Strain analysis of RC t-beams strengthened in shear with variation of U-wrapped GFRP sheet and transverse steel

Abstract

The strengthening of concrete structures with fibre reinforced polymer (FRP)composites has existed since last two decade. The most common way to strengthen structures is in bending, shear and retrofitting of columns. FRP offers excellent corrosion resistance to environmental agents as well as the advantages of high stiffness-to-weight ratio and strength-to-weight ratio. This paper presents an experimental investigation on strain analysis of a reinforced concrete (RC) T-beams strengthened in shea with U-wrapped glass fibre reinforced polymer (GFRP) sheet.A total of eighteen (18)full scale simply supported RC T-beams are tested. Nine beams are used as control beamwith three different stirrups spacing (transverse steel) without GFRP wrap and restnine beams are strengthened in shear with one, two, and three layers of GFRP sheet in U-configuration for each type of stirrup spacing. This study focuses on strain analysisof U-wrapped GFRP sheet, transverse steel reinforcement and longitudinal steel reinforcement. It is observed that the strain in the U-wrapped GFRP sheet is higher in the specimens strengthened with one layer of GFRP, as compared to two and three layers inall the series. The stiffness of GFRP sheet is indirectly proportional to the strain.