Shear strengthening of reinforced concrete beams using NSM/EBR techniques

Abstract

This paper presents the experimental results of research into the behavior of shear-enhanced reinforced concrete R.C beams using steel stirrups, Fiber Reinforced Polymers FRP rods, and Fiber Reinforced Polymers FRP strips. This enhancement was accomplished by the Near Surface Mounted technique NSM. The NSM technique contains a groove on the outside surface of the concrete member to adjust the depth to be less than the cover of the member. After cleaning, the epoxy paste was used to fill half of the groove's depth. In the groove, the particular FRP element is then installed. Finally, the groove is filled with epoxy and the outside surface of the concrete is levelled with so much epoxy. This method enables the fiber reinforcement polymer FRP materials is covered completely by epoxy. The objective of this research is to study the effect of NSM technique on shear resistance for stressed beam. 13 experimental studies of half-scale R.C beams were involved in this paper. The experimental program included two specimens strengthened with steel stirrups, eight specimens strengthened with stirrups of Glass Fiber Reinforced Polymer GFRP rods with the shape of deferent end anchorage and angle, two specimens strengthened with externally bonded GFRP strips. The remaining un-strengthened specimen was allocated for comparison as a control one. The test results included ultimate load of capacity, deflection, cracking, and failure mode. All beams enhanced with GFRP rods showed a capacity improvement ranging from 14% to 85% compared to the reference beam, and compared to the reference beam, beams enhanced with GFRP strips showed a capacity improvement ranging from 7% to 22%.