Stability Analysis of the Network Arch Bridge Considering Nonlinear Effects

A networked suspension cable arch bridge is a type of truss arch bridge system where at least two inclined suspension cables intersect, replacing the traditional vertical suspension cables. The cross-arranged networked suspension cables can effectively enhance the vertical stiffness and overall mechanical performance of traditional arch bridges, which has attracted attention in the field of bridge engineering. However, with the increasing span of arch bridges and the widespread use of thin-walled steel structures, structural stability issues have become more prominent. In particular, the risk of instability in steel arch ribs, which are primarily under compression, has become a key factor limiting its engineering application. To systematically analyze the stability performance of a networked suspension cable arch bridge and to explore the impact of different structural arrangement parameters on the overall stability of the structure, this study comprehensively considered geometric nonlinearity, material nonlinearity, and structural initial defects. A parametric spatial bar finite element model was established using nonlinear finite element methods to analyze the effects of varying cable tension forces on the overall stability. The displacement response and nonlinear instability critical load of key nodes on the arch ribs under load were calculated. The results from national and international standards were compared with those obtained using nonlinear finite element methods. Additionally, the study investigated the influence of different rise-to-span ratios, arch rib inclination angles, and cable inclination angles on the stability of the networked suspension cable arch bridge. Results show that variations in the suspension cable tension have little impact on the overall stability of the networked suspension cable arch bridge. The ultimate capacity of arch ribs based on standard methods is more conservative than that obtained through the nonlinear finite element method. The lateral overall stability of network arch bridges improves with increasing rise-to-span ratio and arch rib inclination, while it first increases and then decreases with the increase in cable inclination angle. The lateral stability performance of the bridge is optimal when the cable inclination angle is set between 50° and 60°.