FINITE ELEMENT ANALYSIS OF FRP STRENGTHENED RC COLUMNS UNDER ECCENTRIC LOADING

Abstract

Fiber Reinforced Polymer (FRP) confined concrete columns have been developed for new construction and rebuilding of concrete piers/piles in engineering structures. Design of these FRP confined concrete columns requires an accurate estimate of the performance enhancement due to the confinement mechanism. Therefore, the key is to develop a confinement model, a model that relates the confined concrete strength with the unconfined concrete strength. Several studies have reported on testing reinforced concrete columns with different types of FRP. With the exception of a few studies, most are based on testing columns under concentric loads. It is clear that there is a need to investigate the behavior of such columns under eccentric loads as observed in most of the columns in buildings. Understanding the response of FRP wrapped reinforced concrete columns under eccentric loadings has been the central focus of this dissertation work. In the present study, a 3-D finite element model of FRP confined reinforced concrete column under pure axial loading and eccentric loading has been developed. The finite element model was developed using the finite element software, ANSYS version 10.0. Six parameters have been considered in the present study: namely, Unconfined concrete strength, f' FRP thickness, tfrp (number of FRP layers), orthotropic properties of FRP, percentage of tie bars (in terms of tie bars spacing), percentage of longitudinal steel, and orientation of FRP fibers. The study mainly focused on the effect of these parameters on the confinement effectiveness. This report consists of 6 chapters. Chapter 1 provides an introduction to the study. Chapter 2 explains the FRP material in detail. A brief review of the relevant literature is provided in Chapter 3. In Chapter 4, development of a finite element model for the FRP confined concrete column in ANSYS has been discussed. The results are presented and discussed in chapter 5. Chapter 6 summarizes the conclusions and discusses various recommendations.