Study on effective frequency range of wheel-rail excitation for elevated high-speed railway.

The main frequency bands typically considered in studies on the environmental vibration of high-speed railways often neglect high-frequency components, whereas a comprehensive and reliable excitation source is essential for accurately capturing the vibration characteristics of structural components. Using the CRTS III slab ballastless track and a simply supported box girder bridge as examples, this study develops a 3D slab track-viaduct frequency domain analysis model to investigate the vibration transfer characteristics of the track and substructure under wide frequency input excitations. The model is validated and its computational accuracy verified by comparing field test data with extracted simulation results. A method for determining the effective frequency range of wheel-rail excitations based on the statistical analysis of transferred energy is proposed, and the influence of varying fastener stiffness and vibration isolation pad stiffness is studied. The results show that the environmental vibration induced by the propagation of mid-to-high frequency energy in the bridge cannot be entirely disregarded. When evaluating high-speed railway environmental vibrations, the cutoff frequency band corresponding to a transmission energy threshold greater than 90% should be selected as the effective frequency range of wheel-rail excitations to enhance the accuracy and reliability of the results. Short wavelength excitation sources below 0.3 m remain significant in predicting high-speed railway environmental vibrations, and the potential vibration effects of broader frequency domain wheel-rail excitations, particularly those with wavelengths shorter than 0.07 m, on the bridge and substructure should also be considered.