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Guthrie Rolling Bridge
A Guthrie rolling bridge was a kind of retractable bridge, an 18th-century version of the drawbridge. It was commonly installed as the access across the narrow steep sided ditches characteristic of the polygonal forts of this era. Rolling bridges were unhinged, and remained horizontal as they were retracted within the gates of a fortification, similar in operation to a modern thrust bridge. Running the bridge out Running the bridge out is effected by pushing it along its rails until the outer two wheels are at the edge of the granite sill of the ditch. When the bridge is pushed beyond this point the two outer wheels do not descend the slopes of the granite slabs but instead the bridge remains in a horizontal position. This is due to the centre axle being offset from the centre of the girders causing the bridge to run on its inner two wheels. The middle two wheels follow along the trays. When the bridge is just less than halfway out, the ends of the centre axle then engage in th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bascule Bridge
A bascule bridge (also referred to as a drawbridge or a lifting bridge) is a moveable bridge with a counterweight that continuously balances a span, or leaf, throughout its upward swing to provide clearance for boat traffic. It may be single- or double-leafed. The name comes from the French term for balance scale, which employs the same principle. Bascule bridges are the most common type of movable span because they open quickly and require relatively little energy to operate, while providing the possibility for unlimited vertical clearance for marine traffic. History Bascule bridges have been in use since ancient times, but until the adoption of steam power in the 1850s, very long, heavy spans could not be moved quickly enough for practical application. Types There are three types of bascule bridge and the counterweights to the span may be located above or below the bridge deck. The fixed-trunnion (sometimes a "Chicago" bascule) rotates around a large axle that raises the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nelson Guthrie Bridge
Nelson may refer to: Arts and entertainment * ''Nelson'' (1918 film), a historical film directed by Maurice Elvey * ''Nelson'' (1926 film), a historical film directed by Walter Summers * ''Nelson'' (opera), an opera by Lennox Berkeley to a libretto by Alan Pryce-Jones * Nelson (band), an American rock band * ''Nelson'', a 2010 album by Paolo Conte People * Nelson (surname), including a list of people with the name * Nelson (given name), including a list of people with the name * Horatio Nelson, 1st Viscount Nelson (1758–1805), British admiral * Nelson Mandela, the first black South African president Fictional characters * Alice Nelson, the housekeeper on the TV series ''The Brady Bunch'' * Dave Nelson, a main character on the TV series ''NewsRadio'' * Emma Nelson, on the TV series ''Degrassi: The Next Generation'' * Foggy Nelson, law partner of Matt Murdock in the Marvel Comic Universe * Greg Nelson, on the American soap opera ''All My Children'' * Harriman Nelson, on the T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Retractable Bridge
A retractable bridge is a type of moveable bridge in which the deck can be rolled or slid backwards to open a gap while traffic crosses, usually a ship on a waterway. This type is sometimes referred to as a thrust bridge. Retractable bridges date back to medieval times. Due to the large dedicated area required for this type of bridge, this design is not common. A retractable design may be considered when the maximum horizontal clearance is required (for example, over a canal). Two remaining examples exist in New York City: the Carroll Street Bridge (built 1889) in Brooklyn, and the Borden Avenue Bridge in Queens. A recent example can be found at Queen Alexandra Dock in Cardiff, Wales, where the bridge is jacked upwards before being rolled on wheels. Helix Bridge at Paddington Basin in London is a more unusual example of the type, consisting of a glass shell supported in a helical steel frame, which rotates as it retracts. The Summer Street Bridge over Fort Point Channel in B ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drawbridge
A drawbridge or draw-bridge is a type of moveable bridge typically at the entrance to a castle or tower surrounded by a moat. In some forms of English, including American English, the word ''drawbridge'' commonly refers to all types of moveable bridges, such as bascule bridges, vertical-lift bridges and swing bridges, but this article concerns the narrower historical definition of the term where the bridge is used in a defensive structure. As used in castles or defensive structures, drawbridges provide access across defensive structures when lowered, but can quickly be raised from within to deny entry to an enemy force. Castle drawbridges Medieval castles were usually defended by a ditch or moat, crossed by a wooden bridge. In early castles the bridge might be designed to be destroyed or removed in the event of an attack, but drawbridges became very common. A typical arrangement would have the drawbridge immediately outside a gatehouse, consisting of a wooden deck with one ed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polygonal Fort
A polygonal fort is a type of fortification originating in France in the late 18th century and fully developed in Germany in the first half of the 19th century. Unlike earlier forts, polygonal forts had no bastions, which had proved to be vulnerable. As part of ring fortresses, polygonal forts were generally arranged in a ring around the place they were intended to protect, so that each fort could support its neighbours. The concept of the polygonal fort proved to be adaptable to improvements in the artillery which might be used against them, and they continued to be built and rebuilt well into the 20th century. Bastion system deficiencies The bastion system of fortification had dominated military thinking since its introduction in 16th century Italy, until the first decades of the 19th century. The French engineer Sébastien Le Prestre de Vauban, also devised an effective method to defeat them. Before Vauban, besiegers had driven a sap towards the fort, until they reached the gl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thrust Bridge
A retractable bridge is a type of moveable bridge in which the deck can be rolled or slid backwards to open a gap while traffic crosses, usually a ship on a waterway. This type is sometimes referred to as a thrust bridge. Retractable bridges date back to medieval times. Due to the large dedicated area required for this type of bridge, this design is not common. A retractable design may be considered when the maximum horizontal clearance is required (for example, over a canal). Two remaining examples exist in New York City: the Carroll Street Bridge (built 1889) in Brooklyn, and the Borden Avenue Bridge in Queens. A recent example can be found at Queen Alexandra Dock in Cardiff, Wales, where the bridge is jacked upwards before being rolled on wheels. Helix Bridge at Paddington Basin in London is a more unusual example of the type, consisting of a glass shell supported in a helical steel frame, which rotates as it retracts. The Summer Street Bridge over Fort Point Channel in Bo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Guthrie Bridge
Guthrie may refer to: People * Guthrie (surname), a family name originating in Scotland * Guthrie baronets in the United Kingdom * Clan Guthrie, a Scottish clan * Guthrie Govan (born 1971), British guitar virtuoso and guitar teacher Places * Hundred of Guthrie, County of Way, South Australia * Guthrie, Ontario, Canada * Guthrie, Angus, Scotland United States * Guthrie, Arizona * Guthrie, Illinois * Guthrie, Indiana * Guthrie, Kentucky * Guthrie, Michigan * Guthrie, Missouri * Guthrie, Oklahoma * Guthrie, Texas * Guthrie, West Virginia * Guthrie, Wisconsin * Guthrie County, Iowa * Guthrie Township, Hubbard County, Minnesota Other * Guthrie (company), a Malaysian plantation company * Guthrie test, a medical test performed on newborn infants to detect phenylketonuria * Guthrie Theater The Guthrie Theater, founded in 1963, is a center for theater performance, production, education, and professional training in Minneapolis, Minnesota. The concept of the theater was born in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fort Nelson, Portsmouth
Fort Nelson, in the civil parish of Boarhunt in the English county of Hampshire, is one of five defensive forts built on the summit of Portsdown Hill in the 1860s, overlooking the important naval base of Portsmouth. It is now part of the Royal Armouries, housing their collection of artillery, and a Grade I Listed Building. Description Fort Nelson is a typical Polygonal or Palmerston Fort. It is six-sided with a deep ditch protected by three caponiers. Above each caponier is a well-protected emplacement for 13-inch mortars. It was originally entered by two Guthrie rolling bridges and has a barrack block for 172 officers and other ranks, protected by a V-shaped redan. A large open parade ground gives access to the magazines 40 feet underneath it. There are open emplacements on the ramparts for 64 pounder rifled muzzle-loading guns and RML 6.6-inch howitzers. There are also three Haxo casemates for 7 inch rifled breech-loaders. The Nelson Monument, which gave the fort its nam ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United Kingdom
The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the continental mainland. It comprises England, Scotland, Wales and Northern Ireland. The United Kingdom includes the island of Great Britain, the north-eastern part of the island of Ireland, and many smaller islands within the British Isles. Northern Ireland shares a land border with the Republic of Ireland; otherwise, the United Kingdom is surrounded by the Atlantic Ocean, the North Sea, the English Channel, the Celtic Sea and the Irish Sea. The total area of the United Kingdom is , with an estimated 2020 population of more than 67 million people. The United Kingdom has evolved from a series of annexations, unions and separations of constituent countries over several hundred years. The Treaty of Union between the Kingdom of England (which included Wales, annexed in 1542) and the Kingdom of Scotland in 170 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cambridge Battery
Cambridge Battery ( mt, Batterija ta' Cambridge) is a Victorian-era battery in Sliema, Malta. It is commonly referred to as Fort Cambridge ( mt, Forti Cambridge), although it was never classified as a fort while in use. It originally contained an Armstrong 100-ton gun. History Cambridge Battery was built by the British between 1878 and 1886 above the shore west of the mouth of Grand Harbour, between Sliema Point Battery and Fort Tigné. Construction started on 28 August 1878, and the gate was built in 1880. The battery was completed on 27 November 1886, and construction had cost some £18,819. The battery was built to contain a single Armstrong 100-ton gun: a 450 mm rifled muzzle-loading (RML) gun made by Elswick Ordnance Company, the armaments division of the British manufacturing company Armstrong Whitworth. The battery was paired with Rinella Battery near Kalkara, east of Grand Harbour. The British installed a second pair of 100-ton guns to defend Gibraltar, mount ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rinella Battery
The Rinella Battery ( mt, Batterija ta' Rinella) is a Victorian battery in Kalkara, Malta Malta ( , , ), officially the Republic of Malta ( mt, Repubblika ta' Malta ), is an island country in the Mediterranean Sea. It consists of an archipelago, between Italy and Libya, and is often considered a part of Southern Europe. It lies .... It is commonly referred to as Fort Rinella ( mt, Forti Rinella), although it was never classified as a fort while in use. It was armed with an Armstrong Whitworth, Armstrong 100-ton gun, which survives; the only other surviving gun is at the Napier of Magdala Battery, Gibraltar. Description The Rinella Battery was modestly sized, being designed to operate the single large gun. The fortifications were simple - ditches, caponiers, a counter-scarp gallery and firing points - and designed for infantry; there is no secondary armament. The battery's low profile and subterranean Magazine (artillery), magazine and machinery spaces were protective me ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Moveable Bridge
A moveable bridge, or movable bridge, is a bridge that moves to allow passage for boats or barges. In American English, the term is synonymous with , and the latter is the common term, but drawbridge can be limited to the narrower, historical definition used in some other forms of English, in which ''drawbridge'' refers to only a specific type of moveable bridge often found in castles . An advantage of making bridges moveable is the lower cost, due to the absence of high piers and long approaches. The principal disadvantage is that the traffic on the bridge must be halted when it is opened for passage of traffic on the waterway. For seldom-used railroad bridges over busy channels, the bridge may be left open and then closed for train passages. For small bridges, bridge movement may be enabled without the need for an engine. Some bridges are operated by the users, especially those with a boat, others by a bridgeman (or bridge tender); a few are remotely controlled using video-cam ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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