Experimental Investigation On Retrofitting Of Reinforced Concrete Columns Using Externally Bonded Cfrp Sheets Under Axial Compression

Abstract

Reinforced concrete (RC) columns are vital structural members that are likely to lose their integrity after a period of time due to ageing, environmental exposure, growing service loads and deficiencies during construction. These composites such as Carbon Fiber Reinforced Polymer (CFRP) composites are found to be effective retrofitting solution due to its high strength to weight ratio, corrosion resistance and ease of installation. But there are only a few cases of limited experimental research studies that have comprehensively and systematically examined the effect of externally bonded CFRP confinement with various wrapping configurations on axial compression performance of RC columns. This study experimentally examines the effectiveness of the CFRP sheet retrofitting using the axial compression tests performed on 10 RC column specimens, which include 5 control and 5 RC column specimens with CFRP sheet retrofitting. The experimental program focuses on the performance of the CFRP confined structure in terms of the ultimate axial load capacity, the axial displacement of the structure, structural stiffness, ductility index, strength enhancement ratio, and failure mode of the structure. The CFRP-retrofitted specimens showed 29.8% enhancement in the ultimate load capacity, 24.5% improvement in structural stiffness, 36.2% improvement in ductility index and 17.6% decrease in axial displacement in comparison to control specimens. It is found from the results that, the load carrying capacity and the deformation properties of RC columns are significantly enhanced with the use of externally bonded CFRP sheets and hence it is concluded that this type of strengthening method is suitable to enhance the service life and structural safety of the existing RC infrastructural structures with the usage of CFRP sheets.