A new formulation for prediction of the shear capacity of FRP in strengthened reinforced concrete beams

Abstract

The use of fiber-reinforced polymer (FRP) to strength the concrete beams is an efficient method in retrofitting of preexisting structures. The application of FRP sheets makes to have higher shear strength, but the common equations in determining the shear strength are no longer effective. In this paper, a new formulation is presented to predict the shear contribution of FRP in strengthened reinforced concrete beams. The formula is produced using the multigene genetic programming (MGP) machine. For this purpose, a set of experimental data is collected from the literature. The shear capacity of FRP in reinforced concrete (RC) beams is considered as the output data, while other variables are considered as the input data. MGP is trained with the experimental data and a formula is produced. The results of the proposed formula are compared with the experimental data to show the ability of the proposed formula. Also, these results are compared with those obtained from the available formulas, approximation models and published researches. Results show that the proposed formula is able to predict the shear capacity of FRP in strengthened RC beams with a higher precision than the other evaluated methods such as CIDAR, Fib.TG9.3, ACI and CSA. The mean absolute percentage error for the MGP formula was reduced about 74% in comparison with the CIDAR equations. Also, the root-mean-squared-error of the MGP formula was decreased near 71% in comparison with the Fib.TG9.3 equations.