BEHAVIOUR OF FRP WRAPPED SQUARE CONCRETE COLUMNS

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 this 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 of circular concrete columns confined with FRP. Very less research in the area of the behavior of square reinforced concrete columns wrapped externally with FRP sheets has been done. The data available for square columns are still limited. Hence there is a need to investigate the behavior of such columns under axial compression. Understanding the response of the FRP wrapped square reinforced concrete columns under axial compression loading is the central focus of this dissertation work. It is a well established fact now that, concrete columns, when confined by suitable reinforcement arrangements, results in increase in both the strength and ductility. With the increasing consciousness of designing earthquake resistant structures, the factors like gain in strength and ductility becomes much more important. In the present study, experimental investigation has been done to study the behavior of reinforced square concrete columns strengthened with GFRP and a model has been proposed to evaluate the confinement effectiveness provided by the GFRP. The columns are tested under uni-axial compression loading. Various parameters are considered in this study. A parametric study has been carried out to understand the effect of different parameters on the behavior of confined square concrete columns. Height of the specimen, number of layers and corner radius are the parameters considered for the study. This report consists of 6 chapters. Chapter 1 provides an introduction to the study. A brief review of the relevant literature is provided in Chapter 2. Detail experimental programme has been discussed in Chapter 3 to study the behavior of the square columns. The results and the analytical equations are presented and discussed in Chapter 4. Chapter 5 summarizes the conclusions and discusses future scope of the work.