and positions (the area of sheets is equal in different cases) are studied under torsional loading. Results showed that strengthening the mid portion of the FRP provides better results and incorporation of FRP sheets delays the ingress of diagonal shear cracks in faces of the RC beams which in turn increases the torsional moment capacity and reduces shear stresses in faces of the RC beam.