Shear Behavior of Precast Concrete Segmental Beams with External Tendons

Abstract

Precast concrete segmental beams (PCSBs) with external tendons have become more and more popular all over the world for achieving the advantage of rapid construction. This paper focuses on the effects of shear span-depth ratios, joint types (monolithic, dry, and epoxy), joint number, and joint location on the shear behavior of PCSBs with external tendons. A total of 14 specimens with external tendons were fabricated and tested, which included three monolithic specimens, six segmental specimens with dry joints, and five segmental specimens with epoxy joints. The crack propagation, failure mode, deflection, and stresses of prestressing strands were recorded. It was found that joint location plays an important role in the shear strength of PCSBs with dry joints when compared with monolithic specimens. The failure processes and failure modes of PCSBs were independent of joint types. The experimental results also revealed that the joint number had an effect on the deflection and stress of external tendons. Specifically, the shear behavior of PCSBs with dry joints had no evident difference from that with epoxy joints. The strength of beams with external tendons was predicted using the strut-and-tie model. AASHTO and Chinese codes conservatively predicted the shear strength of PCSBs with external tendons when the shear span-depth ratio was less than 2.5. The actual prestressing force in external tendons can accurately predict the ultimate strength of beams with external tendons at different shear span ratios.