Behavior of Large-Scale Circular and Square RC Columns Confined with Carbon Fiber-Reinforced Polymer under Uniaxial Compression

Abstract

Most experimental studies concerning the stress-strain behavior of concrete columns confined with carbon fiber-reinforced polymer (CFRP) focused on plain concrete columns with small section. In this study, 34 concrete columns with large-scale circular and square cross section confined with CFRP were tested under axial compression to investigate the influence of sectional dimensions, internal steel reinforcement and thickness of CFRP jackets on the stress-strain behaviors. Test results indicated that the confinement of CFRP resulted in significant increase in axial stress and strain for circular RC columns, while remarkable enhancement in axial strain but slightly in axial stress for square RC columns. The stress-strain responses of CFRP-confined square RC columns were significantly influenced by sectional dimensions and internal transverse reinforcement. The typical confinement ratio, which is obtained from studies on CFRP-confined unreinforced concrete columns with small cross sections, was not applicable for the case of large-scale square RC columns.