New Sensors and Digital Data Processing Algorithms for Monitoring Railway Bridges

An overview of sensors and the algorithms used to monitor the dynamic response of railway bridges is presented. Attention was paid to the importance of displacement monitoring, which directly testifies to the stiffness of the bridge, whereas the acceleration response is affected by many other parameters. The measurements of displacements in an automatic, unattended mode nearly always create considerable difficulties. Major difficulties are encountered especially in case of structures with restricted or impossible access to the area under them (bridges over busy roads, railway lines or rivers). Due to the specific nature of long-term bridge displacement monitoring systems using inertial sensors—inclinometers and accelerometers were elaborated. The application of the system was presented on truss bridge located in railway line with intensive traffic of passenger and freight trains and on arch bridge located in high-speed railway. Also a bridge load monitoring system using intelligent bearings that measure the reaction force, angle of rotation and temperature is presented. The developed monitoring system makes it possible to automatically distinguish dynamic changes occurring from train journeys and static changes from temperature changes. The system has been tested on a plate girder bridge with short span length. The monitoring systems presented here could be the basic elements of a “Future Smart Bridge” that will control both the amount of load and the structure's response to that load in the future.