Three-dimensional Finite Element Analysis of Circular Reinforced Concrete Column Confined with FRP using Plasticity Model

A prediction of reinforced concrete column capacity confined with FRP remains one of the challenging research area. One of the challenges are the inaccuracy of the effective confinement area of the concrete core which is used to estimate the reinforced concrete (RC) columns capacity. Considering these challenges, the use of plasticity model to predict the behavior of FRP wrapped RC column is a very attractive solution. In this study, a three dimensional non-linear finite element analysis based on plasticity formulation is presented. The proposed flow rule is able to automatically adjust the dilation rate of concrete from the state of active to passive confinement and vice versa. The flow rule has a specific dilation rate formulation that includes the lateral modulus (EL) parameter to observe the confinement effectiveness. This study focuses on the modelling of circular reinforced concrete column confined with FRP using FEM. The steel rebar is modelled as a truss element with elastic-perfectly plastic material behavior. Both the concrete and FRP elements are modelled as 8-noded hexahedral element. FRP elements are considered as transversally isotropic material with determined fibers orientation. The non-linear analysis performed using the finite element code developed by the authors. For comparisons, a validation of the predicted stress-strain responses with the experimental results are presented.