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This article is about the structure. For the card game, see Contract bridge. For other uses, see Bridge (disambiguation) and Bridges (disambiguation).
The Akashi Kaikyō Bridge in Japan, currently the world's longest suspension span.
The double-decked George Washington Bridge, connecting New York City to Bergen County, New Jersey, USA, is the world's busiest bridge, carrying 102 million vehicles annually.[1][2]
The Siosepol bridge over Zayandeh River is an example of Safavid dynasty (1502–1722) bridge design. Esfahan, Iran



The Oxford English Dictionary traces the origin of the word bridge to an Old English word brycg, of the same meaning, derived from the hypothetical Proto-Germanic root brugjō. There are cognates in other Germanic languages.


The first bridges were made by nature itself—as simple as a log fallen across a stream or stones in a river. The first bridges made by humans were probably spans of cut wooden logs or planks and eventually stones, using a simple support and crossbeam arrangement. Some early Americans used trees or bamboo poles to cross small caverns or wells to get from one place to another. A common form of lashing sticks, logs, and deciduous branches together involved the use of long reeds or other harvested fibers woven together to form a connective rope capable of binding and holding together the materials used in early bridges.


The Arkadiko Bridge is one of four Mycenaean corbel arch bridges part of a former network of roads, designed to accommodate chariots, between Tiryns and Epidauros in the Peloponnese, in Greece. Dating to the Greek Bronze Age (13th century BC), it is one of the oldest arch bridges still in existence and use. Several intact arched stone bridges from the Hellenistic era can be found in the Peloponnese in southern Greece[3]

The greatest bridge builders of antiquity were the ancient Romans.[4] The Romans built arch bridges and aqueducts that could stand in conditions that would damage or destroy earlier designs. Some stand today.[5] An example is the Alcántara Bridge, built over the river Tagus, in Spain. The Romans also used cement, which reduced the variation of strength found in natural stone.[6] One type of cement, called pozzolana, consisted of water, lime, sand, and volcanic rock. Brick and mortar bridges were built after the Roman era, as the technology for cement was lost then later rediscovered.

The Arthashastra of Kautilya mentions the construction of dams and bridges.[7] A Mauryan bridge near Girnar was surveyed by James Princep.[8] The bridge was swept away during a flood, and later repaired by Puspagupta, the chief architect of emperor Chandragupta I.[8] The bridge also fell under the care of the Yavana Tushaspa, and the Satrap Rudra Daman.[8] The use of stronger bridges using plaited bamboo and iron chain was visible in India by about the 4th century.[9] A number of bridges, both for military and commercial purposes, were constructed by the Mughal administration in India.[10]

Although large Chinese bridges of wooden construction existed at the time of the Warring States, the oldest surviving stone bridge in China is the Zhaozhou Bridge, built from 595 to 605 AD during the Sui Dynasty. This bridge is also historically significant as it is the world's oldest open-spandrel stone segmental arch bridge. European segmental arch bridges date back to at least the Alconétar Bridge (approximately 2nd century AD), while the enormous Roman era Trajan's Bridge (105 AD) featured open-spandrel segmental arches in wooden construction.


During the 18th century there were many innovations in the design of timber bridges by Hans Ulrich, Johannes Grubenmann, and others. The first book on bridge engineering was written by Hubert Gautier in 1716. A major breakthrough in bridge technology came with the erection of the Iron Bridge in Coalbrookdale, England in 1779. It used cast iron for the first time as arches to cross the river Severn.

With the Industrial Revolution in the 19th century, truss systems of wrought iron were developed for larger bridges, but iron did not have the tensile strength to support large loads. With the advent of steel, which has a high tensile strength, much larger bridges were built, many using the ideas of Gustave Eiffel.


Types of bridges[edit]


Structure type[edit]

Bridges may be classified by how the forces of tension, compression, bending, torsion and shear are distributed through their structure. Most bridges will employ all of the principal forces to some degree, but only a few will predominate. The separation of forces may be quite clear. In a suspension or cable-stayed span, the elements in tension are distinct in shape and placement. In other cases the forces may be distributed among a large number of members, as in a truss, or not clearly discernible to a casual observer as in a box beam.

BeamBridge-diagram.svgBeam bridge
Beam bridges are horizontal beams supported at each end by substructure units and can be either simply supported when the beams only connect across a single span, or continuous when the beams are connected across two or more spans. When there are multiple spans, the intermediate supports are known as piers. The earliest beam bridges were simple logs that sat across streams and similar simple structures. In modern times, beam bridges can range from small, wooden beams to large, steel boxes. The vertical force on the bridge becomes a shear and flexural load on the beam which is transferred down its length to the substructures on either side[12] They are typically made of steel, concrete or wood. Beam bridge spans rarely exceed 250 feet (76 m) long, as the flexural stresses increase proportional to the square of the length (and deflection increases proportional to the 4th power of the length).[13] However, the main span of the Rio-Niteroi Bridge, a box girder bridge, is 300 metres (980 ft).

The world's longest beam bridge is Lake Pontchartrain Causeway in southern Louisiana in the United States, at 23.83 miles (38.35 km), with individual spans of 56 feet (17 m).[14] Beam bridges are the most common bridge type in use today.

TrussBridge-diagram.svgTruss bridge
CantileverBridge-diagram.svgCantilever bridge
Cantilever bridges are built using cantilevers—horizontal beams supported on only one end. Most cantilever bridges use a pair of continuous spans that extend from opposite sides of the supporting piers to meet at the center of the obstacle the bridge crosses. Cantilever bridges are constructed using much the same materials & techniques as beam bridges. The difference comes in the action of the forces through the bridge.


ArchBridge-diagram.svgArch bridge

With the span of 220 metres (720 ft), the Solkan Bridge over the Soča River at Solkan in Slovenia is the second largest stone bridge in the world and the longest railroad stone bridge. It was completed in 1905. Its arch, which was constructed from over 5,000 tonnes (4,900 long tons; 5,500 short tons) of stone blocks in just 18 days, is the second largest stone arch in the world, surpassed only by the Friedensbrücke (Syratalviadukt) in Plauen, and the largest railroad stone arch. The arch of the Friedensbrücke, which was built in the same year, has the span of 90 m (300 ft) and crosses the valley of the Syrabach River. The difference between the two is that the Solkan Bridge was built from stone blocks, whereas the Friedensbrücke was built from a mixture of crushed stone and cement mortar.[15]

The world's current largest arch bridge is the Chaotianmen Bridge over the Yangtze River with a length of 1,741 m (5,712 ft) and a span of 552 metres (1,811 ft). The bridge was open April 29, 2009 in Chongqing, China.[16]

TiedarchBridge-diagram.svgTied arch bridge
SuspensionBridge-diagram.svgSuspension bridge


CableStayedBridge-diagram.svgCable-stayed bridge
Cable-stayed bridges, like suspension bridges, are held up by cables. However, in a cable-stayed bridge, less cable is required and the towers holding the cables are proportionately higher.[18] The first known cable-stayed bridge was designed in 1784 by C. T. (or C. J.) Löscher.[19][20]

The longest cable-stayed bridge since 2012 is the Russky Bridge in Vladivostok, Russia.

Fixed or movable bridges[edit]

A collapsed span of this bridge was reopened with a temporary bridge.


Double-decked bridges[edit]

Double-decked (or double-decker) bridges have two levels, such as the George Washington Bridge, connecting New York City to Bergen County, New Jersey, USA, as the world's busiest bridge, carrying 102 million vehicles annually;[1][2] truss work between the roadway levels provided stiffness to the roadways and reduced movement of the upper level when the lower level was installed three decades following the upper level. The Tsing Ma Bridge and Kap Shui Mun Bridge in Hong Kong have six lanes on their upper decks, and on their lower decks there are two lanes and a pair of tracks for MTR metro trains. Some double-decked bridges only use one level for street traffic; the Washington Avenue Bridge in Minneapolis reserves its lower level for automobile traffic and its upper level for pedestrian and bicycle traffic (predominantly students at the University of Minnesota). Likewise, in Toronto, the Prince Edward Viaduct has five lanes of motor traffic, bicycle lanes, and sidewalks on its upper deck; and a pair of tracks for the Bloor–Danforth subway line on its lower deck. The western span of the San Francisco – Oakland Bay Bridge also has two levels.

Robert Stephenson's High Level Bridge across the River Tyne in Newcastle upon Tyne, completed in 1849, is an early example of a double-decked bridge. The upper level carries a railway, and the lower level is used for road traffic. Other examples include Britannia Bridge over the Menai Strait and Craigavon Bridge in Derry, Northern Ireland. The Oresund Bridge between Copenhagen and Malmö consists of a four-lane highway on the upper level and a pair of railway tracks at the lower level. The Tower Bridge is different example of a double-decked bridge, with the central section consisting of a low level bascule span and a high level footbridge.


Main article: Viaduct


Three-way bridges[edit]

The three-way Tridge
Main article: Three-way bridge

A three-way bridge has three separate spans which meet near the center of the bridge. The bridge appears as a "T" or "Y" when viewed from above. Three-way bridges are extremely rare. The Tridge, Margaret Bridge, and Zanesville Y-Bridge are examples.

Bridge types by use[edit]

A bridge can be categorized by what it is designed to carry, such as trains, pedestrian or road traffic, a pipeline or waterway for water transport or barge traffic. An aqueduct is a bridge that carries water, resembling a viaduct, which is a bridge that connects points of equal height. A road-rail bridge carries both road and rail traffic. A bridge can carry overhead power lines as does the Storstrøm Bridge.


Bridges are subject to unplanned uses as well. The areas underneath some bridges have become makeshift shelters and homes to homeless people, and the undersides of bridges all around the world are spots of prevalent graffiti. Some bridges attract people attempting suicide, and become known as suicide bridges.

Bridge types by material[edit]

The Iron Bridge completed in 1779 was the first cast iron bridge.

The materials used to build the structure are also used to categorize bridges. Until the end of the 18th Century, bridges were made out of timber, stone and masonry. Modern bridges are currently built in concrete, steel, fiber reinforced polymers (FRP), stainless steel or combinations of those materials. Living bridges have been constructed of live plants such as tree roots in India and vines in Japan.




Bridge maintenance[edit]


Highway bridge with steel hollow box sections, performed for lifetime extension by welding aftertreatment

Bridge failures[edit]



Bridge monitoring[edit]

There are several methods used to monitor the stress on large structures like bridges. The most common method is the use of an accelerometer, which is integrated into the bridge while it is being built. This technology is used for long-term surveillance of the bridge.[21]


Visual index[edit]

See also[edit]


  3. ^ Kutz, Myer (2011). Handbook of Transportation Engineering, Volume II: Applications and Technologies, Second Edition. McGraw-Hill Professional. ISBN 978-00-7161-477-1. 
  5. ^ "History of BRIDGES". Retrieved 2012-01-04. 
  6. ^ "Lessons from Roman Cement and Concrete". Retrieved 2012-01-04. 
  7. ^ Dikshitar, V. R. R. Dikshitar (1993). The Mauryan Polity, Motilal Banarsidass, p. 332 ISBN 81-208-1023-6.
  8. ^ a b c Dutt, Romesh Chunder (2000). A History of Civilisation in Ancient India: Vol II, Routledge, p. 46, ISBN 0-415-23188-4.
  11. ^ Sapp, Mark E. (February 22, 2008). "Welding Timeline 1900–1950". Retrieved 2008-04-29. 
  12. ^ "Beam bridges". Design Technology. Retrieved 2008-05-14. 
  13. ^ Structural Beam Deflection Stress Bending Equations / Calculation Supported on Both Ends Uniform Loading. Engineers Edge. Retrieved on 2013-04-23.
  14. ^ "A big prefabricated bridge". Life 40 (22): 53–60. 28 May 1956. 
  15. ^ Gorazd Humar (September 2001). Charles Abdunur, ed. "Arch'01: troisième Conférence internationale sur les ponts en arc Paris:" (in English, French). Paris: Presses des Ponts. pp. 121–124. ISBN 2-85978-347-4.  |chapter= ignored (help)
  16. ^ "Longest bridge, steel arch bridge". Guinness World Records. Retrieved 2013-02-18. 
  17. ^ Sigmund, Pete (2007-02-07). "The Mighty Mac: A Sublime Engineering Feat". Construction Equipment Guide. Retrieved 2008-05-14. 
  19. ^ Earliest cable-stayed bridge
  20. ^ Earliest cable-stayed bridge
  21. ^ "The new Minnesota smart bridge". Retrieved 2012-01-30. 
  22. ^ "Basic Principles of Vibrometry". Retrieved 2012-01-25. 

Further reading[edit]

  • Kinney, A. R.; el al. (2003). Worshiping Siva and Buddha: The Temple Art of East Java. University of Hawaii Press. ISBN 0-8248-2779-1.
  • Buck, William; el al. (2000). Ramayana. University of California Press. ISBN 0-520-22703-4.

External links[edit]