GIKEN LTD. announces that the Gyropress Method™, a rotary cutting press-in method for tubular piles, has been adopted for elevated viaduct replacement works in the undergrounding of the Shutoko at Nihonbashi in Tokyo, following its adoption for river-widening construction last year.
In the project being carried out near the Edobashi junction, part of the existing elevated viaduct above the Nihonbashi River will be removed and replaced with a new elevated connecting route linking to an underground tunnel. To maintain traffic flow of more than 100,000 vehicles per day during construction, a temporary bypass route is being provided. GIKEN SEKO CO., LTD., a group company of GIKEN, is constructing tubular pile well foundations for the four piers supporting the temporary bypass route. The work is highly challenging due to the hard ground conditions at the site as well as the requirement for complete watertightness due to the need for excavating the well foundations and adding concrete in subsequent construction stages. In July 2026, the press-in of tubular piles for the first well foundation was completed, and work on the remaining three foundations is scheduled to commence sequentially.
The adoption of the Gyropress Method™ for this project demonstrates its excellent applicability and versatility for infrastructure renewal projects in urban environments. In addition to piling on water, the method can be applied in highly constrained sites crowded with obstructions such as bridge piers, while minimising vibration and noise impacts on nearby buildings and condominiums. Going forward, GIKEN will continue to capitalise on the advantages of the Gyropress Method™ to support the smooth implementation of the undergrounding project. At the same time, GIKEN will further strengthen proposals for the renewal of other ageing infrastructure throughout Japan.
■ Elevated Viaduct Replacement Works for the Mukojima Line Connection Section
To facilitate the partial removal of the existing elevated viaduct connecting the Inner Circular Route and Route 6 Mukojima Line above Nihonbashi, as well as the construction of a new connecting route, the project is being carried out in phases by gradually shifting traffic onto the temporary bypass route while maintaining traffic flow. Construction work to transfer inbound traffic to the temporary route has been underway since 2024. Ultimately, the temporary bypass route will be removed, and a new road connecting to the newly constructed underground route will be opened to traffic.
* Image source: Metropolitan Expressway Co., Ltd. website (Illustration on the left partially modified by GIKEN LTD.)
(https://www.shutoko.jp/ss/nihonbashi-tikaka/construction/03/)
■ GIKEN Group Construction Details
The temporary bypass route is planned to pass over the Nihonbashi River immediately adjacent to the existing Mukojima Line. The work site is extremely constrained, with existing bridge piers and buildings on the opposite bank situated in close proximity. In constructing the well foundations, which have a diameter of 10.2 m, the working space available on barges serving as the construction yard was extremely limited, while overhead clearance was 10 m or less. To address these constraints, an improved lifting device was attached to the mast of the GYRO PILER™, enabling efficient use of the available space and allowing the entire process, from pile pitching to press-in, to be completed. Tubular piles can be directly pressed in by rotary cutting press-in while minimising vibration and noise, without producing excess slurry, thereby keeping the impact on the surrounding environment to a minimum. In addition, the ability of the Gyropress Method™ to penetrate hard ground with N-values ranging from 50 to 150 further demonstrates the advantages of the method.
■ Watertight Sealing Method Between Piles
After the piles are installed, the inside of the well foundations must be excavated and concrete added. Therefore, complete watertightness was required over a depth of 20 m, from the top of the piles down into the ground. As this depth exceeded the practical range of the conventional method using mortar jackets, a new approach was adopted for the first time, combining the Gyropress Method™ with a high-pressure jet grouting method commonly used for ground improvement. First, two small diameter tubular piles were pressed in between the piles installed using the Gyropress Method™. The enclosed area formed by the large and small piles was then excavated, and grout was jetted at ultra-high pressure through a rod from its tip. Once the ground had been sufficiently hardened to a certain depth, the remaining section was sealed using mortar jackets, completing the watertight treatment.
■ Construction Overview (Upon Completion of the First Well Foundation)
| Project name | Upper Structure, Pier, and Foundation Construction Works (Revised) for the Connection Section between the Shuto Inner Circular Route (Nihonbashi Section) and Route 6 Mukojima Line |
|---|---|
| Location | Nihonbashi 1-chome to Koami-cho, Chuo-ku, Tokyo |
| Project owner | Metropolitan Expressway Co., Ltd. |
| Main contractor | KAJIMA-TOA Civil Engineering JV (JFE-MMB-KAJIMA-TOA Different-Construction-Discipline JV) |
| Sub-contractor | GIKEN SEKO CO., LTD. |
| Equipment | GYRO PILER™ F401 (with a Lifting Device) |
| Pile specifications | 24 tubular piles (1 m in diameter, 45 m in length) 48 small diameter tubular piles (318.5 ㎜ in diameter, 16.5 m in length) |
■Profile of GIKEN Group
GIKEN developed the SILENT PILER™, the world’s first reaction-based, non-vibratory hydraulic pile driving machine that operates with minimal noise impacts. The GIKEN Group now actively promotes its press-in technology worldwide and contributes to the construction industry by proposing and implementing innovative solutions. The innovative press-in technology provides a unique solution and the adoption of this technology has spread to over 40 nations and regions.
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