Long-Term behavior of FRP-strengthened RC Beams

Abstract

The study was aimed at investigating both experimentally and analytically the long-term deflection, crack width and residual strength of RC beams strengthened with glass FRP system. The effect of three major actions such as sustained loading, cyclic loading and tropical weathering were investigated. Deflections and crack widths of RC beams were found effectively controlled by the addition of FRP laminates and the control was found in tandem with flexural strength enhancement. The residual flexural strength and ductility of the beams were found reduced with weathering effect while failure mode changed from concrete crushing to brittle FRP rupture. Analytical approaches and empirical formulae were proposed for the calculation of long-term deflection and crack width under sustained or cyclic loading. An analytical model is proposed to determine the residual flexural strength of GFRP-strengthened RC beam subjected to combined sustained loading and weathering effect. Subsequently, a strength reduction factor is proposed.