Shear Behavior of Externally Prestressed Concrete Beams with Draped Tendons

摘要

Nine T-beams, prestressed with external tendons, were tested to failure to investigate the effect of prestressing, shear span-depth ratio, shear reinforcement, and bend angle of external tendons on the shear behavior and ultimate capacity of externally prestressed concrete beams. Test results indicated that the application of straight tendons did not change the load-transfer path and the entire configuration of arch action. A new fan-shaped crack region was found beyond the shear span when draping external tendons, which was defined as the secondary fan-shaped crack region. Considering the effect of draped tendons by supplementing the secondary arch action for shear strength of externally prestressed concrete beams, a new truss arch model was proposed. The accuracy of the proposed model was verified by testing results, and compared with the shear-strength predictions of ACI 318-11, AASHTO LRFD, and MC2010.