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28-613: The Eldean Covered Bridge is a historic covered bridge spanning the Great Miami River in Miami County, Ohio north of Troy . Built in 1860, it is one of the nation's finest surviving examples of a Long truss , patented in 1830 by engineer Stephen H. Long . At 224 feet (68 m) in length for its two spans, it is the longest surviving example of its type. It was listed on the National Register of Historic Places in 1975, and

56-409: A crossbeam (the tie beam ) to the apex of a triangular truss . The king post, itself in tension , connects the apex of the truss with its base, holding up the tie beam (also in tension) at the base of the truss. The post can be replaced with an iron rod called a king rod (or king bolt) and thus a king rod truss. The king post truss is also called a "Latin truss". In traditional timber framing,

84-407: A crown post looks similar to a king post, but it is very different structurally: whereas the king post is in tension, usually supporting the tie beam as a truss, the crown post is supported by the tie beam and is in compression . The crown post rises to a crown plate immediately below collar beams which it supports; it does not rise to the apex like a king post. Historically a crown post was called

112-427: A cutwater feature on its northern (upstream) side. The total structure length is 231 feet (70 m), with each span about 108 feet (33 m) and 21 feet (6.4 m) wide. The roadway has a width of 17 feet (5.2 m) and a maximum clearance of 13 feet (4.0 m). The bridge has a gabled metal roof, vertical board sheathing on the outside, and small square apertures framed in each side for light. County Road 33

140-416: A hammerbeam roof . The king post truss is used for simple roof trusses and short-span bridges. It is the simplest form of truss in that it is constructed of the fewest truss members (individual lengths of wood or metal). The truss consists of two diagonal members that meet at the apex of the truss, one horizontal beam that serves to tie the bottom end of the diagonals together, and the king post which connects

168-488: A king post in England but this usage is obsolete. An alternative truss construction uses two queen posts (or queen-posts). These vertical posts, positioned along the base of the truss, are supported by the sloping sides of the truss, rather than reaching its apex. A development adds a collar beam above the queen posts, which are then termed queen struts. A section of the tie beam between the queen posts may be removed to create

196-736: A mile in length, but was destroyed by ice and flooding in 1832. The longest, historical covered bridges remaining in the United States are the Cornish–Windsor Bridge , spanning the Connecticut River between New Hampshire and Vermont, and Medora Bridge , spanning the East Fork of the White River in Indiana. Both lay some claim to the superlative depending upon how the length is measured. In

224-416: Is really a misnomer as the system was more widely used than that. The difference between a Norman truss and a king post truss is the tie beam in a Norman truss is technically a collar beam (a beam between the rafters above the rafter feet) where the king post truss the rafters land on top of a tie beam. King posts are also used in the construction of some wire-braced aircraft, where a king post supports

252-527: The Schöllenen Gorge shows multiple king posts suspended from the apex of the falsework upon which the masonry arch has been laid. In this example, beams in compression are supported by each king post several feet below the apex, and the bottom of the king posts can clearly be seen to be unsupported. Architectural historians in the French colonial cities St Louis , Missouri and New Orleans , Louisiana use

280-651: The 1820s. Extant bridges from that decade include New York 's Hyde Hall Bridge and Pennsylvania 's Hassenplug Bridge , both built in 1825, and the Haverhill–Bath Covered Bridge and the Roberts Covered Bridge , in New Hampshire and Ohio respectively, both built in 1829. The longest covered bridge ever built was constructed in 1814 in Lancaster County , Pennsylvania, and spanned over

308-638: The 1950s, peaking at about 400 covered bridges. These mostly used the Howe, Town, and Burr trusses. Today, there are 58 covered bridges in New Brunswick , including the world's longest, the Hartland Bridge . Ontario has just one remaining covered bridge, the West Montrose Covered Bridge . Roofed, rather than covered bridges, have existed for centuries in southern Europe and Asia. In these cases,

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336-518: The U.S., although it states that only 670 of those were standing when the 1959 edition was published. The tallest (35 feet high), built in 1892, is the Felton Covered Bridge , just north of Santa Cruz, California . Between 1969 and 2015, the number of surviving covered bridges in Canada declined from about 400 to under 200. In 1900, Quebec had an estimated 1,000 covered bridges. Relative to

364-665: The apex to the horizontal beam below. For a roof truss, the diagonal members are called rafters , and the horizontal member may serve as a ceiling joist . A bridge would require two king post trusses with the driving surface between them. A roof usually uses many side-by-side trusses depending on the size of the structure. Pont-y-Cafnau , the world's first iron railway bridge, is of the king post type. King posts were used in timber-framed roof construction in Roman buildings, and in medieval architecture in buildings such as parish churches and tithe barns . The oldest surviving roof truss in

392-500: The cover is to protect the users of the bridge rather than the structure. Examples include: In addition to being practical, covered bridges were popular venues for a variety of social activities and are an enduring cultural icon; for example: King post In aircraft design a strut called a king post acts in compression, similarly to an architectural crown post. Usage in mechanical plant and marine engineering differs again, as noted below. A king post extends vertically from

420-592: 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 can 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. Surviving covered bridges often attract touristic attention due to their rarity, quaint appearance, and bucolic settings. Many are considered historic and have been

448-525: The mid-19th century, the use of cheaper wrought iron and cast iron led to metal rather than timber trusses. Metal structures did not need protection from the elements, so they no longer needed to be covered. The bridges also became obsolete because most were single-lane, had low width and height clearances, and could not support the heavy loads of modern traffic. As of 2004 , there were about 750 left, mostly in eastern and northern states. The 2021 World Guide to Covered Bridges lists 840 covered bridges in

476-499: The most popular designs was the Burr Truss , patented in 1817, which used an arch to bear the load, while the trusses kept the bridge rigid. Other designs included the King , Queen , Lattice , and Howe trusses . Early trusses were designed with only a rough understanding of the engineering dynamics at work. In 1847, American engineer Squire Whipple published the first correct analysis of

504-611: The precise ways that a load is carried through the components of a truss, which enabled him to design stronger bridges with fewer materials. About 14,000 covered bridges have been built in the United States, mostly in the years 1825 to 1875. The first documented was the Permanent Bridge , completed in 1805 to span the Schuylkill River in Philadelphia . However, most other early examples of covered bridges do not appear until

532-567: The rest of North America, Quebec was late in building covered bridges, with the busiest decade for construction being the 1930s. Initially, the designs were varied, but around 1905, the design was standardised to the Town québécois , a variant on the lattice truss patented by Ithiel Town in 1820. The designer is unknown. About 500 of these were built in the first half of the 20th century. They were often built by local settlers using local materials, according to standard plans. The last agricultural colony

560-657: The structure. This bridge is one of the finest and least-altered examples of this truss type. With the demise of the Old Blenheim Bridge in New York, it is also the longest example of the type. On December 23, 2016, the Eldean Covered Bridge was designated a National Historic Landmark . 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

588-595: The subject of historic preservation campaigns. 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 . They tend to be in isolated places, making them vulnerable to vandalism and arson. The oldest surviving truss bridge in

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616-434: The term "Norman roof" to refer to a steeply pitched roof; it is supported by what they call a "Norman truss" which is similar to a king post truss. This is a through-purlin truss consisting of a tie beam and paired truss blades, with a central king post to support the roof ridge. The name derives from a belief that this system of construction was introduced to North America by settlers from Normandy in northern France, but it

644-463: The top cables or "ground wires" supporting the wing. Only on the ground are these wires from the kingpost in tension, while in the air under positive g flight they are unloaded. The very robust hinge connecting the boom to the chassis in a backhoe , similar in function and appearance to a large automotive kingpin , is called a king post. On a cargo ship or oiler a king post is an upright with cargo-handling or fueling rig devices attached to it. On

672-544: The world is a king post truss in Saint Catherine's Monastery , Egypt, built between 548 and 565. King posts also appear in Gothic Revival architecture , Queen Anne style architecture and occasionally in modern construction. King post trusses are also used as a structural element in wood and metal bridges. A painting by Karl Blechen circa 1833 illustrating construction of the second Devil's Bridge ( Teufelsbrücke ) in

700-620: The world is the Kapellbrücke in Switzerland, first built in the 1300s. Modern-style timber truss bridges were pioneered in Switzerland in the mid-1700s. Germany has 70 surviving historic wooden covered bridges. Most bridges were built to cross streams, and the majority had just a single span . Virtually all contained a single lane. A few two-lane bridges were built, having a third, central truss. Many different truss designs were used. One of

728-471: Was designated a National Historic Landmark in 2016. The Eldean Covered Bridge is located north of the city of Troy, spanning the Great Miami River between Concord Township and Staunton Township on a now-bypassed segment of County Road 33. It is a two-span structure, mounted on cut stone abutments and a central pier. The western abutment and central pier have been capped in concrete, and the pier has

756-684: Was founded in 1948, and the last bridge was built by the Ministry of Colonisation in 1958 in Lebel-sur-Quévillon . There are now 82 covered bridges in Quebec, Transports Québec including the Félix-Gabriel-Marchand Bridge , the province's longest covered bridge. In Quebec covered bridges were sometimes known as pont rouges (red bridges) because of their typical colour. Like Quebec, New Brunswick continued to build covered bridges into

784-503: Was laid out in 1847, providing access to a hamlet originally serving the Miami and Erie Canal to the east. The present bridge was built in 1860, and is the second to stand on the site. The bridge trusses were built to a patented design by engineer Stephen H. Long . The Long truss was the first truss structure to be designed using engineering principles, and it introduced the idea of prestressed elements which are used to counteract active load on

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