Creep Induced Deflections of Concrete Elements Reinforced with Polymer Composite Bars

With the increasing costs of steel reinforcement and corrosion related problems, the construction industry is looking for alternative materials to substitute steel reinforcement. This paper studies the application of composite fiber reinforced polymer bars to reinforce concrete flexural elements. As an example, Glass Fiber Reinforced Polymer (GFRP) composite bars have a modulus of elasticity of approximately 1/6 of the modulus of elasticity of steel reinforcement. This fact makes the design of GFRP-reinforced concrete elements governed by serviceability requirements, rather than by strength requirements in most cases. In addition to that, polymer composite bars have been shown to creep under sustained loads. Therefore, this paper presents an analytical method that can be used to compute the deflections induced by creep in polymer composite reinforced concrete flexural elements. This method can be a valuable tool for the design of concrete elements reinforced with polymer composite bars where deflections are the governing design factor.