- Related Topics:
- bridge
- cable structure
cable-stayed bridge
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What is a cable-stayed bridge?
A cable-stayed bridge is a bridge where the deck's weight is supported by tension in nearly straight diagonal cables that run to one or more vertical towers. The towers then transfer the cable forces through vertical compression to the foundations, which also puts the deck into horizontal compression.
Cable-stayed bridges are often constructed using the cantilever method, where, after the tower is built, one cable and a section of the deck are constructed in each direction. Each section of the deck is prestressed before continuing. The process is repeated until the deck sections meet in the middle, where they are connected, and the ends are anchored at the abutments.
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How does a cable-stayed bridge support its weight?
A cable-stayed bridge supports the weight of its deck using diagonal cables under tension that run to one or more vertical towers. The towers then transfer the cable forces through vertical compression to the foundations. The tensile forces in the cables also put the deck into horizontal compression. Cable-stayed bridge construction typically uses the cantilever method, where after the tower is built, a cable and deck section are constructed in each direction. Each deck section is prestressed before continuing, and the process repeats until the deck sections connect in the middle.
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What are the main parts of a cable-stayed bridge?
A cable-stayed bridge is a bridge in which the deck's weight is supported by straight diagonal cables under tension that run to vertical towers. The towers then transfer the cable forces through vertical compression to the foundations. The cables also put the deck into horizontal compression.
After workers sink caissons and erect towers and anchorages, construction typically follows the cantilever method. After building the tower, workers construct one cable and a section of the deck in each direction. They prestress each deck section before continuing. The process repeats until the deck sections meet in the middle, where they connect, and the ends anchor at the abutments.
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How do cable-stayed bridges differ from suspension bridges?
Cable-stayed and suspension bridges are distinct types of bridges. Suspension bridges use curved cables under tension to support vertical loads, which are then transferred to towers and anchorages. In contrast, cable-stayed bridges use nearly straight diagonal cables in tension to carry vertical loads from the main span directly to vertical towers. These towers then transfer the cable forces through vertical compression to the foundations, while the cables also put the deck into horizontal compression.
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Why are cable-stayed bridges often used for long spans?
Cable-stayed bridges are often used for long spans because of their efficient design and load distribution. In cable-stayed bridges, the weight of the deck is supported by nearly straight diagonal cables under tension, running to vertical towers. The towers then transfer the cable forces through vertical compression to the foundations. The tensile forces in the cables also put the deck into horizontal compression. This design allows for longer spans compared to beam bridges, where the distance between supports is limited due to bending. The use of materials like prestressed concrete and steel in cable-stayed bridges further enhances their ability to handle both compression and tension forces, crucial for supporting heavy loads over significant distances.
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What are some famous examples of cable-stayed bridges?
Cable-stayed bridges support the deck's weight using diagonal cables under tension that run to vertical towers, which then transfer force to the foundations.
Examples:
* Strömsund Bridge in Sweden, an early example, features two cables attached high on the tower, fanning out to support the deck.
* Oberkasseler Bridge in Germany uses a single tower with four cables in a harp arrangement.
* Bonn-Nord Bridge in Germany was the first to use many thin cables, allowing for a thinner deck.
* Sunshine Skyway Bridge in Florida employs a single plane of cables that fan out down the center of the deck.
* Millau Viaduct in France is the world’s highest road bridge.3 Britannica SourcesCreated from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.
cable-stayed bridge, bridge form in which the weight of the deck is supported by a number of nearly straight diagonal cables in tension running directly to one or more vertical towers. The towers transfer the cable forces to the foundations through vertical compression. The tensile forces in the cables also put the deck into horizontal compression.
Construction of cable-stayed bridges usually follows the cantilever method, so their construction begins with the sinking of caissons and the erection of towers and anchorages. After the tower is built, one cable and a section of the deck are constructed in each direction. Each section of the deck is prestressed before continuing. The process is repeated until the deck sections meet in the middle, where they are connected. The ends are anchored at the abutments.
Cable-stayed bridges offer a variety of possibilities to the designer regarding not only the materials for deck and cables but also the geometric arrangement of the cables. Early examples, such as the Strömsund Bridge in Sweden (1956), used just two cables fastened at nearly the same point high on the tower and fanning out to support the deck at widely separated points. By contrast, the Oberkasseler Bridge, built over the Rhine River in Düsseldorf, Germany, in 1973, used a single tower in the middle of its twin 254-metre (846-foot) spans; the four cables were placed in a harp or parallel arrangement, being equally spaced both up the tower and along the centre line of the deck. The Bonn-Nord Bridge in Bonn, Germany (1966), was the first major cable-stayed bridge to use a large number of thinner cables instead of relatively few but heavier ones—the technical advantage being that, with more cables, a thinner deck might be used. Such multicable arrangements subsequently became quite common. The box girder deck of the Bonn-Nord, as with most cable-stayed bridges built during the 1950s and ’60s, was made of steel. From the 1970s, however, concrete decks were used more frequently.
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The designs of cable-stayed bridges in the United States have reflected trends in both cable arrangement and deck material. The Pasco-Kennewick Bridge (1978) over the Columbia River in Washington state supported its centre span of 294 metres (981 feet) from two double concrete towers, the cables fanning down to the concrete deck on either side of the roadway. The same designers created the East End Bridge (1985) across the Ohio River, which has a major span of 270 metres (900 feet) and a minor span of 182 metres (608 feet). The single concrete tower is shaped like a long triangle in the traverse direction, and the cable arrangement is of the fan type, but, while the Pasco-Kennewick Bridge has two parallel sets of cables, the East End has but one set, fanning out from a single plane at the tower into two planes at the composite steel and concrete deck, so that, as one moves from pure profile to a longitudinal view, the cables do not align visually. The Sunshine Skyway Bridge (1987), designed by Eugene Figg and Jean Mueller over Tampa Bay in Florida, has a main prestressed-concrete span of 360 metres (1,200 feet). It too employs a single plane of cables, but these remain in one plane that fans out down the centre of the deck.
The Dames Point Bridge (1987), designed by Howard Needles in consultation with Ulrich Finsterwalder, was the longest cable-stayed bridge in the United States until the opening of the Arthur Ravenel Bridge in South Carolina in 2005. The Dames Point Bridge crosses the St. Johns River in Jacksonville, Florida, and its main span is 390 metres (1,300 feet), with side spans of 200 metres (660 feet). From H-shaped towers of reinforced concrete, two planes of stays in harp formation support reinforced-concrete girders. The towers are carefully shaped to avoid a stiff appearance. In 2011 the Arthur Ravenel Bridge in turn was surpassed by the opening of the John James Audubon Bridge in Louisiana. The only bridge over the Mississippi River between Natchez, Mississippi, and Baton Rouge, Louisiana, the John James Audubon Bridge has a main span of 482 metres (1,583 feet).