Possibilities and challenges of NSM for the flexural strengthening of RC structures

Near surface mounted (NSM) is a technique that has been used to increase the flexural and the shear resistance of reinforced concrete (RC) structures. The performance of the NSM for the flexural strengthening of RC beams and slabs was already well proved, from research to case-studies. However, the influence of some variables that govern the effectiveness of the NSM, such is the case of the distance between consecutive bars, the reinforcement ratio of existing longitudinal steel bars, the relative position between longitudinal steel and FRP bars, the concrete strength class, and the type and layer thickness of the adhesive is still not well understood. Strengthening procedures need also some improvements in order to increase the effectiveness of this technique. These topics are discussed in the present work, based on the research already done. Specific issues that need extra and deep research are addressed.National Science Foundation(13-05-04-FDR-00031