Research on reasonable position of FRP tendons in concrete beams prestressed with bonded and/or unbonded FRP tendons

Fiber reinforcement polymers (FRPs) have high strength; they are well suited for prestressing tendons in corrosive environment. Concrete structures prestressed with FRP tendons usually exhibit brittle failure models due to the brittle nature of the FRP composites. Based on different mechanical properties of prestressed concrete structures, a combination of bonded and/or unbonded prestressing tendons was used in order to improve the ductility. This paper presents a nonlinear analysis method of concrete beams prestressed with FRP tendons based on ANSYS software, the reasonable position of FRP tendons are detailed discussed. The results of nonlinear finite element analysis showed that if the reinforcement of prestressed beam was the same, the carrying capacity of concrete beam prestressed with bonded FRP tendons was highest; the capacity of unbonded prestressed beam was secondly, and the external unbonded prestressed beam without deviators was lowest. By combination of different FRP tendons, or different tension ratio, or different placement, the properties and failure models of concrete beams prestressed with FRP tendons can be improved.