Experimental study of hybrid FRP reinforced concrete beams

Fiber-reinforced polymer (FRP) has become a practical alternative construction material for replacing steel bars as reinforcement in concrete structures. However, the brittleness of FRP greatly reduces the ductility of FRP-reinforced concrete (FRPRC) beams. In order to improve its flexural ductility, and at the same time retain the high strength feature of the FRP bars, it is proposed that steel longitudinal reinforcement should be added to form a hybrid FRPRC beam. Twelve specimens consisting of plain concrete beams, steel-reinforced concrete (SRC) beams, pure FRPRC beams and hybrid FRPRC beams were fabricated and tested. The test results show the hybrid FRPRC beams behave in a more ductile manner when compared with the pure FRPRC beams. Also, it is observed that a higher degree of over-reinforcement in the beam specimen resulted in a more ductile FRPRC beams. Hence, the addition of steel reinforcement can improve the flexural ductility of FRPRC members, and over-reinforcement is a preferred approach in the design of FRPRC members.