Viaduct

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Viaduct
The 1812 Laigh Milton Viaduct in Ayrshire – the oldest surviving railway bridge in Scotland
The 1812 Laigh Milton Viaduct in Ayrshire – the oldest surviving railway bridge in Scotland
AncestorTrestle bridge, Box girder bridge
RelatedAqueduct
DescendantNone
CarriesExpressways, highways, streets, railways
Span rangeShort (multiple)
Materialreinforced concrete, prestressed concrete, masonry
MovableNo
Design effortmedium
Falsework requiredavailable for use, since viaducts are all composed of low bridges.

A viaduct is a specific type of bridge that consists of a series of arches, piers or columns supporting a long elevated railway or road. Typically a viaduct connects two points of roughly equal elevation, allowing direct overpass across a wide valley, road, river, or other low-lying terrain features and obstacles.[1][2] The term viaduct is derived from the Latin via meaning "road", and ducere meaning "to lead". It is a 19th-century derivation from an analogy with ancient Roman aqueducts.[1] Like the Roman aqueducts, many early viaducts comprised a series of arches of roughly equal length.

Over land

The Ouse Valley Viaduct in Sussex, England

The longest viaduct in antiquity may have been the Pont Serme which crossed wide marshes in southern France.[3] At its longest point, it measured 2,679 meters with a width of 22 meters.

Viaducts are commonly used in many cities that are railroad

railroad yards that are needed for freight trains there, and also cross the multi-track railroad lines that are needed for heavy rail traffic. These viaducts provide grade separation
and keep highway and city street traffic from having to be continually interrupted by the train traffic. Likewise, some viaducts carry railroads over large valleys, or they carry railroads over cities with many cross-streets and avenues.

Many viaducts over land connect points of similar height in a landscape, usually by bridging a river valley or other eroded opening in an otherwise flat area. Often such valleys had roads descending either side (with a small bridge over the river, where necessary) that become inadequate for the traffic load, necessitating a viaduct for "through" traffic.

Bloor-Danforth subway line on the lower deck, over the steep Don River valley
. Others were built to span settled areas, crossing over roads beneath—the reason for many viaducts in London.

Over water

The Millau Viaduct

Viaducts over water make use of islands or successive arches. They are often combined with other types of bridges or tunnels to cross navigable waters as viaduct sections, while less expensive to design and build than tunnels or bridges with larger spans, typically lack sufficient horizontal and vertical clearance for large ships. See the

Chesapeake Bay Bridge-Tunnel
.

The

longest bridge in the world as of 2011.[6]

Land use below viaducts

Deansgate Metrolink station
in Manchester.

Where a viaduct is built across land rather than water, the space below the arches may be used for businesses such as car parking, vehicle repairs, light industry, bars and nightclubs. In the United Kingdom, many railway lines in urban areas have been constructed on viaducts, and so the infrastructure owner Network Rail has an extensive property portfolio in arches under viaducts.[7] In Berlin the space under the arches of elevated subway lines (S-Bahn) is used for several different purposes, including small eateries or bars.

Past and future

Delhi-Gurgaon Expressway), China, Bangladesh, Pakistan, and Nicaragua, elevated expressways have been built and more are under construction to improve traffic flow, particularly as a workaround of land shortage when built atop surface roads.[citation needed
]

Other uses have been found for some viaducts. In Paris, France, a repurposed rail viaduct provides a garden promenade on top and workspace for artisans below. The garden promenade is called the Coulée verte René-Dumont while the workspaces in the arches below are the Viaduc des Arts. The project was inaugurated in 1993. Manhattan's High Line, inaugurated in 2009, also uses an elevated train line as a linear urban park.

In Indonesia viaducts are used for railways in

tunnel after several decades of use because it was seismically unsafe.[citation needed
]

The Viaduc des Arts, Paris, France.

See also

References

  1. ^ a b "viaduct – Definition of viaduct in English by Oxford English Dictionary". OED. Retrieved 21 September 2020.
  2. ^ "Definition of VIADUCT". www.merriam-webster.com. Retrieved 27 March 2018.
  3. ISBN 0-521-39326-4
    , p. 99
  4. ^ Brownlee, Christy (March 2005) "Taking the high road: France's new bridge helps a small town dodge traffic—and set a new world record" SuperScience 16(6): pp.12–15;
  5. ^ Davidsen, Judith (April 1993) "A new "lite" rail viaduct formula: Norman Foster designs a rapid-transit viaduct for Rennes, France" Architectural Record 181(4): p.26;
  6. ^ Longest bridge, Guinness World Records. Last accessed July 2011.
  7. ^ "Light Industrial Units To Let/Rent | Small Industrial Space". Archived from the original on 17 May 2012.
  8. ^ "Toronto built, then demolished an expressway" (PDF). tac-atc.ca. Archived from the original (PDF) on 6 July 2011. Retrieved 27 March 2018.

External links

  • Media related to Viaducts at Wikimedia Commons
  • The dictionary definition of Viaduct at Wiktionary
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