Research on the Radar Non-contact Testing Technology of High-speed Railway Bridges

Research purposes: China has built more than 30 000 km high-speed railway, among which bridges account for a large proportion. The large amount of bridges, varieties of bridge types and complex structures have posed great challenges to the inspection and maintenance work in the future. Due to that the high-speed railway is operated in a closed manner, the safety and timeliness requirements of bridge inspection are very demanding. Thus, it is urgent to develop the off-site remote non-contact testing technology, so as to provide technical guarantee to the safe operation of high-speed railway. Research conclusions:(1) The differential interferometric microwave radar is capable of carrying out continuous, dynamic, long-distant and non-contact inspections without weather and time limitation, which can provide on-line monitoring of the structural parameters of high-speed railway bridges. (2) The technique was used to the Tianxingzhou Changjiang River Bridge in Wuhan, by which the frequencies of the stay cables and the condition of the railway deck were monitored out of the bridge site, without interruption to the normal operation of the railway, and the monitoring results were good. The engineering practice can be taken as reference for other similar projects. (3) Radar can carry out effective and synchronized testing of the dynamic deformation in the central of multiple stay cables, the vibration signals are distinct and the frequency resolution is high. It can not only extract the frequency spectrum of the stay cables themselves, but also accurately extract the modal frequency of the integral bridge structure. (4) Radar testing technology can be widely used in the on-line diagnosis of mechanical parameters of high-speed railway bridge structure, and the evaluation of structural health. © 2020, Journal of Railway Engineering Society, Editorial Department. All right reserved.