Experimental and analytical investigation into the flexural performance of RC beams with partially and fully bonded NSM FRP bars/strips

Thirteen reinforced concrete (RC) beams strengthened with partially and fully bonded near surface mounted (NSM) reinforcement and one unstrengthened beam (CB) were prepared and tested in order to study the effect of bond length, construction details and fiber reinforced polymer (FRP) characteristics on flexural performance. Carbon fiber reinforced polymer (CFRP) bars and strips and glass fiber reinforced polymer (GFRP) bars were used as the NSM reinforcement. Two bonded lengths (384 mm and 480 mm in each shear span) were studied for beams strengthened with partially bonded NSM reinforcement, while the bond length was 2000 mm in beams strengthened with fully bonded NSM reinforcement. The effect of transverse wrapping and end anchorage on the behavior and load capacity of strengthened beams was also studied. The results showed that the RC beam strengthened with fully bonded NSM FRP had greater stiffness and bearing capacity than the beams with partially bonded NSM FRP. The use of NSM FRP with end anchorage or with transverse wrapping for the strengthening of RC beams increased their load carrying capacity and stiffness. The analytical model predicted well the response of the tested beams.