A bridge is a structure built to span a physical obstacle without blocking the way underneath. It is constructed for the purpose of providing passage over the obstacle, which is usually something that is otherwise difficult or impossible to cross. There are many different designs of bridges, each serving a particular purpose and applicable to different situations. Designs of bridges vary depending on factors such as the function of the bridge, the nature of the terrain where the bridge is constructed and anchored, and the material used to make it, and the funds available to build it.
A suspension bridge is a type of bridge in which the deck is hung below suspension cables on vertical suspenders. The first modern examples of this type of bridge were built in the early 1800s. Simple suspension bridges, which lack vertical suspenders, have a long history in many mountainous parts of the world.
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.
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.
A trestle bridge is a bridge composed of a number of short spans supported by closely spaced frames. A trestle is a rigid frame used as a support, historically a tripod used to support a stool or a pair of isosceles triangles joined at their apices by a plank or beam such as the support structure for a trestle table. 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.
The Westham Island Bridge, which is a single-lane, wood-deck truss bridge over Canoe Pass near the mouth of the Fraser River, connects Westham Island with the Delta mainland, in Metro Vancouver.
Hampden Bridge is a heritage-listed single-span suspension bridge that carries Moss Vale Road (B73) across the Kangaroo River, in Kangaroo Valley, in the City of Shoalhaven local government area of New South Wales, Australia. The bridge was designed by Ernest de Burgh and built by Loveridge and Hudson. The property is owned by Transport for NSW. It was added to the New South Wales State Heritage Register on 2 August 2019.
A flitch beam is a compound beam used in the construction of houses, decks, and other primarily wood-frame structures. Typically, the flitch beam is made up of a vertical steel plate sandwiched between two wood beams, the three layers being held together with bolts. In that common form it is sometimes referenced as a steel flitch beam. Further alternating layers of wood and steel can be used to produce an even stronger beam. The metal plates within the beam are known as flitch plates.[1] Flitch beams were used as a cost-effective way to strengthen long-span wooden beams, and have been largely supplanted by more recent technology.
A girder bridge is a bridge that uses girders as the means of supporting its deck. The two most common types of modern steel girder bridges are plate and box.
The Anoka–Champlin Mississippi River Bridge, also known as the Ferry Street Bridge, is a 10-span open spandrel concrete deck arch bridge that spans the Mississippi River between Anoka and Champlin, Minnesota, United States. It was built in 1929 by the Minneapolis Bridge Company, replacing an 1884 bridge at the same site.
Tharwa Bridge is a four span Allan truss bridge that provides a high-level crossing point across the Murrumbidgee River, allowing traffic between Canberra and Tharwa village. It is the oldest surviving bridge in the Australian Capital Territory.
King's Highway 71, commonly referred to as Highway 71, is a provincially maintained highway in the Canadian province of Ontario. The 194-kilometre-long (121 mi) route begins at the Fort Frances–International Falls International Bridge in Fort Frances, continuing from US Highway 53 (US 53) and US 71 in Minnesota, and travels west concurrently with Highway 11 for 40 kilometres (25 mi) to Chapple. At that point, Highway 11 continues west while Highway 71 branches north and travels 154 kilometres (96 mi) to a junction with Highway 17 just east of Kenora. Highway 71 forms a branch of the Trans-Canada Highway for its entire length, with the exception of the extremely short segment south of Highway 11 in Fort Frances.
Blackfriars Bridge in London, Ontario, Canada is a wrought iron bowstring arch through truss bridge, crossing the North Thames River. The bridge was constructed in 1875 and carries single-lane vehicles, bicycles and pedestrians from Blackfriars Street to Ridout Street North.
The 1950 Tacoma Narrows Bridge is a suspension bridge in the U.S. state of Washington that carries the westbound lanes of Washington State Route 16 across the Tacoma Narrows strait, between the city of Tacoma and the Kitsap Peninsula. Opened on October 14, 1950, it was built in the same location as the original Tacoma Narrows Bridge, which collapsed due to a windstorm on November 7, 1940. It is the older of the twin bridges that make up the Tacoma Narrows Bridge crossing of the Tacoma Narrows, and carried both directions of traffic across the strait until 2007. At the time of its construction, the bridge was, like its predecessor, the third-longest suspension bridge in the world in terms of main span length, behind the Golden Gate Bridge and George Washington Bridge; it is now the 46th longest suspension bridge in the world.
The Hadley Parabolic Bridge, often referred to locally as the Hadley Bow Bridge, carries Corinth Road across the Sacandaga River in Hadley, New York, United States. It is an iron bridge dating from the late 19th century.
Dickabram Bridge is a heritage-listed road-and-rail bridge over the Mary River between Miva and Theebine, both in the Gympie Region, Queensland, Australia. It was the major bridge on the Kingaroy railway line. It was designed by Henry Charles Stanley and built from 1885 to 1886 by Messrs Michael McDermott, Owens & Co. It is also known as Mary River Bridge (Miva). The bridge was registered on the former Register of the National Estate in 1988.
The Bethanga Bridge is a steel truss road bridge that carries the Riverina Highway across Lake Hume, an artificial lake on the Murray River in Australia. The dual heritage-listed bridge crosses the border between the Australian states of New South Wales and Victoria, linking the Victorian towns of Bellbridge and Bethanga with the regional New South Wales city of Albury.
The Lincoln Covered Bridge is a historic covered bridge, just south of U.S. Route 4 in West Woodstock, Vermont. Built in 1877, it is one of the only known examples of a wooden Pratt truss bridge in the United States. It was listed on the National Register of Historic Places in 1973.
The Perley Bridge was a bridge connecting Hawkesbury, Ontario and Grenville, Quebec. It crossed the Ottawa River via Chenail Island. It was named for George Perley, Canadian Member of Parliament representing the Argenteuil district in southern Quebec. He first advocated for a crossing at Hawkesbury in 1909. The bridge was known as the Hawkesbury–Grenville Bridge, or less frequently the Grenville–Hawkesbury Bridge prior to its completion in 1931 when the name Perley was applied. It was replaced by the Long-Sault Bridge in 1998.
The Murrumbidgee River railway bridge is a heritage-listed railway bridge across the Murrumbidgee River located on the Tumut railway line at Gundagai in the Cootamundra-Gundagai Regional Council local government area of New South Wales, Australia. It was built in 1903. It is also known as the Gundagai Rail Bridge over Murrumbidgee River and the Murrumbidgee River Railway Bridge. The property was added to the New South Wales State Heritage Register on 2 April 1999.
