Parameter Analysis for the Flexural Performance of Concrete Beams Using Near-Surface Mounted-Strengthening Application

In this paper, a systematical study on the influence of strengthening parameters on the flexural performance of RC beams using the NSM application was carried out. Experimental results consist of two reference beams and 25 beams divided into two groups using NSM systems with various embedded bars and strengthening configurations were presented. Additionally, theoretical analysis was conducted to enrich the research on the parameters affecting the strength and failure mode of the beams. The accuracy of the theoretical formulas has been verified through experimental results, and the average value of the ratio between the theoretical and experimental values is approximately 0.9. Results indicated that NSM technology is an effective approach for strengthening RC structures. Compared with the control specimens, the maximum load-bearing capacity of the beams with the NSM system experiences a remarkable enhancement of nearly 140%. The flexural behavior of the beams strengthened by the NSM system are closely related to the material properties (steel bar, NSM bars, concrete, and filler), location of the cutoff points, external confinement, and prestress level. The NSM bars characterized by high strength and high elasticity prove to be far more advantageous in enhancing the strength of the strengthened specimens. The research findings can provide theoretical support for the practical engineering applications of the NSM technology in strengthening reinforced concrete structures.