A bunker is a defensive military fortification. Bunkers are mostly below ground, compared to blockhouses which are mostly above ground. In Military science, a blockhouse is a small isolated Fort in the form of a single building They were used extensively in World War I and World War II on a tactical level, while during the Cold War, massive bunker complexes were built to house both strategic (command & control) infrastructure as well as government personnel and stores for the event of a nuclear war. World War I (abbreviated WWI; also known as the First World War, the Great War, and the War to End All World War II, or the Second World War, (often abbreviated WWII) was a global military conflict which involved a majority of the world's nations, including Cold War is the state of conflict tension and competition that existed between the United States and the Soviet Union (USSR and their respective allies from the

Contents 1 Types 1.1 Trench 1.2 Pillbox 1.3 Artillery 1.4 Industrial 1.5 Personal 2 Design 2.1 Blast protection 2.2 Nuclear protection 2.3 General features 3 Famous installations 4 See also 5 References & Notes 6 External links

Types

Trench

This type of bunker is a small concrete structure, partly dug into the ground, which is usually a part of a trench system. Such bunkers give the defending soldiers better protection than the open trench and also include top protection against aerial attack (grenades, mortar shells). A trench is a type of excavation or depression in the ground Trenches are generally defined by being deeper than they are wide (as opposed to a wider Gully or Ditch A mortar is a muzzle-loading Indirect fire weapon that fires shells at low velocities short ranges and high-arcing ballistic trajectories A shell is a payload-carrying Projectile, which as opposed to shot, contains an explosive or other filling though modern usage includes large solid projectiles They also provide shelter against the weather. ^[2]

The front bunker of a trench system usually includes machine guns or mortars and forms a dominant shooting post. For other uses of the phrase see Machine Gun (disambiguation. The rear bunkers are usually used as command posts or Tactical Operations Center (TOC), for storage and as field hospitals to attend to wounded soldiers. Command and control can be defined as the exercise of Authority and Direction by a properly designated Commander over assigned and attached Forces A Tactical Operations Center (TOC is a command post for Police, Paramilitary, or Military operations A Tactical Operations Center (TOC is a command post for Police, Paramilitary, or Military operations A hospital is an institution for Health care providing treatment by specialised staff and equipment and often but not always providing for

Pillbox

Dug-in guard posts (with loopholes through which to fire guns) and made from concrete are also known as 'pillboxes'. The originally jocular name arose from their perceived similarity to the cylindrical boxes in which medical pills were once sold. ^[3] They are in effect a trench firing step hardened to protect against small-arms fire and grenades and raised to improve the field of fire.

Their use seems to have developed during the period of the First World War when defence in depth using the Machine Gun Corps was being perfected. World War I (abbreviated WWI; also known as the First World War, the Great War, and the War to End All Defence in depth is a Military strategy sometimes referred to as elastic defence or deep defence. The Machine Gun Corps (MGC was a corps of the British Army, formed in October 1915 in response to the need for more effective use of Machine guns on the Western However, most of those seen in Britain, having been left over from the 1940 invasion scare, are designed for use by riflemen rather than for machine gunners. British anti-invasion preparations of World War II entailed a large-scale division of military and civilian mobilization in response to the threat of invasion For other uses of the phrase see Machine Gun (disambiguation. The concrete nature of pillboxes means that they are a feature of prepared positions and their original use is likely to have been in the Hindenburg Line. The Hindenburg Line (also known as the Siegfried Line) was a vast system of defences in northeastern France during World War I. This is likely to have been the time when they acquired their incongruous English name. The Oxford English Dictionary's earliest record of the use of the word pillbox in connection with a defensive post is from 13 September 1917, after the German withdrawal onto the Hindenburg Line. The Oxford English Dictionary ( OED) published by the Oxford University Press (OUP is a comprehensive Dictionary of the English

Pillboxes are often camouflaged in order to conceal their location and to maximize the element of surprise. Camouflage became an essential part of modern Military tactics after the increase in accuracy and rate of fire of weapons during the 19th century They may be part of a trench system, form an interlocking line of defence with other pillboxes by providing covering fire to each other (defence in depth), or they may be placed to guard strategic structures such as bridges and jetties. Defence in depth is a Military strategy sometimes referred to as elastic defence or deep defence.

Many pillboxes were built before WWII in the Czech Republic in defence against the German invasion of Czechoslovakia. The Czech Republic ( ˈt͡ʃɛskaː ˈrɛpuˌblɪka short form in Česko ˈt͡ʃɛskɔ also called Czechia, None of these were actually used in the end, since the German military met no resistance when coming to the country because the country was effectively forced to capitulate as a result of Allies annexing the country's border lands to Germany. The Munich Agreement (Mnichovská dohoda Mníchovská dohoda Münchner Abkommen Accords de Munich was an agreement regarding the Sudetenland, which were areas along borders

Artillery

Many artillery installations, especially for naval artillery have historically been protected by extensive bunker systems. Naval Artillery or naval rifles refers to Warship -mounted Guns used in Naval warfare for attacking enemy vessels These usually housed the crews serving the weapons, protected the ammunition against counter-battery fire, and in numerous examples also protected the guns themselves, though this was usually a trade-off reducing their fields of fire.

Since artillery bunkers were often constructed for very large guns in a pre-defined location and as part of a larger system of defenses (such as for a port town or a seacoast), they are amongst the largest individual pre-Cold War bunker types found. The walls of installations like the 'Batterie Todt' in northern France were up to 3. During the Second World War, cross-Channel guns were long-range Coastal artillery pieces placed on the English Channel coasts of Kent, England 5 m thick, with the gun inside capable of reaching over the English Channel to the opposite coast. ^[4]

Industrial

Typical industrial bunkers include mining sites, food storage areas, dumps for materials, data storage, and sometimes living quarters. They were built mainly by nations like Germany during World War II to protect important industries from aerial bombardment. A bomb is any of a range of devices that typically rely on the Exothermic Chemical reaction of an Explosive material to produce an extremely Many mines in France and Germany were transformed into bunkers by both the Germans and the French in World War I and World War II. Mining is the extraction of valuable Minerals or other geological materials from the earth usually (but not always from an Ore body This article is about the country For a topic outline on this subject see List of basic France topics. Germany, officially the Federal Republic of Germany ( ˈbʊndəsʁepuˌbliːk ˈdɔʏtʃlant is a Country in Central Europe. World War I (abbreviated WWI; also known as the First World War, the Great War, and the War to End All World War II, or the Second World War, (often abbreviated WWII) was a global military conflict which involved a majority of the world's nations, including

Industrial bunkers are also built for control rooms of dangerous activities, e. g. tests of rocket engines or explosive experiments. They are also built in order to perform dangerous experiments in them or to store radioactive or explosive goods. Such bunkers also exist on non-military facilities.

Personal

Experts in preparedness for war (such as Cresson Kearny, see below) recommend purchasing and stockpiling the materials for an expedient blast or fallout shelter, and then constructing it only if war appears very likely. A fallout shelter is an enclosed space specially designed to protect occupants from radioactive debris or fallout resulting from a Nuclear explosion. In real wars, such materials almost immediately become unavailable as emergency construction depletes stocks. The storage needed is modest, and the materials are inexpensive in peacetime, and easy to inspect and maintain.

When a house is purpose-built with a bunker, the normal location is a reinforced below-grade bathroom with large cabinets.

Today some vendors provide true bunkers engineered to provide good protection to individual families at modest cost. One common design approach uses fiber-reinforced plastic shells. A fibre-reinforced plastic ( FRP) (also fibre-reinforced polymer) is a Composite material comprising a Polymer matrix reinforced with fibres Compressive protection may be provided by inexpensive earth arching. The overburden is designed to shield from radiation. To prevent the shelter from floating to the surface in high groundwater, some designs have a skirt held-down with the overburden.

Design

Blast protection

Bunkers deflect the blast wave from nearby explosions to prevent ear and internal injuries to people sheltering in the bunker. An explosion is a sudden increase in Volume and release of Energy in an extreme manner usually with the generation of high Temperatures and the release While frame buildings collapse from as little as 3 psi (0. The pound per square inch or more accurately pound-force per square inch (symbol psi or lbf/in² or lbf/in²) is a unit of 2 bar) of overpressure, bunkers are regularly constructed to survive several hundred psi (over 10 bar). The bar (symbol bar) decibar (symbol dbar) and the millibar (symbol mbar, also mb are units of Pressure. Overpressure can mean In Geology: the Pressure regime in a stratigraphic unit that exhibits higher-than- Hydrostatic pressure in This substantially decreases the likelihood that a bomb can harm the structure. A bomb is any of a range of devices that typically rely on the Exothermic Chemical reaction of an Explosive material to produce an extremely

The basic plan is to provide a structure that is very strong in physical compression. Physical compression is the result of the subjection of a material to Compressive stress, resulting in reduction of Volume. The most common purpose-built structure is a buried, steel reinforced concrete vault or arch. Reinforced concrete is Concrete in which reinforcement bars (" Rebars quot or fibers have been incorporated to strengthen a material that would otherwise be A Vault (French voute Italian volta German Gewölbe Polish sklepienie, Spanish An arch is a structure that spans a space while supporting weight (e Most expedient (makeshift) blast shelters are civil engineering structures that contain large buried tubes or pipes such as sewage or rapid transit tunnels. Improvised purpose-built blast shelters normally use earthen arches or vaults. To form these, a narrow (1-2 metre) flexible tent of thin wood is placed in a deep trench (usually the apex is below grade), and then covered with cloth or plastic, and then covered with 1-2 meters of tamped earth.

A large ground shock can move the walls of a bunker several centimeters in a few milliseconds. Bunkers designed for large ground shocks must have sprung internal buildings, hammocks, or bean-bag chairs to protect inhabitants from the walls and floors.

Nuclear protection

Nuclear bunkers must also cope with the underpressure that lasts for several seconds after the shock wave passes, and block radiation. For the music album by Converter see Shock Front For the 1977 horror film see Shock Waves A shock wave (also called Radiation, as in Physics, is Energy in the form of waves or moving Subatomic particles emitted by an atom or other body as it changes from a higher energy Usually these features are easy to provide. The overburden (soil) and structure provide substantial radiation shielding, and the negative pressure is usually only 1/3 of the overpressure. Soil, often typeset as SOiL, is a four piece rock band from Chicago Illinois United States founded by Shaun Glass Tom Schofield Tim King and Adam Zadel

General features

The doors must be at least as strong as the walls. The usual design is a trap-door, to minimize the size and expense. To reduce the weight, the door is normally constructed of steel, with a fitted steel lintel and frame. Very thick wood also serves, and is more resistant to fire because it chars rather than melts. If the door is on the surface and will be exposed to the blast wave, the edge of the door is normally counter-sunk in the frame so that the blast wave or a reflection cannot lift the edge. A bunker should have two doors. Door shafts may double as ventilation shafts to reduce digging.

In bunkers inhabited for prolonged periods, large amounts of ventilation or air conditioning must be provided in order to prevent ill effects of heat. Ventilation is the intentional movement of Air from outside a building to the inside The term air conditioning refers to the cooling and dehumidification of indoor air for Thermal comfort. In bunkers designed for war-time use, manually-operated ventilators must be provided because supplies of electricity or gas are unreliable. One of the most efficient manual ventilator designs is the Kearny Air Pump. The Kearny Air Pump is an expedient Air pump used to ventillate a shelter Ventilation openings in a bunker must be protected by blast valves. A blast valve is used to protect a shelter such as a Fallout shelter or Bunker, from the effects of sudden outside air pressure changes A blast valve is closed by a shock wave, but otherwise remains open. One form of expedient blast valve is tire-treads nailed or bolted to frames strong enough to resist the maximum overpressure.

If a bunker is in a built-up area, it may have to include water-cooling or an immersion tub and breathing tubes to protect inhabitants from fire storms.

Bunkers must also protect the inhabitants from normal weather, including rain, summer heat and winter cold. A normal form of rainproofing is to place plastic film on the bunker's main structure before burying it. Thick (5-mil or 0. 13 mm), inexpensive polyethylene film serves quite well, because the overburden protects it from degradation by wind and sunlight. Polyethylene or polythene ( IUPAC name poly(ethene) is a Thermoplastic commodity heavily used in consumer products (notably the

Famous installations

Famous bunkers include the World War II V-weapon installations in Germany (Mittelwerk), in France (e. Central Works (German Mittelwerk) was the underground WWII rocket and aircraft factory in Germany that was operated by the government Central Works Ltd. g. La Coupole, and Éperlecques) and the Cold War installations in the United States (Cheyenne Mountain, Site R, and The Greenbrier) and Canada (Diefenbunker). La Coupole ("The Cupola" is the name of a World War II Bunker constructed by Nazi Germany in a former Limestone Quarry Éperlecques (Sperleke is a commune in the Pas-de-Calais département in the Nord-Pas-de-Calais region of France. The United States of America —commonly referred to as the Cheyenne Mountain is a mountain located on the southwest side of Colorado Springs Colorado, USA, and is home to the Cheyenne Mountain Air Force Station The Raven Rock Mountain Complex ( RRMC) is a United States government facility on Raven Rock a mountain in the U The Greenbrier is a Mobil four star and AAA Five Diamond Award winning Luxury resort located in the town of White Sulphur Springs in Greenbrier The seven Emergency Government Headquarters (commonly referred to as Diefenbunkers) are Nuclear fallout shelters that were built across Canada at the height The Soviet Union maintained huge bunkers (one of the secondary uses of the very deeply dug Moscow Subway system was as nuclear shelters), and in Albania, Enver Hoxha dotted the country with hundreds of thousands of bunkers. The Union of Soviet Socialist Republics (USSR was a constitutionally Socialist state that existed in Eurasia from 1922 to 1991 The Moscow Metro (Московское метро which spans almost the entire Russian capital, is the world's second most heavily used Rapid-transit This article is about the country in southern Europe For a topic outline on this subject see List of basic Albania topics. (ɛnˈvɛɾ ˈhɔdʒa 16 October 1908 11 April 1985 was the leader of the People's Republic of Albania from the end of World War II until his death in 1985 as the Dictators and potentates like Saddam Hussein often spent massive sums building fortresses beneath their palaces. Saddam Hussein Abd al-Majid al-Tikriti ( Arabic: ar صدام حسين عبد المجيد التكريتي --> April 28 1937 &ndash December 30 Osama bin Laden at one time was also rumoured to be hiding in massive 'underground fortresses' in Tora Bora, though these would only be natural features strengthened and extended to some degree. Osama bin Laden, with some spelling variations is the name used in English to refer to (أسامة بن محمد بن عوض بن لادن born 10 March Tora Bora (Pashto توره بوره “black cellar”) Tora Bora (Pashto توره بوره “black dust”) known locally as Spīn Ghar is a cave complex situated

See also

General topics:

• Air-raid shelter
• Blast shelter
• Blockhouse
• British Field Defences of WWII
• Bunker buster
  • Nuclear bunker buster
• Earth sheltering
• Fallout shelter
• Flak tower
• Hesco bastion
• Observation post
• Martello tower

Specific bunkers:

• Bankstown Bunker, an Australia air defence headquarters bunker in Sydney, Australia
• Burlington, a city-sized bunker beneath Wiltshire, United Kingdom
• Cheyenne Mountain, the underground base of NORAD
• Führerbunker, the Berlin bunker of Adolf Hitler
• World War II line-type bunker systems
  • Atlantic Wall, coasts of Western Europe, built by Nazi Germany during WWII
  • GHQ Line, southern England, built by Great Britain during WWII
  • Maginot Line, eastern France, built by France, pre-WWII
  • Siegfried Line, western Germany, built by Germany during WWI and again pre-WWII
  • Taunton Stop Line, southwest England, built by Great Britain during WWII

References & Notes

• Kearny, Cresson, Nuclear War Survival Skills (1990), ISBN 094248701X (online copy)

External links

• Bunkers or bunker systems:
  • Europe Bunker Pictures (images, locations and information, mainly Atlantikwall, also some about Cold War structures)
  • Europe WW2 bunkers in Europe (reference website about museums and sites of WW2 pillboxes, bunkers and other defensive structures with maps and photos)
  • Great Britain Coastal Defences North Norfolk (image collection of WW2 coastal defences)
  • Great Britain Pillboxes UK (reference website about WW2 pillboxes and other defensive structures)
  • Great Britain UK Heritage: Pillboxes (short article about "Miniature modern castles")
  • Great Britain Subterranea Britannica: Cold War (information on Cold War-era underground structures in Britain)
  • Italy Some [German] Fortifications Observed in Italy (a WWII intelligence Intelligence Bulletin report including photos)

The Atlantikwall ( English: Atlantic wall) was an extensive system of coastal fortifications built by the German Third Reich Cold War is the state of conflict tension and competition that existed between the United States and the Soviet Union (USSR and their respective allies from the Cold War is the state of conflict tension and competition that existed between the United States and the Soviet Union (USSR and their respective allies from the

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