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Aqueduct Bridge (Potomac River)
The Aqueduct Bridge, also called the Alexandria Aqueduct, was a bridge that carried traffic between the Georgetown (Washington, D.C.), Georgetown neighborhood of Washington, D.C. and Rosslyn, Virginia. The bridge existed from 1843 to 1923. It was built to transport cargo-carrying boats on the Chesapeake and Ohio Canal in Georgetown across the Potomac River to the Alexandria Canal (Virginia), Alexandria Canal. The same eight pier (architecture), piers supported two bridges: a wooden water bridge, canal bridge and an iron truss bridge carrying a roadway and an tram, electric trolley line. The canal was later topped with a wooden roadway bridge. The bridge was closed in 1923 after the construction of the nearby Key Bridge (Washington, D.C.), Key Bridge, and demolished in 1933. One arched stone abutment on the Georgetown (north) end survives; it is overseen by the National Park Service as an historic site. History First bridge In 1830, merchants from Alexandria, Virginia, which ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Potomac River
The Potomac River () is in the Mid-Atlantic (United States), Mid-Atlantic region of the United States and flows from the Potomac Highlands in West Virginia to Chesapeake Bay in Maryland. It is long,U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map. Retrieved August 15, 2011 with a Drainage basin, drainage area of , and is the fourth-largest river along the East Coast of the United States. More than 6 million people live within its drainage basin, watershed. The river forms part of the borders between Maryland and Washington, D.C., on the left descending bank, and West Virginia and Virginia on the right descending bank. Except for a small portion of its headwaters in West Virginia, the #North Branch Potomac River, North Branch Potomac River is considered part of Maryland to the low-water mark on the opposite bank. The South Branch Potomac River lies completely within the state of West Virginia except for its headwaters, which lie i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Queen-post
A queen post is a tension member in a truss that can span longer openings than a king post truss. A king post uses one central supporting post, whereas the queen post truss uses two. Even though it is a tension member, rather than a compression member, they are commonly still called a post. A queen post is often confused with a queen strut, one of two compression members in roof framing which do not form a truss in the engineering sense. The double punch truss appeared in Central Europe during the Renaissance. Architecture A queen-post bridge has two uprights, placed about one-third of the way from each end of the truss. They are connected across the top by a beam and use a diagonal brace between the outer edges. The central square between the two verticals is either unbraced (on shorter spans), or has one or two diagonal braces for rigidity. A single diagonal reaches between opposite corners; two diagonal braces may either reach from the bottom of each upright post to the ce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Washington And Old Dominion Railroad
The Washington and Old Dominion Railroad (colloquially referred to as the W&OD) was an intrastate short-line railroad located in Northern Virginia, United States. The rail transport, railroad was a successor to the bankruptcy, bankrupt Washington and Old Dominion Railway and to several earlier railroads, the first of which began operating in 1859. The railroad closed in 1968. The Railroad's oldest line extended from Alexandria, Virginia, Alexandria on the Potomac River northwest to Bluemont, Virginia, Bluemont at the base of the Blue Ridge Mountains near Snickers Gap, not far from the boundary line between Virginia and West Virginia. The railroad's route largely paralleled the routes of the Potomac River and the present Virginia State Route 7. The single-tracked line followed the winding course of Four Mile Run upstream from Alexandria through Arlington County, Virginia, Arlington County to Falls Church, Virginia, Falls Church. At that point, the railroad was above the Atlantic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cantilever
A cantilever is a rigid structural element that extends horizontally and is unsupported at one end. Typically it extends from a flat vertical surface such as a wall, to which it must be firmly attached. Like other structural elements, a cantilever can be formed as a beam, plate, truss, or slab. When subjected to a structural load at its far, unsupported end, the cantilever carries the load to the support where it applies a shear stress and a bending moment. Cantilever construction allows overhanging structures without additional support. In bridges, towers, and buildings Cantilevers are widely found in construction, notably in cantilever bridges and balconies (see corbel). In cantilever bridges, the cantilevers are usually built as pairs, with each cantilever used to support one end of a central section. The Forth Bridge in Scotland is an example of a cantilever truss bridge. A cantilever in a traditionally timber framed building is called a jetty or forebay. In the sou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Great Falls And Old Dominion Railroad
The Great Falls and Old Dominion Railroad (GF&OD) was an interurban trolley line that ran in Northern Virginia during the early 20th century. History Chartered in 1900 by a group of local landowners and acquired in 1902 by John Roll McLean (owner of ''The Washington Post'') and Senator Stephen Benton Elkins, the 15-mile electrified railroad began operating from Georgetown in Washington, D.C., in 1906. The first trial run was in March 1906, but only went as far as Difficult Run and the first scheduled car reached Great Falls Park in Fairfax County, Virginia, on July 3 of that year. They laid a second track in 1908. From Georgetown, the railroad crossed the Potomac River on a superstructure built on the upstream side of the old Aqueduct Bridge to Rosslyn in Arlington, where it made connections with an older electric trolley line, the Washington, Arlington & Falls Church Railway (see Northern Virginia trolleys). From Rosslyn, the railroad traveled northwest along the north si ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Baltimore And Ohio Railroad
The Baltimore and Ohio Railroad was the oldest railroads in North America, oldest railroad in the United States and the first steam engine, steam-operated common carrier. Construction of the line began in 1828, and it operated as B&O from 1830 until 1987, when it was merged into the Chessie System. Its lines are today controlled by CSX Transportation. Founded to serve merchants from Baltimore who wanted to do business with settlers crossing the Appalachian Mountains, the railroad competed with several existing and proposed Central Avenue (Albany, New York), turnpikes and canals, including the Erie Canal, Erie and Chesapeake and Ohio Canal. The railroad began operation in 1830 on a 13-mile line between Baltimore and Ellicott City, Maryland, Elliot's Mill in Maryland. Horse-drawn cars were replaced by steam locomotives the following year. Over the following decades, construction continued westward. During the American Civil War, the railroad sustained much damage but proved cru ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Georgetown Branch
The Metropolitan Subdivision is a railroad line owned and operated by CSX Transportation in Washington, D.C. and Maryland. The 53-mile line runs from Washington, D.C., northwest to Weverton, Maryland, along the former Metropolitan Branch of the Baltimore and Ohio Railroad, opened in 1873.CSX Transportation"Northern Region, Baltimore Division, Timetable No. 4." Effective 2005-01-01. At its southeast end, north of Washington Union Station, the Metropolitan Subdivision meets the Capital Subdivision (formerly the B&O's Washington Branch) and Amtrak's Northeast Corridor. It meets the Old Main Line Subdivision at Point of Rocks, Maryland. At its northwest end, at Weverton, the line joins the Cumberland Subdivision. MARC Train's Brunswick Line uses the entire subdivision, as does Amtrak's ''Capitol Limited''. The electrified tracks of the Red Line of the Washington Metro share the subdivision's right-of-way along two stretches: from the junction with the Capital Subdivision in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States Secretary Of War
The secretary of war was a member of the President of the United States, U.S. president's United States Cabinet, Cabinet, beginning with George Washington's Presidency of George Washington, administration. A similar position, called either "Secretary at War" or "Secretary of War", had been appointed to serve the Congress of the Confederation under the Articles of Confederation between 1781 and 1789. Benjamin Lincoln and later Henry Knox held the position. When Washington was inaugurated as the first President under the United States Constitution, Constitution, he appointed Knox to continue serving as Secretary of War. The secretary of war was the head of the United States Department of War, War Department. At first, he was responsible for all military affairs, including United States Navy, naval affairs. In 1798, the United States Secretary of the Navy, secretary of the Navy was created by statute, and the scope of responsibility for this office was reduced to the affairs of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Potomac Aqueduct Bridge (road)
The Aqueduct Bridge, also called the Alexandria Aqueduct, was a bridge that carried traffic between the Georgetown neighborhood of Washington, D.C. and Rosslyn, Virginia. The bridge existed from 1843 to 1923. It was built to transport cargo-carrying boats on the Chesapeake and Ohio Canal in Georgetown across the Potomac River to the Alexandria Canal. The same eight piers supported two bridges: a wooden canal bridge and an iron truss bridge carrying a roadway and an electric trolley line. The canal was later topped with a wooden roadway bridge. The bridge was closed in 1923 after the construction of the nearby Key Bridge, and demolished in 1933. One arched stone abutment on the Georgetown (north) end survives; it is overseen by the National Park Service as an historic site. History First bridge In 1830, merchants from Alexandria, Virginia, which was still part of the District of Columbia at the time, proposed linking their city to Georgetown to capitalize on the new Chesa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States Army Corps Of Engineers
The United States Army Corps of Engineers (USACE) is the military engineering branch of the United States Army. A direct reporting unit (DRU), it has three primary mission areas: Engineer Regiment, military construction, and civil works. USACE has 37,000 civilian and military personnel, making it one of the world's largest public engineering, design, and construction management agencies. The USACE workforce is approximately 97% civilian, 3% active duty military. The civilian workforce is mainly located in the United States, Europe and in select Middle East office locations. Civilians do not function as active duty military and are not required to be in active war and combat zones; however, volunteer (with pay) opportunities do exist for civilians to do so. The day-to-day activities of the three mission areas are administered by a lieutenant general known as the chief of engineers/commanding general. The chief of engineers commands the Engineer Regiment, comprisi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aqueduct Bridge - C 1900 From Georgetown - Washington DC
Aqueduct may refer to: Structures *Aqueduct (bridge), a bridge to convey water over an obstacle, such as a ravine or valley *Navigable aqueduct, or water bridge, a structure to carry navigable waterway canals over other rivers, valleys, railways or roads *Aqueduct (water supply), a watercourse constructed to convey water **Acequia, a community-operated watercourse used in Spain and former Spanish colonies in the Americas ** Aryk, an artificial channel for redirecting water in Central Asia and other countries ** Elan aqueduct carries water to Birmingham **Levada, an irrigation channel or aqueduct specific to the Portuguese island of Madeira **Puquios, underground water systems in Chile and Peru *Roman aqueduct, water supply systems constructed during the Roman Empire **Aqueduct of Segovia, a Roman aqueduct in Segovia, Spain Anatomy *Cerebral aqueduct in the brain *Vestibular aqueduct in the inner ear Places *Aqueduct, former name of Monolith, California, U.S. *Aqueduct, New Yo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trestle Support
In structural engineering, a trestle support (or simply trestle) is a structural element with rigid Beam (structure), beams forming the equal sides of two parallel isosceles triangles, joined at their Apex (geometry), apices by a Plank (wood), plank or beam. Sometimes additional rungs are stretched between the two beams. A pair of trestle legs can support one or several boards or planks, forming a trestle table or trestle desk. A network of trestle supports can serve as the framework for a trestle bridge, and a trestle of appropriate size to hold wood for sawing is known as a sawhorse. Trestle table A trestle table is a table with trestle legs. In shape and manufacture, it sometimes resembles variations of the antique field desk, which were used by officers close to the battlefield. Trestle legs come in two kinds: *Fixed trestle legs, where the angle between the legs is a fixed joint. *Folding trestle legs, where the angle is hinged, to make them more compact and portable. I ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
