Monitoring of a Timber Footbridge

Abstract: Alvsbacka Bridge was erected in the summer of 2011. During the planningof the construction researchers from LTU and SP Tr¨a designed ahealth monitoring system that constantly measures different parameterson the bridge. The motivation for health monitoring systems is several:Bridge safety, verification of the design and complement during inspections.Health monitoring of infrastructure is common, many bridges areequipped with health monitoring systems. Timber bridges are rarely monitored.This research project is looking to answer what type of sensorsis suitable for bridges in order to make them smart. The smartness ofthe bridge in this case is to help optimize bridge maintenance, assurethe service life and build knowledge about measurements on large timberconstructions. This thesis presents the monitoring system of the bridge,moisture content monitoring and studies the weather effects on the bridge.The monitoring system of ¨Alvsbacka Bridge consists of several differentsensor systems that continuously measure temperature, moisture content,movements, cable forces, wind velocity, wind direction. The monitoringsystem had some problems with sensors not communicating. Long termmoisture content monitoring show anticipated results and the bridge deckmovements are close to the theoretical values.