Tetrapod (structure)
{{short description|Concrete breakwater element}}
{{About|the structure|four-limbed vertebrates|Tetrapod}}
File:Tetrapods Graciosa Island 02.jpg, Azores]]
File:Liepaja Karosta falochron polnocny 2.jpg
File:Tetrapods_protecting_a_marina_on_Crete.jpg, Greece.]]
A tetrapod is a form of wave-dissipating concrete block used to prevent erosion caused by weather and longshore drift, primarily to enforce coastal structures such as seawalls and breakwaters. Tetrapods are made of concrete, and use a tetrahedral shape to dissipate the force of incoming waves by allowing water to flow around rather than against them, and to reduce displacement by interlocking.{{Cite web|url=http://www.brighthubengineering.com/geotechnical-engineering/42962-what-are-tetrapods/|title=What are Tetrapods? (Tetrapods Resist Wave Impact and Prevent Beach Erosion)|website=Brighthub Engineering|access-date=2017-08-02}}{{Cite web|url=https://www.degruyter.com/downloadpdf/j/ijnaoe.2014.6.issue-4/ijnaoe-2013-0224/ijnaoe-2013-0224.pdf|title=Effects of vertical wall and tetrapod weights on wave overtopping in rubble mound breakwaters under irregular wave conditions|last=Park |display-authors=etal |first=Sang Kil|date=2014|access-date=2 August 2014}}
Invention
Tetrapods were originally developed in 1950 by Pierre Danel and Paul Anglès d'Auriac of Laboratoire Dauphinois d'Hydraulique (now Artelia) in Grenoble, France, who received a patent for the design.Pierre Danel and Paul Anglès d'Auriac (1963) Improvements in or relating to artificial blocks for building structures exposed to the action of moving water [https://worldwide.espacenet.com/publicationDetails/biblio?DB=EPODOC&II=3&ND=3&adjacent=true&locale=en_EP&FT=D&date=19631231&CC=MY&NR=6300031A&KC=A#] The French invention was named {{lang|fr|tétrapode}}, derived from Greek {{lang|el|tetra-}} {{gloss|four}} and {{lang|el|-pode}} {{gloss|foot}}, a reference to the tetrahedral shape. Tetrapods were first used at the thermal power station in Roches Noires in Casablanca, Morocco, to protect the sea water intake.{{Cite journal|last=Danel|first=Pierre|date=1953|title=TETRAPODS|url=https://journals.tdl.org/icce/index.php/icce/article/view/1812|journal=Coastal Engineering Proceedings|language=en|volume=1|issue=4|pages=28|doi=10.9753/icce.v4.28|issn=2156-1028|doi-access=free}}{{Cite web|url=https://icce-ojs-tamu.tdl.org/icce/index.php/icce/article/viewFile/2276/1967|title=The Tetrapod|last=Danel|first=Pierre|date=1967|access-date=2 August 2017}}
Adoption
Tetrapods have become popular across the world, particularly in Japan; it is estimated that nearly 50 percent of Japan's {{convert|35000|km|sp=us}} coastline has been covered or somehow altered by tetrapods and other forms of concrete. Their proliferation on the island of Okinawa, a popular vacation destination in Japan, has made it difficult for tourists to find unaltered beaches and shoreline, especially in the southern half of the island.{{Cite news|url=http://www.japantimes.co.jp/life/2007/07/22/to-be-sorted/tetrapods/|title=TETRAPODS|last=Hesse|first=Stephen|date=2007-07-22|work=The Japan Times Online|access-date=2017-08-02|language=en-US|issn=0447-5763}}
Similar designs
{{excerpt|Wave-dissipating concrete block|only=paragraphs}}
See also
- {{annotated link|Artificial reef}}
- {{annotated link|Breakwater (structure)}}
- {{annotated link|Coastal management}}
- {{annotated link|Coastal erosion}}
- {{annotated link|Ocean surface wave}}
- {{annotated link|Riprap}}
- {{annotated link|Seawall}}
References
{{Reflist}}
Further reading
- {{cite book|last=Lagasse|first=P.F. |title=Countermeasures to protect bridge piers from scour|year=2007|publisher=Transportation Research Board|location=Washington, D.C.|isbn=978-0-309-09909-7|url=https://books.google.com/books?id=p_rwqGK9igEC&q=tetrapod+concrete}}
- {{cite web|last=Hesse|first=Stephen|title=The Japan Times environment columnist|url=http://search.japantimes.co.jp/cgi-bin/fl20070722x1.html|work=Don't You Just Love 'Em ... Tetrapods |publisher=The Japan Times|access-date=13 May 2011}}
- {{cite book|editor-last=Zimmerman|editor-first=Claus|title=Environmentally friendly coastal protection : proceedings of the NATO Advanced Research Workshop on Environmentally Friendly Coastal Protection Structures, Varna, Bulgaria, 25-27 May 2004|year=2005|publisher=Springer|location=Dordrecht|isbn=978-1-4020-3299-8|url=https://books.google.com/books?id=djHjPj4hmcoC&q=tetrapod+concrete|edition=Online-Ausg.}}
- {{cite web|last= Wijers-HasegawaHesse|first=Yumi|title=Tetrapodistas: Beauty beheld in huge concrete forms|url=http://search.japantimes.co.jp/cgi-bin/fl20070722x2.html |publisher=The Japan Times }}
- {{cite web|last=Hesse|first=Stephen|title=Loving and Loathing Japan's Concrete Coasts, Where Tetrapods Reign |url=http://japanfocus.org/-Stephen-Hesse/2481 |publisher=The Asia-Pacific Journal: Japan Focus }}
{{commons category|Tetrapods}}
{{coastal management}}