In bridges that have been in service for several decades, water leaks containing antifreeze agents spread to the ends of girders due to damage to the expansion and contraction equipment, etc. It is estimated that some of them are narrow, but it is difficult to investigate because of the narrow space. Especially, at the end of the prestressed concrete bridge (PC bridge), a fixing device for PC steel is installed, and immediate development of investigation, diagnosis and repair technology is required. The NSRV method is a method that enables visual confirmation of the narrow space between girder end spaces and investigation of the amount of internal salt, and repairs within a limited time.

NSRV method: Vertical girder-end Repair method at Narrow Space