Combined Shear and Bending Behavior of Joints in Precast Concrete Segmental Beams with External Tendons

Abstract

Precast concrete segmental bridges with external tendons are becoming widely constructed all over the world. The main objective of this study is to obtain a further understanding of the behavior of joints when they are subjected to combined shear and bending. Nine specimens of precast concrete segmental beams (PCSBs) with external tendons were match cast and tested: six of the specimens were tested under combined shear and bending; two specimens were tested under pure bending; and one specimen was tested under direct shear. Failure processes and modes, joint resistance, and strains of stirrups and prestressing tendons were recorded in the tests. Based on the results of the experiment, the study analyzed the mechanism of combined shear and bending resistance for dry and epoxied joints when loads were located in the immediate vicinity of the joint. Additionally, simplified failure modes of dry and epoxied joints subjected to combined shear and bending were presented in this paper. On the basis of the simplified failure modes, formulas were deduced for evaluating the resistance of joints when failure occurred in a joint section with loads applied in the immediate vicinity of the joints. The formulas provided a rational prediction of the joint resistance under combined shear and bending, which in turn verified the rationality of the proposed failure modes.