FBG based intelligent monitoring system of the Tianjin Yonghe Bridge

摘要

Optical fiber Bragg grating ( FBG) has been accepted widely throughout the civil infrastructures, especially for bridges. In this paper, a new case study, FBG-based intelligent monitoring system of the Tianjin Yonghe Bridge is introduced. For this case, techniques of FBG sensors installation have been tested and 40 FBG strain sensors, 10 FBG temperature sensors and 96 FRP-OFBG based smart cable sensors have been successfully installed on Yonghe Bridge. The concrete strain change and cables load gradients have been monitored during the bridge static test using those FBG sensors. And besides, after the bridge was completed, the strain course under traffic load and temperature changes were monitored with these sensors. The monitoring results show that traffic fluxes and possible fatigue damages can be conveniently analyzed, which can be applied for structural health diagnosis. The monitoring system has stood the ordeal for more than 2 years, which shows that the FBG can meet the demands of long-term monitoring of the bridge.