Axial Behaviour of Concrete Filled Steel Tubular Column with External FRP Confinement

Abstract

A column is a vertical member which excellently takes load by compression. Basically, column is a compression member as load acts along its longitudinal axis. Bending moment may occur due to eccentric loading, wind, earthquake or accidental loads. Column transfers the load of the structure of slabs, beams above to below lying foundation and finally load is transferred to the soil. Position of the columns should be so that there are no tensile stresses developed at the cross section of the columns. Composite columns have an important application in the composite construction and they are widely used in high rise buildings and bridge piers. A popular trend in composite columns is to fill steel tubes with concrete core, since the steel and concrete combined together to contribute to increasing the strength of the section. In recent years, FRP jacketing has become famous to retrofit of already existing damaged structures. The lightweight, extreme strength and corrosion resistance of fiber reinforced polymers create them especially more suitable for repair and strengthening. Numbers of experimental studies have demonstrated that FRP confinement could significantly increase energy absorption and ductility of structures. A large number of studies has been recently carried out on the characteristics of externally applied FRP and highlighting the use of externally applied FRP for retrofitting of structural elements. In this study, the compressive behaviors of Concrete Filled Steel-Tubes (CFT) confined with Fibre Reinforced Polymers (FRPs) were investigated. CFT columns of varying height (0.9m, 1.2m, 1.5m and 1.8m), different types of FRPs (Glass, Basalt, Carbon) and number of plies (single and double plies) are chosen as varying parameter to study the behaviour of CFT columns. First the materials to be used in the project are analysed for their properties. The characteristic compressive strength of concrete taken in this study was 25 MPa. Feasibility study is a preliminary study undertaken to determine, analyse and selec