Shear strengthening of rc beams with BFRP by using different wrapping methods

In this study, the experimental study and comparative analysis were performed on the results of the deficient shear strength RC beams strengthened with basalt fiber reinforced polymer composites by using strip winding method with different orientation angle. 150×250 mm rectangular cross section RC beams with 2000 mm long were produced in laboratory environment. S420 reinforcement steel and C16 concrete class were used in the RC beams. RC beams were Designed to have one side of the beam with a deficient shear capacity and the other side were designed to have sufficient capacity, also, all beams were designed to have sufficient capacity in terms of bending load capacity. BFRP were used for strengthening the insufficient shear capacity side of RC beams by using epoxy resin in various bonding reinforcement schemes such as 45° U strips, 45° U strips along with two horizontal strips, 45° completely warped stirps, 90° completely warped continues sheets and side bonding continues sheets. BFRP strengthened RC beams and the control beam specimens were tested in the laboratory by 4-point bending experiment with constant rate of loading. The average shear capacities, shear deformation, deflection capacities and shear crack width values on the beam surface of all beam specimens were examined. In addition, the experimental shear strengthening results were compared with Chen and Teng model, Khalifa and Nanni model, ACI 440.2 R and FIB-TG 9.3 guidelines. Tests showed that the externally adhesive bonded flexible BFRP composites are effective in strengthening RC beams in shear. In addition, the most efficient results among the various strengthening techniques examined were obtained with completely wrapped sheets and 45° completely wrapped strips. Also, there was an improvement in shear capacity between 61% to 113% in all RC beam samples reinforced with BFRP composites when they were compared to the control beams. Four prediction models available in literature for predicting the shear contribution of BFRP composites to the shear capacity of BRFP strengthened beams were used to compare it with the experimental results and it showed that close results were obtained with Fib-TG 9.3 model.