Gabion

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Gabions with cannon, from a late 16th century illustration.

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Reinforced earth with gabions, Sveti Rok, Croatia.

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Up close view of a bank protection made with mattresses in Vrtižer, Slovakia.

Gabions (from Italian gabbione meaning "big cage"; from Italian gabbia and Latin cavea meaning "cage") are cages, cylinders, or boxes filled with soil or sand that are used in civil engineering, road building, and military applications. For erosion control caged riprap is used. For dams or foundation construction, cylindrical metal structures are used. In a military context, earth or sand-filled gabions are used to protect artillery crews from enemy fire.

Leonardo da Vinci designed a type of gabion called a Corbeille Leonard ("Leonard[o] basket") for the foundations of the San Marco Castle in Milan.

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Bridge abutment with gabions.

Civil engineering

In civil engineering a gabion wall is a retaining wall made of rectangular containers (baskets) fabricated of thick galvanized wire, which are filled with stone and stacked on one another, usually in tiers that step back with the slope rather than vertically.

The most common civil engineering use of gabions is to stabilize shorelines or slopes against erosion. Other uses include retaining walls, temporary floodwalls, to filter silt from runoff, for small or temporary/permanent dams, river training, channel lining. They may be used to direct the force of a flow of flood water around a vulnerable structure. Gabions are also used as fish barriers on small streams.

Gabion baskets have some advantages over loose riprap because of their modularity and ability to be stacked in various shapes; they are also resistant to being washed away by moving water. Gabions also have advantages over more rigid structures because they can conform to ground movement, dissipate energy from flowing water, and drain freely. Their strength and effectiveness may increase with time in some cases, as silt and vegetation fill the interstitial voids and reinforce the structure. They are sometimes used to keep stones which may fall from a cutting or cliff from endangering traffic on a thoroughfare.^{[citation needed]}

As all methods of construction, gabions have an approximated life expectancy, and in the case of gabions it relies on the lifespan of the wire and not on the contents of the basket as the structure will fail when the wire fails. In one scenario PVC-coated galvanized gabions have been estimated to survive for 60 years. http://www.maccaferri-northamerica.com/files/USA028_FallsRoadMD.pdf Some gabion manufacturers guarantee a structural consistency of 50 years. Although galvanized steel wire is most widely used, stainless steel wire gabions are also developed and used. http://www.gabions.net/featured_projects_2.html

Gabions have also been used in building, as in the Dominus Winery in Napa Valley, California. The exterior is formed by modular wire mesh gabions containing locally quarried stone; this construction creates an environment of moderate temperatures within the building.

Military use

In the medieval era, gabions were round cages with open tops and bottoms, made from wickerwork and filled with earth for use as military fortifications. These early military gabions were used to protect field artillery gunners. The wickerwork cylinders were light and could be carried relatively conveniently in the ammunition train, particularly if they were made in several diameters to fit one inside another. At the site of use in the field, they could be stood on end, staked in position, and filled with soil to form an effective wall around the gun. Today, gabions are often used to protect forward operating bases (FOBs) against explosive, fragmentary, indirect fires such as mortar or artillery fire. Examples of areas within a FOB that make extensive use of gabions would be sleeping quarters, mess halls, or any place where there will be a large concentration of unprotected soldiers.

See also

• Cellular confinement, a modern form of gabion cages.
• Gabion Report, WRL Research Report No 156, October 1979, C.T Brown et al.
• Hesco bastion, a modernized version of the same concept.
• Maccaferri gabions, The family who introduced wire mesh gabions into modern civil engineering.

References

• Freeman, Gary E.; Fischenich, Craig J.(May 2000), "Gabions for Streambank Erosion Control", Environmental Laboratory, U.S. Army Corps of Engineers.

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