Comparative Analysis on Mechanical Performance of Concrete Inclined Tension Rods with Square and Circular Steel Pipes in Cable-Stay Girder Anchorage Zone of Low-Pylon Cable-Stayed Bridge

Liang Zhang

doi:10.63313/AERpc.9103

Authors

Liang Zhang Central South University of Forestry and Technology, Changsha, China Author

DOI:

https://doi.org/10.63313/AERpc.9103

Keywords:

Low-pylon cable-stayed bridge, Inclined tension rod, Concrete-filled steel tube (CFST), Confinement effect, Finite element analysis

Abstract

Aiming at the inherent performance bottlenecks of reinforced concrete (RC) inclined tension rods in the cable-girder anchorage zone of low-pylon cable-stayed bridges, such as low ductility and significant post-peak damage localization, an optimized scheme of prestressed concrete-filled steel tube (CFST) inclined tension rod is proposed. Taking the Luzhou Tuojiang Railway Super Large Bridge, a low-pylon cable-stayed bridge with a span arrangement of (146+292+146) m, as the engineering background, a three-dimensional nonlinear finite element model is established based on ANSYS APDL. The whole-process mechanical behaviors of three schemes, namely RC, square CFST and circular CFST inclined tension rods, under the most unfavorable cable force are comparatively analyzed, and the influence law of section form on mechanical performance is revealed from the perspective of confinement mechanism. The results show that compared with the RC scheme, the ultimate bearing capacity of the two CFST schemes is increased by 115.3% and 124.2%, the initial secant stiffness is increased by 61.9% and 63.2%, and the displacement ductility coefficient is increased by 33.5% and 49.4%, respectively. The uniform circumferential confinement provided by the circular section completely eliminates the weak confinement area at the mid-span of the square steel tube wall, and the load rises steadily at the large deformation stage. The circular CFST scheme with a diameter of 560 mm, wall thickness of 16 mm, Q345 steel tube, C60 core concrete and confinement coefficient ξ=0.829 is recommended as the optimal design scheme. The research results can provide a reference for the engineering design of inclined tension rods in the cable-girder anchorage zone of low-pylon cable-stayed bridges.

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