In the Great East Japan Earthquake that occurred on March 11, 2011, many buildings suffered from natural seawater dipping due to the tsunami. It has become clear that corrosion progresses in nail that had submerged in natural seawater compared to nail that had not submerged in natural seawater. However, processing for this has not been developed. Therefore, in this research, we experimentally explored the possibility of continuous use of nail in wooden building submerged in natural seawater by tsunami. In order to verify the usefulness of rinsing by fresh water, the following experiment was conducted. At first, the wood specimens with nail was submerged in natural seawater, artificial seawater, and sodium chloride solutions. Nails were driven into the wood specimens before submerged and after submerged. Secondly, the rust of specimens, which was rinsed by fresh water or not, was quantified after promoting accelerated rusting. The nail was visually confirmed that the progress of corrosion was suppressed in the nail which was rinsed with fresh water after submerged in natural seawater. However, no significant difference in the degree of corrosion due to the presence or absence of rinsing with fresh water from the quantification of the rust. Each study result was subjected to a significant difference study for each submerged period depending on the presence or absence of rinsing with fresh water. Regarding the calculation results, from this study, there is no significant difference in rinsing with fresh water under any condition, I seemed that it was ineffective. In conclusion, it was confirmed that fresh water rinsing may be inappropriate as a countermeasure against nail that submerged in the natural seawater.

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