A flume is a human-made channel for water , in the form of an open declined gravity chute whose walls are raised above the surrounding terrain, in contrast to a trench or ditch . Flumes are not to be confused with aqueducts , which are built to transport water; flumes use flowing water to transport materials. Flumes route water from a diversion dam or weir to a desired materiel collection location. Flumes are usually made up of wood , metal or concrete .
16-417: Many flumes took the form of wooden troughs elevated on trestles , often following the natural contours of the land. Originating as a part of a mill race , they were later used in the transportation of logs in the logging industry, known as a log flume . They were also extensively used in hydraulic mining and working placer deposits for gold , tin and other heavy minerals. The term flume comes from
32-416: 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
48-412: A braced frame in timber framing . Historically, mortise and tenon joints were used to joint bents to posts and beams due to the unavailability of nails. Bents are generally pre-assembled, either at the timber framing company's shop or at the construction site. After the basic post and beam structure of the frame has been set in place, the bents are then lifted and simply lowered into place one by one by
64-457: A change in floor elevation, or a combination of the two. Flow measurement flumes typically consist of a converging section, a throat section, and a diverging section. Not all sections, however, need to be present. In the case of the Cutthroat flume , the converging section directly joins the diverging section, resulting in a throat section of no length (hence the term "Cutthroat"). Other flumes omit
80-435: A sawmill, or for various processes in the hydraulic method of gold-mining. A diversionary flume is used to transfer water from one body to another, such as between two reservoirs. Log flumes use the flow of water to carry cut logs and timber downhill, sometimes many miles, to either a sawmill or location for further transport. Some varieties of flumes are used in measuring water flow of a larger channel. When used to measure
96-495: 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.e., rafters, joists, posts, pilings, etc., that repeat on parallel planes along the length of the structure. The term bent is not restricted to any particular material. Bents may be formed of wooden piles, timber framing, steel framing, or even concrete. Traditional timber frame bents were one component of
112-399: 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
128-519: 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 bynt , and the German is bind . Compare this with the term bend for a class of knots. Bents are the building blocks that define the overall shape and character of
144-426: Is usually called a sawbuck table . A trestle bridge is composed of a number of short spans supported by closely spaced trestle frames. Each supporting frame is a bent . A trestle differs from a viaduct in that viaducts have towers that support much longer spans and typically have a higher elevation. Timber and iron trestles (i.e. bridges) were extensively used in the 19th century, particularly for railroads. In
160-401: The level (or pound) above to the level below the lock, so that the level below would have sufficient water. In competitive swimming , specialized flumes with transparent sides are often employed by coaches to analyze a swimmer's technique. The speed of the flow is variable to accommodate the full spectrum of swimming styles and ability. Trestle support In structural engineering ,
176-409: The 21st century, steel and sometimes concrete trestles are occasionally used to bridge particularly deep valleys, while timber trestles remain common in certain areas. Timber trestles remain common in some applications, most notably for bridge approaches crossing floodways , where earth fill would dangerously obstruct floodwater. Many timber trestles were built in the 19th and early 20th centuries with
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#1732848594467192-587: The Old French word flum , from the Latin flumen , meaning a river. It was formerly used for a stream, and particularly for the tail of a mill race . It is used in America for a very narrow gorge running between precipitous rocks, with a stream at the bottom, but more frequently is applied to an artificial channel of wood or other material for the diversion of a stream of water from a river for purposes of irrigation, for running
208-400: The diverging section (Montana, USGS Portable Parshall, and HS / H / HL flumes). Flumes offer distinct advantages over sharp-crested weirs: Styles of flow measurement flumes include: Cutthroat , HS / H / HL-type, Khafagi, Montana , RBC, Parshall , Palmer-Bowlus , Trapezoidal, and Venturi Flume . In some nineteenth-century canals, a bypass flume diverted water around a lift lock from
224-481: The expectation that they would be temporary. Timber trestles were used to get the railroad to its destination. Once the railroad was running, it was used to transport the material to replace trestles with more permanent works, transporting and dumping fill around some trestles and transporting stone or steel to replace others with more permanent bridges. Bent (structural) A bent in American English
240-403: The flow of water in open channels, a flume is defined as a specially shaped, fixed hydraulic structure that under free-flow conditions forces flow to accelerate in such a manner that the flow rate through the flume can be characterized by a level-to-flow relationship as applied to a single head (level) measurement within the flume. Acceleration is accomplished through a convergence of the sidewalls,
256-476: The framework for a trestle bridge , and a trestle of appropriate size to hold wood for sawing is known as a sawhorse . 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: In the United States, a table or desk supported by X-shaped trestles
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