Fast Warning Method for Rigid Hangers in a High-Speed Railway Arch Bridge Using Long-Term Monitoring Data

Excessive vibration of arch bridge hangers is a potential threat to the driving safety of high-speed trains; therefore, it is important to study the vibration characteristics and fast warning method of the hanger under environmental factors such as high-speed train load and ambient excitation. The Nanjing Dashengguan Yangtze River Bridge, the longest high-speed railway arch bridge in the world, with a design speed of 300 km/h, was selected as the research subject in this paper to investigate the fast warning method for rigid hangers in a high-speed railway arch bridge. This work analyzes the influence of environmental factors on the hanger's transverse vibration characteristics using long-term monitoring data: several transverse vibration characteristics of the hanger, which are induced by train or ambient wind, were obtained through vibration data collected from the structural health monitoring system; eight train load cases were classified; and the methods of excluding train speed, temperature, and ambient wind are introduced. This paper proposes a method for establishing a reference service condition database including different subdatabases for a hanger. Finally, three reference service condition subdatabases are provided as examples to introduce the fast warning method. The conclusions show that environmental factors influence a hanger's transverse vibration characteristics, and environmental factors must be considered in the condition evaluation of the hangers. All of these provide a systematic method for establishing a hanger's reference service condition database, which can be used for fast warning of hanger anomalies in a high-speed railway arch bridge.