Real-time alarming of ship-collision accidents for bridges

With the development of the economy, more traffic infrastructures are in needed. A great number of bridges crossing rivers or oceans are built. While, the bridge accidents due to typhoon, earthquake, ship-collision and so on have occurred more frequently, which causes severe loss of life and property. Because of the lack of real-time alarming systems, evitable loss may be caused. This paper presents a method for real-time alarming of ship-collision accidents for bridges using the monitoring data of acceleration or displacement. The variation rate of the monitoring data at any sampling instant is first calculated. The Euler distance of the change rate is then obtained. Through calculating the cumulative probability of the Euler distance, the alarming threshold will be determined for the normal state of the bridge. When a ship-collision accident occurs, the calculated Euler distance is greater than the early-determined alarming threshold, which means that the bridge is under an abnormal condition. The alarming system will be triggered and the bridge should be inspected, maintained and even closed if necessary. This paper analyzed the monitoring data of the ship-collision accidents in 2005 and 2009 for a large span cable-suspension bridge using the proposed alarming method. It proves to be an efficient and effective method for the real-time alarming of ship collision accidents for the bridge.