A Review on Nonlinear Finite Element Analysis of Reinforced Concrete Beams Retrofitted with Fiber Reinforced Polymers

Abstract

Fiber reinforced polymers materials have a wide use in a variety of applications, which are produced with a range of different stiffness and strength characteristics. However, these materials share identical orthotropic properties and ductility. In contrast, the ordinary concrete is isotropic and brittle material. This review study provides an efficient and simple three-dimensional frame finite element that able to estimate accurately the load-carrying capacity and deflection of reinforced concrete (RC) beams strengthened with fiber reinforced polymer (FRP) strips, plates or rods. In the context of a force base formulation (FB), which referred as fiber reinforced polymer force based beam, the proposed finite element considers distributed plasticity with the individual layer of the cross sections. Hundred seventy-six different specimen of retrofitted reinforced concrete beams have been included in the experimental database and numerical simulation in this study. These beams elements can model the collapse due to crush of concrete, reinforcing steel yielding, rod pull out, FRP rupture, diagonal shear, FRP debonding and cover separation. Three and four point bending loading tests were used to predict the load-carrying capacity and the deflection response of reinforced concrete beams. Based on several researches, experimental measurements and numerical simulations are compared according to different collected data. The numerical simulation results have a good agreement with the corresponding experimental results. From the statistical analysis study, it was found that the concrete strength is the most influential factor on the shear strength of the reinforced beams strengthened by FRP in the case of U-jacketing anchorage system. Where, the shear strength increased by 10.5%, 8.6% for tensile rupture and debonding failures, respectively, with increases in concrete strength. As a result, the simplicity, available requirements and computational efficiency of finite element simulation are the main advantages for using this analysis in various applications.