The Risk Assessment On The Bay Bridge During Its Service Life

With the continuous improvement of China’s economic strength and rapid economicdevelopment of coastal areas, the bay bridge and coastal bridge as economic developmentfoundation construction unceasingly, especially grate bridge grand bridge.At the monment ofthe rapid development of the cause of the bridge,there is the problem in the current bridgeresearch field needs to be solved.The problem is how to estimate the bay bridge’s risk forensuring the service life of the bay bridge through improving the management, maintenancelevel.Take a bay bridge as an example to analyse the risk during its service life. The bay bridgehas many risk influencing factors during operation because the environment is different.indifferent sea areas.Firstly the article uses fuzzy analytic hierarchy process to analysis eightmain influence factors of the bay bridge such as ship-bridge collision, scour, seawatercorrosion, overload, earthquake, storm surge, freetakeze-thaw, sabotage.Then determiningtheir weight and membership grade. After that the most important factor is ship-bridgecollision.In solving consistency index of fuzzy analytic hierarchy process, the article usesMatlab to write the relevant procedures so that the solving process is more convenient.Secondly the article uses least square method and one of finite element analysis software–Midas to analyse the main factors of ship-bridge collision and simulating the response ofinternal force of the bridge. Finally the article introduces the BP neural network technology,Monte Carlo and classical probability method to scientific and exhaustive analyse the risk ofship-bridge collision according to the simulation data and actual weather conditions.The analysis results are those the probability of the bridge crashed because of the shipvoyaging in transverse direction,strong wind and dense fog is0.747%,and the probability ofthe bridge crashed because of the ship voyaging in longitudinal directions is0.115%.According to bridge risk hierarchies,the frist one is chance happenings,the other is highlyunlikely to happen.Sowe should strengthen the strict management and real-time monitoring ofthe whole bridge, especially in the wind of the fog weather conditions.We can ensure that abridge and the people’s lives and property security if we take preventive measures in time.