Exploring new NSM reinforcements for the flexural strengthening of RC beams: experimental and numerical research

摘要

Carbon-fiber-reinforced-polymer (CFRP) composite materials applied according to near-surface-mounted (NSM)technique constitute an effective technique for the flexural and shear strengthening of reinforced-concrete (RC)structures. However, the NSM CFRP reinforcement ratio is limited by the thickness of concrete cover of thelongitudinal tensile steel bars, and the minimum distance between consecutive CFRPs, below which prematurefracture of surrounding concrete occurs due to group effect. Hence, the current study aims to experimentally andnumerically evaluate the strengthening potentialities of a novel NSM system (with high CFRP ratio capability) for theflexural strengthening of RC beams. This new system combines externally-bonded-reinforcement (EBR) and NSMtechniques in the same application using T-shaped CFRP profiles. The obtained experimental results of the RC beamsstrengthened with CFRP profiles are presented and discussed with the aim of evaluating the influence of CFRP profilereinforcement ratio on the strengthening efficiency of this technique. A developed 3D finite-element (FE) approach isused to simulate the experimental tests. After demonstrating its good predictive performance, a series of parametricstudies is performed to assess the influence of the main material properties, and ratio of bond area to cross sectionalarea of the CFRP profiles on the efficiency of the proposed system.