The Condition Monitoring Based on Fiber Bragg Grating of Continuously Welded Line Track at Subway Viaduct Section of a Certain City

The performance of real-time inspection and measurement of the stability of continuously welded line steel track at subway viaduct section of a certain city by using fiber Bragg grating displacement, stress and temperature sensors. Two temperature sensors and four stress sensors are installed at the waist of steel track, to monitor respectively the real-time temperature of steel track and the internal stress produced by the steel track due to temperature change, in the mean time four displacement sensors are installed at the junction between steel track and roadbed slab and the junction of subway track upper surface expansion joint, so that steel track creeping quantity(relative to bridge) and longitudinal displacement quantity of the fixed end of subway viaduct bridge (relative to simply supported beam) may be achieved. According to the results, the monitoring error for longitudinal displacement quantity of fixed end of the bridge is 1mm, the monitoring error value for steel track creeping quantity is 2mm, the monitoring value of track temperature conforms to the actual track temperature value. The monitoring method provided by the system for every parameter of continuously welded line steel track at subway viaduct section has solved the problem of monitoring difficulty arising from subway operation characteristics, and has also provided maintenance basis in the mean time.