Impact Coefficient Of Railway Bridge Based On Vehicle-Bridge Coupling Vibration Analysis

With the increase of train running speed and more high-speed railway constructed, the dynamic interactions between vehicles and bridge are more and more outstanding. Bridge impact coefficient is the comprehensive reflection of the dynamic characteristics and interactions of the train, track and bridge system. It is of great significant theory and engineering value to obtain the influencing factors and rules of bridge impact coefficient, thereby ensuring the bridge’s dynamic reliability and train’s operation safety. Taking a railway simply supported beam bridge and a long-span railway cable-stayed bridge as research objects, the influencing factors of bridge impact coefficient are analyzed by using the vehicle-bridge coupling vibration analysis method. The main research contents of this thesis are as follows:(1) Studies on bridge impact coefficient are reviewed; the methods of calculation of railway bridge impact coefficient in some bridge specifications are briefly introduced; and the research significance on railway bridge impact coefficient is expounded.(2) Taking the track irregularity as the exciting source of vehicle-bridge system, the coupling vibration model and dynamic equations of vehicle-bridge system is developed by connecting the vehicle system with the bridge system via the compatibility conditions between vehicles and bridge.(3) Three-dimensional finite element dynamic models of a32meters railway simply supported beam bridge and a long-span railway cable-stayed bridge are established respectively, by which the self vibration characteristics of two bridges are obtained.(4) Based on the analysis method of vehicle-bridge system, the influence rules of bridge impact coefficient are discussed from three aspects of the vehicle, track and bridge. To the railway simply supported beam bridge, influencing factors such as vehicle speed, track irregularity, train consist, bridge damping, stiffness and quality of the bridge, span arrangement are discussed. And to the long-span railway cable-stayed bridge, influencing factors such as vehicle speed, track irregularity, train consist, bridge damping, traffic direction are discussed.At last, the main contributions and conclusions of this thesis are summarized, and some further research problems concerning are set forward.