A STUDY ON STRENGTHENING OF CONCRETE FILLED STEEL TUBULAR SECTIONS USING FRP COMPOSITES

Abstract

In the era, an extensive variety of composite columns and beams are newlineavailable, but the concrete filled steel tubular (CFST) sections are the most newlinecommonly used one. Owing to their structural benefits such as reduced cross newlinesection, high strength, improved fire resistance, greater apparent stiffness and newlineexcellent seismic resistant structural properties like high ductility and energy newlineabsorption, the use of CFST beams and columns has become increasingly newlinepopular in the construction industry. For a variety of reasons such as fire, newlineageing, environmental degradation and overloading, the infrastructure newlineconcerned with concrete filled tubular and other metallic structures become newlinestructurally unsatisfactory. Therefore, actions like implementation of newlinestrengthening techniques with the new materials become essential to combat newlinethis problem. Due to their in-service and superior mechanical properties such newlineas high strength and stiffness, carbon fibre reinforced polymer (CFRP) newlinecomposites make them excellent material for repairing, upgrading and newlineretrofitting of metallic structure. In this research work, an extensive study has newlinebeen carried out to investigate the suitability of carbon fibre reinforced newlinepolymer for strengthening of concrete filled steel tubular sections under newlineflexure and axial compression and also to study the effect of increase in newlinenumber of layers in enhancing the stiffness of the members. newline The main objective of this study is to experimentally investigate the newlinestructural improvements of concrete filled steel tubular sections with normal newlinestrength concrete externally bonded with fibre reinforced polymer (FRP) newlinecomposites. For this study, compact mild steel tubes were used with the main newlinevariable being FRP characteristics. newline Another part of investigation focused on the flexural behaviour of newlinesquare concrete filled steel tubular sections externally bonded with newlineunidirectional carbon fibre reinforced polymer composites under four point newlineloading. newline