Influence of Random Track Irregularities on Dynamic Response of Bridge/Track Structure/High-Speed Train Systems

Random vertical track irregularities are one of essential vibration sources in bridge, track structure and high-speed train systems.The common model of such irregularities is a stationary and ergodic Gaussian process.The study presents the results of numerical dynamic analysis of advanced virtual models of composite BTT (bridge/ballasted track structure/high-speed train) systems.The analysis has been conducted for a series of types of single-span simply-supported railway composite (steel-concrete) bridges, with a symmetric platform, located on lines with ballasted track structure adapted for high-speed trains.The bridges are designed according to Polish bridge standards.A new methodology of numerical modeling and simulation of dynamic processes in BTT systems has been applied.The methodology takes into consideration viscoelastic suspensions of rail-vehicles, nonlinear Hertz wheel-rail contact stiffness and one-side wheel-rail contact, physically nonlinear elastic-damping properties of the track structure, random vertical track irregularities, approach slabs and other features.Computer algorithms of FE (finite element) modeling and simulation were programmed in Delphi.Both static and dynamic numerical investigations of the bridges forming the series of types have been carried out.It has been proved that in the case of common structural solutions of bridges and ballasted track structures, it is necessary to put certain limitations on operating speeds, macadam ballast and vertical track roughness.