Redistribution of Moment in Concrete Continuous Beams Reinforced with Steel Rebars and Fiber-Reinforced Polymer

Abstract

Researchers and industrialist interest in fiber reinforced polymer (FRP) to be used as an alternative material to steel rebars in reinforced concrete structures (RC) steadily increases. That is due to its advantages over steel rebars. Some of these advantages are corrosion resistance, nonconductivity, high tensile strength, and low weight ratio. Several studies have been introduced to study the effect of using FRP rebars instead of steel rebars on the durability problem of reinforced concrete structures under different circumstances, such as bridge decks and roadbeds which may contain a massive amount of steel reinforcement. The reinforced concrete (RC) structure constituted by FRP rebars, called FRP-RC, possess less ductile behavior compared with the conventional reinforced concrete. One of the advantages of the ductility structural system is the ability to redistribute moments over critical sections, which allows more flexibility in structural design. To improve the ductility of FRP-RC, it is proposed to add a certain amount of steel rebars in FRP-RC, so the ductility of steel rebars can reduce the brittleness of FRP, called hybrid section. Eleven 3D models were carried out based on finite element software (ANSYS). Two different types of longitudinal rebars were used (FRP and steel) to reinforce the positive and the negative moments. The validation of numerical results was confirmed by experimental results, then the parametric studies were conducted to study and evaluate the effects of hybrid sections on the redistribution percentage (β%) of continuous RC beam. The results of these models showed that a preferable redistribution percentage could be obtained through an appropriate percentage of steel reinforcement ratio to the FRP reinforcement ratio of hybrid sections.