GIKEN LTD. (Head Office: Kochi-shi, Kochi; President: Shinnosuke Moribe; hereafter “GIKEN”) has developed reaction bases, which are special attachments that streamline underwater construction of tubular piles*, and the press-in construction method that uses them (Patent No. 4728787). In recognition of this technology, GIKEN received the Invention Encouragement Award at the 2022 Shikoku Local Commendation for Invention Awards organized by the Japan Institute of Invention and Innovation (JIII).
In this system, detachable reaction bases with the same shape as the tubular piles being placed are attached to the pile heads to extend the length of the piles. After construction, the reaction bases can be easily removed. In this way, piles can be pressed into place under the water surface. The system eliminates the process of cutting and removing piles underwater, which was required with the previous underwater piling method, and dramatically reduces construction time and costs. It also contributes considerably toward carbon neutrality by reducing CO2 emissions and material usage in the construction process.
This technology eliminates the waste experienced with the previous underwater piling method, through space-saving and temporary work platform free construction, even when installing underwater tubular piles. It is expected to be used much more in the future to meet a range of needs such as protecting river banks, strengthening harbor and port quays, preventing scouring, and earthquake proofing piers. By streamlining construction work and contributing to the development of a sustainable society, this technology will help drive greater adoption of the ImplantTM Method.
* Construction method where the planned level of piles to be placed is underwater (planned height of the top edge of piles)
■ Streamlining Construction of Underwater Tubular Piling
—Cutting of piles required with conventional methods
Compact press-in machines employ press-in technologies for driving piles downward into the earth as the self-propelled machines move across the tops of already placed piles. To prevent the machines from being submerged when working over water, construction must be possible at a level higher than the water level. When underwater pilings are used to avoid impacting water channels and tides, the piles must be cut at the planned level and the excess portion removed after press-in work is completed. This resulted in longer construction periods and higher costs, while material offcuts were discarded.
—Construction streamlined with reaction bases
GIKEN therefore developed reaction bases as special attachments to the tops of piles. In addition to eliminating the need to cut and remove piles after pressing-in construction is complete, the detachable bases can be reused many times. This has dramatically reduced construction time and costs, while also contributing to decarbonization by reducing CO2 emissions and material usage during construction.
■ Construction procedure
1. Pitch and press-in tubular piles, and then lift off the end reaction base.
2. Pitch into the press-in machine and attach to the top of the next pile.
3. Drive in the reaction base, pressing in the pile to the specified position.
■ Examples of adoption
This technology was first used in November 2005 to reinforce river banks in Omuta, Fukuoka Prefecture. It was also used in September 2018 in river improvement work over a wide area of Nagoya, Aichi Prefecture. Both projects were completed quickly, economically, and to a high level of precision without requiring temporary work platforms.
■ Local Commendation for Invention Awards
The Local Commendation for Invention Awards were established in 1921 to encourage and foster invention in each region, and to contribute to improvements in science and technology and promotion of regional industry. Japan is divided into the eight regions of Hokkaido, Tohoku, Kanto, Chubu, Kinki, Chugoku, Shikoku and Kyushu, with commendations given to inventors and others in each region who have achieved excellence in inventions, concepts, and designs. Entries are judged by a selection committee of academic experts and representatives of JIII, the organizer of the awards.
This award is the 20th time that GIKEN technologies have received awards. Other recent awards received include the 2011 JIII Chairman’s Commendation for the ECO CycleTM mechanical bicycle parking facility, the 2012 Encouragement Prize of the Minister of Education, Culture, Sports, Science and Technology for the GYRO PILERTM rotary cutting press-in machine for tubular piles, and the 2020 Shikoku Bureau of Economy, Trade and Industry Bureau Head Award for the Skip Lock MethodTM of pressing in piles.
■Profile of GIKEN Group
GIKEN developed the SILENT PILERTM, the world's first reaction-based hydraulic pile jacking machine, installing piles with no noise and vibration. GIKEN Group now actively promotes the Press-in Technology worldwide and contributes to the construction industry by proposing and implementing innovative solutions. The innovative technology of press-in provides a unique solution and the adoption of this technology has grown to more than 40 nations and regions.
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