Dynamic Analysis Of Coupled Wind-train-bridge System Considering Triangular Wind Barriers

The width of bridge tower is usually larger than the length of vehicle for long span suspension bridge. When the vehicle pass through the bridge tower area,the wind load acting on it will decrease and increase suddenly, which affects the running safety and comfort of the vehicle seriously. In this paper, the new built Wu Feng Shan suspension bridge is taken as the engineering background and triangular wind barriers are arranged in the beginning and end of bridge towers. The shielding effects of the bridge tower and the triangular wind barriers are incorporated by taking the surface integral of the wind load.The inter-system intreation is adopted to solve the vehicle-bridge equations.The main work of this paper is as follows:(1) The history and development of suspension bridge and wind-vehicle-bridge system analysis methods are reviewed. Wu Feng Shan suspension bridge with highway and railway is taken as the engineering background. Its finite element model has been established and its self-vibration characteristic has been analysised.(2) A detailed exposition of vehicle model, bridge model, track model,wheel rail force and solution method of vehicle-bridge coupling equation is given.(3) The static wind load of the bridge is calculated according to the aerodynamic coefficients. Based on the harmonic synthesis method, the wind speed history at the bridge site is simulated and the time history of the fluctuating wind load are obtained by the difference theory.(4) Based on the assumption that the wind load is uniformly distributed on the surface of car body, the wind load formula while vehicle pass through the triangular wind barriers and bridge tower is given and the wind load curve of vehicle is caculated according to the vehicle aerodynamic coefficients obtained from wind tunnel tests.(5) The safety and comfort evaluation index of vehicle were briefly introduced, and the dynamic response of vehicle and bridge under different triangular barrier length, wind speed and train speed were calculated and analysised. The influence of different triangular wind barrier length on vehicle bridge dynamic response is discussed.This study shows that in order to insure the stability and safety of vehicle, a 50m triangular wind barrier can be setted before and after the bridge tower. When the average wind velocity is above 25m/s, the train speed should be controlled under 160km/h to satisfy the running safety.