Shear strengthening of reinforced concrete continuous beams

Abstract

This paper presents the results of an experimental investigation to evaluate the contribution of carbon-fibrereinforced polymer sheets in enhancing the shear strength of continuous reinforced concrete beams. A total of five, two-span concrete continuous beams with rectangular cross-section were tested. One beam without strengthening was used as the control and the other four beams were strengthened with different arrangements of polymer sheets.The variables selected were various wrapping schemes and anchorage length of the polymer sheet. The aim was to develop a better understanding of the shear contribution of polymer and to investigate the potential for cost savings by minimising the area of externally bonded polymer sheets. Test results were compared with four existing shear prediction models available in the literature. The results indicate that the polymer sheet significantly enhanced the shear strength of the beams, and that the area of polymer sheet can be minimised with marginal compromise on the shear carrying capacity of strengthened concrete beams.

Effect of bond surface area on the shear strength of carbon fibre reinforced polymer (CFRP) strengthened reinforced concrete beams

“…Table 3 shows that the shear resistance of RC beams can be improved by epoxy-bonded CFRP fabric strips as U-wrapped placed at 900 to the horizontal axis of the beam. These results are similar to those found by Ahmad et al [30], who concluded that CFRP material can be used to increase the shear performance. The results demonstrated that the CFRP fabric strips effectively improve the shear strength of RC beams, but the contribution shows variation dependent upon the bond surface area.…”

“…It is clear from Table 2 and Figure 4, that the mid-span deformations at failure for Beams FA-0, VR2A, VR2B, VR2C, VR2D, VR2E and VR2F were 4.1, 5.9, 6.3, 9.5, 6.7, 7.5 and 8.6 mm respectively, while the ductility indexes were 1.05, 1.56, 1.9, 2.6, 2.08, 2.2 and 2.5 respectively. Figure 4 shows that beam FA-0 is initially stiffer than all the CFRP fabric U-wrapped strengthened Beams (VR2A, VR2B, VR2C, VR2D, VR2E and VR2F), which is similar to the work of Ahmad et al, [30].…”