关键词: 桥梁工程； 钢管混凝土系杆拱桥； 吊杆损伤； 索力重分布； 主梁刚度

Abstract: Taking a decommissioned highway concrete-filled steel tubular tied-arch bridge as the subject, the influence of hanger damage on cable force redistribution and the mechanical behavior of the main girder was systematically investigated through in-situ progressive damage tests and refined numerical simulations. The experimental results show that under localized most unfavorable load conditions, hanger damage causes cable force redistribution. The cable force in the damaged hanger drops sharply, while that in the adjacent hanger increases significantly (the influence is mainly confined to the adjacent second hanger, with negligible effects beyond the second hanger). Moreover, as the damage location approaches mid-span, the redistribution of cable forces becomes more concentrated in the adjacent hangers, exhibiting an approximately symmetric diffusion pattern. The maximum increment in main girder deflection is only 1 mm, indicating that hanger damage has a negligible effect on the stiffness of the main girder. The numerical simulation results reveal that after the fracture of an outer steel strand, the axial forces in the adjacent steel strands within the same layer increase sharply in an inverted “V” shape at the fracture location, while the axial forces in the inner steel strands rise overall. The cable force in the central steel strand increases by 20% ~ 29%, forming a load-bearing system dominated by the central steel strand.

Key words: bridge engineering; concrete-filled steel tubular (CFST) tied-arch bridge; hanger damage; cable force redistribution; main girder stiffness