FACTOID # 29: 73.3% of America's gross operating surplus in motion picture and sound recording industries comes from California.
 Home   Encyclopedia   Statistics   States A-Z   Flags   Maps   FAQ   About 


FACTS & STATISTICS    Advanced view

Search encyclopedia, statistics and forums:



(* = Graphable)



Encyclopedia > Pill box

A bunker is a defensive warfare fortification to protect personnel or equipment. In military science, defense (or defence) is the art of preventing an enemy from conquering territory. ... War is a state of widespread conflict between states, organisations, or relatively large groups of people, which is characterised by the use of lethal violence between combatants or upon civilians. ... Nakhal Fort, one of the best-preserved forts in Oman. ...

A bunker is also:
  • a hazard, usually filled with sand, on a golf course.
  • a storage bin or tank for a bulk product, such as coal, fuel oil or wood
  • a marine heavy fuel oil. Deep-sea ships use different grades of "bunker", grades being IFO (International Fuel Oil) 180 or 380.

Bunkers in Albania
Bunkers in Albania

Bunkers are mostly below ground, while a blockhouse is mostly above ground level. They were used extensively in World War I and World War II. In the 1950s, the bunker became part of Americana culture. A famous bunker is the North American Aerospace Defense Command (NORAD). Some installations are giant underground complexes. The Soviet Union maintained huge bunkers during the Cold War. In Albania, Enver Hoxha littered the small country with 500,000 - 700,000 bunkers. Hazard is a term used in evaluating safety: A hazard is a potential unwanted event. ... Golf is a game where individual players or teams hit a ball into a hole using various clubs, and is one of the few ball games that does not use a fixed standard playing area. ... Coal is a fossil fuel extracted from the ground by underground mining or open-pit mining (strip mining). ... A tree trunk as found at the Veluwe, The Netherlands Wood derives from woody plants, notably trees but also shrubs. ... Bunkers in Albania (image under GFDL from Marc Morell used with permission) File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Bunkers in Albania (image under GFDL from Marc Morell used with permission) File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... A 19th-century-era block house in Fort York, Toronto In military science, a blockhouse is a small, isolated fort in the form of a single building. ... Clockwise from top: Trenches in frontline, a British Mark I Tank crossing a trench, the Royal Navy battleship HMS Irresistible sinking after striking a mine at the battle of the Dardanelles, a Vickers machine gun crew with gas masks and a Sopwith Camel biplane. ... Combatants Allied Powers Axis Powers Commanders {{{commander1}}} {{{commander2}}} Strength {{{strength1}}} {{{strength2}}} Casualties 17 million military deaths 7 million military deaths World War II, also known as the Second World War, was a mid-20th century conflict that engulfed much of the globe and is accepted as the largest and deadliest... // Events and trends This map shows two essential global spheres during the Cold War in 1959. ... Popular culture, or pop culture, is the vernacular (peoples) culture that prevails in any given society. ... The word culture, from the Latin colere, with its root meaning to cultivate, generally refers to patterns of human activity and the symbolic structures that give such activity significance. ... The NORAD shield. ... The NORAD shield. ... For the generic term for a high-tension struggle between countries, see cold war (war). ... Enver Hoxha, (IPA , October 16, 1908–April 11, 1985) was the paramount leader of Albania from the end of World War II until his death in 1985, as the First Secretary of the Communist Albanian Party of Labour. ...


Bunkers as part of a trench system

Another type of bunker or blockhouse is a little concrete post, 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). The front bunker of a trench system usually includes machine guns or mortars and form a domainant shooting post. The Rear bunkers are usually used as command posts, for storage and as field hospitals to attend to wounded soldiers. A ditch with water can be used for drainage and irrigation. ... Grenade may refer to: The well-known hand grenade commonly used by soldiers. ... US soldier firing an M224 60-mm mortar. ... A shell is a projectile, which, as opposed to a bullet, is not solid but contains an explosive or other filling, though modern usage includes large projectiles without a filling. ... A machine gun is a fully-automatic firearm that is capable of firing bullets in rapid succession. ... A Command Post is a term, of military origin, referring to a field location from where the person in charge of a situation issues orders. ... A physician visiting the sick in a hospital. ...


A pillbox on the East coast of England. Part of the defences were built during World War II (the railings are a modern addition)
A pillbox on the East coast of England. Part of the defences were built during World War II (the railings are a modern addition)

Dug-in guard posts (with loopholes for firing through) and made from concrete are also known as "pillboxes". The originally jocular name arose from their perceived similarity to the cylindrical boxes in which medicinal pills were once sold. They are in effect a trench firing step hardened to protect against small-arms fire and grenades and raised a little to improve the field of fire. A pillbox on the East coast on England. ... A pillbox on the East coast on England. ...

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. 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. 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. 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. Clockwise from top: Trenches in frontline, a British Mark I Tank crossing a trench, the Royal Navy battleship HMS Irresistible sinking after striking a mine at the battle of the Dardanelles, a Vickers machine gun crew with gas masks and a Sopwith Camel biplane. ... 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 Front in World War I. The Heavy Branch of the MGC were the first to use tanks in combat... 1940 (MCMXL) was a leap year starting on Monday (link will take you to calendar). ... A machine gun is a fully-automatic firearm that is capable of firing bullets in rapid succession. ... The Hindenburg Line was a vast system of defences in Northern France constructed by the Germans during the winter of 1916– 17 during World War I; the Germans called it the Siegfried Line. ... The Oxford English Dictionary (OED) is a comprehensive dictionary published by the Oxford University Press (OUP). ...

Pillboxes are often camouflaged in order to conceal their location and to maximize the element of surprise. 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. Anolis caroliensis showing blending camouflage and counter-shading. ...

Industrial bunker

Typical industrial bunkers include mining sites, food storage areas, dumps for materials, and sometimes living quarters.

Design of Blast-resisting Bunkers

Bunkers deflect the blast wave from nearby explosions to prevent ear and internal injuries to people sheltering in the bunker. While frame buildings collapse from as little as 3 psia of overpressure, bunkers are regularly constructed to survive several hundred psia. This substantially decreases the likelihood that a bomb can harm the structure. Pounds-force per Square Inch (PSI) is a non-SI unit of pressure 1 psi approximately equals 6. ... Overpressure, in geology, is a term used to describe the pressure regime in a stratigraphic unit that exhibits higher-than-hydrostatic pressure in its pore structure. ...

The basic plan is to provide a structure that is very strong in compression. The most common purpose-built structure is a buried, steel-reinforced concrete vault or arch. Most expedient 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. In architecture, a vault is an arched structure of masonry, forming a ceiling or canopy. ... Isometric view of a typical arch An arch is a curved structure capable of spanning a space while supporting significant weight (e. ...

Nuclear bunkers must also cope with the underpressure that lasts for several seconds after the shockwave passes, and prompt radiation. Usually these features are easy to provide. The overburden and structure provide substantial radiation shielding, and the negative pressure is usually only 1/3 of the overpressure.

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 must have two doors. Normally one door is convenient, and the other is strong. Door shafts may double as ventilation shafts to reduce the digging.

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.

Earth is an excellent insulator. In bunkers inhabited for prolonged periods, large amounts of ventilation or air-conditioning must be provided in order to prevent heat prostration. 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".

Ventilation openings in a bunker must be protected by blast valves. A blast valve is closed by a shock wave, but otherwise remains open. One form of expedient blast valve are 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 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), inexpensive polyethylene film serves quite well, because the overburden protects it from degradation by wind and sunlight. Polyethylene or polyethene is a thermoplastic commodity heavily used in consumer products (over 60M tons are produced worldwide every year). ...

Experts in preparedness (Such as Cresson Kearny, see below) for war recommend purchasing and stockpiling the materials for an expedient blast or fallout shelter, and then constructing it only if war appears very likely. In real wars, such materials have almost immediately become unavailable as emergency construction depleted 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.

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. 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. A properly designed, properly installed home shelter does not become a sinkhole in the lawn. Fibre reinforced plastic (FRP) is a composite material comprising a polymer matrix reinforced with fibres usually of glass, carbon, or aramid (and in the case of Duroplast even cotton or wool) and is commonly used in aerospace, automotive and marine industries. ...

See also

One of six Flak towers built during World War II in Vienna. ... The Führerbunker (or Fuehrerbunker) is a common name for a certain complex of subterranean rooms in Berlin, Germany where Adolf Hitler committed suicide during World War II. The bunker was the last of Hitlers Führerhauptquartiere or Fuehrer Headquarters (another was the famous Wolfsschanze). ... A bunker buster bomb is designed to penetrate hardened targets or targets buried deep underground. ... Bunker-busting nuclear weapons are a proposed type of nuclear weapon that would be designed to penetrate into soil, rock or concrete to deliver a low-yield nuclear warhead. ... A sign pointing to an old fallout shelter in New York City. ... Air raid shelters are structures for the protection of the civil population as well as military personnel against enemy attacks from the air. ... The Maginot Line (named after French minister of defense André Maginot) was a line of concrete fortifications, tank obstacles, machine gun posts and other defenses which France constructed along its borders with Germany and with Italy in the wake of World War I. Generally the term describes either the entire... Bunker on the Siegfried line The original Siegfried line was a line of defensive forts and tank defenses built by Germany along their border with France in 1916-1917 during World War I. However, in English, Siegfried line more commonly refers to the similar World War II defensive line, built... German coast artillery in the Pas-de-Calais area, with laborers at work on casemate. ... A pillbox on the GHQ Line The GHQ Line was a defence line built in the United Kingdom during World War II to contain an expected German invasion. ... It has been suggested that Hawthorn, Wiltshire be merged into this article or section. ... Wiltshire (abbreviated Wilts) is a large southern English county. ...


Kearny, Cresson, "Nuclear War Survival Skills"

External links

Wikimedia Commons has media related to:
  • British World War 2 Pillboxes
  • UK Heritage: Pillboxes - "miniature modern castles"
  • Subterranea Britannica Information on Cold War-era underground structures in Britain
  • British World War 2 Pillboxes in Malta
  • German Fortifications Observed in Italy (WWII intelligence report)
  • Image of one of the hochbunker of Vienna
  • Image of the hochbunker of Trier
  • Information on Australian World War 2 Fortifications
  • Bunker Pictures: Pictures, locations, information about bunkers from WW2 and The Atlantikwall



Share your thoughts, questions and commentary here
Your name
Your comments

Want to know more?
Search encyclopedia, statistics and forums:


Press Releases |  Feeds | Contact
The Wikipedia article included on this page is licensed under the GFDL.
Images may be subject to relevant owners' copyright.
All other elements are (c) copyright NationMaster.com 2003-5. All Rights Reserved.
Usage implies agreement with terms, 1022, m