Effect of FRP wrapping on axial behavior of concrete and cyclic behavior of external RC beam column joints

Abstract

The study focuses on the effect of confinement due to transverse reinforcement and FRP jacketing on the axial behavior of concrete and external beam-column joints (i.e., T-joints) before and after retrofitting. The effectiveness of confinement is firstly evaluated by stress — strain behavior of square prism specimen under pure axial compression. These specimens are prepared with different amount of transverse reinforcement and FRP wraps (number of layers). Secondly, the cyclic tests are also carried out on beam-column joint specimens, with two different configurations of reinforcement detailing and retrofitted by externally bonded FRP wrapping. One specimen is designed to comply with gravity load design codes and the other with detailing according to Indian Standards. GFRP wrapping is used for retrofitting of damaged joints with epoxy resin. GFRP jacketing comes out to be an effective technique to regain the strength and stiffness of damaged joints. Also significant gain in strength and strain is observed under pure axial compression.