Effect of reinforcement ratio on the flexural performance of hybrid FRP reinforced concrete beams

Abstract

Fiber reinforced polymer (FRP) is widely used in concrete structures due to its high tensile strength and superior corrosion resistance. However, the FRP reinforced concrete (FRPRC) shows a less ductile behavior compared to the conventional steel reinforced concrete. In order to improve the strength and flexural ductility simultaneously, a hybrid reinforcement system composed of FRP and steel bars has been proposed and adopted in design recently. In hybrid FRPRC beams, FRP and steel reinforcements play different roles in improving strength and ductility. The hybrid reinforcement ratio between FRP and steel, Af/As, has a significant influence on the flexural performance of hybrid FRPRC beams as it affects the balance between strength and ductility in the flexural design. Here, the effect of hybrid reinforcement ratio on the flexural performance of concrete beams in both under- and over- reinforced scenarios is studied using three-dimensional finite element models. The results from the finite element models show that a preferable strength and ductility performance can be obtained through an appropriate design of hybrid reinforcement ratio. Such information helps us determine an appropriate range of hybrid reinforcement ratio and provide a design guideline for hybrid FRPRC beams for optimizing the strength and ductility performance.