Confinement of heat-damaged RC circular columns using CFRP fabrics

The confinement of concrete with fibre-reinforced polymer (FRP) composites can significantly enhance its strength and ductility. This is due to their high strength-to-weight and stiffness-to-weight ratios and their ability to be readily formed into various cross-sectional shapes. Most of the available ambient temperature studies for achieving the compression strength and ductility of confined concrete have been done on standard cylinders. However, there is a lack of knowledge on confinement of circular RC columns, in which the concrete is damaged by fire and then uniformly confined using carbon fibre-reinforced polymer (CFRP) sheets. This paper presents a residual confinement study based on 10 identical circular RC columns with dimensions of Ø 204 × 750mm, previously damaged by elevated temperatures and retrofitted externally using CFRP fabrics and then tested under axial compression. The testing involved the RC columns being loaded during both the heating and cooling phases as would be the case with real structural elements in a fire. The results indicate that CFRP fabric can considered an excellent technique for strengthening heat-damaged RC columns