Ancestor | Truss bridge |
---|---|
Related | None |
Descendant | None |
Carries | Pedestrians, livestock, vehicles |
Span range | short to medium |
Material | wood planks |
Movable | No |
Design effort | medium |
Falsework required | Sometimes |
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. [1] 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. [2]
The double punch truss appeared in Central Europe during the Renaissance. [3]
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 center of the upper beam, or form a corner-to-corner "X" inside the square. [4]
A truss is an assembly of members such as beams, connected by nodes, that creates a rigid structure.
Timber framing 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.
A truss bridge is a bridge whose load-bearing superstructure is composed of a truss, a structure of connected elements, usually forming triangular units. The connected elements may be stressed from tension, compression, or sometimes both in response to dynamic loads. The basic types of truss bridges shown in this article have simple designs which could be easily analyzed by 19th and early 20th-century engineers. A truss bridge is economical to construct because it uses materials efficiently.
The Ashtabula River railroad disaster was the failure of a bridge over the Ashtabula River near the town of Ashtabula, Ohio, in the United States on December 29, 1876. A Lake Shore and Michigan Southern Railway train, the Pacific Express, passed over the bridge as it failed. All but the lead locomotive plunged into the river. The train's oil lanterns and coal-fired heating stoves set the wooden cars alight. Firefighters declined to extinguish the flames, leaving individuals to try to pull survivors from the wreck. Many who survived the crash burned to death in the wreckage. The accident killed approximately 92 of the 160 people aboard. It was the worst rail accident in the U.S. in the 19th century and the worst rail accident in U.S. history until the Great Train Wreck of 1918.
A hammerbeam roof is a decorative, open timber roof truss typical of English Gothic architecture and has been called "...the most spectacular endeavour of the English Medieval carpenter". They are traditionally timber framed, using short beams projecting from the wall on which the rafters land, essentially a tie beam which has the middle cut out. These short beams are called hammer-beams and give this truss its name. A hammerbeam roof can have a single, double or false hammerbeam truss.
Framing, in construction, is the fitting together of pieces to give a structure support and shape. Framing materials are usually wood, engineered wood, or structural steel. The alternative to framed construction is generally called mass wall construction, where horizontal layers of stacked materials such as log building, masonry, rammed earth, adobe, etc. are used without framing.
Whites Bridge is a 120-foot-long (37 m) Brown truss covered bridge, originally erected in 1869 in Keene Township, Michigan, United States, near Smyrna on the Flat River. Carrying Whites Bridge Road across the Flat River, it is located north of the Fallasburg Bridge and south of Smyrna. The original bridge was among the area's best-known 19th century structures. The bridge was completely destroyed by fire, on the morning of July 7, 2013. In July 2016, approval was granted for rebuilding a replica bridge, which was completed in April 2020.
A Howe truss is a truss bridge consisting of chords, verticals, and diagonals whose vertical members are in tension and whose diagonal members are in compression. The Howe truss was invented by William Howe in 1840, and was widely used as a bridge in the mid to late 1800s.
A Brown truss is a type of bridge truss, used in covered bridges. It is noted for its economical use of materials and is named after the inventor, Josiah Brown Jr., of Buffalo, New York, who patented it July 7, 1857, as US patent 17,722.
A king post is a central vertical post used in architectural or bridge designs, working in tension to support a beam below from a truss apex above.
A collar beam or collar is a horizontal member between two rafters and is very common in domestic roof construction. Often a collar is structural but they may be used simply to frame a ceiling. A collar beam is often called a collar tie but this is rarely correct. A tie in building construction is an element in tension rather than compression and most collar beams are designed to work in compression to keep the rafters from sagging. A collar near the bottom of the rafters may replace a tie beam and be designed to keep the rafters from spreading, thus are in tension: these are correctly called a collar tie.
The Cornish–Windsor Covered Bridge is a 156-year-old, two-span, timber Town lattice-truss, interstate, covered bridge that crosses the Connecticut River between Cornish, New Hampshire, and Windsor, Vermont. Until 2008, when the Smolen–Gulf Bridge opened in Ohio, it had been the longest covered bridge in the United States.
In structural engineering, a Warren truss or equilateral truss is a type of truss employing a weight-saving design based upon equilateral triangles. It is named after the British engineer James Warren, who patented it in 1848.
A timber roof truss is a structural framework of timbers designed to bridge the space above a room and to provide support for a roof. Trusses usually occur at regular intervals, linked by longitudinal timbers such as purlins. The space between each truss is known as a bay.
The Denison Bridge is a heritage-listed footbridge over the Macquarie River in Bathurst, New South Wales, Australia. It is the fourth oldest metal truss bridge existing in Australia.
A post is a main vertical or leaning support in a structure similar to a column or pillar but the term post generally refers to a timber but may be metal or stone. A stud in wooden or metal building construction is similar but lighter duty than a post and a strut may be similar to a stud or act as a brace. In the U.K. a strut may be very similar to a post but not carry a beam. In wood construction posts normally land on a sill, but in rare types of buildings the post may continue through to the foundation called an interrupted sill or into the ground called earthfast, post in ground, or posthole construction. A post is also a fundamental element in a fence. The terms "jack" and "cripple" are used with shortened studs and rafters but not posts, except in the specialized vocabulary of shoring.
The Stony Creek Bridge is a bridge located on a private road over Stony Creek in Olive Township, Clinton County, Michigan. It was listed on the National Register of Historic Places in 1999. It is the last example of a queen post truss bridge extant in Michigan.
American historic carpentry is the historic methods with which wooden buildings were built in what is now the United States since European settlement. A number of methods were used to form the wooden walls and the types of structural carpentry are often defined by the wall, floor, and roof construction such as log, timber framed, balloon framed, or stacked plank. Some types of historic houses are called plank houses but plank house has several meanings which are discussed below. Roofs were almost always framed with wood, sometimes with timber roof trusses. Stone and brick buildings also have some wood framing for floors, interior walls and roofs.
Morpeth Bridge is a heritage-listed road bridge over the Hunter River at Morpeth, New South Wales, Australia. It was designed by Percy Allan and built from 1896 to 1898 by Samuel McGill. It is also known as Morpeth Bridge over the Hunter River. The property is owned by Transport for NSW.
Old Cobram-Barooga Bridge is a heritage-listed former road bridge and now footbridge over the Murray River at Barooga-Cobram Road, Barooga, New South Wales, Australia. The bridge links Barooga with Cobram, its sister town in Victoria. It was designed by Ernest de Burgh (engineer) and the New South Wales Department of Public Works and built from 1900 to 1902. It is also known as RMS Bridge No 3247. It is owned by Transport for NSW. It was added to the New South Wales State Heritage Register on 1 April 2016.
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