A NUMERICAL METHOD FOR ANALYZING THE DYNAMIC LOAD IN BRIDGE-HEAD BUMPING CONSIDERING THE ROLLING TRACE OF WHEEL AND THE ANALYSIS OF INFLUENCING FACTORS

For analyzing the dynamic load of vehicle in bridge-head bumping, a disk model is presented according to the actual shape of the wheel, and the rolling trace during the wheel passing through the staggered platform at bridge head is considered. By means of finite element modelling of the vehicle and the corresponding equilibrium equations, the vertical and horizontal dynamic loads during the vehicle passing the bridge head are analyzed quantitatively. Numerical examples show that the dynamic load of the vehicle is reduced when the rolling trace of the wheel is considered, and it is related to the moving speed, the suspension of the vehicle and the height difference of the staggered platform; for example, 1) The maximum dynamic load is proportional to the height difference of the staggered platform; 2) For the wheel independently suspended, the maximum dynamic load is proportional to the moving speed of the vehicle, whereas for the wheel dependently suspended, it fluctuates when the speed increases; 3) When the vehicle gets on the bridge, the maximum load of all the wheels is applied just on the staggered platform, whereas when the vehicle gets off the bridge, the maximum load of the front and the middle wheels is applied far away from the staggered platform, but that of the rear wheels is adjacent; 4) It should be noted that the impact factor when the vehicle passes through the staggered platform at the bridge-head may be higher than that provided by the design codes of bridges.