Influence of damping on seismic-induced track geometric irregularity spectrum in high-speed railway track-bridge system

Track irregularities are an important factor affecting the safety, smoothness, comfort, and lifespan of high-speed railway track structures. Damping greatly affects the seismic response, and the influence of damping on seismic-induced track geometric irregularities is of significant interest. In this study, the simple-supported beam bridge of the CRTS-II ballastless track high-speed railway was adopted as the research object. A power spectral density curve spectrum of seismic-induced track geometric irregularity based on guarantee rate was established, and the influence of structural damping ratio on the power spectral density curve under different earthquake intensities was analysed. A simplified calculation method for power spectral density curve of seismic-induced track geo-metric irregularity was proposed. The main findings of this work are as follows: (1) Seismic-induced track ir-regularities of high-speed railway bridges are dominated by alignment irregularity, and a segmented polynomial function can be fitted to the power spectral density curve of the seismic-induced track irregularity based on guarantee rate; (2) Seismic-induced track irregularities of high-speed railway bridges worsen as structural damping decreases and peak ground acceleration increases; (3) More spikes are observed in the high-frequency waveband of the power spectral density curve, and seismic-induced track irregularity results in more high fre-quency periodic components.

Automated summary

Track irregularities are important for the safety and lifespan of high-speed railway track structures. Damping has a significant impact on the seismic response and the influence of damping on seismic-induced track geometric irregularities is of interest. This study focuses on a simple-supported beam bridge of the CRTS-II ballastless track high-speed railway. A power spectral density curve spectrum of seismic-induced track geometric irregularity was established based on guarantee rate, and the influence of structural damping ratio on the power spectral density curve was analyzed. The findings show that seismic-induced track irregularities worsen with decreasing damping and increasing peak ground acceleration, and more spikes and high-frequency periodic components are observed in the power spectral density curve.