EXPERIMENT STUDY ON MECHANICAL BEHAVIOR OF REINFORCED CONCRETE BEAMS STRENGTHENED WITH NEAR SURFACE MOUNTED (NSM) CFRP RODS

The near surface mounted (NSM) carbon fiber-reinforced polymer (CFRP) (which usually be abbreviated as CFRP-NSM method) was a new strengthening technology for reinforced concrete (RC) structures, in which the CFRP rods or strips were mounted in the groves by bond material, and the CFRP rods or strips could work together with existing RC members, thus to strengthen the RC members. Considering four different bond materials, pullout test of 12 specimens were firstly conducted to study the bond performance between the CFRP rods and concrete. Then 11 RC cantilever beams specimens were tested to study the mechanical behavior of the beams strengthened with NSM CFRP rods. Based on experiment results, the failure modes, strains of CFRP rods mounted in the RC beams and the cracking type were examined, and moreover, the influence of the type of bond material, the load pattern and the diameters of the CFRP bars were studied. The experimental results demonstrates that the CFRP-NSM strengthening technology enhances the bearing capacity of RC cantilever beams due to the strength provided by the mounted CFRP rods. Therefore, the CFRP-NSM strengthening technology can improve mechanical behaviors of RC members and has potential to be more widely applied in the future.