Flexural behavior of polyvinyl alcohol ( PVA) fiber concrete beam reinforced with hybrid glass fiber reinforced polymer ( GFRP) bars and steel bars

Degradation of steel reinforced concrete (RC) infrastructure due to reinforcement corrosion results in significant damage and economic loss. In this paper, glass fiber reinforced polymer (GFRP) bars are used to replace the steel bars at the corners, and the steel bars that are easy to be corroded are placed inside the member. The flexural performance of polyvinyl alcohol (PVA) fiber concrete beams reinforced with hybrid GFRP and steel bars is studied by test. A total of five test beams were designed to explore the influence of three variables, namely, the content of PVA fiber, the area ratio of GFRP bar to steel bar, and the actual reinforcement rate, on the flexural performance of the test beam. The failure mode, ultimate load, load–strain relationship of bars in the tensile zone, load–strain relationship of concrete, and crack width were evaluated. The test results show that PVA fiber concrete beams reinforced with hybrid GFRP and steel bars have similar failure modes as RC beams. The ultimate load of the test beam with the PVA fiber content of 4.5 and 7.5 kg/m 3 is increased by 19.3% and 20.6%, respectively. The expressions of reinforcement ratio under the two limit failure states are deduced, and the calculation formula of ultimate bearing capacity of PVA fiber concrete beams reinforced with hybrid GFRP and steel bars is established. Considering the addition of fiber, the calculation formula of maximum crack width of PVA fiber concrete beams reinforced with hybrid GFRP and steel bars is established. It can be used to predict the crack width under short‐term load.