Yusuke NOZOE
Study on Objectiveness Quantification of Corrosion Evaluation in Weathering Steel Surfaces
Eiji IWASAKI
In recent years, with the expectation to reduce maintenance costs through repainting, the application of weathering steels to bridges is increasing¡¤due to the formation of protective rust, weathering steel can be used in unpainted conditions. However, since the formation of protective rust can easily be affected by the environment, an accurate evaluation method for monitoring and diagnosing rust state of existing bridges is needed.
Usually the rust appearance evaluation method and the scotch tape test are the most used for monitoring and diagnosing rust state of existing weathering steel bridges due to its convenience and simplicity. But the big variation of the results that is seen between different tests and evaluators is a problem that must be considered.
In this study, the rust state evaluation of a weathering steel bridge in Niigata Prefecture was performed. The data collected from this assessment together with a neural network model were used to quantify the objectiveness of the rust appearance evaluation method.
The results obtained are described as follows:
1)The rust state level 1 and 2 can¡Çt be estimated if the input parameter is only defined by colorimetric analysis. Also it was determined that the rust thickness was not suitable to estimate the rust state level of the bridge.
2)It was possible to obtain a high evaluation accuracy using the scotch tape test results in the input parameters. Especially, on the fluctuations and in the average particle size input parameters.
3)By using the data of the beam lower section in the input data as well as in the observation data, it was possible to obtain high estimation accuracy.
4)It is necessary to consider the estimation precision as well as the estimation error.
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