광섬유 센서를 이용한 경량전철 교량에 대한 동적응답 모니터링

초록

Among many types of light rail transits (LRT), the rubber-tired automated guide-way transit (AGT) is prevalent in many countries due to its advantages such as good acceleration/deceleration performance, high climb capacity, and reduction of noise and vibration. However, AGT is generally powered by high-voltage electric power feeding system and it can cause electromagnetic interference (EMI) to measurement sensors for structural monitoring of railway structures such as bridges, tunnels and etc. The fiber optic sensor system is free from EMI and has been successfully applied in many applications of civil engineering. Especially, fiber Bragg grating (FBG) sensors are the most widely used because of its good multiplexing capabilities. This paper investigates a prestressed concrete girder railroad bridge using FBG based sensors to monitor the dynamic response of the bridge with a test train which passes over the bridge at different speeds ranging from 10km/h to 50km/h. The results show that the measured data from FBG based sensors are free from EMI though electric sensors are not, especially in the case of electric strain gage. It is crucial in the health monitoring of structures including high voltage power feeding system.