Multi-dimensional characteristics investigation of track geometry on kilometer-level span high-speed railway suspension bridge

Temperature-induced deformation of kilometer-level span suspension bridges leads to high-amplitude static long-wave track irregularities, which are uncommon in the operation and maintenance of track engineering. To enhance the understanding of targeted maintenance for large-span high-speed railway bridges, the time-frequency domain distribution characteristics of track irregularities were analyzed based on the track measurement data of a kilometer-level span high-speed railway suspension bridge. The overall characteristics of bridge-track smoothness were introduced firstly combined with Butterworth filtering and power spectral density. Then, to address the problem in which the track wavelength component is complex and varies in the mileage domain, a new method is proposed to analyze the track vertical deviation from four dimensions, namely mileage, amplitude, wavelength, and temperature. Wavelength decomposition of the track vertical deviation data is performed using a Butterworth filter, and the maximum value of the amplitude signal is investigated section-by-section every 10 m in the mileage domain. Finally, the cause of the long-wave component is analyzed from the perspective of temperature sensitivity. The results show that the elevation of track-bridge system is linearly related to temperature changes. As the temperature decreases by 1 ℃, the track elevation of midspan varies by 40.7 mm. There are two deformation modes of the bridge, namely the upward arch of the main span and the reverse-bending deformation near the main tower, which govern the deformation mode and wavelength component of the track, and the influence ranges are approximately 900 m near the midspan and 300 m near the main tower respectively. As it gets closer to the midspan, the wavelength affected by the bridge deformation increases, exceeding 306 m at the midspan and 78 m near the main tower. Closer to the midspan position, the wavelength sensitive to temperature is larger, and it starts at 140 m at the midspan. The conclusions can provide theoretical support for the static alignment management of kilometer-level high-speed railway bridge lines.