Flexural behavior of concrete beams reinforced with innovative FRP wrapped steel bars

Abstract

Corrosion is the main problem in the use of steel for reinforcing concrete structures. Steel rebars after corrosing causes strength and stiffness degradation of the concrete structures. To prevent the corrosion of steel, in this paper an innovative hybrid rebar produced by wrapping Fiber Reinforced Polymer (FRP) around a steel core is proposed. The FRP wrapping would prevent direct exposure of steel surface to the contaminating environment and hence would improve the life of the reinforcement and the concrete structures. Results of the experimental and analytical studies carried out to understand the behavior of the concrete beams reinforced with hybrid rebars are presented in this paper. Type of fibers (glass or carbon fibers), wrapping length of the FRP and shear stirrups spacing are the primary variables considered in the experimental program. Test results indicate that the type of fibers and the FRP wrapping length affect the failure modes, ultimate load, and the load-deflection behavior of the beams. The volume fraction of the fibers and the strength of the fibers used in the hybrid rebars affect the flexural behavior of the beams and it is found that there is large scope for using hybrid rebars with carbon fiber wrapping as reinforcement in the concrete structures. The predicted ultimate flexural loads of the beams reinforced using hybrid rebars with carbon fibers are in good agreement with the test results.