Study on stiffness and recoverability of Fiber Reinforced Polymers-Reinforced Concrete (FRP-RC) composite T-beams with prefabricated Basalt fiber-reinforced polymers shell

Abstract

This paper focuses on the stiffness and recoverability of a new type of composite beam, the Fiber Reinforced Polymers-Reinforced Concrete (FRP-RC) beam, in which steel bars are the main reinforcement. Ten pieces of beams under both static and cyclic bending load were conducted. Fiber-reinforced polymer profile made by the vacuum infusion molding process is used as reinforcement in the composite beams, in which basalt fiber-reinforced polymer sheets were axially laid at the bottom of the beams in order to improve bearing capacity, and hoop-directionally laid at the lateral side of the beams with the advantages of improving the shear resistance. A finite element model is proposed to predict nonlinear deflections and stresses. The flexural stiffness and recoverability index of this new type of composite beam are studied. The results show that the recoverability of the FRP-RC composite beam is better than that of the normal RC beam and it increases along with the fiber-reinforced polymers reinforcement ratio. Stiffness calculation formulas at various stages and residual deformation formulas are proposed. Finally, the calculation results and test results are compared, which shows that the formulas for stiffness and deformation demonstrate good precision.