Road Bridge Transition Section Of The Road - Vehicle Dynamic Interaction Characteristics

With continuous enhancement of vehicle speed, increasing of traffic density and aggravation loading, the demand of the bridge-approach pavement of freeway is getting higher. In fact, vehicle and pavement is a synthesized system. Vehicles' vibration will be caused by the pavement roughness that under differential settlement. Vehicle again exerts to the pavement by dynamic loading. To get a comprehensive analysis of dynamic characteristics, the vehicle dynamic load and the criterion of calculation as well as the dynamic response characteristics of the bridge-approach pavement are investigated in this paper by theoretical research, numerical modeling and spot investigation. The chief research contents and achievements are summarized as follows:1. The plane analysis model of two typical bridge-approach are established. The variation rule of post-construction settlement of bridge-approach and the longitudinal unequal settlement change relations are investigated by using finite difference method.2. The hyperbolic curve is chosen as longitudinal settlement curve of bridge-approach by calculated curve's fitting. The calculations have good agree with the results of the actual project survey result, which show the calculation model and results reasonable. The hyperbolic model is proposed to describe longitudinal unequal settlement.3. The vehicle vibration model and geometric model of bridge-approach are established. MATLAB program is used to simulate numerically the random dynamic vehicle load which is caused by unequal settlement when the vehicle is passing the bridge-approach pavement. In the mean time, it is discussed the relationship between dynamic vehicle load index and structural parameters of bridge-approach, tire damping, vehicle speed, vehicle load and bridge length.4. Three-dimensional finite element dynamic model is established. The dynamic displacement, the dynamic stress and the strain, the shearing stress under the vehicle dynamic load are calculated through ANSYS finite element software. Moreover, the dynamic response characteristics are discussed with the impact of horizontal load, vehicle speed and vehicle load.5. The correspondence value of the pavement design index is checked. The suggestion of asphalt pavement design is put up by discussing design index rationality of asphalt pavement design specifications.