Open Access

ARTICLE

In-Plane Bearing Capacity of CFST Truss Arch Bridges with Geometric Defects

Chao Luo¹, Zhengsong Xiang^1,2, Yin Zhou^1,*, Dingsong Qin³, Tianlei Cheng⁴, Qizhi Tang¹

1 State Key Laboratory of Mountain Bridge and Tunnel Engineering, Chongqing Jiaotong University, Chongqing, 400074, China
2 Sichuan Road and Bridge Construction Group Co., Ltd., Chengdu, 610093, China
3 China Railway First Group Eighth Engineering Co., Ltd., Chongqing, 401147, China
4 Chongqing Expressway Group Co., Ltd., Chongqing, 401120, China

* Corresponding Author: Yin Zhou. Email:

Structural Durability & Health Monitoring 2025, 19(3), 683-703. https://doi.org/10.32604/sdhm.2025.061549

Received 27 November 2024; Accepted 05 February 2025; Issue published 03 April 2025

Abstract

Failure tests were conducted on two concrete-filled steel tubular (CFST) truss arch bridges with a span of approximately 12 m to investigate the influence of initial geometric defects on the in-plane bearing capacity of CFST truss arch bridges. The effects of antisymmetric defect on the ultimate bearing capacity, failure mode, structural response, and steel–concrete confinement effect of CFST truss arch bridges under quarter-point loading were analyzed. On this basis, numerical simulations were conducted to investigate the in-plane bearing capacity of CFST truss arch bridges further under different scenarios. The initial defect form of the arch was obtained by using theoretical deduction, and the theoretical basis for the weakening of the ultimate bearing capacity of the arch bridge caused by geometric defects was clarified. Results indicate that the antisymmetric defect does not change the four-hinge failure mode of the model arch under quarter-point loading but increases the local cracking area and crack density of the concrete inside the pipe. The sine geometric defect with an amplitude of L/250 resulted in a 44.4% decrease in the yield load of the single hinge of the model arch, a 10.5% decrease in the failure load of the four hinges, and a 40.9% increase in the maximum vertical deformation during failure. At the initial stage of loading, the steel pipe and the concrete inside the pipe were subjected to relatively independent forces. After reaching 67% of the ultimate load, the catenary arch ribs began to produce a steel pipe concrete constraint effect. The initial geometric defects resulted in a decrease in the load when the constraint effect occurred. The antisymmetric defects with the same amplitude have a greater impact on the in-plane bearing capacity of the CFST arch bridge than the initial geometric defects with symmetry. The linear deviation at L/4 caused by construction must be controlled to be less than L/600 to ensure that the internal bearing capacity of the CFST arch bridge reaches 95% of the design bearing capacity. The structural deformation caused by geometric initial defects increases linearly with the increase in defect amplitude. The bearing capacity is weakened because the structural deflection and bending moment are amplified by initial defects.

---

Keywords

---