Acable-stayed bridge is a type ofbridge that has one or moretowers (orpylons), from whichcables support the bridge deck. A distinctive feature is the cables orstays, which run directly from the tower to the deck, normally forming a fan-like pattern or a series of parallel lines. This is in contrast to the modernsuspension bridge, where the cables supporting the deck are suspended vertically from the main cables, which run between the towers and are anchored at both ends of the bridge. The cable-stayed bridge is optimal for spans longer thancantilever bridges and shorter than suspension bridges. This is the range within which cantilever bridges would rapidly grow heavier, and suspension bridge cabling would be more costly.
Cable-stayed bridges found wide use in the late 19th century. Early examples, including theBrooklyn Bridge, often combined features from both the cable-stayed and suspension designs. Cable-stayed designs fell from favor in the early 20th century as larger gaps were bridged using pure suspension designs, and shorter ones using various systems built ofreinforced concrete. It returned to prominence in the later 20th century when the combination of new materials, larger construction machinery, and the need to replace older bridges all lowered the relative price of these designs.[1]
Chain-stayed bridge by theRenaissancepolymathFausto Veranzio, from 1595/1616. Prior to industrial manufacture of heavy wire rope (steel cable), suspended or stayed bridges were firstly constructed with linked rods (chain).
The earliest known surviving example of a true cable-stayed bridge in the United States is E.E. Runyon's largely intact wrought ironBluff Dale Suspension bridge with wooden stringers and decking inBluff Dale, Texas (1890), or his weeks earlier but ruinedBarton Creek Bridge betweenHuckabay, Texas andGordon, Texas (1889 or 1890).[2][3] In the twentieth century, early examples of cable-stayed bridges included A. Gisclard's unusual Cassagnes bridge (1899),[4] in which the horizontal part of the cable forces is balanced by a separate horizontal tie cable, preventing significant compression in the deck, and G. Leinekugel le Coq's bridge[5] atLézardrieux inBrittany (1924).Eduardo Torroja designed a cable-stayed aqueduct[6] at Tempul in 1926.[7]Albert Caquot's 1952 concrete-decked cable-stayed bridge[8] over the Donzère-Mondragon canal atPierrelatte is one of the first of the modern type, but had little influence on later development.[7] The steel-deckedStrömsund Bridge designed byFranz Dischinger (1955) is, therefore, more often cited as the first modern cable-stayed bridge.
Other key pioneers includedFabrizio de Miranda,Riccardo Morandi, andFritz Leonhardt. Early bridges from this period used very few stay cables, as in theTheodor Heuss Bridge (1958). However, this involves substantial erection costs, and more modern structures tend to use many more cables to ensure greater economy.
Cable-stayed bridges may appear to be similar tosuspension bridges, but they are quite different in principle and construction. In suspension bridges, large main cables (normally two) hang between the towers and areanchored at each end to the ground. This can be difficult to implement when ground conditions are poor. The main cables, which are free to move on bearings in the towers, bear the load of the bridge deck. Before the deck is installed, the cables are undertension from their own weight. Along the main cables smaller cables or rods connect to the bridge deck, which is lifted in sections. As this is done, the tension in the cables increases, as it does with thelive load of traffic crossing the bridge. The tension on the main cables is transferred to the ground at the anchorages and by downwardscompression on the towers.
Difference between types of bridges
Suspension bridge
Cable-stayed bridge, fan design
In cable-stayed bridges, the towers are the primary load-bearing structures that transmit the bridge loads to the ground. Acantilever approach is often used to support the bridge deck near the towers, but lengths further from them are supported by cables running directly to the towers. That has the disadvantage, unlike for the suspension bridge, that the cables pull to the sides as opposed to directly up, which requires the bridge deck to be stronger to resist the resulting horizontalcompression loads, but it has the advantage of not requiring firm anchorages to resist the horizontal pull of the main cables of a suspension bridge. By design, all static horizontal forces of the cable-stayed bridge are balanced so that the supporting towers do not tend to tilt or slide and so must only resist horizontal forces from the live loads.
The following are key advantages of the cable-stayed form:
Much greater stiffness than the suspension bridge, so that deformations of the deck under live loads are reduced
Can be constructed by cantilevering out from the tower – the cables act both as temporary and permanent supports to the bridge deck
For a symmetrical bridge (in which thespans on either side of the tower are the same), the horizontal forces balance and largeground anchorages are not required
There are four major classes of rigging on cable-stayed bridges:mono,harp,fan, andstar.[9]
Themono design uses a single cable from its towers and is one of the lesser-used examples of the class.
In theharp orparallel design, the cables are parallel, or nearly so, so that the height of their attachment to the tower is proportional to the distance from the tower to their mounting on the deck.
In thefan design, the cables all connect to or pass over the top of the towers. The fan design is structurally superior with a minimum moment applied to the towers, but, for practical reasons, the modified fan (also called the semi-fan) is preferred, especially where many cables are necessary. In the modified fan arrangement, the cables terminate near the top of the tower but are spaced from each other sufficiently to allow better termination, improved environmental protection, and good access to individual cables for maintenance.[10]
In thestar design, another relatively rare design, the cables are spaced apart on the tower, like the harp design, but connect to one point or a number of closely spaced points on the deck.[11]
Difference between types of bridges
mono design
harp design
fan design
star design
All seven column arrangements of a cable-stayed bridge
There are also seven main arrangements for support columns:single,double,portal,A-shaped,H-shaped,inverted Y, andM-shaped. The last three are hybrid arrangements that combine two arrangements into one.[9]
Thesingle arrangement uses a single column for cable support, normally projecting through the center of the deck, but in some cases located on one side or the other. Examples:Millau Viaduct in France andSunshine Skyway Bridge in Florida.
Thedouble arrangement places pairs of columns on both sides of the deck. Examples:Øresund Bridge between Denmark and Sweden, andZolotoy Bridge in Russia.
Theportal is similar to the double arrangement but has a third member connecting the tops of the two columns to form a door-like shape or portal. This offers additional strength, especially against transverse loads. Examples:Hale Boggs Bridge in Louisiana andKirumi Bridge in Tanzania.
TheA-shaped design is similar in concept to the portal but achieves the same goal by angling the two columns towards each other to meet at the top, eliminating the need for the third member. Examples:Arthur Ravenel Jr. Bridge in South Carolina,Helgeland Bridge in Norway, andChristopher S. Bond Bridge in Missouri.
Theinverted Y design combines theA-shaped on the bottom with thesingle on top. Examples:Pont de Normandie in France andIncheon Bridge in South Korea.
TheM-shaped design combines twoA-shaped arrangements, side by side, to form an M. This arrangement is rare, and is mostly used in wide bridges where a singleA-shaped arrangement would be too weak. Examples:Fred Hartman Bridge in Texas, and its planned sister bridgeShip Channel Bridge, also in Texas.
Depending on the design, the columns may be vertical, angled relative to vertical, or curved.
Far more radical in its structure, thePuente del Alamillo (1992) uses a singlecantilever spar on one side of a single span, with cables on one side only to support the bridge deck. Unlike other cable-stayed types, this bridge exerts considerable overturning force upon its foundation, and the spar must resist bending caused by the cables, as the cable forces are not balanced by opposing cables. The spar of this particular bridge forms thegnomon of a large gardensundial. Related bridges by the architectSantiago Calatrava include thePuente de la Mujer (2001),Sundial Bridge (2004),Chords Bridge (2008), andAssut de l'Or Bridge (2008).
Cable-stayed bridges with more than three spans involve significantly more challenging designs than do two-span or three-span structures.
In a two-span or three-span cable-stayed bridge, the loads from the main spans are normally anchored near the endabutments by stays in the end spans. For more spans, this is not the case, and the bridge structure is less stiff overall. This can create difficulties in both the design of the deck and the pylons.Examples of multiple-span structures in which this is the case includeTing Kau Bridge, where additional 'cross-bracing' stays are used to stabilise the pylons;Millau Viaduct, where twin-legged towers are used; andGeneral Rafael Urdaneta Bridge, where very stiff multi-legged frame towers were adopted. A similar situation with a suspension bridge is found at both theGreat Seto Bridge andSan Francisco–Oakland Bay Bridge, where additional anchorage piers are required after every set of three suspension spans – this solution can also be adapted for cable-stayed bridges.[12]
The Twinkle-Kisogawa is an extradosed design, with long gaps between the cable supported sections.
Anextradosed bridge is a cable-stayed bridge with a more substantial bridge deck that, being stiffer and stronger, allows the cables to be omitted close to the tower and for the towers to be lower in proportion to the span. The first extradosed bridges were theGanter Bridge andSunniberg Bridge in Switzerland. The first extradosed bridge in the United States, thePearl Harbor Memorial Bridge was built to carry I-95 across the Quinnipiac River in New Haven, Connecticut, opening in June 2012.
A cradle system carries the strands within the stays from the bridge deck to bridge deck, as a continuous element, eliminating anchorages in the pylons. Each epoxy-coated steel strand is carried inside the cradle in a one-inch (2.54 cm) steel tube. Each strand acts independently, allowing for removal, inspection, and replacement of individual strands. The first two such bridges are thePenobscot Narrows Bridge, completed in 2006, and theVeterans' Glass City Skyway, completed in 2007.[13]
Aself-anchored suspension bridge has some similarity in principle to the cable-stayed type in that tension forces that prevent the deck from dropping are converted into compression forces vertically in the tower and horizontally along the deck structure. It is also related to thesuspension bridge in having arcuate main cables with suspender cables, although the self-anchored type lacks the heavy cable anchorages of the ordinary suspension bridge. Unlike either a cable-stayed bridge or a suspension bridge, the self-anchored suspension bridge must be supported byfalsework during construction and so it is more expensive to construct.
Changtai Yangtze River Bridge, connecting the cities of Changzhou and Taizhou across the Yangtze River in China, opened in 2025. It has the world's longest span, at 1,208 metres (3,963 ft) meters
Aswan Bridge, crossing over theNile river, located in the city ofAswan, Egypt.[23] It was built by the Holding Company for Roads, Bridges and Land Transport Projects.[24][25]
Clark Bridge, named after explorerWilliam Clark, carries U.S. 67 between Illinois and Missouri. Opened in 1994, the 108-foot-wide bridge (33 m) replaced theold Clark Bridge, a truss bridge built in 1928 which was only 20 feet (6.1 m) wide. The bridge is sometimes referred to as theSuper Bridge as its construction process was documented in the 1997NOVA episodeSuper Bridge, which highlighted the challenges of building the bridge, especially during theGreat Flood of 1993. Total length is 4,620 feet (1,408 m) with a longest span of 756 feet (230 m).
Erasmus Bridge crosses theNieuwe Maas inRotterdam,Netherlands. The southern span of the bridge has an 89 metres (292 ft) bascule bridge for ships that cannot pass under the bridge. The bascule bridge is the largest and heaviest in West Europe and has the largest panel of its type in the world.
TheGordie Howe International Bridge currently under construction, connectingDetroit, Michigan withWindsor, Ontario, will have two inverted "Y" shaped towers built on the banks of theDetroit River, six-lanes for automotive traffic, and a cycle and walking path. It will be 2.5 kilometres (1.6 miles) long. Once completed in 2025, it will have the longest main span of any cable-stayed bridge in North America at 853 metres (2,799 feet).
Jiaxing-Shaoxing Sea Bridge,Zhejiang Province, China. The bridge is an eight-lane structure that spans 10,100 metres (6.3 mi) acrossHangzhou Bay, connectingJiaxing andShaoxing, two cities of Zhejiang province. It was opened on 23 July 2013 and is currently the longest cable-stayed bridge in the world.
Kap Shui Mun Bridge: Road-rail cable-stayed bridge with longest span when opened
Kosciuszko Bridge: This connects the boroughs of Brooklyn and Queens in New York City, replacing a truss bridge of the same name. The first cable-stayed span (temporarily carrying three lanes in each direction) opened to traffic in April 2017. A second, nearly identical span opened on 29 August 2019.[26]
Millau Viaduct, the bridge with the tallest piers in the world: 341 metres (1,119 ft) tall and roadway 266 metres (873 ft) high, spanning the riverTarn in France. With a total length of 2,460 metres (8,070 ft) and seven towers, it also has the longest cable-stayed suspended deck in the world.
Most SNP (Bridge of the Slovak National Uprising) – the world's longest cable-stayed bridge to have one pylon and one cable-stayed plane (Bratislava, Slovakia, 1967–1972)
Most SNP (Nový most), the world's longest cable-stayed bridge in category with one pylon and with one cable-stayed plane, spanning theDanube inBratislava,Slovakia. The main span is 303 metres (994 ft), total length 430.8 metres (1,413 ft). The only member ofWorld Federation of Great Towers that is primarily used as a bridge. It houses a flying-saucer restaurant at the top of pylon 85 metres (279 ft) tall.
Oresund Bridge, a combined two-track rail and four-lane road bridge with a main span of 490 metres (1,610 ft) and a total length of 7.85 kilometres (4.88 mi), crossing theÖresund betweenMalmö, Sweden, and theDanish Capital Region.
Pelješac Bridge connects the southeastern Croatian exclave to the rest of the country.
Queensferry Crossing (formerly the Forth Replacement Crossing) is a road bridge in Scotland. It is built alongside the existing, suspension,Forth Road Bridge across theFirth of Forth and upon completion in 2017 became the longest triple-tower cable-stayed bridge in the world at 2700m.[30]
Rande Bridge in Spain near Vigo is the highway cable-stayed bridge with the longest and slenderest span in the world at the time of construction (1973–1977). Three long spans of 148 metres (486 ft) + 400 metres (1,300 ft) + 148 metres (486 ft). Pylons in concrete, girder in steel.
Rio-Antirio bridge crosses theGulf of Corinth nearPatras, Greece. At a total length of 2,880 metres (9,450 ft) and four towers, it has the second longest cable-stayed suspended deck (2,258 metres (7,408 ft) long) in the world, with only the deck of the Millau Viaduct in southern France being longer at 2,460 metres (8,070 ft). However, as the latter is also supported by bearings at the pylons apart from cable stays, the Rio–Antirrio bridge deck might be considered the longest cable-stayed fully suspended deck in the world.
Second Severn Crossing between England andWales is 3.186 miles (5.127 km) long, consisting of a single central navigation span over the "Shoots" channel and approach viaducts on either side.[31]
TheTappan Zee Bridge, the replacement for theoriginal bridge, is atwin-deck cable-stayed bridge opened in 2017 and 2018, and is both the southernmostHudson River-crossing bridge entirely within New York State, and the first cable-stayed bridge in North America to match Boston's Zakim Bridge (see below) overall road-deck width figure of 183 feet (56 meters), spanning eight lanes.
Varina-Enon Bridge, Carries I-295 across the James River between Henrico and Chesterfield Counties in Virginia. Varina-Enon Bridge features the world's first use of precast concrete delta frames for construction of its 630 feet (190 m) cable-stayed main span. It is an instrumental part of the Peregrine Falcon program overseen by theVirginia Department of Transportation.
Vasco da Gama Bridge inLisbon, Portugal is the longest bridge in Europe, with a total length of 17.2 kilometres (10.7 mi), including 0.829 kilometres (0.515 mi) for the main bridge, 11.5 kilometres (7.1 mi) in viaducts and 4.8 kilometres (3.0 mi) in extension roads.
Zárate–Brazo Largo Bridges over the Paraná Guazú and Paraná de las Palmas Rivers inArgentina (1972–1976) are the first two road and railway long-span cable-stayedsteel bridges in the world. Spans: 110 metres (360 ft) + 330 metres (1,080 ft) + 110 metres (360 ft).
Vidyasagar Setu, also known as the Second Hooghly Bridge, over theHooghly river, happens to be the first and longest such bridge in India and one of the longest in Asia. It connects the twin cities ofHowrah andKolkata.
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