|
Bangabandhu Bridge
Bangabandhu Bridge, also known as the Jamuna Multi-purpose Bridge ( bn, যমুনা বহুমুখী সেতু ''Jomuna Bohumukhi Setu'') is a bridge opened in Bangladesh in June 1998. It connects Bhuapur on the Jamuna River's east bank to Sirajganj on its west bank. It was the 11th longest bridge in the world when constructed in 1998 and at present is the 6th longest bridge in South Asia. The Jamuna River, which it spans, is one of the three major rivers of Bangladesh, and is fifth largest in the world in discharge volume. History of construction The river Jamuna (Brahmaputra), along with the lower stretch of the Padma (Ganges) divides Bangladesh into nearly two equal halves. Until now all road and rail communication between the two parts of the country has had to rely on time-consuming ferry services that were often disrupted because of navigability problems. The need for a bridge over the Jamuna River was felt, especially by the people living in northwestern Ba ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jamuna River (Bangladesh)
The Jamuna River ( bn, যমুনা ''Jomuna'') is one of the three main rivers of Bangladesh. It is the lower stream of the Brahmaputra River, which originates in Tibet as Yarlung Tsangpo, before flowing into India and then southwest into Bangladesh. The Jamuna flows south and joins the Padma River (''Pôdda''), near Goalundo Ghat, before meeting the Meghna River near Chandpur. It then flows into the Bay of Bengal as the Meghna River. The Brahmaputra-Jamuna is a classic example of a braided river and is highly susceptible to channel migration and avulsion. It is characterised by a network of interlacing channels with numerous sandbars enclosed between them. The sandbars, known in Bengali as ''chars'', do not occupy a permanent position. The river deposits them in one year, very often to be destroyed later, and redeposits them in the next rainy season. The process of bank and deposit erosion together with redeposition has been going on continuously, making it difficult to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Navigability
A body of water, such as a river, canal or lake, is navigable if it is deep, wide and calm enough for a water vessel (e.g. boats) to pass safely. Such a navigable water is called a ''waterway'', and is preferably with few obstructions against direct traverse that needed avoiding, such as Rock (geology), rocks, reefs or trees. Bridges built over waterways must have sufficient air draft, clearance. High discharge (hydrology), flow speed may make a channel (geography), channel unnavigable due to risk of ship collisions. Waters may be unnavigable because of ice, particularly in winter or high-latitude regions. Navigability also depends on context: a small river may be navigable by smaller craft such as a motorboat or a kayak, but unnavigable by a larger cargo ship, freighter or cruise ship. Shallow rivers may be made navigable by the installation of canal locks, locks that regulate flow and increase upstream water level, or by dredging that deepens parts of the stream bed. Inland w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Railway
Rail transport (also known as train transport) is a means of transport that transfers passengers and goods on wheeled vehicles running on rails, which are incorporated in tracks. In contrast to road transport, where the vehicles run on a prepared flat surface, rail vehicles (rolling stock) are directionally guided by the tracks on which they run. Tracks usually consist of steel rails, installed on sleepers (ties) set in ballast, on which the rolling stock, usually fitted with metal wheels, moves. Other variations are also possible, such as "slab track", in which the rails are fastened to a concrete foundation resting on a prepared subsurface. Rolling stock in a rail transport system generally encounters lower frictional resistance than rubber-tyred road vehicles, so passenger and freight cars (carriages and wagons) can be coupled into longer trains. The operation is carried out by a railway company, providing transport between train stations or freight customer facilit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metre Gauge
Metre-gauge railways are narrow-gauge railways with track gauge of or 1 metre. The metre gauge is used in around of tracks around the world. It was used by European colonial powers, such as the French, British and German Empires. In Europe, large metre-gauge networks remain in use in Switzerland, Spain and many European towns with urban trams, but most metre-gauge local railways in France, Germany and Belgium closed down in the mid-20th century, although many still remain. With the revival of urban rail transport, metre-gauge light metros were established in some cities, and in other cities, metre gauge was replaced by standard gauge. The slightly-wider gauge is used in Sofia. Examples of metre-gauge See also * Italian metre gauge * Narrow-gauge railways A narrow-gauge railway (narrow-gauge railroad in the US) is a railway with a track gauge narrower than standard . Most narrow-gauge railways are between and . Since narrow-gauge railways are usually built with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Broad Gauge
A broad-gauge railway is a railway with a track gauge (the distance between the rails) broader than the used by standard-gauge railways. Broad gauge of , commonly known as Russian gauge, is the dominant track gauge in former Soviet Union (CIS states, Baltic states, Georgia and Ukraine), Mongolia and Finland. Broad gauge of , commonly known as Irish Gauge, is the dominant track gauge in Ireland, and the Australian states of Victoria and Adelaide. Broad gauge of , commonly known as Iberian gauge, is the dominant track gauge in Spain and Portugal. Broad gauge of , commonly known as Indian gauge, is the dominant track gauge in India, Pakistan, Bangladesh, Sri Lanka, Argentina, Chile, and on BART (Bay Area Rapid Transit) in the San Francisco Bay Area. This is the widest gauge in common use anywhere in the world. It is possible for trains on both Iberian gauge and Indian gauge to travel on each other's tracks with no modifications in the vast majority of cases. History In Gr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dual Gauge
In railway engineering, "gauge" is the transverse distance between the inner surfaces of the heads of two rails, which for the vast majority of railway lines is the number of rails in place. However, it is sometimes necessary for track to carry railway vehicles with wheels matched to two different gauges. Such track is described as dual gauge – achieved either by addition of a third rail, if it will fit, or by two additional rails. Dual-gauge tracks are more expensive to configure with signals and sidings, and to maintain, than two separate single-gauge tracks. It is therefore usual to build dual-gauge or other multi-gauge tracks only when necessitated by lack of space or when tracks of two different gauges meet in marshalling yards or passenger stations. Dual-gauge tracks are by far the most common configuration, but triple-gauge tracks have been built in some situations. Background The rail gauge is the most fundamental specification of a railway. Rail tracks and whee ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carriageway
A carriageway (British English) or roadway (North American English) consists of a width of road on which a vehicle is not restricted by any physical barriers or separation to move laterally. A carriageway generally consists of a number of traffic lanes together with any associated shoulder, but may be a sole lane in width (for example, a highway offramp). Description A single carriageway road (North American English: undivided highway) has one carriageway with 1, 2 or more lanes together with any associated footways (North American English: sidewalk) and road verges (North American English: tree belt). A dual carriageway road (North American English: divided highway) has two roadways separated by a central reservation (North American English: median). A local-express lane system (also called collector-express or collector-distributor) has more than two roadways, typically two sets of 'local lanes' or 'collector lanes' and also two sets of 'express lanes'. "Cars only" lanes m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bridge
A bridge is a structure built to span a physical obstacle (such as a body of water, valley, road, or rail) without blocking the way underneath. It is constructed for the purpose of providing passage over the obstacle, which is usually something that is otherwise difficult or impossible to cross. There are many different designs of bridges, each serving a particular purpose and applicable to different situations. Designs of bridges vary depending on factors such as the function of the bridge, the nature of the terrain where the bridge is constructed and anchored, and the material used to make it, and the funds available to build it. The earliest bridges were likely made with fallen trees and stepping stones. The Neolithic people built boardwalk bridges across marshland. The Arkadiko Bridge (dating from the 13th century BC, in the Peloponnese) is one of the oldest arch bridges still in existence and use. Etymology The '' Oxford English Dictionary'' traces the origin of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deck (bridge)
A deck is the surface of a bridge. A structural element of its Superstructure#bridge, superstructure, it may be constructed of concrete, steel, grating, open grating, or wood. Sometimes the deck is covered by a track ballast, railroad bed and railroad track, track, asphalt concrete, or other form of pavement (material), pavement for ease of vehicle crossing. A concrete deck may be an integral part of the bridge structure (T-beam or double tee structure) or it may be supported with I-beams or steel girders. When a bridge deck is installed in a through truss, it is sometimes called a floor system. A suspended bridge deck will be suspended from the main structural elements on a suspension or arch bridge. On some bridges, such as a Tied-arch bridge, tied-arch or a Cable-stayed bridge, cable-stayed, the deck is a primary structural element, carrying tension or compression to support the span. A deck bridge is one in which the deck itself is the main structural element, itself carr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Viaducts
A viaduct is a specific type of bridge that consists of a series of arches, piers or columns supporting a long elevated railway or road. Typically a viaduct connects two points of roughly equal elevation, allowing direct overpass across a wide valley, road, river, or other low-lying terrain features and obstacles. The term ''viaduct'' is derived from the Latin ''via'' meaning "road", and ''ducere'' meaning "to lead". It is a 19th-century derivation from an analogy with ancient Roman aqueducts. Like the Roman aqueducts, many early viaducts comprised a series of arches of roughly equal length. Over land The longest in antiquity may have been the Pont Serme which crossed wide marshes in southern France. At its longest point, it measured 2,679 meters with a width of 22 meters. Viaducts are commonly used in many cities that are railroad hubs, such as Chicago, Birmingham, London and Manchester. These viaducts cross the large railroad yards that are needed for freight trains there, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inclined Plane
An inclined plane, also known as a ramp, is a flat supporting surface tilted at an angle from the vertical direction, with one end higher than the other, used as an aid for raising or lowering a load. The inclined plane is one of the six classical simple machines defined by Renaissance scientists. Inclined planes are used to move heavy loads over vertical obstacles. Examples vary from a ramp used to load goods into a truck, to a person walking up a pedestrian ramp, to an automobile or railroad train climbing a grade. Moving an object up an inclined plane requires less force than lifting it straight up, at a cost of an increase in the distance moved. The mechanical advantage of an inclined plane, the factor by which the force is reduced, is equal to the ratio of the length of the sloped surface to the height it spans. Owing to conservation of energy, the same amount of mechanical energy (work) is required to lift a given object by a given vertical distance, disregarding losses ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Span (architecture)
Span is the distance between two intermediate supports for a structure, e.g. a beam (structure), beam or a bridge. A span can be closed by a solid beam or by a rope. The first kind is used for bridges, the second one for power lines, overhead telecommunication lines, some type of Antenna (radio), antennas or for aerial tramways. The span is a significant factor in finding the strength and size of a beam as it determines the maximum bending moment and Deflection (engineering), deflection. The maximum bending moment M_ and deflection \delta_in the pictured beam is found using: :M_ = \frac :\delta_ = \frac = \frac where :q = Uniformly distributed load :L = Length of the beam between two supports (span) :E = Modulus of elasticity :I = Area moment of inertia Note that the maximum bending moment and deflection occur midway between the two supports. From this it follows that if the span is doubled, the maximum moment (and with it the tensile stress, stress) will quadruple, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
_Jamuna_Bridge.JPG "Click for more on -> Bangabandhu Bridge")
_track%2C_South_Australian_Railways.jpg "Click for more on -> Dual Gauge")
