A bridge is a structure designed to span an obstacle, such as a river or railway, allowing vehicles, pedestrians, and other loads to pass across. Most bridges consist of a flat deck, supported by beams, arches, or cables. These structures rest on a foundation that is carefully designed to transfer the weight of the bridge to the subsoil without settling.
Bridges can be constructed in a wide variety of forms, determined by the location, intended purpose, and available construction technologies. Simple bridge structures include beam bridges made from logs, and suspension bridges made of ropes or vines. The Romans and ancient Chinese built major arch bridges of timber, stone, and brick. During the Renaissance, advances in science and engineering led to wider bridge spans and more elegant designs. Concrete was perfected in the early 19th century, and arch bridges are now built primarily of concrete or steel.
With the Industrial Revolution came mass-produced steel, which enabled the creation of more complex formsincluding truss and cantilever bridgesthat permitted bridges to cross wide rivers or deep valleys. The longest spans use suspension or cable-stayed designs, both of which rely on high-strength steel cables to support the deck. Over time, the maximum achievable span of bridges has steadily increased, reaching in 2022. Other bridge forms include multi-span viaducts, which can cross wide valleys; trestles, a common design for carrying heavy trains; and movable bridges including drawbridges and swing bridges.
The design of a bridge must satisfy many requirements, namely connecting to a transportation network, providing adequate clearances, and safely transporting its users. A bridge must be strong enough to support its own weight as well as the weight of the traffic passing over it. It must also tolerate violent, hard-to-predict stresses imposed by the environment, including winds, floods, and earthquakes. To meet all these goals, bridge engineers typically use limit state design processes and the finite element method.
Many bridges are admired for their beauty, and some spectacular bridges serve as iconic landmarks that provide a sense of pride and identity for the local community. In art and literature, bridges are frequently used as metaphors to represent connection or transition. Bridges can create beneficial impacts on a community, including shorter transport times and increased gross domestic product; and also negative effects such as increased pollution and contributions to global warming.
History
Antiquity
thumb|right|alt=A stone arch bridge passing over a river valley|upright=1.6|The Pont du Gard aqueduct in France was built by the Roman Empire .
The earliest forms of bridges were simple structures for crossing wetlands and creeks, consisting of wooden boardwalks or logs.<ref name=early>{{Multiref
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}}</ref> Pilingswhich are critical elements of bridge constructionwere used in Switzerland around 4,000 BC to support stilt houses built over water. Several corbel arch bridges were built 13th century BC by the Mycenaean Greece culture, including the Arkadiko Bridge, which is still in existence. In the 7th century BC, Assyrian king Sennacherib constructed stone aqueducts to carry water near the city of Nineveh; one of the aqueducts crossed a small valley at Jerwan with five corbelled arches, and was long and wide. In Babylonia in 626 BC, a bridge across the Euphrates was built with an estimated length of . In India, the Arthashastra treatise by Kautilya mentions the construction of bridges and dams. Ancient China has an extensive history of bridge construction, including cantilever bridges, rope bridges, and bridges built across floating boats.<ref>{{Multiref
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The ancient Romans built many durable bridges using advanced engineering techniques.<ref name=roman>{{Multiref
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}}</ref> Many Roman aqueductssome still standing today used a semicircular arch style. Examples include the Alcántara Bridge in Spain and the Pont du Gard in France.<ref>{{Multiref
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}}</ref> The Romans used cement as a construction material, which could be mixed with small rocks to form concrete, or mixed with sand to form mortar to join bricks or stones. Some Roman cements, particularly those containing volcanic ash, were waterproof.<ref>{{Multiref
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300 to 1400
thumb|left|alt=A graceful stone bridge spanning a river, with trees in the background|The Anji Bridge, which uses a shallow segmental arch, was built in China 600 AD.
The oldest surviving stone bridge in China is the Anji 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.<ref name=anji>{{Multiref
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--> Rope bridges, a simple type of suspension bridge, were used by the Inca civilization in the Andes mountains of South America prior to European colonization in the 16th century.<ref>{{Multiref
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In Medieval Europe, bridge design capabilities declined after the fall of Rome, but revived in the High Middle Ages in France, England, and Italy with the construction of bridges like the Pont d'Avignon, bridges of the Durance river, and the Old London Bridge.<ref name=MedEv>{{Multiref
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}}</ref> Surviving examples include the Ponte Vecchio in Florence, the Old Exe Bridge, and the Monnow Bridge in Wales.
1400 to 1750
thumb|right|alt=A white bridge, covered with a roof, passing over a canal with buildings on both sides|The Rialto Bridge, built in 1591, crosses the Grand Canal in Venice.
In 15th- and 16th-century Europe, the Renaissance brought a new emphasis on science and engineering.<ref>{{Multiref
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}}</ref> Figures such as Galileo Galilei, Fausto Veranzio, and Andrea Palladio (author of I quattro libri dell'architettura) wrote treatises that applied a rigorous, analytic approach to architecture and building. Their innovations included truss bridges and stone segmental arches, resulting in Florence's Ponte Santa Trinita, the Rialto Bridge in Venice, and Paris's Pont Neuf.<ref>{{Multiref
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1750 to 1900
In the late 18th century, the design of arch bridges was revolutionized in Europe by Jean-Rodolphe Perronet and John Rennie. They designed arches that were flatter than semicircular Roman arches, which yielded faster construction times, better water flow under the bridge, and slimmer piers. These designs were used for the Pont de la Concorde and New London Bridge.<ref name=rennie>{{Multiref
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thumb|alt=A large suspension bridge, with large towers made of stone|The mass production of steel enabled the construction of large suspension bridges. The Brooklyn Bridge, built in the 1870s, was the first suspension bridge to use steel for its cables.
With the advent of the Industrial Revolution, iron became an important construction material for bridges. Both cast iron (which is strong under compression, but brittle) and wrought iron (which was more ductile and better under tension) were used for building bridges.<ref>{{Multiref
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The age of railways began in the 1820s, and led to major innovations in bridge design. Britain is representative of how railways influenced bridge-building in industrialized nations: led by designers Isambard Kingdom Brunel, Robert Stephenson, and Joseph Locke, British railway bridges steadily grew in size as the decades passed. Notable bridges of that era include the High Level Bridge (1849), Royal Border Bridge (1850), Britannia Bridge (1850), Royal Albert Bridge (1859), and Clifton Suspension Bridge (1864). The number of railway bridges in Britain increased from 30,000 to 60,000 during the Railway Mania era.<ref>{{Multiref
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}}</ref> Railway bridges primarily used masonry and stone arch designs, because those could withstand the tremendous loads imposed by trains, but iron beam designs (on masonry or stone piers) were also used. The abundance of inexpensive lumber in North America led that continent to favor timber as a bridge material: using truss designs (for long spans) and trestle designs (for spanning deep ravines).<ref name=timber>{{Multiref
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The mass production of steel in the late 19th century provided a new material for bridges, enabling lighter, stronger truss bridges and cantilever bridges; and steel wires replaced iron bars as the preferred material for suspension bridge cables.<ref>{{Multiref
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--><!-- The flexible and dynamic nature of suspension bridges requires special design considerations to safely carry rail traffic.<ref name=SuspRail>{{Multiref
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1900 to present
thumb|alt=A suspension bridge crossing a deep rocky The Sidi M'Cid Bridge in Algeria was the highest bridge in the world when it was built in 1912.
Throughout the 20th century, new bridgesby designer Othmar Ammann and othersrepeatedly broke records for span distances, enabling transportation networks to cross increasingly wider rivers and valleys.<ref>{{Multiref
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}}</ref> The late 20th century saw several major innovations in bridge design. Extradosed bridges were introduced and found widespread use, predominantly in Japan. In China, concrete-filled steel tubes were adopted as a new approach to building arch bridges. Fiber-reinforced polymerswhich do not suffer from the rust problems that plague steelwere used in bridges for many applications, such as beams, deck slabs, prestressing cables, wraps on the exterior of concrete elements, and internal reinforcing within concrete. In the 21st century, a bridge span exceeded for the first time with the construction of the 1915 Çanakkale Bridge.
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Etymology
The Oxford English Dictionary traces the origin of the word bridge to the Old English word brycg, of Germanic origin. There is a possibility that the word can be traced farther back to Proto-Indo-European *bʰrēw-.
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Uses
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thumb|alt=A bridge, topped with soil and vegetation, passing over a highway|This wildlife crossing bridge is in Israel.
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The purpose of any bridge is to traverse an obstacle. A bridge can provide support and transport for railways, cars, pedestrians, pipelines, cables, or any combination of these. Aqueducts were developed early in human history, and carried water to towns and cities. Canal systems sometimes include navigable aqueducts (also called canal bridges) to carry boats across a valley or ravine.
Transportation
[[File:Magdeburg Kanalbrücke aerial view 13.jpg|thumb|right
|alt=A bridge carrying canal with water, passing over a valley|The Magdeburg Water Bridge in Germany carries boats across a valley. ]]
Until the early 19th century, most bridges were designed to carry pedestrians, horses, and horse-drawn carriages. Following the invention of railways, many rail bridges were built; in Britain the number of bridges doubled during the railway-building boom in the mid-19th century. Railway bridges have unique requirements because of the heavy loads they carrya single locomotive can weigh . Railway bridges are designed to minimize deflection (bending under load), to maximize robustness (localize the damage caused by accidents), and to tolerate heavy impacts (sudden shocks from, for example, rail wheels striking an imperfection in the track). These requirements led railways to avoid curved bridges, suspension bridges, and cable-stayed bridges; instead, straight beam or truss bridges are commonly used. The explosive growth of motorway networks in the 20th century required bridges to span ever longer distances to reach islands and cross valleys, along with the urban introduction of elevated railways and monorails.
Grade separation
An important application of bridges is improving safety and traffic flow at traffic junctions where roads or railways cross at ground level. Such intersections require vehicles to stop, and lead to slower traffic, wasted fuel, and higher incidence of collisions. One technique to mitigate these issues is to build a bridge, enabling one of the roads to pass over the other: this process is known as grade separation.<ref>{{multiref
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Pedestrians
Some bridges, known as footbridges, are devoted to pedestrian traffic. They range from simple boardwalks enabling passage over marshy land to elevated skybridgesincluding the Minneapolis Skyway Systemwhich shield pedestrians from harsh winter weather.<ref>{{Multiref
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Military
Military bridges are an important type of equipment in the field of military engineering. They perform a variety of wartime roles, namely quickly traversing obstacles in the midst of battle, or facilitating resupply behind front lines. Military bridges can be categorized as wet bridges that rest on pontoon floats, and dry bridges that rest on piers, river banks, or anchorages. A crude mechanism to cross a small ravine is to place a fascine (a large bundle of pipes or logs) into the ravine to enable vehicles to drive across.
[[File:PontBailey.jpg|thumb|left
| alt=A metal bridge in a forest
| Invented for wartime use, Bailey bridges found civilian use after WWII.]]
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Armoured vehicle-launched bridges are carried on purpose-built vehicles. These vehicles typically have the same cross-country performance as a tank, and can carry a bridge to an obstacle and deploy ("launch") the bridge.<ref>{{Multiref
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During wartime, bridges are often damaged by bombing or by combat engineers. Bridges can be valuable targets because they are immobile, relatively easy to spot from the air, and damage to the bridge can disrupt the enemy's transportation network.<ref>{{Multiref
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Other
Some bridges accommodate uses other than transportation. Pipeline bridges carry oil pipes or water pipes across valleys or rivers. Many historical bridges supported buildings, including shrines, factories, shops, restaurants, and houses. Notable examples were the Old London Bridge and Ponte Vecchio. Some bridges built in Europe in the Middle Ages incorporated chapels into their design. In the modern era, bridge-restaurants can be found at some highway rest areas; these support a restaurant or shops directly above the highway and are accessible to drivers moving in both directions. Examples include the Will Rogers Archway over the Oklahoma Turnpike and the several Illinois Tollway oasis locations. The Nový Most bridge in Bratislava features a restaurant set atop its single tower. Conservationists use wildlife bridges to reduce habitat fragmentation and animal-vehicle collisions.<ref>{{Multiref
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Structure and form
Bridges are primarily classified by their basic structural design: arch, truss, cantilever, suspension, cable-stayed, or beam.<ref>{{Multiref
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Basic structures
The choice of bridge structure to use in a particular situation is based on many factors, including aesthetics, environment, cost, and purpose. Some bridge spans combine two types of basic structures; for instance, the Brooklyn Bridge is primarily a suspension structure, but also uses cable-stays.<ref>{{Multiref
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Arch bridge
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| alt2 = An arched bridge spanning a river, deck suspended below the arch by vertical lines
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Arch bridges consist of a curved arch, under compression, which supports the deck either above or below the arch. The shape of the arch can be a semicircle, ellipse, pointed arch, or segment of a circle.<ref>{{Multiref
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Truss bridge
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| alt1 = A bridge spanning a river, consisting of several triangles, with the bridge deck forming the lower edge of the set of triangles
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| image2 = Inverted truss bridge.svg
| alt2 = A bridge spanning a river, consisting of several triangles, with the bridge deck forming the upper edge of the set of triangles
| caption2 = Deck truss
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A truss bridge is composed of multiple, connected triangular elements.<!--
--> The set of triangles form a rigid whole, which rests on the foundation at both ends, applying a vertical force downward. The deck can be carried on top of the truss ("deck truss") or at the bottom of the truss ("through truss").<ref>{{Multiref
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}}</ref> Through trusses are useful when more clearance under the bridge is required; deck trusses permit oversize loads and do not interfere with overhead objects, such as electrical lines. The individual bars can be made of iron or wood, but most modern truss bridges are made of steel. The horizontal bars along the top are usually in compression, and the horizontal bars along the bottom are usually in tension. Bars connecting the top and bottom may be in tension or compression, depending on the layout of the triangles. Trusses typically have a span-to-depth ratio (the width of a structure divided by its height) ranging from 10 to 16, compared to beam bridges which typically have a ratio ranging from 20 to 30. Trusses tend to be relatively stiff, and are commonly used for rail bridges which are required to carry very heavy loads.
Cantilever bridge
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| alt1= A bridge spanning a river, where there is a solid pier in the middle of the river, and the entire bridge is resting on that pier (and not resting on the banks of the river).
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Cantilever bridges consist of beams or trusses that are rigidly attached to a support (pier or anchorage) and extend horizontally from the support without additional supports.<ref>{{Multiref
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Some cantilever bridges have a suspended span (beam or truss) in the center, connecting the two cantilevers where they meet.<ref>{{Multiref
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--> Cantilever construction is a method of building a bridge superstructure, which can be utilized for arch and cable-stayed bridges, as well as cantilever bridges. In this technique, construction begins at a support (specifically a pier, abutment, or tower) and extends outwards across the obstacle, with no support from below.<ref>{{Multiref
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Suspension bridge
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| alt2 = A bridge spanning a river, with a single tall tower in the middle of the river, and a curved cable passing from one riverbank to the other, passing over the top of the tower. The bridge deck (road) is suspended from the curved cable by vertical lines.
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Suspension bridges have large, curved cables attached to the tops of tall towers, and suspend the bridge deck from the cables. In the early 19th century, the first modern suspension bridgessuch as the Jacob's Creek Bridgewere chain bridges that used iron bars rather than bundled wires for the cables. After steel wire became widely available, longer cables could be built by stringing hundreds of wires between the towers and bundling them, enabling suspension bridges to achieve spans long. When the bridge crosses a river, stringing the wires across the large span is a complex process.<ref>{{Multiref
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Cable-stayed bridge
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Cable-stayed bridges are similar to suspension bridges, but the cables that support the deck connect directly to the towers. The inclined cables may be arranged in a fan pattern or a harp pattern.<ref>{{Multiref
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}}</ref> Modern cable-stayed bridges became popular after World War II, when the design was used for many new bridges in Germany. When traversing a wide obstacle, designers have a choice of suspension or cable-stayed structures. Suspension bridges can achieve a longer span, but cable-stayed bridges use less cable for a given span size, do not require anchorages, and the deck can be readily built by cantilevering outward from the towers.<ref>{{Multiref
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Beam bridge
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Beam bridges are simple structures consisting of one or more parallel, horizontal beams or girders that span an obstacle.<ref name=beam>{{multiref
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Other forms
In addition to the basic bridge structures, there are many other forms of bridges. The following sections describe some of the more common forms, but are not an exhaustive list.
Movable bridge
thumb|alt=A tall drawbridge, open, over a river|Tower Bridge in London is a movable bridge.
Movable bridges are designed so that all or part of the bridge deck can be moved, usually to permit tall trafficsuch as tall boats or shipsto pass by.<ref>{{Multiref
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}}</ref> Notable movable bridges include El Ferdan Railway Bridge in Egypt, Erasmusbrug bascule in Rotterdam, and Limehouse Basin footbridge in London. In the modern era, designers sometimes create unusual movable bridges with the intention of establishing signature bridges for a town or locality. Examples include the Puente de la Mujer swing bridge in Buenos Aires, the Gateshead Millenniuma rare example of a tilt bridgeover the River Tyne, and the Hörn Bridge in Germany.
Long multi-span bridge
thumb|left|alt=A large bridge, consisting of multiple tall sections, passing over a wide valley|The Millau Viaduct crosses the Tarn river valley in France.
There are a variety of terms that describe long, multi-span bridgesincluding viaduct, trestle, continuous, and causeway. The usage of the terms can overlap, but each has a specific focus.<ref>{{Multiref
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}}</ref> Viaducts (carrying vehicles) and aqueducts (carrying water) are bridges crossing a valley or underpass, supported by multiple arches or piers.<ref>{{Multiref
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}}</ref> Romans built many aqueducts, some of which are still standing today. Notable viaducts include Penponds Viaduct in England, Garabit Viaduct in France, Tunkhannock Viaduct in Pennsylvania, and Millau Viaduct in France.
A trestle bridgecommonly used in the 19th century for railway bridges consists of multiple short spans supported by closely spaced structural elements. A trestle is similar to a viaduct, but viaducts typically have taller pier supports and longer spans. A continuous truss bridge is a long, single truss that rests upon multiple supports. A continuous truss bridge may use less material than a series of simple trusses because a continuous truss distributes live loads across all the spans (in contrast to a series of simple trusses, where each truss must be capable of supporting the entire live load). Visually, a continuous truss looks similar to a cantilever bridge, but a continuous truss experiences hogging stresses at the supports and sagging stresses between the supports.<ref name=contTruss>{{Multiref
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Extradosed
alt=A concrete bridge over a river|thumb|The Shinmeisai Bridge (foreground) in Japan is an example of an extradosed bridge.
An extradosed bridge combines features of a box girder bridge and a cable-stayed bridge.<ref>{{Multiref
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--> Extradosed bridges are appropriate for spans ranging from to . Unlike suspension bridges or cable-stayed bridges, the towers of an extradosed bridge often rest on the deck (rather than on a footing) and are solidly connected to the deck. Because of the relatively flat angle of the cables, the cables of an extradosed bridge compress the deck horizontally, performing a function comparable to prestressing wires that are used within concrete girders. Extradosed bridges may be appropriate in applications where the deck must have a shallow depth to maximize clearance under the bridge; or where towers must be relatively short to abide by aviation safety constraints.
Pontoon bridge
thumb|alt=A concrete bridge over a large body of water|Floating concrete pontoons support the weight of the [[Nordhordland Bridge as it crosses a deep fjord in Norway.
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A pontoon bridge, also known as a floating bridge, uses floats or shallow-draft boats to support a continuous deck for pedestrian or vehicle travel over water.<ref>{{Multiref
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During the Second Persian invasion of Greece, Persian ruler Xerxes built a large pontoon bridge across the Hellespont, consisting of two parallel rows of 360 boats.<ref>{{Multiref
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Several pontoon bridges are in use in the modern world. Washington state in the US has several, including Hood Canal Bridge. In Norway, Nordhordland Bridge crosses a deep fjord by resting on floating concrete pontoons. Many armies have pontoon bridges that can be rapidly deployed, including the PMP Floating Bridge, designed by the USSR.
Design
Design process
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The process for designing a new bridge typically goes through several stages, progressively refining the design. An early step in the design processsometimes called conceptual designis to consider the multiple requirements that a bridge must satisfy. Requirements that are directly related to function include lifespan, safety, climate, soil condition, traffic volume, the size and nature of the obstacle to be traversed, and clearance required for passage underneath.<ref name=reqmnt>{{Multiref
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}}</ref> Other constraints may include construction cost, maintenance cost, aesthetics, time available for construction, owner preference, and experience of the builders. Some bridge designs consider factors such as impact on the environment and wildlife, and the bridge's economic, social, and historic relationship to the local community. After the requirements of a bridge are established, a bridge designer uses structural analysis methods to identify candidate designs. Several designs may meet the requirements. The value engineering methodology can be used to select a final design from multiple alternatives. This methodology evaluates candidate designs based on weighted scores assigned to several different criteria, including cost, service life, durability, availability of resources, ease of construction, construction time, and maintenance cost.
An important requirement considered during the design process is the service life, which is a specific number of years that the bridge is expected to remain in operation with routine maintenance (and without requiring major repairs).<ref>{{Multiref
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Specifications and standards
One of the requirements a new bridge must satisfy is compliance with the local bridge design specifications and codes whichin some countriesmay be legally binding requirements.<ref>{{Multiref
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}}</ref> In many countries, these specifications are developed and published by standards organizations that define acceptable bridge-building practices and designs. In Europe, the organization is the European Committee for Standardization, and the standards it publishes are the Eurocodes. In the United States, the American Association of State Highway and Transportation Officials (AASHTO) publishes the AASHTO LRFD Bridge Design Specifications. Canada's bridge standard is the Canadian Highway Bridge Design Code, developed by the non-profit CSA Group. Agencies that regulate aviation or waterways may also impose standards that dictate some aspects of a bridge design, such as requirements for aviation warning lights at the top of bridge towers, or navigational warning lights on bridge supports located in navigable waterways.<ref>{{Multiref
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Aesthetics
thumb|left|alt=A train moving atop a stone bridge in an attractive valley|upright=1.3|The [[Brusio spiral viaducta part of the Bernina railway in Switzerlandis a World Heritage Site.
]]
A bridge's appearance is one of the factors considered during its design. Attractive bridges can have a positive impact on a community, and some bridges can even be considered as works of art.<ref>{{Multiref
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}}</ref> Qualities that influence the perceived attractiveness of a bridge include proportion, color, texture, order, refinement, environmental integration, and functionality.
The art historian Dan Cruickshank notes that bridges are regarded as manifestations of human imagination and ambition, and that many bridges transcend their original utilitarian role and become a work of art. He writes "[a] great bridge has an emotional impact, it has a sublime quality and a heroic beauty that moves even those who are not accustomed to having their senses inflamed by the visual arts."
Material
<!--
thumb|alt=A construction site with a halfway built concrete structure|This concrete bridge support is being prepared for a concrete pour. After the concrete cures, the green reinforcing bars will be permanently embedded inside.
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<!--
{{multiple image
| header = Prestressed_concrete
| caption_align = center
| image1 = Acero postesado.jpg
| alt1 = A concrete beam with several steel cables emerging from holes in the side of the beam
| caption1 = These post-tensioned cables are tightened with hydraulic jacks to ensure the concrete stays in compression.
--> <!--
thumb|alt=A large concrete section of a bridge is suspended above the ground by a large crane.|The small circular holes in this section of [[box girder will hold prestressing cables, which run the length of the girder.]]
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A bridge designer can select from a wide variety of materials, including wood, brick, rope, stone, iron, steel, and concrete.<ref>{{Multiref
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Wood is an inexpensive renewable resource with a high strength-to-weight ratio, but it is rarely used for modern roadway bridges because it is prone to degradation from the environment, and is much weaker than steel or concrete. Wood is primarily used in beam or truss bridges including covered bridges, and is also used to build large trestle bridges for railways.<ref>{{Multiref
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}}</ref> When wood is used, it is often in the form of glued laminated timber. Masonry includes stone and brick, and is suitable only for elements of a bridge that are under compression (as opposed to tension), therefore, masonry is limited to structures such as arches or foundations.<ref>{{Multiref
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thumb|alt= An ornate bridge made of iron, passing over a small, lush valley|The Iron Bridge in Shropshire, England, completed in 1781, is the first major bridge made entirely of cast iron.
Ironincluding cast iron and wrought ironwas used extensively from the late 18th century to late 19th century, primarily for arch and truss structures. Iron is relatively brittle, and has been replaced by steel for all but ornamental uses.<ref>{{Multiref
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}}</ref> Steel is one of the most common materials used in modern bridges because it is strong in both compression and tension. Steel was made in small quantities in antiquity, but became widely available in the late 19th century following invention of new smelting processes. Truss bridges and beam bridges are often made of steel, and steel wires are an essential component of virtually all suspension bridges and cable-stayed bridges.<ref>{{Multiref
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}}</ref> Steel is a critical component in concrete bridges, because steel reinforcing bars or steel prestressed cables must be embedded within concrete to make it sufficiently strong.<ref>{{Multiref
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Concrete is commonly used in modern bridges, and many roadway bridges are built primarily with a reinforced concrete beam structure, often of the box girder variety.{{efn|
High-performance concrete is becoming more commonly used in bridges (compared to conventional concrete) because it suffers less damage from heavy traffic and lasts longer. Conventional concrete has strength about 25 to 50 MPa, whereas high-performance concrete has strength about 50 to 100 MPa.
}} The shape of concrete elements is determined by the formwork (mold) into which the concrete is poured (cast): the concrete will adopt the shape of the formwork as it cures.<ref>{{Multiref
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}}</ref> Concrete is a strong and inexpensive material, but is brittle and can crack when in tension. If concrete is used in elements that may experience tension, prestressed cables are usually embedded within the concrete and tightened, which compresses the concrete.<ref name=prestress>{{Multiref
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}}</ref> When a horizontal beam is placed into the bridge and carries a load, the undesirable tension (produced by the tendency of the beam to sag) is counteracted by the compression from the prestressed cables. The prestressed cables can be pre-tensioned (stretched beforeand whilethe concrete cures); or post-tensioned (placed within tubes in the concrete, and tightened after the concrete cures).<ref name="Cruickshank 2010 322–327">{{Multiref
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Double-deck bridge
<!--
thumb|alt=A long, straight, flat bridge over a large body of water|The Padma Bridge in Bangladesh carries rail traffic on the lower deck and vehicular traffic on the upper deck.
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Designers may choose to use a double-deck design (also known as double-decked or double-decker), that carries two decks on top of each other. This technique can be used to increase the amount of traffic a bridge can carry; or when the location constrains the size of the bridge. Double-deck bridges also permit two different kinds of traffic to be safely carried. For example, motor vehicles can be separated from pedestrians or railways. Some double-deck bridges carry rail on one deck, and vehicles on the other deck. An early example was the Niagara Falls Suspension Bridge, and a modern example is the Dom Luís I Bridge in Portugal. Because of their ability to carry large amounts of motor vehicles, double-deck bridges are often found near large cities carrying cars on both decks, for example, the DuSable Bridge in Chicago, Tsing Ma Bridge in Hong Kong, the Øresund Bridge connecting Copenhagen and Malmö, and the Shimotsui-Seto Bridge near Kurashiki. The George Washington Bridge in New York carries 14 motor vehicle lanes (eight above, six below), and is the world's busiest bridge, carrying over 100 million vehicles annually.
Load analysis
thumb|alt=A very large suspension bridge passing over a large body of water|upright=1.3|The [[San Francisco–Oakland Bay Bridge is designed to withstand severe earthquakes. The eastern span, shown above, is a self-anchored suspension bridge which can survive a once-in-1,500-year earthquake.
]]
A bridge design must accommodate all loads and forces that the bridge might reasonably experience. The totality of the forces that the bridge must tolerate is the structural load, which is often divided into three components: dead load, live load, and environmental load. The dead load is the weight of the bridge itself. The live load is all forces and vibrations caused by traffic passing over the bridge, including weight, braking, and acceleration.<!--
{{efn|
An important component of the live load carried by a bridge is the vehicle and rail traffic the bridge carries.<ref name=traffic>{{multiref
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In addition to the weight of the vehicle, other forces must be considered, including braking, acceleration, centrifugal forces, and resonant vibrations.<ref name=braking>.
</ref>
For roadways, the loads imposed by truck traffic far exceed the loads imposed by passenger cars, and so the bridge design process focuses on trucks.
The loads created by trains and vehicles can be determined by modelling, or by relying on data and algorithms contained in engineering specifications published by Eurocode or AASHTO organizations. Alternatively, weigh-in-motion technology can measure loads on existing bridges with comparable traffic patterns, providing real-world data which can be used to evaluate a proposed bridge design.
--> The environmental load encompasses all forces applied by the bridge's surroundings, including weather, earthquakes, mudslides, water currents, flooding, soil subsidence, frost heaving, temperature fluctuations, and collisions.<ref name=load>{{Multiref
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{{efn|In addition to classifying loads as dead/live/environmental, an alternative is: dead (or permanent) load (bridge structure) and live (or transient) load (traffic and environment).<ref>{{Multiref
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For sporadic events like floods, earthquakes, collisions, and hurricanes, bridge designers select a maximum severity that the design must accommodate. The severity is based on the return period, which is average time between events of a given magnitude. Return periods range from 10 to 2,500 years, depending on type of event and the country in which the bridge is located.<ref name=returnPeriod>{{Multiref
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Authors discussing international bridge design policies provide return period examples of 10, 50, 350, 475, 500, 1,000, 2,000, and 2,500 years.
}} Longer return periods are used for bridges that are a critical part of the transportation infrastructure. For example, if the bridge is a key lifeline in case of emergencies, the designer may utilize relatively long return period, for instance, 2,000 years; in this example, the design must endure the strongest storm that is expected to happen once every 2,000 years.
Stress and strain
The load forces acting on a bridge cause the components of the bridge to become stressed. Stress is a measure of the internal force experienced within a material. Strain is a measure of how much a bridge component bends, stretches, or twists in response to stress. Some strain (bending or twisting) may be acceptable in a bridge component if the material is elastic. For example, steel can tolerate some stretching or bending without failing. In contrast, concrete is inelastic, and the change in its shape when stressed is negligible (until the stress becomes excessive and the concrete fails).<ref name=stressstrain>{{Multiref
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A critical phase of the design process is calculating the maximum stress that each bridge component will experience, and selecting an appropriate design and size for the components to ensure they will safely tolerate the loads on the bridge. Stresses are categorized based on the nature of the force that causes the stress, namely: compression, tension, shear, and torsion. Compression forces compact a component by pushing inward (for example, as felt by a bridge foundation when a heavy tower is resting on it). Tension is a stretching force experienced by a component when pulled (for example by the cables of a suspension bridge). Shear is a sliding force experienced by a component when two offset external forces are applied in opposite directions (for example, during an earthquake when the upper part of a structure is pulled north, and the lower part is pulled south). Torsion is a twisting force.<ref name=stress>{{multiref
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<!--
thumb|alt=A computer app displaying a bridge with engineering data|Engineers use [[finite element method software tools to evaluate a bridge design.<ref>{{Multiref
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The bridge design process typically employs structural analysis methods that divide the bridge into smaller components, and analyze the components individually, subject to certain constraints. A proposed bridge design is then usually modeled with formulas or computer applications.<ref name=computr>{{Multiref
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}}<!--
{{efn|Bridge design models include both mathematical models and numerical models. The mathematical models that assess bridge loads and stresses are complex formulas that typically include differential equations. Solving these formulas directly is virtually impossible, so numerical models are used to provide approximate, but accurate, results.
}}
{{efn|An alternative to the finite element method is the simpler, but less powerful, finite strip method. The finite element method models a proposed bridge by dividing it into numerous small, interconnected pieces, and applying a computer algorithm to the pieces. The algorithm simulates the stresses on the bridge that are caused by the loads, and can iterate over time to simulate dynamic movements.
}}
--> To ensure that a proposed bridge design is sufficiently strong to endure foreseeable stresses, many bridge designers use limit state design methodologies (used in Europe and China) or Load and Resistance Factor Design (LRFD) methodologies (used in US).<ref>{{Multiref
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These methodologies add a margin of safety to the bridge design by incorporating safety factors into the design process.
The safety factors are applied two ways: (a) increasing the assumed loads and stresses the bridge will experience; and (b) decreasing the assumed strength of the bridge's structure.
A bridge designer evaluates the output of the models to determine if the design meets the design goals. Many criteria are evaluated when determining if a bridge design is sufficient, including deflection, cracking, fatigue, flexure, shear, torsion, buckling, settlement, bearing, and sliding. The criteria, and their allowable values, are termed limit states. The set of limit states selected for a design are based on the bridge's structure and purpose.<ref>{{Multiref
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Vibration
[[File:FEMA - 2816 - Photograph by FEMA News Photo taken on 01-17-1994 in California.jpg|thumb|alt=A collapsed concrete bridge, with a broken support pier
|The 1994 Northridge earthquake damaged several bridges.<ref>{{Multiref
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Many loads imposed on a bridgewind, earthquakes, and vehicular trafficcan cause a bridge to experience irregular or periodic forces, which may cause bridge components to vibrate or oscillate.<ref>{{Multiref
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Winds can produce a variety of vibrational forces on a bridge, including flutter, galloping, and vortex shedding.<ref name=flutter_vortex>{{Multiref
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<!--
The Eurocode guideline for bridge design specifies that vibration stress due to moving vehicles should be accounted for by including an additional 10% to 70% of the vehicles' static load; the exact value depends on the span length, the number of traffic lanes, and the type of stress (bending moment or shear force).
-->
If resonance issues are identified in the design process, they must be mitigated. Common techniques to address vibration include increasing the rigidity of the bridge deck by adding trusses and adding dampers to cables and towers.<ref>{{Multiref
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{{efn|
One mechanism used to combat oscillations is a tuned mass damper, which was first used in the Pont de Normandie in 1995.<ref>{{Multiref
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--> Neglecting to account for vibrations and oscillations can lead to bridge failure.<!--
{{efn|
An early example of a bridge failure related to resonant vibration was the Angers Bridge collapsed in 1850, killing over 200 people, partly due to soldiers marching on the bridge in a manner that increased resonant oscillations. In spite of advances in engineering technologies, modern bridges continue to experience severe swaying issues when large numbers of pedestrians are walking on the bridge, even when they are not marching in a synchronized manner.
}}
--> The Tacoma Narrows Bridge collapsed in 1940 in winds of , even though the bridge was designed to withstand winds up to . Investigations revealed that the designer failed to account for wind-induced flutter and resonant vibrations.<ref name=narrows>{{Multiref
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The Golden Gate Bridge was damaged in 1951 due to wind forces, and as a result was reinforced with additional stiffening elements.
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Bridges can suffer severe damage when subjected to earthquake ground motions.<ref>{{Multiref
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{{efn|Government agencies that have published earthquake engineering standards for bridges include: Chinese Ministry of Transport, Japan Road Association, European Committee for Standardization, American Association of State Highway and Transportation Officials, and California Department of Transportation.
}}
-->
Construction
The structural elements of a bridge are generally divided into the substructure and the superstructure. The substructure consists of the lower portions of the bridge, including the footings, abutments, piers, pilings, anchorages, and bearings. The superstructure rests upon the substructure, and consists of the deck, trusses, arches, towers, cables, beams, and girders.<ref>{{Multiref
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Construction process
[[File:Schematic diagram showing some structural elements of a bridge.svg|thumb|alt=A schematic diagram identifying the various parts of a hypothetical bridge|right|upright=1.2|Some elements of a fictional bridge. 1 Approach, 2 Arch, 3 Truss, 4 Abutment, 5 Bearing, 6 Deck and beams, 7 Pier Cap, 8 Pier, 9 Piling, 10 Footing, 11 Caisson, 12 Subsoil.<ref>{{Multiref
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Construction of a bridge is typically managed by construction engineers, who are responsible for planning and supervising the construction process. Important aspects of this role include budgeting, scheduling, periodically conducting formal design reviews, and communicating with the bridge designers to interpret and update the design plans.<ref>{{Multiref
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The forces experienced by a bridge during construction can be larger or have a different nature than the forces it will experience after completion. The bridge design process typically focuses on the strength of the fully completed bridge, but it should also consider the unusual stresses that individual elements will experience during construction. Special techniques may be required during construction to avoid excessive stresses, such as temporary supports under the bridge, temporary bracing or reinforcement, or permanently strengthening specific elements.<ref>{{Multiref
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Substructure
alt=Two schematic diagrams showing how force is transmitted in a flat bridge compared to an arched bridge|thumb|left|upright=1.2|Abutments are an important element of a substructure. Beam bridges (left) direct force vertically into the abutments; some arch bridges (right) direct forces diagonally. 1 Deck, 2 Abutments, 3 Subsoil, 4 Load on bridge, 5 Force from abutment into subsoil.
Construction of all bridge types begins by creating the substructure. The first elements built are usually the footings and abutments, which are typically large blocks of reinforced concrete, entirely or partially buried underground. The footings and abutments support the entire weight of the bridge, and transfer the weight to the subsoil.<ref name=foundation>{{Multiref
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Abutments are usually located at the ends of a bridge deck, where it reaches the subsoil. They direct the weight into the subsoil, either vertically or diagonally.<ref name=abutDiag>{{Multiref
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Constructing supports in water
thumb|alt=A large concrete structure in the middle of a river, kept dry by a steel wall surrounding it|This concrete bridge pier is being built within a steel cofferdam.
<!--
| image2 = Caisson Schematic diagram.svg
| alt2 = A schematic diagram showing the cross section of a structure used to excavate bridge foundations under water
| caption2 = To build a bridge pier in water, caissons may be used to hold workers and machinery during excavation.
}}
-->
When bridge supports (piers or towers) are built in a river, lake, or ocean, special technologies must be utilized. Caissons can be used to provide a workspace while constructing the submerged portion of the supports. A caisson is a large, watertight, hollow structure, open on the bottom. It is usually sunk to the bottom of the water and workers can work inside, preparing the ground for the footings. When excavation is complete, a caisson is typically filled with concrete to create all or part of the footing.<ref name=caisson>{{multiref
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Another approach for constructing foundations in water is a box caisson, which is a large steel or concrete box, open on top, which is towed by tugboats to the bridge site, then sunk to the bottom and filled with concrete.<ref name=boxCaisson>{{Multiref
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Bearings
thumb|upright=0.9|alt=Two cylinders of steel, supporting a large steel bridge, and resting on a concrete support| Bearings can prevent damage to the superstructure by permitting small movements.
Bearings are often placed between the superstructure and the substructure at the points of contact. Bearings are mechanical devices that enable small movementswhich may result from thermal expansion and contraction, material creep, or minor seismic events. Without bearings, the bridge structure may be damaged when such movements occur. Bearings can be selected to permit small rotational or slipping movements in a specific direction, without permitting movements in other directions. Types of bearings used on bridges include hinge bearings, roller bearings, rocker bearings, sliding bearings, spring bearings, and elastomeric bearings.<ref name=bearing>{{Multiref
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Superstructure
<!--
thumb|alt=A huge wooden arch structure, over which an arch bridge is being built|This temporary [[falsework will be removed after an arch is built over it.]]
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After the substructure is complete, the superstructure is built, resting on the substructure. Beam bridge superstructures may be built in place, or fabricated off-site (precast) and transported to the bridge site.<ref>{{Multiref
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thumb|left|alt=A bridge being constructed, with two large cranes on top|[[Gantry crane|Gantries are one technique used to gradually assemble a bridge deck.<ref>{{Multiref
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Arch bridge superstructure construction methods depend on the material. Concrete or stone arches use a temporary wood structure known as falsework or centering to support the arch while it is built.<ref name=falsework>{{Multiref
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Cantilever bridge superstructures are usually built incrementally by proceeding outward from anchorages or piers. Most cantilever superstructures can be built without temporary support piers, as the bridge can support itself as it extends outward. A similar process is used for steel or concrete cantilevers: prefabricated sections may be positioned at ground (or water) level and hoisted into place with a gantry, or may be transported horizontally along the previously completed portion of the cantilever. Concrete cantilevers require steel prestressing cables to be passed through tubes within each section and tightened, which will put the concrete into compression.<ref>{{Multiref
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Cable-stayed bridge superstructures begin with the construction of one or more towers which rest directly on footings that are part of the substructure. The deck is constructed in pieces beginning at the towers and moving outward. The pieces can be put into place by hoisting, supporting from below, launching, or cantilevering from the portion of the deck that has been assembled.<ref name=CabStyConstr>{{Multiref
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If the deck is made of concrete, steel prestressing cables are inserted through tubes inside each deck section, and tightened to put the concrete into compression.<ref>{{Multiref
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Suspension bridge superstructure construction usually begins with the towers. The towers may be steel or concrete, and rest directly on footings. The large cables are created by hauling a large pulley back and forth across the span, stringing multiple wires between the anchorages in each pass, in a process termed spinning. After the wires are spun, they are bundled together to form the cables. The cables are securely fastened to the anchorages at both ends. Vertical wires called hangers are suspended from the cables, then small sections of the deck are attached to the hangers, and the sections are attached to each other.<ref>{{Multiref
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Towers
thumb|alt=A thick steel cable passing over the top of a suspension bridge tower|A suspension bridge cable transfers its load to the tower by resting on a curved saddle.
<!--
upright=1.3|alt=A diagram showing a curved line passing over a curved object on top of a tower; and another diagram showing two lines that each of which end inside a tower|thumb|A cable transfers its load to a tower by either (a) passing over a curved saddle (left image); or (b) the end of the cable is anchored into the tower (right image). Key: 1 Cable, 2 Saddle, 3 Anchor, 4 Tower.
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<!--
|image2=Verazanno Narrows bridge cable anchorage.jpg
|width2=200
|alt2=Many parallel steel wires, attached at one end to a large concrete block
|caption2=A large concrete anchorage (right) holds the end of a suspension bridge cable, visible here as multiple wire strands (left).-->
<!--
[[File:CableStayedBridge Multi-Strand Anchor.jpg|thumb|alt=A steel cylinder with several thick wires passing through it|Anchors like this are used at both ends of a cable in a cable-stayed bridge, to attach the cable to the tower and to the deck.
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Towers, made of either concrete or steel, are an important component of the superstructure of cable-stayed bridges and suspension bridges. Concrete is generally suitable for towers up to about tall, whereas steel towers can be taller.<ref>{{Multiref
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}}</ref> Towers support the bridge cables, which hold the weight of the deck and the traffic. Most of the load imposed on a tower is applied vertically downward on the tower, rather than sideways. Towers experience a compression stress, in contrast to cables, which experience a tension stress. There are two mechanisms used to attach a cable to a tower: saddles or anchors. Saddles are curved structures which allow a cable to pass through (or over the top of) a tower. An anchor holds the end of a cable. Saddles are often used in suspension bridges, and anchors are often used in cable-stayed bridges.<ref>{{Multiref
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Cables
[[File:Verrazano-Narrows Bridge- The Beginning (15694087186).jpg|thumb|left|alt=Two men are standing high in the air on a walkway, and a wheel is above them, suspended by wires.|A spinning wheel pulls two wires at a time to gradually build up a suspension bridge cable.
]]
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{{multiple image
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| image1 = Suspension bridge cable cross section strands wires.svg
| alt1 = A circular cross section, showing 37 smaller circles inside a large circle; and a small dot inside one of the small circles
| caption1 = This cross-section of a cable shows 37 strands, where each strand consists of multiple small wires.<ref>{{Multiref
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Steel cables are an element of both cable-stayed bridges and suspension bridges. Cables are made of one or more strands, and each strand consists of multiple wires. A wire is a thin, flexible piece of solid steel, of higher tensile strength than normal steel, and with a diameter of 3mm to 7mm.
Cables are typically constructed at the bridge site by unspooling wires or strands from large reels.<ref>{{Multiref
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--> Large suspension bridges may use cables that are over in diameter and weigh over .<ref>{{Multiref
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|. 94 tonnes per strand.
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Before building the cables of a suspension bridge, temporary catwalks must be constructed to support the wires while they are drawn across the span and over the tops of the towers.<ref>{{Multiref
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The air spinning method was used for all suspension bridges until the prefabricated strand method was invented in the 1960s.
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The air spinning method is slower because it requires the spinning pulley to cross the span thousands of times, pulling a pair of wires each time.<ref name=AS_PPWS>{{Multiref
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After 300 to 500 wires are pulled, aluminum bands are used to bundle them into strands. The wires within a strand may be parallel, or they may wrap around each other in a twisted (spiral) pattern. Air spinning always produces strands that contain parallel wires. The prefabricated strand method can utilize strands with parallel or twisted wires.
<!--
After all the wires have been drawn across the full span and are connected to the towers, they are compacted into a tight bundle by a hydraulic device that moves along the cable and compresses the wires together.<ref>{{Multiref
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Deck
thumb|right|alt=A large concrete arch bridge being constructed|The deck of this arch bridge is being [[incremental launching|horizontally pushed onto the substructure with jacks.<ref name=launch>{{Multiref
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The deck of a bridge is the flat, horizontal surface that extends across the full span of a bridge. Decks generally rest on beams or box girders. When a deck is rigidly attached to its supporting beams or girders, they function together as a single structure.<ref name=deckgirder>{{Multiref
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}} Below the ribs are steel floor beams, placed crosswise to the ribs. Orthotropic steel decks are more expensive than concrete steel decks, but weigh less. They are useful in applications where weight is critical, a thin deck is required, or the environment is subject to earthquakes or extreme cold weather.
Many decks have a wearing surface on top, which is a layer of material designed to be periodically replaced after it is worn away by vehicular traffic. Wearing surfaces are typically made of aggregate (small rocks) mixed with a binder such as asphalt, polyurethane, epoxy resins, or polyester.<!--
asphalt, polyurethane, epoxy resins, or polyester.
--><ref>{{Multiref
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Constructing the deck (and its supporting beams or girders) can be difficult when the bridge is over water or a deep valley. A variety of techniques are available, and the choice depends on the topography of the site, the deck material (concrete or steel), traffic or obstacles under the bridge, and whether sections can be built off-site and transported to the bridge. Methods of deck construction include building atop temporary supports, jacking up from the ground, incremental launching (building the entire deck on the approach road and pushing it horizontally), lifting from below with a hoist mounted on the bridge, cantilevering (incrementally extending the deck, starting from towers or abutments), and lifting with a floating crane.<ref name=constrMethod>{{Multiref
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Protection
<!--
alt=A thick, old wire cable, with paint that is partially worn off|thumb|Paint can be used to reduce deterioration of steel components. Steel bridges need to be repainted periodically, as seen in this wire hanger from the Golden Gate Bridge, which is painted international orange.
-->
To achieve the designed service life, a bridge must be protected from deterioration by incorporating certain features into the design. Bridges can deteriorate due to a variety of causes, including rust, corrosion, chemical actions, and mechanical abrasion. Deterioration is sometimes visible as rust on steel components, or cracks and spalling in concrete. Deterioration can be slowed with various measures, primarily aimed at excluding water and oxygen from the bridge elements. Techniques to prevent water-based damage include drainage systems, waterproofing membranes (such as polymer films), and eliminating expansion joints. Concrete bridge elements can be protected with waterproof seals and coatings. Reinforcing steel within concrete can be protected by using high-quality concrete and increasing the thickness of the concrete surrounding the steel. Steel elements of a bridge can be protected by paints or by galvanizing with zinc.<ref>{{Multiref
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Bridge scour is a potentially serious problem when bridge footings are located in water. Currents in the water can cause the sand and rocks around and below the footings to wash away over time. This effect can be mitigated by placing a cofferdam around the footings, or surrounding the footings with large, carefully placed rocks.<ref>{{Multiref
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}}</ref> Bridges with supports in navigable waterways are designed to withstand ship strikes up to a specific, predefined magnitude. In addition to waterway markings and pilot warning systems, bridge supports in water may be surrounded by physical protections such as fenders, pilings, or small artificial islands.
Operation and financing
Management
After a bridge is completed and becomes operational, management processes are employed to ensure that it remains open to traffic, avoids safety incidents, and achieves its intended lifespan. These processescollectively referred to as bridge management include technical activitiesnamely, maintenance, inspection, monitoring, and testing. In addition to technical tasks, management encompasses planning, budgeting, and prioritization of maintenance activities. Bridge managers use bridge management systems and life-cycle cost analysis methodologies to manage a bridge and estimate the maintenance costs of a bridge throughout its lifetime.<ref>{{Multiref
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Maintenance
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|caption = A crew of workers are using a maintenance traveler (the mobile cage structure) to inspect the Clifton Suspension Bridge.
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Maintenance activities seek to prolong the life of the bridge, reduce lifecycle costs, and ensure the safety of the community. Maintenance tasks can be categorized as corrective tasks and preventive tasks. Corrective tasks are implemented in response to unexpected issues that arise, for example, repairing structural elements (piers, beams, girders, towers, or cables) and replacing bearings.
Preventive tasks include washing, painting, lubricating bearings, sealing the deck, filling cracks, removing snow, filling potholes, and repairing minor issues with structures and electrical fixtures. Some preventive tasks are performed on a periodic schedule. An example schedule for periodic bridge maintenance tasks is:
washing entire structure (1–2 years);
sealing deck surface (4–6 years);
lubricating bearings (4 years);
painting steel bridge components (12–15 years);
replacing the deck's wearing surface (12 years);
sealing sidewalks (5 years);
filling cracks (4 years);
and cleaning drains (2 years).. Maintenance periods shown are from the New York City Department of Transportation.
Inspection and monitoring
thumb|right|alt=A tall bridge covered in temporary scaffolding|Scaffolding is erected under the Sitterviadukt rail bridge in Switzerland while maintenance on the deck truss is performed.
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|caption = Concrete can degrade and spall, as seen in this bridge pier, exposing internal steel reinforcing bars.
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An important part of maintenance is inspecting a bridge for damage or degradation, and taking steps to mitigate any issues detected. Degradation can come from environmental sources, including expansion/contraction from freeze/thaw cycles, rain, oxidation of steel, and sea spray. Human activities may also cause damage, for example: vehicular traffic, mechanical abrasion, poor bridge design, and improper repair procedures.<ref>{{Multiref
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Relying solely on visual inspection to assess degradation of a bridge can be unreliable, so inspectors use a variety of nondestructive testing techniques. These techniques include hammer strike tests, ultrasonic pulse velocity tests, seismic tomography, and ground penetrating radar.<ref>{{Multiref
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}}</ref> Various electrical tests that assess permeability and resistance can give insight into the condition of surface concrete. X-rays can be passed through concrete to obtain data about concrete density and condition. Videography using slender probes can be used where access is available. Measurements of the state of a bridge may be made automatically and periodically using structural health monitoring (SHM) technologies. Some testingtermed destructive testingrequires removing samples from the bridge and taking them to a laboratory for analysis with microscopes, sonic devices, or X-ray diffraction. Destructive testing is performed by removing cores drilled from concrete, or a small piece of steel wire cut from a cable.<!--
SHM places permanent sensors at critical locations in the bridge, which may be sampled at any time to obtain data about stresses and chemical degradation. The sensors may be placed in the bridge during construction, or while it is in operationfor example, to monitor the quality of a repair.<ref>{{Multiref
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To evaluate the condition of large steel cables, electrical coils are moved along the cable, measuring the induction of the cable, which can reveal corrosion issues. Detailed measurements of the external surface of a bridge can be recorded using lidar technology. Comparing measurements taken at multiple points in time can reveal long-term changes.
A variety of structural tests may be performed to evaluate a bridge's condition. One test involves placing loads in selected locations on the bridge, and measuring the resulting deflections: sensitive instruments measure how much the bridge elements bend or twist, and the results can reveal if the element is not performing within expected limits. Another test involves jacking the bridge deck off its supports slightly, and measuring the force required. Cables can be evaluated by vibrating them and measuring their dynamic response.
-->
Financing
Funding for bridge construction and operation comes from a variety of sources, including fuel taxes, annual vehicle registration fees, tolls, congestion fees, and usage fees based on satellite tracking. Some bridgesparticularly in developing countriesare financed by international sources including the World Bank or China's Belt and Road Initiative.<ref>{{Multiref
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The cost of building a bridge is typically borne by government agencies, but since 1990 an increasing number of bridges are built and paid for by private companies using a public–private partnership (PPP) agreement. In a PPP project, the government grants the right to build the bridge to a company, and the company recoups its expenses by collecting tolls for a fixed period of time.<ref>{{Multiref
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Failures
thumb|alt=A broken bridge, which has fallen into the water over which it used to pass|The Nanfang'ao Bridge in Taiwan collapsed because of excessive corrosion that went undetected.
<!--
| image1 = Francis_Scott_Key_Bridge_and_Cargo_Ship_Dali_NTSB_view_(cropped).jpg
| caption1 = This bridge in Balimore collapsed after a powerless containership collided with it.
thumb|left|alt=A concrete bridge, passing over a lake, that is broken, with many pieces having fallen into the water|This bridge in the US failed during Hurricane Katrina.
-->
Bridge failures are of special importance to structural engineers, because the analyses of the failures provide lessons learned that serve to improve design and construction processes.<ref>{{Multiref
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(improper design and construction method, collision, overloading, fire, corrosion, and lack of inspection and
maintenance). Over time, bridge failures have led to significant improvements in bridge design, construction, and maintenance practices.<ref>{{Multiref
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In the modern era, in spite of advances in bridge engineering methodologies, bridge failures continue to occur regularly.<ref>{{Multiref
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--> It did not open until two years laterafter dampers were installed.<ref name=millen>{{Multiref
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Society and culture
Signature bridges
[[File:炫彩津门35大沽桥.jpg|thumb|right
|alt=A large bridge crossing a river, in nighttime, with skyscrapers in the background|The Dagu Bridge in China was designed to be a signature bridge.]]
Many bridgesknown as signature bridgesare strongly identified with a particular community.<ref>{{Multiref
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}} Large suspension bridges, in particular, are often regarded as iconic landmarks that symbolize the cities in which they are located. Notable examples include the Brooklyn Bridge in New York; the Golden Gate Bridge in San Francisco; the Clifton Suspension Bridge in Bristol; and the Széchenyi Chain Bridge in Budapest. Some visually impressive bridges, such as the Dagu Bridge in China, are designed with the express goal of creating a landmark for the host city.<ref>{{Multiref
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}}</ref> Dan Cruickshank notes that some bridges have the ability to "transform a place a community and ... can make its mark on the landscape and in men's minds, capture the imagination, engender pride and sense of identity and define a time and place."
Economic and environmental impact
Bridges can have significant impactsboth positive and negative on a community's environment, society, and economy. During the bridge design process, these effects may be modeled with life cycle sustainability assessment or building information modeling, and the results can be used to adjust the bridge's design to improve its effect on the environment, society, and economy.<ref name=sustain>{{Multiref
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Positive effects of a new bridge can include shorter transport times, employment opportunities, improvements to social equity, improved productivity, and increases to the gross domestic product (GDP). Construction of a new bridge can increase wages in the surrounding region, but can also increase income inequity between genders (men see larger wage gains than women) and between education levels (higher-educated persons see more gains than lower-educated persons).<ref>{{Multiref
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Global warming can be exacerbated by the creation of a new bridge, because the production of concrete significantly contributes to the greenhouse effect. Although bridges can boost the economy of the surrounding region, they also increase environmental pollution proportionally. Corruption endemic in the construction industry (including bridge building) can produce negative societal and economic consequences.<ref name=corrupt>{{Multiref
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Suicide
Suicides are sometimes carried out by jumping off bridges. This method can account for 20% to 70% of suicides in urban areas with access to tall bridges. In some regions, suicide by jumping disproportionately affects young adults, who tend to have lower inhibitory control. Specific bridges can gain notoriety and attract persons experiencing a suicidal crisis, which creates a feedback loop. High-risk bridges often have suicide prevention barriers installed, which dramatically decrease the suicide rate on the bridge. Installing barriers on a high-risk bridge generally reduces the jumping suicide rate in a region, although in some instances, other bridges become substitutes.
Profession and regulation
<!--
thumb|left|The Institution of Civil Engineers, located in London, is the world's oldest professional civil engineering association.
-->
The profession of civil engineeringwhich includes the discipline of bridge buildingbegan to be formalized in the 18th century when a school of engineering was created in France within the Corps des Ponts et Chaussées at the École de Paris, under the direction of Jacques Gabriel. In 1747 the first school dedicated to bridge building was founded: the École Nationale des Ponts et Chaussées<!--
--> led by French engineers Daniel-Charles Trudaine and Jean-Rodolphe Perronet. The first professional organization focused on civil engineering was the Institution of Civil Engineers founded in 1818 in the UK, initially led by Thomas Telford.
In the modern era, bridge engineering is regulated by national organizations, such as the National Council of Examiners for Engineering and Surveying (US), the Canadian Council of Professional Engineers (Canada), and the Engineering Council (UK). In many countries, bridge engineers must be licensed or meet minimal educational requirements. Some countries require engineers to pass qualification examinations, for example, in the US engineers must pass the Fundamentals of Engineering exam followed by the Principles and Practice of Engineering exam. In Poland, bridge engineers are required to obtain certification by accumulating several years of experience under a senior engineer, and passing an exam administered by the Polish Chamber of Civil Engineers. International cooperation in the field of engineering is facilitated by the World Federation of Engineering Organizations.
<!-- ===Numismatics===
alt=A colorful 500-euro banknote illustrated with a bridge and a map of Europe|thumb|The 500 euro banknote displays a cable-stayed bridge.
Bridges have been featured on coins since antiquity. In 1996, the European Commission held a competition to select art for the euro banknotes. Robert Kalina, an Austrian designer, won with a set of illustrations of bridges, chosen because they symbolize links between states in the union and with the future. The designs were supposed to be devoid of any identifiable characteristics, so as to not show favoritism to specific countries. But the initial designs by Kalina were discovered to be of specific bridges, including the Rialto and the Pont de Neuilly, and so were changed to be more generic. Each banknote denomination depicts a bridge design representative of a certain architectural era.<ref name=euro>{{Multiref
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The eras utilized for bridge images on Euro banknotes are:
Classical (€5),
Romanesque (€10),
Gothic (€20),
Renaissance (€50),
Baroque and Rococo (€100),
19th-century iron and glass (€200), and 20th-century (€500).}}-->
Art and culture
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|alt = A man blowing a trumpet, with a rainbow in the background
|caption = In Norse mythology, the Bifröst rainbow bridge connects Earth with Asgard.
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<!--
thumb|alt=The cover of a book, which has an illustration of a Catholic priest standing before a mountain and a bridge|upright=0.7|The Pulitzer Prize-winning novel The Bridge of San Luis Rey revolves around a bridge failure that killed five people.-->
<!--
{{Quote box
| qalign = center
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| quote = <poem>
Reaching for the world, as our lives do,
As all lives do, reaching that we may give
The best of what we are and hold as true:
Always it is by bridges that we live.</poem>
| source = Philip Larkin "Bridge for the Living" (1981)<ref>{{Multiref
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Bridges occur extensively in art, legend, and literature, often employed as metaphors or symbols of human accomplishment, lifespan, or experience.<ref>{{Multiref
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}}</ref> In Norse mythology, the home of the godsAsgardis connected to the earth by Bifröst, a rainbow bridge. Many bridges in Europe are named Devil's Bridge, and in some cases have folkloric stories that explain why the bridge is associated with the devil. Christian legend holds that St. Bénézet lifted a huge boulder to begin construction of the Pont Saint-Bénézet bridge, and went on to found the apocryphal Bridge-Building Brotherhood. Bridges feature prominently in paintingsoften in the backgroundas in the Mona Lisa.
In the modern era, bridges continue to feature prominently in culture. Bridges are often the setting for pageants, celebrations, and processions. Authors have used bridges as the centerpiece of novels, notably The Bridge on the Drina by Ivo Andrić and Thornton Wilder's The Bridge of San Luis Rey. British poet Philip Larkin, inspired by the construction of the Humber Bridge near his home, wrote "Bridge for the Living" in 1981.<ref>{{Multiref
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}}</ref> Neighboring nations have chosen to designate some shared bridges as friendship bridges or peace bridges.<ref>{{Multiref
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}}</ref> In 1996, the European Commission held a competition to select art for the euro banknotes. Robert Kalina, an Austrian designer, won with a set of illustrations of bridges, chosen because they symbolize links between states in the union and paths to the future.<ref name=euro>{{Multiref
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See also
- International Association for Bridge and Structural Engineering
- European Engineer
- World Federation of Engineering Organizations
- Regulation and licensure in engineering
- National Council of Examiners for Engineering and Surveying USA
- Canadian Council of Professional Engineers
- Chartered Engineer (UK)
- Engineering Council UK
- Civil engineer
- American Society of Civil Engineers
- Institution of Civil Engineers UK?
- Canadian Society for Civil Engineering
-->
References
Footnotes
Citations
Sources
Books
- {{cite book
| last=Abdunur
| first=Charles
| chapter=Inspection, Monitoring, and Assessment
| title=The Manual of Bridge Engineering
| editor-last=Ryall
| editor-first=Michael
| isbn=978-0-7277-2774-9
| chapter-url=https://archive.org/details/manualofbridgeen0000unse/page/883
| access-date=1 September 2025
| year=2000
| publisher=Thomas Telford
| pages=883–942
}}
- {{cite book
|last = Adams
|first = Charles Kendall
|author-link = Charles Kendall Adams
|title = Universal Cyclopædia and Atlas
|date = 1909
|oclc = 707041389
|publisher = D. Appleton and Company
|pages = 161–174
|url = https://books.google.com/books?id=TttTAAAAYAAJ
|access-date = September 1, 2022
|language = en
|chapter = Bridges
}}
- {{cite book
| title=Bridge Engineering Handbook. Vol 5. Construction and Maintenance
| edition = Second
| first= Sreenivas
| last= Alampalli
| chapter = Bridge Maintenance
| pages = 269–298
| editor-last1=Chen
| editor-first1= Wai-Fah
| editor-last2 = Duan
| editor-first2 = Lian
| isbn= 978-1-4398-5233-0
| doi=10.1201/b16467
| year=2014
| publisher=CRC Press
}}
- {{cite book
| title=Bridge Engineering Handbook. Vol 5. Construction and Maintenance
| edition = Second
| first= Mourad
| last= Bakhoum
| chapter = Bridge Construction Methods
| pages = 567–627
| editor-last1=Chen
| editor-first1= Wai-Fah
| editor-last2 = Duan
| editor-first2 = Lian
| isbn= 978-1-4398-5233-0
| doi=10.1201/b16467
| year=2014
| publisher=CRC Press
}}
- {{Cite book
| title=Design of Highway Bridges: An LRFD Approach
| last=Barker
| first=Richard M.
| isbn=978-1-119-64631-0
| url=https://archive.org/details/designofhighwayb0000bark_s2n4
| access-date=1 September 2025
| year=2007
| publisher=Wiley
}}
- {{Cite book
| title=Mechanics of Materials
| last=Beer
| first=Ferdinand
| author-link=Ferdinand P. Beer
| isbn=9789339217624
| url=https://archive.org/details/mechanicsofmater0000beer_a6t7
| access-date=17 September 2025
| year=2017
| publisher=McGraw Hill
}}
- {{Cite book
| title=The Creation of Bridges: From Vision to Reality - the Ultimate Challenge of Architecture, Design and Distance
| last=Bennett
| first=David
| isbn=978-1-55041-552-0
| url=https://archive.org/details/creationofbridge0000davi
| access-date=1 September 2025
| year=1999
| publisher=Aurum Press
}}
- {{cite book
|last = Bennett
|first = David
|chapter = The History and Aesthetic Development of Bridges
|title = The Manual of Bridge Engineering
|editor-last = Ryall
|editor-first = Michael
|isbn = 978-0-7277-2774-9
|chapter-url = https://archive.org/details/manualofbridgeen0000unse/page/1
|access-date = 1 September 2025
|year = 2000
|publisher = Thomas Telford
|pages = 1–42
}}
- {{cite book
|title = Handbook of International Bridge Engineering
|last = Biliszczuk
|first = Jan
|display-authors = etal
|chapter = Bridge Engineering in Poland
|pages = 593–634
|editor-last1 = Chen
|editor-first1 = Wai-Fah
|editor-last2 = Duan
|editor-first2 = Lian
|isbn = 978-1-4398-1029-3
|url = https://archive.org/details/handbookofintern0000unse_j3m6
|access-date = 1 September 2025
|year = 2014
|publisher = Taylor & Francis
}}
- {{cite book
| last=Birnstiel
| first=Charles
| chapter=Moveable Bridges
| title=The Manual of Bridge Engineering
| editor-last=Ryall
| editor-first=Michael
| isbn=978-0-7277-2774-9
| chapter-url=https://archive.org/details/manualofbridgeen0000unse/page/663
| access-date=1 September 2025
| year=2000
| publisher=Thomas Telford
| pages=663–698
}}
- {{cite book
| title=Bridge Engineering Handbook. Vol 5. Construction and Maintenance
| edition = Second
| first= Simon
| last= Blank
| display-authors=etal
| chapter = Concrete Bridge Construction
| pages = 67–84
| editor-last1=Chen
| editor-first1= Wai-Fah
| editor-last2 = Duan
| editor-first2 = Lian
| isbn= 978-1-4398-5233-0
| doi=10.1201/b16467
| year=2014
| publisher=CRC Press
}}
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| last=Brown
| first=David
| title=Bridges: Three Thousand Years of Defying Nature
| date=2005
| publisher=Mitchell Beazley
| isbn=978-1-84533-080-4
| url=https://archive.org/details/bridgesthreethou0000davi
| access-date=1 September 2025
}}
- {{cite book
| title=Bridge Engineering Handbook. Vol 1. Fundamentals
| edition = Second
| first= Steve
| last= Cai
| display-authors=etal
| chapter = Wind Effects on Long-Span Bridges
| pages = 535–554
| editor-last1=Chen
| editor-first1= Wai-Fah
| editor-last2 = Duan
| editor-first2 = Lian
| isbn= 978-1-4398-5234-7
| doi=10.1201/b15616
| year=2014
| publisher=CRC Press
}}
- {{cite book
| last=Chavel
| first=Brandon
| chapter=Bridge Deck Design
| title=Steel Bridge Design Handbook
| publisher=American Institute of Steel Construction
| isbn=
| chapter-url=https://cloud.aisc.org/NSBA/handbook/b917_sbdh_chapter_17.pdf
| access-date=4 November 2025
| year=2022
| archive-date=3 December 2025
| archive-url=https://web.archive.org/web/20251203212340/https://www.aisc.org/globalassets/nsba/design-resources/steel-bridge-design-handbook/b917_sbdh_chapter17.pdf
| url-status=live
}}
- {{cite book
|title = Handbook of International Bridge Engineering
|editor-last1 = Chen
|editor-first1 = Wai-Fah
|editor-last2 = Duan
|editor-first2 = Lian
|isbn = 978-1-4398-1029-3
|url = https://archive.org/details/handbookofintern0000unse_j3m6
|access-date = 1 September 2025
|doi = 10.1201/b15520
|year = 2014
|publisher = Taylor & Francis
}}
- {{cite book
|title = Bridge Engineering Handbook. Vol 5. Construction and Maintenance
|edition = Second
|first1 = Xiaohua
|last1 = Cheng
|first2 = Lian
|last2 = Duan
|chapter = Rehabilitation and Strengthening of Highway Bridge Superstructures
|pages = 443–485
|editor-last1 = Chen
|editor-first1 = Wai-Fah
|editor-last2 = Duan
|editor-first2 = Lian
|isbn = 978-1-4398-5233-0
|url = https://books.google.com/books?id=BCeOAgAAQBAJ
|access-date = 31 October 2025
|year = 2014
|publisher = CRC Press
|archive-date = 24 December 2025
|archive-url = https://web.archive.org/web/20251224082337/https://books.google.com/books?id=BCeOAgAAQBAJ
|url-status = live
}}
- {{cite book
|last1 = Choudhury
|first1 = Jamilur
|last2 = Hasnat
|first2 = Ariful
|title = IABSE-JSCE Joint Conference on Advances in Bridge Engineering-III
|chapter = Bridge Collapses Around the World: Causes and Mechanisms
|isbn = 9789843393135
|chapter-url = https://www.iabse-bd.org/session/k2.pdf
|access-date = 4 November 2025
|year = 2015
|publisher = International Association for Bridge and Structural Engineering
|pages = 26–34
|archive-date = 25 November 2025
|archive-url = https://web.archive.org/web/20251125051032/https://www.iabse-bd.org/session/k2.pdf
|url-status = live
}}
- {{cite book
| last=Collings
| first=David
| chapter=Composite Construction
| title=The Manual of Bridge Engineering
| editor-last=Ryall
| editor-first=Michael
| isbn=0727727745
| chapter-url=https://archive.org/details/manualofbridgeen0000unse/page/407
| access-date=1 September 2025
| year=2000
| publisher=Thomas Telford
| pages=407–448
}}
- {{cite book
|title = Bridge Engineering Handbook. Vol 5. Construction and Maintenance
|edition = Second
|first = Joyce
|last = Copelan
|chapter = Bridge Maintenance
|pages = 337–350
|editor-last1 = Chen
|editor-first1 = Wai-Fah
|editor-last2 = Duan
|editor-first2 = Lian
|isbn = 9781439852330
|url = https://books.google.com/books?id=BCeOAgAAQBAJ
|access-date = 31 October 2025
|year = 2014
|publisher = CRC Press
}}
- {{cite book
|title = Bridges: Heroic Designs that Changed the World
|last = Cruickshank
|first = Dan
|author-link = Dan Cruickshank
|isbn = 9780007881086
|url = https://archive.org/details/isbn_9780007881086
|access-date = 1 September 2025
|year = 2010
|publisher = Harper Collins
}}
<!--
- {{Cite book
|title=Research Perspectives: Traffic Loading on Highway Bridges
| url=https://archive.org/details/researchperspect0000dawe
|access-date=15 September 2025
|first=Peter
|last=Dawe
|date=2003
|publisher=Thomas Telford
|isbn=0727732412
}}
-->
- {{cite book
| title=How to Read Bridges: A Crash Course In Engineering and Architecture
| last=Denison
| first=Edward
| isbn=9781408171769
| url=https://archive.org/details/howtoreadbridges0000deni
| access-date=1 September 2025
| year=2012
| publisher=Rizzoli
}}
- {{cite book
| title=The Mauryan Polity
| last=Dikshitar
| first=V.R.R.
| isbn=8120810236
| orig-year=1932
| year=1993
| publisher=Motilal Banarsidass
| url=https://archive.org/details/in.ernet.dli.2015.78927/page/n340/mode/1up?q=bridge
| access-date=20 September 2025
}} Reprinted in 1993.
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|title = Bridge Engineering Handbook. Vol 3. Substructure Design
|edition = Second
|first = Ralph
|last = Dornsife
|chapter = Bearings
|pages = 1–34
|editor-last1 = Chen
|editor-first1 = Wai-Fah
|editor-last2 = Duan
|editor-first2 = Lian
|isbn = 9781439852309
|url = https://books.google.com/books?id=Q6iNAgAAQBAJ
|access-date = 31 October 2025
|year = 2014
|publisher = CRC Press
|archive-date = 26 November 2025
|archive-url = https://web.archive.org/web/20251126234501/https://books.google.com/books?id=Q6iNAgAAQBAJ
|url-status = live
}}
- {{cite book
|title = Bridge Engineering Handbook. Vol 5. Construction and Maintenance
|edition = Second
|first = Jackson
|last = Durkee
|chapter = Steel Bridge Construction
|pages = 1–50
|editor-last1 = Chen
|editor-first1 = Wai-Fah
|editor-last2 = Duan
|editor-first2 = Lian
|isbn = 9781439852330
|url = https://books.google.com/books?id=BCeOAgAAQBAJ
|access-date = 31 October 2025
|year = 2014
|publisher = CRC Press
|archive-date = 24 December 2025
|archive-url = https://web.archive.org/web/20251224082337/https://books.google.com/books?id=BCeOAgAAQBAJ
|url-status = live
}}
- {{cite book
|url=https://books.google.com/books?id=Tkm5UZJz8z0C&q=Bridges+constructed+by+pounding
|last=Edgerton
|first=Robert B.
|year=2010
|title=The Fall of the Asante Empire: The Hundred-Year War For Africa's Gold Coast
|publisher=Simon and Schuster
|isbn=9781451603736
}}
- {{cite book
|title = Finite Element Analysis and Design of Steel and Steel–Concrete Composite Bridges
|last = Ellobody
|first = Ehab
|isbn = 9780124172470
|year = 2014
|publisher = Butterworth-Heinemann
|url = https://archive.org/details/finiteelementana0000ello
|access-date = 1 September 2025
}}
- {{cite book
| last=Elnashai
| first=Amr
| chapter=Seismic Response and Design
| title=The Manual of Bridge Engineering
| editor-last=Ryall
| editor-first=Michael
| isbn=0727727745
| chapter-url=https://archive.org/details/manualofbridgeen0000unse/page/519
| access-date=1 September 2025
| year=2000
| publisher=Thomas Telford
| pages=519–548
}}
<!--
- {{cite book
| last=Farquhar
| first= Daniel
| chapter = Cable-Stay Bridges
| title=The Manual of Bridge Engineering
| editor-last=Ryall
| editor-first= Michael
| isbn= 0727727745
| chapter-url=https://archive.org/details/manualofbridgeen0000unse/page/549
| access-date=1 September 2025
| year=2000
| publisher=Thomas Telford
| pages= 549–594
}}
-->
- {{cite book
|title = Bridge Engineering Handbook. Vol 5. Construction and Maintenance
|edition = Second
|first = Dan
|last = Frangopol
|display-authors = etal
|chapter = Bridge Health Monitoring
|pages = 247–268
|editor-last1 = Chen
|editor-first1 = Wai-Fah
|editor-last2 = Duan
|editor-first2 = Lian
|isbn = 9781439852330
|url = https://books.google.com/books?id=BCeOAgAAQBAJ
|access-date = 31 October 2025
|year = 2014
|publisher = CRC Press
|archive-date = 24 December 2025
|archive-url = https://web.archive.org/web/20251224082337/https://books.google.com/books?id=BCeOAgAAQBAJ
|url-status = live
}}
- {{cite book
|title = Bridge Engineering Handbook. Vol 1. Fundamentals
|edition = Second
|first1 = Kenneth
|last1 = Fridley
|first2 = Lian
|last2 = Duan
|chapter = Timber Design
|pages = 341–369
|editor-last1 = Chen
|editor-first1 = Wai-Fah
|editor-last2 = Duan
|editor-first2 = Lian
|isbn = 9781439852347
|url = https://books.google.com/books?id=WaONAgAAQBAJ
|access-date = 31 October 2025
|year = 2014
|publisher = CRC Press
}}
- {{cite book
|title = Bridge Engineering Handbook. Vol 5. Construction and Maintenance
|edition = Second
|first1 = Gongkang
|last1 = Fu
|first2 = Dinesh
|last2 = Devaraj
|chapter = Bridge Management Using Pontis and Improved Concepts
|pages = 233–245
|editor-last1 = Chen
|editor-first1 = Wai-Fah
|editor-last2 = Duan
|editor-first2 = Lian
|isbn = 9781439852330
|url = https://books.google.com/books?id=BCeOAgAAQBAJ
|access-date = 31 October 2025
|year = 2014
|publisher = CRC Press
|archive-date = 24 December 2025
|archive-url = https://web.archive.org/web/20251224082337/https://books.google.com/books?id=BCeOAgAAQBAJ
|url-status = live
}}
- {{cite book
|title = Bridge Engineering Handbook. Vol 5. Construction and Maintenance
|edition = Second
|first = Ben
|last = Gerwick
|chapter = Substructures of Major Overwater Bridges
|pages = 137–174
|editor-last1 = Chen
|editor-first1 = Wai-Fah
|editor-last2 = Duan
|editor-first2 = Lian
|isbn = 9781439852330
|url = https://books.google.com/books?id=BCeOAgAAQBAJ
|access-date = 31 October 2025
|year = 2014
|publisher = CRC Press
}}
- {{cite book
| title=Cable Supported Bridges: Concept and Design
| last=Gimsing
| first=Niels J.
| isbn=9781119951872
| url=https://archive.org/details/cablesupportedbr0000gims
| access-date=1 September 2025
| year=1997
| edition=Second
| publisher=Wiley
}}
- {{cite book
|title = Bridge Engineering Handbook. Vol 1. Fundamentals
|edition = Second
|first = Frederick
|last = Goettemoeller
|chapter = Bridge Aesthetics: Achieving Structural Art in Bridge Design
|pages = 49–76
|editor-last1 = Chen
|editor-first1 = Wai-Fah
|editor-last2 = Duan
|editor-first2 = Lian
|isbn = 9781439852347
|url = https://books.google.com/books?id=WaONAgAAQBAJ
|access-date = 31 October 2025
|year = 2014
|publisher = CRC Press
|archive-date = 26 November 2025
|archive-url = https://web.archive.org/web/20251126072136/https://books.google.com/books?id=WaONAgAAQBAJ
|url-status = live
}}
- {{cite book
|title = Architetture Autostradali in Italia
|last = Greco
|first = Laura
|isbn = 9788849292121
|year = 2016
|language = Italian
|publisher = :it:Gangemi Editore
|url = https://books.google.com/books?id=_fZTCwAAQBAJ
|access-date = 1 September 2025
}}
- {{cite book
| last=Hewson
| first=Nigel
| chapter=Design of Prestressed Concrete Beams
| title=The Manual of Bridge Engineering
| editor-last=Ryall
| editor-first=Michael
| isbn=0727727745
| chapter-url=https://archive.org/details/manualofbridgeen0000unse/page/241
| access-date=1 September 2025
| year=2000
| publisher=Thomas Telford
| pages=241–314
}}
<!--
- {{cite book
| title=Spanning Washington: Historic Highway Bridges of the Evergreen State
| last=Holstine
| first=Craig
| isbn=9780874222814
| url=https://books.google.com/books?id=NDJSAAAAMAAJ
| access-date=15 September 2025
| year=2005
| publisher=Washington State University Press
}}
-->
- {{cite book
| title=LRFD Bridge Design: Fundamentals and Applications
| last=Huff
| first=T.
| isbn=9781000543377
| url=https://books.google.com/books?id=MCtaEAAAQBAJ
| access-date=10 September 2025
| year=2022
| publisher=CRC Press
}}
- {{cite book
|title = Bridge Engineering Handbook. Vol 3. Substructure Design
|edition = Second
|first1 = Mohammed
|last1 = Islam
|first2 = Amir
|last2 = Malek
|chapter = Shallow Foundations
|pages = 181–238
|editor-last1 = Chen
|editor-first1 = Wai-Fah
|editor-last2 = Duan
|editor-first2 = Lian
|isbn = 9781439852309
|url = https://books.google.com/books?id=Q6iNAgAAQBAJ
|access-date = 31 October 2025
|year = 2014
|publisher = CRC Press
|archive-date = 26 November 2025
|archive-url = https://web.archive.org/web/20251126234501/https://books.google.com/books?id=Q6iNAgAAQBAJ
|url-status = live
}}
- {{cite book
| last1=Jones
| first1=Vardiman
| last2=Howells
| first2=John
| chapter=Suspension Bridges
| title=The Manual of Bridge Engineering
| editor-last=Ryall
| editor-first=Michael
| isbn=0727727745
| chapter-url=https://archive.org/details/manualofbridgeen0000unse/page/595
| access-date=1 September 2025
| year=2000
| publisher=Thomas Telford
| pages=595–662
}}
- {{cite book
|title = Bridge Engineering Handbook. Vol 3. Substructure Design
|edition = Second
|first1 = Michael
|last1 = Knott
|first2 = Zolan
|last2 = Prucz
|chapter = Vesssel Collision Design of Bridges
|pages = 89–112
|editor-last1 = Chen
|editor-first1 = Wai-Fah
|editor-last2 = Duan
|editor-first2 = Lian
|isbn = 9781439852309
|url = https://books.google.com/books?id=Q6iNAgAAQBAJ
|access-date = 31 October 2025
|year = 2014
|publisher = CRC Press
}}
- {{cite book
|title = Bridge Engineering Handbook. Vol 1. Fundamentals
|edition = Second
|first1 = Alexander
|last1 = Krimotat
|chapter = Structural Modeling
|pages = 253–269
|editor-last1 = Chen
|editor-first1 = Wai-Fah
|editor-last2 = Duan
|editor-first2 = Lian
|isbn = 9781439852309
|url = https://books.google.com/books?id=WaONAgAAQBAJ
|access-date = 31 October 2025
|year = 2014
|publisher = CRC Press
|archive-date = 26 November 2025
|archive-url = https://web.archive.org/web/20251126072136/https://books.google.com/books?id=WaONAgAAQBAJ
|url-status = live
}}
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|title = Bridge Engineering Handbook. Vol 1 Fundamentals
|edition = Second
|first = John
|last = Kulicki
|chapter = Highway Bridge Design Specifications
|pages = 113–130
|editor-last1 = Chen
|editor-first1 = Wai-Fah
|editor-last2 = Duan
|editor-first2 = Lian
|isbn = 9781439852309
|url = https://books.google.com/books?id=WaONAgAAQBAJ
|access-date = 31 October 2025
|year = 2014
|publisher = CRC Press
|archive-date = 26 November 2025
|archive-url = https://web.archive.org/web/20251126072136/https://books.google.com/books?id=WaONAgAAQBAJ
|url-status = live
}}
- {{cite book
|title = Bridge Engineering Handbook. Vol 2. Superstructure Design
|edition = Second
|first = John
|last = Kulicki
|chapter = Highway Truss Bridges
|pages = 283–308
|editor-last1 = Chen
|editor-first1 = Wai-Fah
|editor-last2 = Duan
|editor-first2 = Lian
|isbn = 9781439852293
|url = https://books.google.com/books?id=JpClAgAAQBAJ
|access-date = 31 October 2025
|year = 2014a
|publisher = CRC Press
}}
- {{cite book
|title = Bridge Engineering Handbook. Vol 1. Fundamentals
|edition = Second
|first = Fritz
|last = Leonhardt
|chapter = Aesthetics: Basics
|pages = 29–48
|editor-last1 = Chen
|editor-first1 = Wai-Fah
|editor-last2 = Duan
|editor-first2 = Lian
|isbn = 9781439852347
|url = https://books.google.com/books?id=WaONAgAAQBAJ
|access-date = 31 October 2025
|year = 2014
|publisher = CRC Press
|archive-date = 26 November 2025
|archive-url = https://web.archive.org/web/20251126072136/https://books.google.com/books?id=WaONAgAAQBAJ
|url-status = live
}}
- {{cite book
|title = Bridge Engineering Handbook. Vol 3. Substructure Design
|edition = Second
|first = Youzhi
|last = Ma
|chapter = Deep Foundations
|pages = 238–278
|editor-last1 = Chen
|editor-first1 = Wai-Fah
|editor-last2 = Duan
|editor-first2 = Lian
|isbn = 9781439852309
|url = https://books.google.com/books?id=Q6iNAgAAQBAJ
|access-date = 31 October 2025
|year = 2014
|publisher = CRC Press
|archive-date = 26 November 2025
|archive-url = https://web.archive.org/web/20251126234501/https://books.google.com/books?id=Q6iNAgAAQBAJ
|url-status = live
}}
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|title = Bridge Engineering Handbook. Vol 2. Superstructure Design
|edition = Second
|first = Alfred
|last = Mangus
|chapter = Orthotropic Steel Decks
|pages = 589–646
|editor-last1 = Chen
|editor-first1 = Wai-Fah
|editor-last2 = Duan
|editor-first2 = Lian
|isbn = 9781439852293
|url = https://books.google.com/books?id=JpClAgAAQBAJ
|access-date = 31 October 2025
|year = 2014
|publisher = CRC Press
}}
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| last=Mulheron
| first=Mike
| chapter=Protection
| title=The Manual of Bridge Engineering
| editor-last=Ryall
| editor-first=Michael
| isbn=0727727745
| chapter-url=https://archive.org/details/manualofbridgeen0000unse/page/805
| access-date=1 September 2025
| year=2000
| publisher=Thomas Telford
| pages=805–848
}}
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|last = Nath
|first = Ram
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|title = History of Mughal Architecture
|volume = 3
|year = 1982
|isbn = 8170172977
|publisher = Abhinav Publications
|url = https://books.google.com/books?id=ha5fG13V3XcC
|access-date = 17 September 2025
}}
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| last=O'Brien
| first=Eugene
| title=Bridge Deck Analysis
| url=https://archive.org/details/bridgedeckanalys0000obri_m0m0
| access-date=12 September 2025
| year=2015
| edition=Second
| isbn=9781482227239
| publisher=CRC Press
}}
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|last1 = Ogden
|first1 = Brent
|last2 = Cooper
|first2 = Chelsey
|year = 2019
|title = Highway-Rail Crossing Handbook
|edition = 3rd
|isbn = 9781998295067
|url = https://highways.dot.gov/sites/fhwa.dot.gov/files/2022-06/fhwasa18040v2.pdf
|access-date = 7 December 2025
|publisher = Federal Highway Administration
|archive-date = 5 March 2025
|archive-url = https://web.archive.org/web/20250305230722/https://highways.dot.gov/sites/fhwa.dot.gov/files/2022-06/fhwasa18040v2.pdf
|url-status = live
}}
- {{cite book
| last=Petroski
| first=Henry
| author-link=Henry Petroski
| title=To Engineer Is Human: The Role of Failure in Successful Design
| url=https://archive.org/details/toengineerishuma0000henr
| access-date=20 September 2025
| year=1994
| isbn=1566195020
| publisher=Barnes & Noble
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| last=Reddy
| first=J. N.
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| title=An Introduction to the Finite Element Method
| url=https://archive.org/details/introductiontofi0000jnre
| access-date=10 September 2025
| edition=Third
| year=2004
| isbn=9780070607415
| publisher=McGraw Hill
}}
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| last=Ryall
| first=Michael
| chapter=Loads and Load Distribution
| title=The Manual of Bridge Engineering
| editor-last=Ryall
| editor-first=Michael
| isbn=0727727745
| chapter-url=https://archive.org/details/manualofbridgeen0000unse/page/43
| access-date=1 September 2025
| year=2000
| publisher=Thomas Telford
| pages=43–94
}}
- {{cite book
|title = Handbook of International Bridge Engineering
|last = Sakowski
|first = Eric
|chapter = Highest Bridges
|pages = 1251–1306
|editor-last1 = Chen
|editor-first1 = Wai-Fah
|editor-last2 = Duan
|editor-first2 = Lian
|isbn = 9781439810293
|url = https://archive.org/details/handbookofintern0000unse_j3m6
|access-date = 1 September 2025
|year = 2014
|publisher = Taylor & Francis
}}
- {{cite book
| title=In the Wake of Tacoma: Suspension Bridges and the Quest for Aerodynamic Stability
| last=Scott
| first=Richard
| isbn=0784405425
| url=https://archive.org/details/inwakeoftacomasu0000scot
| access-date=1 September 2025
| year=2001
| publisher=ASCE Press
}}
- {{cite book
|url=https://concrete.ethz.ch/assets/sed17.pdf
|access-date=16 October 2025
|author-last=Schlaich
|author-first=Mike
|editor-last1=Schlaich
|editor-first1=Mike
|year=2019
|title=Extradosed Bridges
|chapter=General
|pages=3–8
|isbn=9783857481680
|publisher=International Association for Bridge and Structural Engineering
|archive-date=2 November 2025
|archive-url=https://web.archive.org/web/20251102162115/https://concrete.ethz.ch/assets/sed17.pdf
|url-status=live
}}
<!--
- {{cite book
| last=Shanmugam
| first=N. E.
| chapter = Structural Analysis
| title=The Manual of Bridge Engineering
| editor-last=Ryall
| editor-first= Michael
| isbn= 0727727745
| chapter-url=https://archive.org/details/manualofbridgeen0000unse/page/95
| access-date=1 September 2025
| year=2000
| publisher=Thomas Telford
| pages= 95–224
}}
-->
- {{cite book
|title = Bridge Engineering Handbook. Vol 5. Construction and Maintenance
|edition = Second
|first = Junfeng
|last = Shi
|display-authors = etal
|chapter = Cable-Supported Bridge Construction
|pages = 85–112
|editor-last1 = Chen
|editor-first1 = Wai-Fah
|editor-last2 = Duan
|editor-first2 = Lian
|isbn = 9781439852330
|url = https://books.google.com/books?id=BCeOAgAAQBAJ
|access-date = 31 October 2025
|year = 2014
|publisher = CRC Press
}}
- {{cite book
|title = Bridge Engineering Handbook. Vol 2. Superstructure Design
|edition = Second
|first = John
|last = Shen
|chapter = Concrete Decks
|pages = 573–588
|editor-last1 = Chen
|editor-first1 = Wai-Fah
|editor-last2 = Duan
|editor-first2 = Lian
|isbn = 9781439852293
|url = https://books.google.com/books?id=JpClAgAAQBAJ
|access-date = 31 October 2025
|year = 2014
|publisher = CRC Press
}}
- {{cite book
|title = Bridge Engineering Handbook. Vol 1. Fundamentals
|edition = Second
|first = Donald
|last = Sorgenfrei
|display-authors = etal
|chapter = Railroad Bridge Design Specifications
|pages = 143–158
|editor-last1 = Chen
|editor-first1 = Wai-Fah
|editor-last2 = Duan
|editor-first2 = Lian
|isbn = 9781439852347
|url = https://books.google.com/books?id=WaONAgAAQBAJ
|access-date = 31 October 2025
|year = 2014
|publisher = CRC Press
|archive-date = 26 November 2025
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|url-status = live
}}
- {{cite book
| last=Squier
| first=Ephraim George
| author-link=E. G. Squier
| title=Peru; Incidents of Travel and Exploration in the Land of the Incas
| oclc=2396588
| url=https://archive.org/details/peruincidentsoft00squi
| access-date=13 September 2025
| year=1877
| publisher=Harper & Brothers
}}
- {{cite book
|title = Bridge Engineering Handbook. Vol 1. Fundamentals
|edition = Second
|first = Dagmar
|last = Svecova
|display-authors = etal
|chapter = Application of Fiber Reinforced Polymers in Bridges
|pages = 371–404
|editor-last1 = Chen
|editor-first1 = Wai-Fah
|editor-last2 = Duan
|editor-first2 = Lian
|isbn = 9781439852347
|url = https://books.google.com/books?id=WaONAgAAQBAJ
|access-date = 31 October 2025
|year = 2014
|publisher = CRC Press
|archive-date = 26 November 2025
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|url-status = live
}}
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|last=Talese
|first=Gay
|author-link=Gay Talese
|title=The Bridge: The Building of the Verrazano–Narrows Bridge
|url=https://books.google.com/books?id=cK-pBAAAQBAJ
|isbn=9781620409114
|publisher=Harper & Row
|orig-year=1964
|year=2014
}}
- {{cite book
|title = Bridge Engineering Handbook. Vol 5. Construction and Maintenance
|edition = Second
|first = Benjamin
|last = Tang
|chapter = Accelerated Bridge Development
|pages = 175–206
|editor-last1 = Chen
|editor-first1 = Wai-Fah
|editor-last2 = Duan
|editor-first2 = Lian
|isbn = 9781439852330
|url = https://books.google.com/books?id=BCeOAgAAQBAJ
|access-date = 31 October 2025
|year = 2014a
|publisher = CRC Press
|archive-date = 24 December 2025
|archive-url = https://web.archive.org/web/20251224082337/https://books.google.com/books?id=BCeOAgAAQBAJ
|url-status = live
}}
- {{cite book
|title = Bridge Engineering Handbook. Vol 1. Fundamentals
|edition = Second
|first = Man-Chung
|last = Tang
|author-link = Man-Chung Tang
|chapter = Conceptual Design
|pages = 1–34
|editor-last1 = Chen
|editor-first1 = Wai-Fah
|editor-last2 = Duan
|editor-first2 = Lian
|isbn = 9781439852347
|url = https://books.google.com/books?id=WaONAgAAQBAJ
|access-date = 31 October 2025
|year = 2014
|publisher = CRC Press
|archive-date = 26 November 2025
|archive-url = https://web.archive.org/web/20251126072136/https://books.google.com/books?id=WaONAgAAQBAJ
|url-status = live
}}
- {{cite book
|title = Bridge Engineering Handbook. Vol 2. Superstructure Design
|edition = Second
|first = Teddy
|last = Theryo
|chapter = Segmental Concrete Bridges
|pages = 91–170
|editor-last1 = Chen
|editor-first1 = Wai-Fah
|editor-last2 = Duan
|editor-first2 = Lian
|isbn = 9781439852293
|url = https://books.google.com/books?id=JpClAgAAQBAJ
|access-date = 31 October 2025
|year = 2014
|publisher = CRC Press
}}
- {{cite book
| title=Planning and Design of Bridges
| author=Troitsky
| first=M.S.
| isbn=0471028533
| url=https://archive.org/details/planningdesignof0000troi
| access-date=1 September 2025
| year=1994
| publisher=Wiley
}}
- {{cite book
| last=Troyano
| first=L.F.
| title=Bridge Engineering: A Global Perspective
| publisher=Thomas Telford
| year=2003
| isbn=9780727732156
| url=https://books.google.com/books?id=0u5G8E3uPUAC
| access-date=25 October 2025
}}
- {{cite book
| last=Tytler
| first=I.F.B.
| display-authors=etal
| title=Vehicles and Bridging
| isbn=0080283225
| url=https://archive.org/details/vehiclesbridging0000unse
| access-date=13 September 2025
| year=1985
| series=Battlefield Weapons Systems and Technology
| publisher=Brasey's Defense Publishers
}}
- {{cite book
| last=Vassie
| first=Perry
| chapter=Bridge Management
| title=The Manual of Bridge Engineering
| editor-last=Ryall
| editor-first=Michael
| isbn=0727727745
| chapter-url=https://archive.org/details/manualofbridgeen0000unse/page/849
| access-date=1 September 2025
| year=2000
| publisher=Thomas Telford
| pages=849–882
}}
- {{cite book
|title = Bridge Engineering Handbook. Vol 2. Superstructure Design
|edition = Second
|first = Tina
|last = Vejrum
|chapter = Cable-Stayed Bridges
|pages = 399–434
|editor-last1 = Chen
|editor-first1 = Wai-Fah
|editor-last2 = Duan
|editor-first2 = Lian
|isbn = 9781439852293
|url = https://books.google.com/books?id=JpClAgAAQBAJ
|access-date = 31 October 2025
|year = 2014
|publisher = CRC Press
}}
- {{cite book
|title = Bridge Engineering Handbook. Vol 5. Construction and Maintenance
|edition = Second
|first = Glenn
|last = Washer
|chapter = Nondestructive Evaluation Methods for Bridge Elements
|pages = 301–336
|editor-last1 = Chen
|editor-first1 = Wai-Fah
|editor-last2 = Duan
|editor-first2 = Lian
|isbn = 9781439852330
|url = https://books.google.com/books?id=BCeOAgAAQBAJ
|access-date = 31 October 2025
|year = 2014
|publisher = CRC Press
|archive-date = 24 December 2025
|archive-url = https://web.archive.org/web/20251224082337/https://books.google.com/books?id=BCeOAgAAQBAJ
|url-status = live
}}
- {{cite book
| title=Bridges in History and Legend
| last=Watson
| first=Wilbur J.
| oclc=1393531
| url=https://archive.org/details/bridgesinhistory0000wilb
| access-date=1 September 2025
| year=1937
| publisher=J. H. Jansen
}}
- {{cite book
| title=The Civils: The Story of the Institution of Civil Engineers
| author=Watson
| first=Garth
| isbn=9780727703927
| url=https://archive.org/details/civilsstoryofins0000wats
| access-date=31 October 2025
| year=1988
| publisher=Thomas Telford
}}
- {{cite book
|url = https://books.google.com/books?id=NSs4AAAAIAAJ
|title = Asante in the Nineteenth Century: The Structure and Evolution of a Political Order
|first = Ivor
|last = Wilks
|author-link = Ivor Wilks
|publisher = CUP Archive
|via = Books.google.com
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- {{Cite book
|first=William J.
|last=Wright
|chapter-url=https://www.aisc.org/globalassets/nsba/design-resources/steel-bridge-design-handbook/b905_sbdh_chapter5.pdf
|url=https://www.aisc.org/nsba/design-and-estimation-resources/steel-bridge-design-handbook/
|access-date=18 September 2025
|chapter=Selecting the Right Bridge Type
|title=Steel Bridge Design Handbook
|year=2022
|publisher=American Institute of Steel Construction
|archive-date=5 October 2025
|archive-url=https://web.archive.org/web/20251005094507/https://www.aisc.org/nsba/design-and-estimation-resources/steel-bridge-design-handbook/
|url-status=live
}}
<!--
- {{cite book
| title=Structural Health Monitoring of Long-Span Suspension Bridges
| last=Xu
| first= You Lin
|display-authors = etal
| isbn=9780415597937
| url=https://books.google.com/books?id=9F9pNdAk4WAC
| year=2011
| publisher=Taylor & Francis
}}
-->
- {{cite book
|title = Bridge Engineering Handbook. Vol 1. Fundamentals
|edition = Second
|first = Eiki
|last = Yamaguchi
|chapter = Finite Element Method
|pages = 225–251
|editor-last1 = Chen
|editor-first1 = Wai-Fah
|editor-last2 = Duan
|editor-first2 = Lian
|isbn = 9781439852309
|url = https://books.google.com/books?id=WaONAgAAQBAJ
|access-date = 31 October 2025
|year = 2014
|publisher = CRC Press
|archive-date = 26 November 2025
|archive-url = https://web.archive.org/web/20251126072136/https://books.google.com/books?id=WaONAgAAQBAJ
|url-status = live
}}
- {{cite book
|title = Bridge Engineering Handbook. Vol 4. Seismic Design
|edition = Second
|first = Mark
|last = Yashinsky
|display-authors = etal
|chapter = Earthquake Damage to Bridges
|pages = 53–98
|editor-last1 = Chen
|editor-first1 = Wai-Fah
|editor-last2 = Duan
|editor-first2 = Lian
|isbn = 9781439852323
|url = https://books.google.com/books?id=EqSNAgAAQBAJ
|access-date = 31 October 2025
|year = 2014
|publisher = CRC Press
|archive-date = 20 December 2025
|archive-url = https://web.archive.org/web/20251220004823/https://books.google.com/books?id=EqSNAgAAQBAJ
|url-status = live
}}
- {{cite book
| title=Bridge Engineering: Design, Rehabilitation, and Maintenance of Modern Highway Bridges
| last=Zhao
| first=Jim
| display-authors=etal
| edition=Fourth
| isbn=9781259643101
| url=https://books.google.com/books?id=Ii1zDgAAQBAJ
| access-date=16 September 2025
| year=2017
| publisher=McGraw Hill
| archive-date=26 November 2025
| archive-url=https://web.archive.org/web/20251126062334/https://books.google.com/books?id=Ii1zDgAAQBAJ
| url-status=live
}}
Journals and websites
- {{Cite journal
|last=Ahmad
|first=DM
|date=2025
|title= A Risk-Informed BIM-LCSA Framework for Lifecycle Sustainability Optimization of Bridge Infrastructure
|journal= Buildings
|volume=15
|issue =16
|article-number= 2853
|doi= 10.3390/buildings15162853
|doi-access=free
}}
- {{Cite journal
|last=Bjelić
|first=Igor
|date=2022
|title=Use of Building Materials During the Construction of Trajan's Bridge on the Danube
|journal=Arheologija I Prirodne Nauke
|publisher= Institute of Archaeology, Belgrade
|volume=18
|pages=45–58
|doi=10.18485/arhe_apn.2022.18.4
}}
- {{cite magazine
|title = Building Bridges Can Boost Income for the Rural Poor
|url = https://insights.som.yale.edu/insights/building-bridges-can-boost-income-for-the-rural-poor
|access-date = 20 November 2025
|last = Brooks
|first = Wyatt
|display-authors = etal
|date = 5 August 2021
|magazine = Yale Insights
|publisher = Yale School of Management
}}
- {{cite journal
| last=Brunning
|first=Richard
|year=2001
|title=The Somerset Levels
|journal=Current Archaeology
|publisher=Current Publishing
|volume=XV (4)
|issue=172
|pages=139–143
}}
- {{cite journal
|last1=Burgoyne |first1= C
|last2=Scantlebury |first2= R
|year=2008
|title=Lessons Learned from the Bridge Collapse in Palau
|journal= Proceedings of the Institution of Civil Engineers - Civil Engineering
|volume= 161 |issue= 6 |article-number=700038
|doi= 10.1680/cien.2008.161.6.28
}}
- {{cite journal
| first = Aline
| last = Bütikofer
| display-authors = etal
| title = Building Bridges and Widening Gaps
| journal = The Review of Economics and Statistics
| publisher= MIT Press
| volume = 106
| issue = 3
| pages = 681–697
| year = 2024
| doi = 10.1162/rest_a_01183
}}
- {{cite journal
|last1= Cai
|first1= J.
|last2= Deng
|first2= Z.
|year=2024
| title= The Spatial Impact of High Bridges on Travel Accessibility and Economic Integration in Guizhou, China
|journal= Humanities and Social Sciences Communications
|volume= 11
|issue=
|article-number= 1565
| doi= 10.1057/s41599-024-04106-x
}}
- {{ cite journal
| last1= Cai
|first1= Ming
|last2= Liu
|first2= Yonghong
| date =2012
|pages=301–313
| title = Integrated Benefit Evaluation of Pedestrian Bridge
| volume = 17
| journal = Environmental Modeling & Assessment
|issue= 3
| doi = 10.1007/s10666-011-9292-0
|bibcode= 2012EMdAs..17..301L
}}
<!--
- {{cite web
|url=https://www.transportation.gov/testimony/rebuilding-highway-and-transit-infrastructure-gulf-coast-following-hurricane-katrina-0
|access-date=21 September 2025
|last=Capka
|first=J. Richard
|author-link =J. Richard Capka
|year=2005
|title=Rebuilding Highway and Transit Infrastructure on the Gulf Coast Following Hurricane Katrina
|website=U.S. Department of Transportation
}}
-->
- {{cite web
|url = https://connect.ncdot.gov/projects/research/RNAProjDocs/2018-20%20Final%20Report.pdf#:~:text=Grade%2Dseparated%20intersections%20increase%20the%20capacity%20of%20two,is%20needed%20for%20bicycles%2C%20pedestrians%20and%20driveways
|access-date = 7 December 2025
|last = Chase
|first = Thomas
|display-authors = etal
|year = 2020
|title = Reasonable Alternatives for Grade-Separated Intersections
|publisher = North Carolina Department of Transportation
}}
- {{cite thesis
|url=https://digitalcommons.usu.edu/etd/2163
|access-date=2 October 2025
|last=Cook
|first=Wesley
|year=2014
|publisher=Utah State University
|degree=PhD
|title=Bridge Failure Rates, Consequences, and Predictive Trends
|archive-date=22 November 2025
|archive-url=https://web.archive.org/web/20251122150512/https://digitalcommons.usu.edu/etd/2163/
|url-status=live
}}
- {{cite web
| last=Dahlberg
| first=Justin
| display-authors=etal
| title=Guide for Orthotropic Steel Deck Level 1 Design
| access-date=10 November 2025
| year=2022
| url=https://www.fhwa.dot.gov/bridge/pubs/hif22056.pdf#:~:text=Orthotropic%20steel%20deck:%20A%20system%20where%20a,to%20the%20deck%20directly%20supporting%20live%20loads
| publisher=U. S. Federal Highway Administration
}}
- {{cite journal
|last=Dallard
|first= P.
|display-authors=etal
|title=London Millennium Bridge: Pedestrian-Induced Lateral Vibration
|journal= Journal of Bridge Engineering
|volume= 6
|issue=6
|date=2001
|pages= 412–417
|doi= 10.1061/(ASCE)1084-0702(2001)6:6(412)
}}
- {{cite journal
| title = Productivity and Wage Effects of An Exogenous Improvement in Transport Infrastructure: Accessibility and the Great Belt Bridge
| journal = Regional Science and Urban Economics
| volume = 114
| article-number= 104133
| year = 2025
| doi = 10.1016/j.regsciurbeco.2025.104133
| first= Bruno
|last= De Borger
|display-authors=etal
| bibcode = 2025RSUE..11404133D
}}
- {{cite journal
|journal=Journal of Professional Issues in Engineering Education and Practice
|publisher= American Society of Civil Engineers
|volume=127
|issue=3
|date= July 2001
|pages= 109–115
|last=Delatte
|first= Norbert
|title=Lessons from Roman Cement and Concrete
|doi= 10.1061/(ASCE)1052-3928(2001)127:3(109)
}}
- {{cite journal
|journal=Structural Safety
|volume=27
|issue=3
|date= July 2005
|pages=230–245
|last1=Du
|first1= Jin Sheng
|last2= Au
|first2= Francis T.K.
|title=Deterministic and Reliability Analysis of Prestressed Concrete Bridge Girders: Comparison of the Chinese, Hong Kong and AASHTO LRFD Codes
|doi=10.1016/j.strusafe.2004.10.004
}}
- {{cite book
| chapter = The Evolution of Pipeline Suspension Bridges in North America Since 1952
| title = Pipelines 2002 Beneath Our Feet: Challenges and Solutions (Proceedings)
| pages = 1–10
| date = 2002
| last= Dusseau
| first= Ralph
| publisher = American Society of Civil Engineers
| doi = 10.1061/40641(2002)60
| isbn = 978-0-7844-0641-0
}}
- {{cite web
|last = Engel
|first = Eduardo
|display-authors = etal
|date = 2020
|title = When and How to Use Public-Private Partnerships in Infrastructure: Lessons from the International Experience
|publisher = National Bureau of Economic Research
|url = https://www.nber.org/system/files/working_papers/w26766/w26766.pdf
|access-date = 3 December 2025
|doi = 10.3386/w26766
|archive-date = 9 December 2025
|archive-url = https://web.archive.org/web/20251209215831/https://www.nber.org/system/files/working_papers/w26766/w26766.pdf
|url-status = live
}}
- {{cite journal
|last= French
|first= Patricia Ross
|date= January 1993
|title=Living by Bridges: Philip Larkin's Resisting Subtext
|journal= South Atlantic Review
|volume= 58
|issue=1
|pages= 85–100
|doi=10.2307/3201102
|jstor= 3201102
}}
- {{Cite news
|last=Greenfield
|first=Patrick
|date=23 January 2021
|title=How Creating Wildlife Crossings Can Help Reindeer, Bears – and Even Crabs
|url=http://www.theguardian.com/environment/2021/jan/23/how-wildlife-crossings-are-helping-reindeer-bears-and-even-crabs-aoe
|url-status=live
|archive-url=https://web.archive.org/web/20210123083528/https://www.theguardian.com/environment/2021/jan/23/how-wildlife-crossings-are-helping-reindeer-bears-and-even-crabs-aoe
|archive-date=23 January 2021
|access-date=2021-01-26
|newspaper=The Guardian
}}
- {{cite journal
| title = IABSE Symposium Istanbul 2023 "Long Span Bridges" – A Report
| journal = Structural Engineering International
| volume = 33
| number = 3
| pages = 510–512
| year = 2023
| last= Gülkan
| first= P.
| doi = 10.1080/10168664.2023.2224643
}}
- {{cite journal
|last = Hayward
|first = Alan
|title = The Construction of Railway Bridges
|journal = The International Journal for the History of Engineering & Technology
|volume = 84
|issn = 1758-1214
|url = https://www.tandfonline.com/doi/pdf/10.1179/1758120613Z.00000000037
|access-date = 15 January 2026
|number = 1
|pages = 59–87
|year = 2014
|publisher = Taylor & Francis
|doi = 10.1179/1758120613Z.00000000037
}}
- {{Cite magazine
|last=Honan
|first=David
|year=2018
|title=Railroad Bridges, Viaducts, and Trestles
|magazine=Trains Magazine
|url=https://www.trains.com/trn/train-basics/ask-trains/bridges-viaducts-and-trestles/
|access-date=2020-09-11
}}
- {{cite web
|url=https://www.fhwa.dot.gov/bridge/preservation/docs/hif22052.pdf
|access-date=2 October 2025
|title=Service Life Design Reference Guide
|date=November 2022
|first1=Travis
|last1=Hopper
|first2=Anne-Marie
|last2=Langlois
|display-authors=etal
|website=Federal Highway Administration
}}
- {{cite web
|url=https://static.tti.tamu.edu/tti.tamu.edu/documents/0-6729-1.pdf
|access-date=17 September 2025
|title=Synthesis on Cost-Effectiveness of Extradosed Bridges
|series=Technical Report
|date=March 2016
|first=Jiong
|last=Hu
|display-authors=etal
|website=Texas A&M Transportation Institute
}}
- {{Cite journal
|first1=Satoshi
|last1= Kashima
|first2= Mitsushige
|last2=Sakamoto
|title=Construction of Akashi Kaikyo Bridge Foundation
|journal= IABSE Reports = Rapports AIPC = IVBH Reports
|year=1998
|volume=79
|pages=69–74
|doi= 10.5169/seals-59833
}}
- {{cite journal
| last = Kumar
| first= Saket
|display-authors = etal
| title = Dynamic Response of Double Deck Cable-Stayed Bridge Subjected to Train Load on Lower Deck.
| journal = Journal of Vibration Engineering & Technologies
| volume = 13
| number = 20
| year = 2025
| article-number = 20
| doi = 10.1007/s42417-024-01562-2
| bibcode = 2025JVET...13...20K
}}
- {{cite news
|url = https://www.telegraph.co.uk/global-health/climate-and-people/the-debt-express-chinas-pincer-movement-on-kenya-africa/
|first = Ben
|last = Marlow
|date = 3 September 2025
|title = All Aboard 'The Debt Express': China's pincer Movement on Africa
|newspaper = The Daily Telegraph
|access-date = 11 December 2025
}}
- {{Cite web
|url=https://www.bbc.com/news/world-europe-66229533
|title=Ukraine War: Russia Says Crimean Bridge Partially Open to Cars Again
|date=18 July 2023
|last=McGarvey
|first=Emily
|publisher=BBC
|access-date=18 January 2026
|archive-date=18 July 2023
|archive-url=https://web.archive.org/web/20230718015102/https://www.bbc.com/news/world-europe-66229533
|url-status=live
}}
- {{cite journal
| last1 = Merli
| first1= Roberto
| last2 = Costanza
| first2= Alessandra
| title = Effectiveness of Physical Barriers to Prevent Suicide by Jumping from High-Risk Bridges
| journal = Preventive Medicine Reports
| volume = 42
| number =
| year = 2024
| article-number = 102745
| doi = 10.1016/j.pmedr.2024.102745
| pmid = 38721569
| pmc = 11077020
}}
- {{cite magazine
|title=World's Coolest Animal Bridges
|first=Rachel
|last=Newer
|date=23 July 2012
|magazine=Smithsonian
|publisher=Smithsonian Institution
|access-date=21 February 2019
|url=https://www.smithsonianmag.com/smart-news/worlds-coolest-animal-bridges-5774855/
|archive-date=22 April 2021
|archive-url=https://web.archive.org/web/20210422004837/https://www.smithsonianmag.com/smart-news/worlds-coolest-animal-bridges-5774855/
|url-status=live
}}
- {{cite magazine
| last1 = Nowak
| first1 = Andrzej
| last2 = Iatsko
| first2 = Olga
| date = June 2018
| volume = 48
| issue = 2
| magazine = The Bridge
| title = Are Our Bridges Safe?
| url = https://www.nae.edu/183130/Are-Our-Bridges-Safe
| access-date = 17 November 2025
| publisher = National Academy of Engineering
| archive-date = 12 May 2025
| archive-url = https://web.archive.org/web/20250512044111/https://www.nae.edu/183130/Are-Our-Bridges-Safe
| url-status = live
}}
- {{cite journal
| last1 = Odrobiňák
|first1= Prokop
| display-authors = etal
| year = 2022
|doi=10.3390/app12083788
| title = Load-Carrying Capacity of Bailey Bridge in Civil Applications
| journal = Applied Sciences
|volume=12
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