Steel Bridges In The Marine Environment Durability Diagnostic Study

When other factors (design, construction, maintenance and etc.)steady and reasonable ,the steel bridge in service under the ocean environment will be affected by the ocean, which led to the steel corrosion and decline with service time, and will affect the use of the steel structures in the residual service time. We can obtain the status messages of bridge in service through the corrosion monitoring, which is very important to make sure the safety state of steel bridge structure. but the results obtained from the corrosion monitoring in recently is limited and the analysis methods is not perfect ,which led to the difficult to evaluate the safety state of steel bridge so, how to make good use of the result obtained from the corrosion monitoring , identification the corrosion damage location in steel bridge under the ocean environment after the structures have been used for years, is important to evaluate the safety of the structures predict its residual service life and choose the optimum maintenance strategy. Further instruct the design of newly built structures and the normal use of the structures in service.In this paper based on the previous research result ,the theory of electrochemical mechanism and theory of thermodynamics mechanism of the corrosion of steel bridge under the ocean environment is expatriated ,and the methods of corrosion monitoring is been introduced, making use of environment science, fuzzy math, basic theory of steel structures, theory of artificial neural network, theory of control, and etc , construction a model through the soft of infinity united, identification the corrosion damage location and evaluate the safety of the steel bridge structures in service under ocean environment, Chief work are summarized as follows:1. The corrosion damage of steel bridge structure in service under environment of ocean and the research level of its coherent subject at home and abroad are summarized. At the same time, the necessity and significance of identification the corrosion damage location and evaluate the safety of the steel bridge structures in service under ocean environment are pointed.2. According to the real conditions based on theory of electrochemical mechanism and theory of thermodynamics mechanism, the basic corrosion mechanism under the environment of ocean factors lead to corrosion of the structures and all kinds of corrosion type are studied.3. Based on theory of electrochemical mechanism, many type of corrosion damage monitoring used in engineering in current times are studied and discussed in this paper.4. According to the request of the relevant Standard and Code, the multi-phase fuzzy evaluation method is used to evaluate the safety of the corroded steel bridge structures, and the relevant reliability evaluation methods are suggested.5. Analysis the basic principle of curvature mode and artificial neural network ,a model of corrosion steel bridge structure under environment of ocean is studied through the methods of curvature mode and artificial neutral network, drawing a conclusion that this methods is feasibility6. The chief works are summarized and the problems that need to study are provided.