Toshihide Onda
Study on Corrosion Environment Evaluation and Long-term Corrosion Prediction of Weathering Steel Bridge
Eiji Iwasaki
In recent years, public investment in Japan has been reduced, and low-cost and durable structures are used intensively. One way to reduce costs is reducing the life cycle cost of the structure.In the case of steel bridges, it is necessary to reduce the re-painting costs and maintenance costs.Therefore , in order to try to reduce these costs during structures life cycle, the weathering steel is widely used.Weathering steel possesses the nature of retaining corrosion by rust. But if it isn't under the appropriate environment, corrosion isn't restrained, and its thickness decreases.Therefore, it's important to consider the environmental condition in cases where this steel is used.If the weathering steel can be used under an amount of marine salt less than 0.05mdd(mg/dm2/day), it is known that , after 50 years , the estimated amount of thickness loss is 0.3mm or less.The important factor for corrosion of weathering steel is the marine salt originated by the splash in the seaside area.
In this study, we examined the relationship between corrosion amount and corrosive environment factors , and we examined how to predict the corrosion amount more rational and in a simplified manner.The obtained results in this study is as follows.From the relationship between corrosion amount, wind velocity and the airborne salt amount, it was shown that it is possible to represent the corrosion depletion amount as a function of wind speed.By considering the annual variations and long-term climate variations in environmental factors, it was clarified that it is possible to correct corrosion depletion volume findings.
Please use "previous botton" to return the previous page