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Box-girder Bridge
A box girder bridge, or box section bridge, is a bridge in which the main beams comprise girders in the shape of a hollow box. The box girder normally comprises prestressed concrete, structural steel, or a composite of steel and reinforced concrete. The box is typically rectangular or trapezoidal in cross-section. Box girder bridges are commonly used for highway flyovers and for modern elevated structures of light rail transport. Although the box girder bridge is normally a form of beam bridge, box girders may also be used on cable-stayed and other bridges. Development of steel box girders In 1919, Major Gifford Martel was appointed head of the Experimental Bridging Establishment at Christchurch, Hampshire, which researched the possibilities of using tanks for battlefield engineering purposes such as bridge-laying and mine-clearing. Here he continued trials on modified Mark V tanks. The bridging component involved an assault bridge, designed by Major Charles I ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Richmond, British Columbia
Richmond is a coastal city in the Lower Mainland region of British Columbia, Canada. It occupies almost the entirety of Lulu Island (excluding Queensborough), between the two estuarine distributaries of the Fraser River. Encompassing the adjacent Sea Island (where the Vancouver International Airport is located) and several other smaller islands and uninhabited islets to its north and south, it neighbours Vancouver and Burnaby on the Burrard Peninsula to the north, New Westminster and Annacis Island to the east, Delta to the south, and the Strait of Georgia to the west. The Coast Salish peoples were the first people to inhabit the area of Richmond, with the Musqueam Band naming the site near Terra Nova "spələkʷəqs" or "boiling point". As a member municipality of Metro Vancouver, Richmond is composed of eight local neighbourhoods: Sea Island, City Centre, Thompson, West Richmond, Steveston, South Arm, East Richmond and Hamilton. As of 2022, the city has an estimated pop ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Composite Material
A composite material (also called a composition material or shortened to composite, which is the common name) is a material which is produced from two or more constituent materials. These constituent materials have notably dissimilar chemical or physical properties and are merged to create a material with properties unlike the individual elements. Within the finished structure, the individual elements remain separate and distinct, distinguishing composites from mixtures and solid solutions. Typical engineered composite materials include: *Reinforced concrete and masonry *Composite wood such as plywood *Reinforced plastics, such as fibre-reinforced polymer or fiberglass *Ceramic matrix composites ( composite ceramic and metal matrices) *Metal matrix composites *and other advanced composite materials There are various reasons where new material can be favoured. Typical examples include materials which are less expensive, lighter, stronger or more durable when compared with commo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
British Heavy Tanks Of World War I
British heavy tanks were a series of related armoured fighting vehicles developed by the UK during the First World War. The Mark I was the world's first tank, a tracked, armed, and armoured vehicle, to enter combat. The name "tank" was initially a code name to maintain secrecy and disguise its true purpose by making it appear to be a water transport vehicle for bringing water to the troops at the front line. The tank was developed in 1915 to break the stalemate of trench warfare. It could survive the machine gun and small-arms fire in "no man's land", travel over difficult terrain, crush barbed wire, and cross trenches to assault fortified enemy positions with powerful armament. Tanks also carried supplies and troops. British heavy tanks are distinguished by an unusual rhomboidal shape with a high climbing face of the track, designed to cross the wide and deep trenches prevalent on the battlefields of the Western Front. Due to the height necessary for this shape, an armed turr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Land Mine
A land mine is an explosive device concealed under or on the ground and designed to destroy or disable enemy targets, ranging from combatants to vehicles and tanks, as they pass over or near it. Such a device is typically detonated automatically by way of pressure when a target steps on it or drives over it, although other detonation mechanisms are also sometimes used. A land mine may cause damage by direct blast effect, by fragments that are thrown by the blast, or by both. Landmines are typically laid throughout an area, creating a ''minefield'' which is dangerous to cross. The use of land mines is controversial because of their potential as indiscriminate weapons. They can remain dangerous many years after a conflict has ended, harming civilians and the economy. Seventy-eight countries are contaminated with land mines and 15,000–20,000 people are killed every year while many more are injured. Approximately 80% of land mine casualties are civilians, with children as the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Christchurch, Hampshire
Christchurch () is a town and civil parish in Dorset on the south coast of England. The town had a population of 31,372 in 2021. For the borough the population was 48,368. It adjoins Bournemouth to the west, with the New Forest to the east. Part of the historic county of Hampshire, Christchurch was a borough within the administrative county of Dorset from 1974 until 2019, when it became part of the new Bournemouth, Christchurch and Poole unitary authority. Founded in the seventh century at the confluence of the rivers Avon and Stour which flow into Christchurch Harbour, the town was originally named Twynham but became known as Christchurch following the construction of the priory in 1094. The town developed into an important trading port, and was fortified in the 9th century. Further defences were added in the 12th century with the construction of a castle, which was destroyed during the English Civil War by the Parliamentarian Army. During the 18th and 19th centuries smugglin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Giffard Le Quesne Martel
Lieutenant-General Sir Giffard Le Quesne Martel (10 October 1889 – 3 September 1958) was a British Army officer who served in both the First and Second World Wars. Familiarly known as "Q Martel" or just "Q", he was a pioneering British military engineer and tank strategist. Early life and military career Born into a traditional military family he was the son of Brigadier-General Sir Charles Philip Martel who was Chief Superintendent of Ordnance Factories. He married Maud Mackenzie on 29 July 1922 and they had one son. Martel entered the Royal Military Academy, Woolwich in 1908 and was commissioned as a second lieutenant into the British Army's Royal Engineers on 23 July 1909. Martel was instrumental in the establishment of The Royal Navy and Army Boxing Association in 1911 and was Army and Inter Services boxing champion both before and after World War I. First World War During the First World War, in 1916, as a sapper officer with direct experience of the first British use ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Major (United Kingdom)
Major (Maj) is a military rank which is used by both the British Army and Royal Marines. The rank is superior to captain and subordinate to lieutenant colonel. The insignia for a major is a crown. The equivalent rank in the Royal Navy is lieutenant commander, and squadron leader in the Royal Air Force. History By the time of the Napoleonic wars, an infantry battalion usually had two majors, designated the "senior major" and the "junior major". The senior major effectively acted as second-in-command and the majors often commanded detachments of two or more companies split from the main body. The second-in-command of a battalion or regiment is still a major. File:British-Army-Maj(1856-1867)-Collar Insignia.svg, 1856 to 1867 major's collar rank insignia File:British-Army-Maj(1867-1880)-Collar Insignia.svg, 1867 to 1880 major's collar rank insignia File:British&Empire-Army-Maj(1881-1902).svg, 1881 to 1902 major's shoulder rank insignia During World War I, majors wore the follo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cable-stayed Bridge
A cable-stayed bridge has one or more ''towers'' (or ''pylons''), from which cables support the bridge deck. A distinctive feature are the cables or stays, which run directly from the tower to the deck, normally forming a fan-like pattern or a series of parallel lines. This is in contrast to the modern suspension bridge, where the cables supporting the deck are suspended vertically from the main cable, anchored at both ends of the bridge and running between the towers. The cable-stayed bridge is optimal for spans longer than cantilever bridges and shorter than suspension bridges. This is the range within which cantilever bridges would rapidly grow heavier, and suspension bridge cabling would be more costly. Cable-stayed bridges were being designed and constructed by the late 16th century, and the form found wide use in the late 19th century. Early examples, including the Brooklyn Bridge, often combined features from both the cable-stayed and suspension designs. Cable-stayed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beam Bridge
Beam bridges are the simplest structural forms for bridge spans supported by an abutment or pier at each end. No moments are transferred throughout the support, hence their structural type is known as '' simply supported''. The simplest beam bridge could be a log (see log bridge), a wood plank, or a stone slab (see clapper bridge) laid across a stream. Bridges designed for modern infrastructure will usually be constructed of steel or reinforced concrete, or a combination of both. The concrete elements may be reinforced, prestressed or post-tensioned. Such modern bridges include girder, plate girder, and box girder bridges, all types of beam bridges. Types of construction could include having many beams side by side with a deck across the top of them, to a main beam either side supporting a deck between them. The main beams could be I-beams, trusses, or box girders. They could be half-through, or braced across the top to create a through bridge. Because no moments ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Overpass
An overpass (called an overbridge or flyover in the United Kingdom and some other Commonwealth countries) is a bridge, road, railway or similar structure that crosses over another road or railway. An ''overpass'' and ''underpass'' together form a grade separation. Stack interchanges are made up of several overpasses. History The world's first railroad flyover was constructed in 1843 by the London and Croydon Railway at Norwood Junction railway station to carry its atmospheric railway vehicles over the Brighton Main Line. Highway and road In North American usage, a ''flyover'' is a high-level overpass, built above main overpass lanes, or a bridge built over what had been an at-grade intersection. Traffic engineers usually refer to the latter as a ''grade separation''. A flyover may also be an extra ramp added to an existing interchange, either replacing an existing cloverleaf loop (or being built in place of one) with a higher, faster ramp that eventually bears left, but may b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cross Section (geometry)
In geometry and science, a cross section is the non-empty intersection of a solid body in three-dimensional space with a plane, or the analog in higher-dimensional spaces. Cutting an object into slices creates many parallel cross-sections. The boundary of a cross-section in three-dimensional space that is parallel to two of the axes, that is, parallel to the plane determined by these axes, is sometimes referred to as a contour line; for example, if a plane cuts through mountains of a raised-relief map parallel to the ground, the result is a contour line in two-dimensional space showing points on the surface of the mountains of equal elevation. In technical drawing a cross-section, being a projection of an object onto a plane that intersects it, is a common tool used to depict the internal arrangement of a 3-dimensional object in two dimensions. It is traditionally crosshatched with the style of crosshatching often indicating the types of materials being used. With computed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
