Influence of Random Traffic Flow on Train-Bridge Dynamic Coupling Effect of Long-Span Rail-Cum-Road Suspension Bridge.

For rail-cum-road bridges, when the bridge span increases and road traffic becomes dense, the coupling effect between vehicles and the bridge cannot be ignored. This paper establishes a coupled dynamic analysis model that includes four subsystems: vehicles, trains, tracks, and the bridge. In this system, each vehicle in the random traffic flow is treated as an independent entity with its own motion equations. By focusing on the deformation characteristics of the bridge, the study reveals how vehicles impact train's running stability. Additionally, a parameter analysis is conducted to identify the key influencing parameters of random traffic flow. The results show that the movement of vehicles induces notable deformation in the bridge's main girder, particularly increasing the amplitude of alignment with wavelengths both below 200 m and above 200 m at the bridge tower area, and increasing the amplitude of alignment with wavelengths above 200 m at the main span. This leads to heightened train vibration acceleration and centrifugal acceleration. The maximum train acceleration while crossing the bridge is observed in the bridge tower area, increasing from 0.12 m/s2 in the absence of vehicles to 0.3 m/s2 under the condition with vehicles. Among the parameters of random traffic flow, the average vehicle weight on the bridge significantly influences the vertical acceleration of the train, showing a linear relationship. [ABSTRACT FROM AUTHOR]