Concrete Shear Strength of Normal and Lightweight Concrete Beams Reinforced with FRP Bars

A new equation to predict the contribution of concrete to the shear strength of fiber-reinforced polymer (FRP) reinforced concrete beams without shear reinforcement is proposed. The new equation considers the elastic modulus ratio of the FRP bars to the steel reinforcement, the shear span to depth ratio, and the flexural reinforcement ratio, and was developed using the results of 60 concrete beam tests. The proposed equation more accurately predicted the results of various experiments available in the literature than the equations of an American Concrete Institute standard, and yielded similar degrees to the equations of a Canadian Standards Association standard, despite making somewhat higher predictions. The applicability of the proposed equation to FRP reinforced lightweight concrete beams was investigated using 24 all-lightweight concrete beam tests. The concrete shear strengths of the FRP reinforced all-lightweight concrete beams were equivalent to 75% of the strengths predicted by the proposed equation for normal concrete. Furthermore, with a reduction factor of 0.85, the proposed equation also showed good results for the concrete shear strength of glass FRP (GFRP) reinforced sand-lightweight concrete panels presented in a recently published paper.