cofferdam

　

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1. 防水せき

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2015/07/20 23:40:21」(JST)

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A cofferdam on the Ohio River near Olmsted, Illinois, built for the purpose of constructing the Olmsted Lock and Dam

A cofferdam during the construction of locks at the Montgomery Point Lock and Dam.

The Havana Harbor wreckage of the USS Maine surrounded by a cofferdam, on 16 June 1911

A cofferdam (also called a coffer) is a temporary enclosure built within, or in pairs across, a body of water and constructed to allow the enclosed area to be pumped out, creating a dry work environment for the major work to proceed. Enclosed coffers are commonly used for construction and repair of oil platforms, bridge piers and other support structures built within or over water. These cofferdams are usually welded steel structures, with components consisting of sheet piles, wales, and cross braces. Such structures are typically dismantled after the ultimate work is completed.

For dam construction, two cofferdams are usually built, one upstream and one downstream of the proposed dam, after an alternative diversion tunnel or channel has been provided for the river flow to bypass the dam foundation area. These cofferdams are typically a conventional embankment dam of both earth- and rock-fill, but concrete or some sheet piling also may be used. Typically, upon completion of the dam and associated structures, the downstream coffer is removed and the upstream coffer is flooded as the diversion is closed and the reservoir begins to fill. Dependent upon the geography of a dam site, in some applications, a "U"-shaped cofferdam is used in the construction of one half of a dam. When complete, the cofferdam is removed and a similar one is created on the opposite side of the river for the construction of the dam's other half.

The cofferdam is also used on occasion in the shipbuilding and ship repair industry, when it is not practical to put a ship in drydock for repair or alteration. An example of such an application is certain ship lengthening operations. In some cases a ship is actually cut in two while still in the water, and a new section of ship is floated in to lengthen the ship. Torch cutting of the hull is done inside a cofferdam attached directly to the hull of the ship; the cofferdam is then detached before the hull sections are floated apart. The cofferdam is later replaced while the hull sections are welded together again. As expensive as this may be to accomplish, use of a drydock may be even more expensive. See also caisson.

A 100 ton open caisson that was lowered more than a mile to the sea floor in attempts to stop the flow of oil in the Deepwater Horizon oil spill has been called a cofferdam. It did not work, as methane hydrates froze in the upper levels preventing the containment.

Naval architecture

Inside of a cofferdam on a vessel

A cofferdam may also refer to an insulating space between two watertight bulkheads or decks within a ship. A cofferdam may be a void (empty) space or a ballast space. Cofferdams are usually employed to ensure oil or other chemicals do not leak into machinery spaces. If two different cargoes that react dangerously with each other are carried on the same vessel, one or more cofferdams are usually required between the cargo spaces.

Portable cofferdams

Portable cofferdams are inflatable cofferdams that can be reused. Cofferdams of this type are stretched across the site, then inflated with water from the prospected dry area. Once the area is dry, water still remaining from the dry area can be siphoned over to the wet area.

References

External links

• The dictionary definition of cofferdam at Wiktionary
• Nautical Terms at phrontistery.info
• Portable Cofferdam at phrontistery.info

• http://www.damitdams.com/cofferdam.php

English Journal

• Recurrent oil sheens at the deepwater horizon disaster site fingerprinted with synthetic hydrocarbon drilling fluids.

• Aeppli C1, Reddy CM, Nelson RK, Kellermann MY, Valentine DL.
• Environmental science & technology.Environ Sci Technol.2013 Aug 6;47(15):8211-9. doi: 10.1021/es4024139. Epub 2013 Jul 17.
• We used alkenes commonly found in synthetic drilling-fluids to identify sources of oil sheens that were first observed in September 2012 close to the Deepwater Horizon (DWH) disaster site, more than two years after the Macondo well (MW) was sealed. While explorations of the sea floor by BP confirmed
• PMID 23799238

• Water and sustainable land use at the ancient tropical city of Tikal, Guatemala.

• Scarborough VL1, Dunning NP, Tankersley KB, Carr C, Weaver E, Grazioso L, Lane B, Jones JG, Buttles P, Valdez F, Lentz DL.
• Proceedings of the National Academy of Sciences of the United States of America.Proc Natl Acad Sci U S A.2012 Jul 31;109(31):12408-13. doi: 10.1073/pnas.1202881109. Epub 2012 Jul 16.
• The access to water and the engineered landscapes accommodating its collection and allocation are pivotal issues for assessing sustainability. Recent mapping, sediment coring, and formal excavation at Tikal, Guatemala, have markedly expanded our understanding of ancient Maya water and land use. Amon
• PMID 22802627

• Integrated SPPS on continuous-flow radial microfluidic chip.

• Wang W1, Huang Y, Liu J, Xie Y, Zhao R, Xiong S, Liu G, Chen Y, Ma H.
• Lab on a chip.Lab Chip.2011 Mar 7;11(5):929-35. doi: 10.1039/c0lc00542h. Epub 2011 Jan 26.
• A novel integrated continuous-flow microfluidic system was designed and fabricated for solid phase peptide synthesis (SPPS) using conventional reactants. The microfluidic system was composed of a glass-based radial reaction chip, a diffluent chip, amino acid feeding reservoirs and continuous-flow re
• PMID 21270975

Japanese Journal

• 浮体式仮締切設備

• Hitz技報 = Hitz technical review 76(1), 28-33, 2015
• NAID 40020590129

• 黒杭川ダムのリニューアル―放流管の新設工事―

• ダム工学 23(4), 310-317, 2013
• NAID 130004495239

• Backwards Analysis for Retaining Wall System by Sheet Piles based upon Lateral Wall Displacement in St. Petersburg

• Proceeding of TC302 Symposium Osaka 2011 : International Symposium on Backwards Problem in Geotechnical Engineering and Monitoring of Geo-Construction, 168-173, 2011
• NAID 120005244709

Related Links

• Cofferdam | Define Cofferdam at Dictionary.com

Cofferdam definition, a watertight enclosure placed or constructed in waterlogged soil or under water and pumped dry so that construction or repairs can proceed under normal conditions. See more. Thesaurus Translate Reference ...

• Cofferdam definition of Cofferdam in the Free Online Encyclopedia

cofferdam, temporary barrier for excluding water from an area that is normally submerged. Made commonly of wood, steel, or concrete sheet piling (see pile pile, post of timber, steel, or concrete used to support a structure. Vertical ...

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