Analysis of Vehicle-bridge Coupled Vibration due to Track Irregularities

Research purposes: Track irregularity is usually one of the most important factors that induce vehicle-bridge coupled vibration.Studying the laws of vehicle-bridge coupled vibration due to track irregularity can better provide(theoretical) basis for precise design of(railway) bridges.Research methods:Track random irregularity functions in time domain are established on the basis of H.Hamid's(Power) Spectrum Density(PSD) functions of track irregularities.The track irregularity sample functions are taken as(exciting) source to solve vibration differential equations of vehicle-bridge coupled vibration.This paper also studies the(dynamic) characteristics of railway bridges under moving vehicles.Research results:The Hongshui River railway cable-stayed bridge in Guangxi is taken as example to calculate the(dynamic) response of the bridge under train passage,and the curves of time history of displacement at midpoint of bridge main span for different vehicle velocities and irregularity samples.Research conclusions:The dynamic response of the bridge due to passing trains is related to the speed of train and the change of track irregularity samples,and it is of random characteristics.For the Hongshui River railway cable-stayed bridge,the speed at which the largest lateral displacements occur falls between 75 km/h and 95 km/h.