Evaluation of deflection in concrete members reinforced with fibre reinforced polymer (FRP) bars

The use of fibre reinforced polymer (FRP) reinforcements in concrete structures has increased rapidly in the last 10 years due to their excellent corrosion resistance, high tensile strength, and good non-magnetization properties. However, the low modulus of elasticity of the FRP materials and their non-yielding characteristics results in large deflection and wide cracks in FRP reinforced concrete members. Consequently, in many cases, serviceability requirements may govern the design of such members. This paper describes the development of simple approaches in estimating the deflection of FRP reinforced concrete members subjected to flexural stresses. The predictions of these approaches are compared with the experimental results obtained by testing seven prototype concrete beams reinforced with glass fibre reinforced polymer, GFRP, and carbon fibre reinforced polymer, CFRP, bars. The proposed analytical methods are also substantiated by test results available in the literature from eight concrete slabs reinforced with conventional steel, GFRP, and CFRP bars. Good agreement was shown between the theoretical and the experimental results.