FLEXURAL BEHAVIOR OF CONCRETE BEAMS STRENGTHENED WITH NEAR-SURFACE MOUNTED GFRP BARS

The objective of this study is to investigate the flexural behavior of reinforced concrete beam with near-surface mounted (NSM) GFRP bars. In this paper test on a total of 5 simply supported rectangular cross-section beams strengthened with NSM GFRP bars and two control beams has been carried out. The mode of failure, load-deflection relationship, and load-strain curve of the all specimens are analyzed. Yield and ultimate strengths, deflection and cracks propagation are discussed base on measured data. The results indicate that the embedment length decided on the type of the failure mode. There were two types of failure mode for the beam strengthened with NSM GFRP bars, including the specimens failed by the rupture of the GFRP bars simultaneously with the splitting of epoxy adhesive and shear at the position of GFRP bars at the free end. The yield and ultimate load had a significant increase and the ultimate deflection showed a reduction with the embedment length. Also, there exists a clear redistribution of tensile force to the GFRP as a result of steel yield in the load-stain curve of the strengthened beam. The studies also show that using NSM-FRP bars is practical, significantly increased the flexural capacity and flexural stiffness of reinforced concrete beams.