Global stability of leaning-type steel box arch bridges: mechanistic insights and quantitative evaluation of key design parameters

This is the authors' abstract. We don't add key points for this paper.

Leaning-type arch bridges are attractive for wide-deck urban applications, but their elastic global buckling mechanisms and parameter sensitivities remain insufficiently quantified. This study investigates a leaning-type steel box arch bridge using a three-dimensional finite element model validated against field-measured arch deflections and hanger forces. Linear elastic eigenvalue buckling analyses examine the structural system, rise-to-span ratio, arch stiffness, leaning-arch inclining angle, and transverse-bracing characteristics, together with the coupled effect of rise-to-span ratio and main-arch stiffness. Within the investigated bridge configuration, the integrated leaning-arch–transverse-bracing system increases the stability coefficient by approximately 71% relative to the unbraced main-arch system. A relatively favorable main-arch rise-to-span ratio of approximately 1/7–1/4.5 is identified. Main-arch bending stiffness has a pronounced influence, and its quantitative effect depends on the rise-to-span ratio. Variations in leaning-arch inclining angle produce relatively limited net changes, while further increases in bracing stiffness yield diminishing improvements. For a fixed bracing quantity, balanced spatial distribution over the arch span is more effective than concentrating bracings within a limited region. These findings provide a quantitative basis for comparative stability assessment and preliminary design of similar bridge systems.