Nagoya City Subway
Consisting of six lines that cover 93.3 kilometers (58.0 mi) and serving 87 stations, over 1 million people use the subway daily.
The Problem
Nearly 90% of the subway's track is located underground. This, mixed with the close proximity to the port of Nagoya, has resulted in constant exposure of chloride-rich saltwater to the concrete tunnel walls. This saltwater exposure accelerates the ingress of chlorides into the concrete, eventually reaching the depth of the steel. With steel being exposed to chlorides, rebar corrosion problems can occur.
Our Solution
Our local representative, Credence Corporation, based in Tokyo, worked with the owner and contractor to determine that ongoing saltwater-induced corrosion needed to be mitigated to rehabilitate the subway tunnel. Repairs were completed on the areas of unsound concrete, and Galvashield® XP4 anodes were installed in the repair to mitigate corrosion of the rebar from future chloride ingress.
The Result
The concrete repair and protection system were completed in September 2021 as designed. This galvanic protection system will provide corrosion protection to the city's tunnels for decades to come.
Because of Galvashield's proven track record, the use of this product is now the standard repair method used by the Nagoya City Subway since 2021.
Technology Used
These innovative products and technologies were used on this project.