Infra-Structure

Order Received from Kobe City Waterworks Bureau for “No. 4 Water Transmission Tunnel Renewal Work”
—JFE Engineering’s Largest-Ever Aqua Pipeline Project to Safeguard Kobe’s Main Artery—

Sep. 17, 2026

JFE Engineering Corporation

JFE Engineering Corporation (President and CEO: Kazuyoshi Fukuda; Head Office: Chiyoda-ku, Tokyo) and Kumagai Gumi Co., Ltd. (President: Shin Ueda; Headquarters: Shinjuku-ku, Tokyo) have formed the JFE-Kumagai Joint Venture for Special Construction Works, which has secured an order from the Kobe City Waterworks Bureau for the “No. 4 Water Transmission Tunnel^*1 Rehabilitation Project” (the “Project”). The Project represents the largest aqua pipeline project in JFE Engineering’s history.

It involves rehabilitating the No. 4 Water Transmission Tunnel (Motoyama Junction Well–Futatabi No. 3 Junction Well), a critical artery in Kobe City’s water supply system operational since 1964. The renewal will be achieved by inserting new steel water pipes into the existing horseshoe-shaped tunnel^*2 (internal clear dimensions of approximately 2,540 mm in both width and height) using a Pipe-in-Tunnel installation method. The new steel pipes to be installed within the water transmission tunnel will have a diameter of 2,100 mm, a total length of approximately 9.01 km, and a total steel weight of approximately 6,830 tons. Additionally, steel plate lining is planned for the interior of the junction wells^*3 . Employing a technique similar to the Pipe-in-Pipe Method^*4 —a core expertise of JFE Engineering— this initiative stands as the largest project of its kind to date. The construction schedule spans approximately 54 months, with completion slated for February 2031.

Water transmission tunnels demand long-term durability and sustained water transmission functionality, as suspending operations or carrying out repairs is extremely difficult. The Project section crosses the Gosukebashi Fault^*5 and Suwayama Fault^*6 in the Hanshin region, an area with numerous active faults. Accordingly, JFE Engineering’s proprietary steel pipes for crossing faults (SPF)^*7 , previously supplied to the Kobe City Waterworks Bureau, will also be employed, upgrading the water transmission tunnel to be highly resistant to earthquakes.

Furthermore, the Project will leverage JFE Engineering’s extensive expertise in fabrication, installation, and on-site welding of large-diameter steel water pipes, along with its latest technologies, including a proprietary internal coating machine, a welding quality control system, and an IT management system for centrally managing construction records.

Through high-quality and reliable construction, JFE Engineering will contribute to a stable water supply in Kobe City and remains committed to enhancing the resilience of water infrastructure and extending the service life of waterworks facilities.

*1　An important facility located in the eastern part of Kobe City’s urban area that, together with the No. 3 Water Transmission Tunnel and large-capacity water transmission lines, conveys water purchased from the Hanshin Water Supply Authority to the water transmission tunnels in the western part of the urban area
*2　A water transmission facility with a horseshoe-shaped (U-shaped) cross section
*3　 A junction well is a well- (or chamber-) shaped facility installed where pipelines merge or branch, or to regulate water pressure
*4　PIP (Pipe-in-Pipe) Method A trenchless pipeline renewal method in which new steel pipes are inserted inside aging existing water mains or other pipelines to restore service.
*5　An active fault running northeast to southwest along the southern foot of the Rokko Mountains
*6　An active fault running northeast to southwest along the boundary between Kobe City’s urban area and the Rokko Mountains
*7　Steel Pipes for Crossing Faults (SPF) Special steel water pipes developed by JFE Engineering to withstand large ground displacement of several meters caused by fault movement during earthquakes, protecting the pipes from breakage and maintaining water conveyance functionality

Construction Overview

Client	Kobe City Waterworks Bureau
Project name	FNo. 4 Water Transmission Tunnel Renewal Work
Project location	From 6-28-4 Nishi-Okamoto, Higashinada-ku, Kobe City (Motoyama Junction Well) to 1-149 Ichiriyama, Kobeko Jikata, Chuo-ku (Futatabi No. 3 Junction Well)
Outline of the project	Pipe installation inside existing horseshoe-shaped tunnel (internal clear dimensions of approximately 2,540 mm in both width and height) New pipe diameter: 2,100 mm × approximately 9.01 km (steel weight: approximately 6,830 t) Steel plate lining inside junction wells (SS/SUS)
Construction period	From contract signing (scheduled for September 2026) to February 28, 2031 (approximately 54 months)
Contractor organization	JFE-Kumagai Joint Venture for Special Construction Works
Contract amount (entire project)	14.268 billion yen (excluding tax)