Wakkanai Port, located in the northernmost part of Japan, has a breakwater called “North Breakwater Dome, ” which is reminiscent of ancient Greek architecture. Construction of the North Breakwater Dome was completed in 1936, and an overall rehabilitation was conducted from 1978 to 1981. Currently, the deterioration of the dome is becoming apparent. We examined the remedial measures for deterioration, but the issues were to devise a method for assessing the performance of reinforced concrete members and a reasonable repair method. This is because the inspection range is very large, and the structure of the Dome is a civil engineering heritage. To solve the issues, we devised the deterioration mapping that is created by subdividing of large inspection areas, and by grading into five grades of deterioration based on damage. By using deterioration mapping, it is possible to quantitatively grasp damages in large areas, to quantitatively understand the corrosion state of reinforced concrete members, and to implement reasonable repair on an unit area basis. This paper discusses the effectiveness of the deterioration mapping using the case study of the North Breakwater Dome maintenance.
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