Deflection of GFRP and PVA fibre reinforced concrete beams

Abstract

There is an increasing demand for the use of Fibre Reinforced Polymers (FRP) in Reinforced Concrete (RC) design for various reasons, including electromagnetic neutrality and corrosion resistance. Glass fibre reinforced polymer (GFRP) reinforcing bars are one such alternative to steel reinforcement. Compared with steel, GFRP bars behave linearly elastic up to failure and do not yield, which can cause ductility concern. To compensate for this, the addition of polyvinyl alcohol (PVA) fibres to the concrete mix can improve the ductility response of RC members through improved post-cracking performance. This post-cracking performance is improved by two mechanisms: in the compression region fibres act to restrain concrete crushing, and delay failure, and in the tension region fibres transfer tensile stresses across cracks. This paper reports on an experimental study on the influence of fibre content on the deflection and energy absorption capacity of RC beams, and presents a structural mechanics based model for evaluating the deflection GFRP FRC members. The theoretical loaddeflection responses are compared to the experimental results, showing very good approximation of both the ultimate flexural capacity and the ductility of PVA fibre reinforced concrete members. The good correlation with experimental results confirms the applicability of this structural mechanics based approach in predicting deflections of RC members, and provides engineers with a useful tool to evaluate the ductility and energy absorption capacity of fibre reinforced concrete beams.