Intelligent bridge monitoring system based on 3G

Bridge monitoring system is significant to health diagnosis of railway bridges. This paper proposed and developed a novel architecture for large span bridge monitoring. A 3-level distributed structure is adopted in the monitoring system which includes central server, intelligent acquisition node and local controller. Acquisition nodes are located across the bridge. All the acquisition nodes are managed by one local controller. Every acquisition node has 8 channels which can sample displacement, acceleration and strain of bridge. To get high precision data, a 24bits A/D converter ADS1278 is used. Compare to the traditional method, the proposed architecture has two features. First, the acquisition node is a smart device based on powerful DSP processor. Signals of field sensors are analyzed and realtime compressed in the acquisition node. Only the processing results are sent to local controller through IEEE802.11 wireless network. This operation can relieve load of central server and decrease demand of communication bandwidth. Second, 3G wireless network is utilized to provide enough bandwidth for real-time data transmission between local controller and central server. The intelligent monitoring system has run on a large span railway bridge for six months. Running results show that the proposed system is stable and effective.