Effect of FRP Strips Configuration, Beam Dimensions and Amount of Tensile Rebars on Shear Capacity of Reinforced Concrete Beams

In this paper, the effect of parameters such as the distance, number of layers and cross-sectional area of FRP strips, the amount of longitudinal rebars, dimensions of beam and compressive strength of concrete on shear capacity of reinforced concrete beams with rectangular cross-section stiffened by FRP strips under symmetrical concentrated loads using the finite element method has been studied.The non-linear analysis of 101 reinforced beams has been performed for evaluation of the effect of the parameters on load capacity and mid-span deflection of the beams with and without strengthening. The samples are deivided into six groups, which ultimately have been compared and investigated for load capacity and displacement of the mid-span. Obtained results indicate that for a constant concrete compressive strength, increasing the width and the number of layers of FRP strips increases the load capacity by 26% and 23%, respectively, compared to the control beam. At same time, by increasing of these two parameters the increase of the load capacity decreases. By changing the layout of reinforcing strips with irregular intervals along the beam, the load capacity increase is about 6% to 35%. Also, the increase of the amount of longitudinal rebars from ∅10 to ∅14, increasing the compressive strength of the concrete from 30 MPa to 50 MPa, and increasing the cross-sectional area of the beam from 150 × 300 mm to 150 × 400 mm in unsitffened beams, increase the load capacity by 31%, 23% and 55%, respectively, and decrease the deflection of the mid-span.