In Japan, there have been found a lot of corrosion damages recently in steel bridges aged for fifty or more years. If the strength of a steel structure is decreased by serious corrosion damages, the structure must be repaired to ensure its safety. In order to supplement the strength loss of a steel member with local corrosion, steel plate bonding method is often adopted, where the corroded area is covered with steel plate bonded by adhesive. In this case, surface preparation is the most important issue to bond the cover plates completely. In this method, surface preparation is the most important issue to bond the cover plates completely. However, it is quite difficult to completely remove rust and wastes in the fieldwork of surface preparation. Thus, this paper presents recovery effect of local corroded steel plate by steel plate bonding method when rust is not completely removed. Specimens are rectangular steel plates with irregular surface which imitated local corrosion in the center of plate. Then rust is also imitated rather than actual one to quantitatively evaluate the recovery effect. Axial tensile tests were conducted for these specimens repaired with patch plate. Then, the size of patch plate and amount of rust were changed and investigated how these differences affect the peeling off of the patch plate.
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