Abstract:

The network arch bridge enhances the vertical stiffness and mechanical performance of the structure by employing mutually intersecting inclined hangers, thereby attracting widespread attention. However, as the bridge span increases and thin-walled steel structures are extensively used, the risk of structural instability becomes more prominent. Especially, the compression instability in steel arch ribs deserves more attention. This study comprehensively considers geometric nonlinearity, material nonlinearity, and initial structural imperfections by employing nonlinear finite element methods to develop a parametric spatial finite element model of the hanger network. The influence of varying hanger forces on overall stability is analyzed. The displacement responses at key arch rib point under load are calculated, and the critical load for nonlinear instability is determined. Additionally, a comparative analysis was conducted between the results obtained from design specifications and those from nonlinear finite element methods. The influence of various design parameters including rise-to-span ratio, arch rib inclination, and hanger slope on the stability of network arch bridges was thoroughly investigated. The results indicate that the specification methods conservatively estimate the stability performance compared to finite element methods. The overall lateral stability of network arch bridges increases with the rise-to-span ratio and arch rib inclination, while the effect of the hanger slope on stability initially increases and then decreases.

Key words:

network arch bridge, nonlinear finite element, stability, rise-to-span ratio, arch rib inclination, hanger slope