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Wooden Bridge
A timber bridge or wooden bridge is a bridge that uses timber or wood as its principal structural material. One of the first forms of bridge, those of timber have been used since ancient times. History The most ancient form of timber bridge is the log bridge, created by felling a tree over a gap needing to be crossed. Among the oldest timber bridges is the Holzbrücke Rapperswil-Hurden crossing upper Lake Zürich in Switzerland; the prehistoric timber piles discovered to the west of the Seedamm date back to 1523 B.C. The first wooden footbridge led across Lake Zürich, followed by several reconstructions at least until the late 2nd century AD, when the Roman Empire built a wooden bridge. Between 1358 and 1360, Rudolf IV, Duke of Austria, built a 'new' wooden bridge across the lake that was used until 1878 – measuring approximately in length and wide. On April 6, 2001, the reconstructed wooden footbridge was opened, being the longest wooden bridge in Switzerland. The Kapell ... [...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] |
Reuss (river)
The Reuss (Swiss German: ''Rüüss'') is a river in Switzerland. With a length of and a drainage basin of , it is the fourth largest river in Switzerland (after the Rhine, Aare and Rhône). The upper Reuss forms the main valley of the canton of Uri. The course of the lower Reuss runs from Lake Lucerne to the confluence with the Aare at Brugg and Windisch. The Reuss is one of the four major rivers taking their source in the Gotthard region, along with the Rhine, Ticino and Rhône. Geography Course The Gotthardreuss rises in the Gotthard massif, emerging from Lago di Lucendro (reservoir built in 1947; elevation 2,131 m) in the canton of Ticino and passing into the canton of Uri below the ''Brigghubel'' (1,898 m). The Furkareuss rises east of Furka Pass (2,429 m), early joined by the ''Blaubergbach'' (sourced by two mountain lakes on 2,649 m) and several other creeks sourced by still existing glaciers, such as ''Sidelengletscher'' (3,170 m) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
UNESCO
The United Nations Educational, Scientific and Cultural Organization is a specialized agency of the United Nations (UN) aimed at promoting world peace and security through international cooperation in education, arts, sciences and culture. It has 193 member states and 12 associate members, as well as partners in the non-governmental, intergovernmental and private sector. Headquartered at the World Heritage Centre in Paris, France, UNESCO has 53 regional field offices and 199 national commissions that facilitate its global mandate. UNESCO was founded in 1945 as the successor to the League of Nations's International Committee on Intellectual Cooperation.English summary). Its constitution establishes the agency's goals, governing structure, and operating framework. UNESCO's founding mission, which was shaped by the Second World War, is to advance peace, sustainable development and human rights by facilitating collaboration and dialogue among nations. It pursues this objective t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Timber Framing
Timber framing (german: Holzfachwerk) and "post-and-beam" construction are traditional methods of building with heavy timbers, creating structures using squared-off and carefully fitted and joined timbers with joints secured by large wooden pegs. If the structural frame of load-bearing timber is left exposed on the exterior of the building it may be referred to as half-timbered, and in many cases the infill between timbers will be used for decorative effect. The country most known for this kind of architecture is Germany, where timber-framed houses are spread all over the country. The method comes from working directly from logs and trees rather than pre-cut dimensional lumber. Hewing this with broadaxes, adzes, and draw knives and using hand-powered braces and augers (brace and bit) and other woodworking tools, artisans or framers could gradually assemble a building. Since this building method has been used for thousands of years in many parts of the world, many styles ... [...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 beams forming the equal sides of two parallel isosceles triangles, joined at their apices by a 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. In the United States, a table or desk supported b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bent (structural)
A bent in American English is a transverse rigid frame (or similar structures such as three-hinged arches). Historically, bents were a common way of making a timber frame; they are still often used for such, and are also seen in small steel-frame buildings, where the term portal frame is more commonly used. The term is also used for the cross-ways support structures in a trestle. In British English this assembly is called a "cross frame". The term ''bent'' is probably an archaic past tense of the verb ''to bind'', referring to the way the timbers of a bent are joined together. The Dutch word is ''bint'' (past participle ''gebint''), the West Frisian is , and the German is . Compare this with the term bend for a class of knots. Bents are the building blocks that define the overall shape and character of a structure. They do not have any sort of pre-defined configuration in the way that a Pratt truss does. Rather, bents are simply cross-sectional templates of structural members, i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Abutment
An abutment is the substructure at the ends of a bridge span or dam supporting its superstructure. Single-span bridges have abutments at each end which provide vertical and lateral support for the span, as well as acting as retaining walls to resist lateral movement of the earthen fill of the bridge approach. Multi-span bridges require piers to support ends of spans unsupported by abutments. Dam abutments are generally the sides of a valley or gorge, but may be artificial in order to support arch dams such as Kurobe Dam in Japan. The civil engineering term may also refer to the structure supporting one side of an arch, or masonry used to resist the lateral forces of a vault.Pevsner, N. (1970) ''Cornwall''; 2nd ed. Harmondsworth: Penguin; p. 245 The impost or abacus of a column in classical architecture may also serve as an abutment to an arch. The word derives from the verb "abut", meaning to "touch by means of a mutual border". Use in engineering An abutment may be us ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Virginia Tech
Virginia Tech (formally the Virginia Polytechnic Institute and State University and informally VT, or VPI) is a Public university, public Land-grant college, land-grant research university with its main campus in Blacksburg, Virginia. It also has educational facilities in six regions statewide, a research center in Punta Cana, Dominican Republic, and a study-abroad site in Riva San Vitale, Switzerland. Through its Virginia Tech Corps of Cadets, Corps of Cadets Reserve Officers' Training Corps, ROTC program, Virginia Tech is a United States Senior Military College, senior military college. Virginia Tech offers 280 undergraduate and graduate degree programs to some 34,400 students; as of 2015, it was the state's second-largest public university by enrollment. It manages a research portfolio of $522 million, placing it among the top 50 universities in the U.S. for total research expenditures, top 25 in computer and information sciences and top 10 in engineering, with the latter t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stringer 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 are t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
US Forest Service
The United States Forest Service (USFS) is an agency of the U.S. Department of Agriculture that administers the nation's 154 national forests and 20 national grasslands. The Forest Service manages of land. Major divisions of the agency include the Chief's Office, National Forest System, State and Private Forestry, Business Operations, and Research and Development. The agency manages about 25% of federal lands and is the only major national land management agency not part of the U.S. Department of the Interior, which manages the National Park Service, the U.S. Fish and Wildlife Service, and the Bureau of Land Management. History The concept of national forests was born from Theodore Roosevelt's conservation group, Boone and Crockett Club, due to concerns regarding Yellowstone National Park beginning as early as 1875. In 1876, Congress formed the office of Special Agent in the Department of Agriculture to assess the quality and conditions of forests in the United States. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Covered Bridge
A covered bridge is a timber-truss bridge with a roof, decking, and siding, which in most covered bridges create an almost complete enclosure. The purpose of the covering is to protect the wooden structural members from the weather. Uncovered wooden bridges typically have a lifespan of only 20 years because of the effects of rain and sun, but a covered bridge could last over 100 years. In the United States, only about 1 in 10 survived the 20th century. The relatively small number of surviving bridges is due to deliberate replacement, neglect, and the high cost of restoration. European and North American truss bridges Typically, covered bridges are structures with longitudinal timber-trusses which form the bridge's backbone. Some were built as railway bridges, using very heavy timbers and doubled up lattice work. In Canada and the U.S., numerous timber covered bridges were built in the late 1700s to the late 1800s, reminiscent of earlier designs in Germany and Switzerland. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
US Congress
The United States Congress is the legislature of the federal government of the United States. It is bicameral, composed of a lower body, the House of Representatives, and an upper body, the Senate. It meets in the U.S. Capitol in Washington, D.C. Senators and representatives are chosen through direct election, though vacancies in the Senate may be filled by a governor's appointment. Congress has 535 voting members: 100 senators and 435 representatives. The U.S. vice president has a vote in the Senate only when senators are evenly divided. The House of Representatives has six non-voting members. The sitting of a Congress is for a two-year term, at present, beginning every other January. Elections are held every even-numbered year on Election Day. The members of the House of Representatives are elected for the two-year term of a Congress. The Reapportionment Act of 1929 establishes that there be 435 representatives and the Uniform Congressional Redistricting Act requires tha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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