A gabion (from Italian gabbione meaning "big cage"; from Italian gabbia and Latin cavea meaning "cage") is a cage, cylinder or box filled with rocks, concrete, or sometimes sand and soil for use in civil engineering, road building, military applications and landscaping.
For erosion control, caged riprap is used. For dams or in foundation construction, cylindrical metal structures are used. In a military context, earth- or sand-filled gabions are used to protect sappers, infantry, and artillerymen 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.
The most common civil engineering use of gabions was refined and patented by Gaetano Maccaferri in the late 19th century in Sacerno, Emilia Romagna and used to stabilize shorelines, stream banks or slopes against erosion. Other uses include retaining walls, noise barriers, temporary flood walls, silt filtration from runoff, for small or temporary/permanent dams, river training, or 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 screens on small streams. Gabion stepped weirs are commonly used for river training and flood control; the stepped design enhances the rate of energy dissipation in the channel, and it is particularly well suited to the construction of gabion stepped weirs.
A gabion wall is a retaining wall made of stacked stone-filled gabions tied together with wire. Gabion walls are usually battered (angled back towards the slope), or stepped back with the slope, rather than stacked vertically.
The life expectancy of gabions depends on the lifespan of the wire, not on the contents of the basket. The structure will fail when the wire fails. Galvanized steel wire is most common, but PVC-coated and stainless steel wire are also used. PVC-coated galvanized gabions have been estimated to survive for 60 years.Some gabion manufacturers guarantee a structural consistency of 50 years.
In the United States, gabion use within streams first began with projects completed from 1957 to 1965 on North River, Virginia and Zealand River, New Hampshire.More than 150 grade-control structures, bank revetments and channel deflectors were constructed on the two U.S. Forest Service sites. Eventually, a large portion of the in-stream structures failed due to undermining and lack of structural integrity of the baskets. In particular, corrosion and abrasion of wires by bedload movement compromised the structures, which then sagged and collapsed into the channels. Other gabions were toppled into channels as trees grew and enlarged on top of gabion revetments, leveraging them toward the river channels.
Gabions have also been used in building, as in the Dominus Winery in the Napa Valley, California, by architects Herzog & de Meuron, constructed between 1995 and 1997. The exterior is formed by modular wire mesh gabions containing locally quarried stone; this construction allows air movement through the building and creates an environment of moderate temperatures inside.
There are various special designs of gabions to meet particular functional requirements and some special terms for particular forms have come into use. For example:
Early gabions were round cages with open tops and bottoms, made from wickerwork and filled with earth for use as military fortifications. 38 These early military gabions were most often used to protect sappers and siege artillery gunners. :39 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, or rapidly construct a bulletproof parapet along a sap. During the Crimean War, local shortages of brushwood led to use of scrap hoop-iron from hay bales in its stead; this in turn led to purpose-built sheet-iron gabions. :182:
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 are sleeping quarters, mess halls, or any place where there would be a large concentration of unprotected soldiers. Gabions are also used for aircraft revetments, blast walls, and similar structures. A gabion is often referred to as a "Hesco bastion".
Gabions may be used for attenuating dynamic load as those resulting from impacts by vehicles or rockfall for example. First, gabions may be suitable as a vehicle restraint system in scenic lower speed roads.Second, when used as facing of earth-reinforced structures with a vertical face, gabions offer a more deformable surface to impact compared to other classical geotechnical alternatives. This higher deformability results from crushing and large displacements of the fill content. As a result, the impact load transmitted to the structure is reduced, due to both impact energy dissipation and peak force attenuation. In an optimization process, the fill material can be adapted to meet specific requirements, in terms of impact response. This in particular led to the use of recycled materials (tires and ballast from railway tracks) in the core of some rockfall protection embankments.
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Retaining walls are relatively rigid walls used for supporting soil laterally so that it can be retained at different levels on the two sides. Retaining walls are structures designed to restrain soil to a slope that it would not naturally keep to. They are used to bound soils between two different elevations often in areas of terrain possessing undesirable slopes or in areas where the landscape needs to be shaped severely and engineered for more specific purposes like hillside farming or roadway overpasses. A retaining wall that retains soil on the backside and water on the frontside is called a seawall or a bulkhead.
A geologic hazard is one of several types of adverse geologic conditions capable of causing damage or loss of property and life. These hazards consist of sudden phenomena and slow phenomena: :)
Breakwaters are structures constructed near the coasts as part of coastal management or to protect an anchorage from the effects of both weather and longshore drift.
A spillway is a structure used to provide the controlled release of water from a dam or levee downstream, typically into the riverbed of the dammed river itself. In the United Kingdom, they may be known as overflow channels. Spillways ensure that water does not damage parts of the structure not designed to convey water.
Earthworks are engineering works created through the processing of parts of the earth's surface involving quantities of soil or unformed rock.
In stream restoration, river engineering or coastal engineering, revetments are sloping structures placed on banks or cliffs in such a way as to absorb the energy of incoming water. In military engineering they are structures, again sloped, formed to secure an area from artillery, bombing, or stored explosives. River or coastal revetments are usually built to preserve the existing uses of the shoreline and to protect the slope, as defense against erosion.
Geotextiles are permeable fabrics which, when used in association with soil, have the ability to separate, filter, reinforce, protect, or drain. Typically made from polypropylene or polyester, geotextile fabrics come in three basic forms: woven, needle punched, or heat bonded.
Concrete recycling is the use of rubble from demolished concrete structures. Recycling is cheaper and more ecological than trucking rubble to a landfill. Crushed rubble can be used for road gravel, revetments, retaining walls, landscaping gravel, or raw material for new concrete. Large pieces can be used as bricks or slabs, or incorporated with new concrete into structures, a material called urbanite.
Hard engineering involves the construction of physical structures to protect coasts from erosion. Such structures include seawalls, gabions, breakwaters, groynes and tetrapods.
The Concertainer, known colloquially as the HESCO MIL, Hesco barrier, or Hesco bastion, is a modern gabion primarily used for flood control and military fortifications. It is made of a collapsible wire mesh container and heavy duty fabric liner, and used as a temporary to semi-permanent levee or blast wall against small-arms fire and/or explosives. It has seen considerable use in Iraq and Afghanistan.
Training or entrance training refers to coastal structures built to constrain a river discharging across a littoral coast so that it discharges only where desired. Untrained entrances on sandy coasts tend to move widely and violently to discharge into the ocean, often upsetting those enjoying land nearby. With many cities constructed close to rivers, such management has historically been considered a necessary course of action, even though ecologically, non-intervention would be better and more sustainable.
Beach evolution occurs at the shoreline where sea, lake or river water is eroding the land. Beaches exist where sand accumulated from centuries-old, recurrent processes that erode rocky and sedimentary material into sand deposits. River deltas deposit silt from upriver, accreting at the river's outlet to extend lake or ocean shorelines. Catastrophic events such as tsunamis, hurricanes, and storm surges accelerate beach erosion.
A blast wall is a barrier designed to protect vulnerable buildings or other structures and the people inside them from the effects of a nearby explosion, whether caused by industrial accident, military action or terrorism.
Cellular confinement systems (CCS)—also known as geocells—are widely used in construction for erosion control, soil stabilization on flat ground and steep slopes, channel protection, and structural reinforcement for load support and earth retention. Typical cellular confinement systems are geosynthetics made with ultrasonically welded high-density polyethylene (HDPE) strips or novel polymeric alloy (NPA)—and expanded on-site to form a honeycomb-like structure—and filled with sand, soil, rock, gravel or concrete.
A Maccaferri gabion is a name given to a type of gabion produced by the Maccaferri family.
A stepped spillway is a spillway with steps on the spillway chute to assist in the dissipation of the kinetic energy of the descending water. This eliminates or reduces the need for an additional energy dissipator, such as a body of water, at the end of the spillway downstream.
River bank failure can be caused when the gravitational forces acting on a bank exceed the forces which hold the sediment together. Failure depends on sediment type, layering, and moisture content.
Officine Maccaferri SpA (Maccaferri) is an Italian multinational company, headquartered in Zola Predosa, Bologna. The company specialises in products for the construction industry. Maccaferri's products are used for: retaining structures, soil reinforcement, embankment stabilisation, river and canal hydraulic works, coastal protection, erosion control, rockfall mitigation, debris flows and avalanche protection. The company provides technical support to designers, contractors and end-users.
A flexible debris-resisting barrier is a structure used to mitigate debris flows or to contain flow-entrained woods. These structures mainly consist of interconnected metallic components. Flexible debris-resisting barrier are derived from rockfall barriers and were first proposed in the middle of the 1990s in the USA.
A rockfall protection embankment is an earthwork built in elevation with respect to the ground to intercept falling rock fragments before roads, buildings are reached.