Types of suspension bridges

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A suspension bridge supports its structural load with cables, ropes, or chains anchored at each end. Cables on the earliest suspension bridges were anchored in the ground; some modern suspension bridges anchor the cables to the ends of the bridge itself. Earliest suspension bridges had no towers or piers but the majority of larger modern suspension bridges have them. [1] All of the 14 longest bridges in the world are suspension bridges.

Contents

Types

Types of suspension bridge include:

Simple suspension bridge : the earliest known type of suspension bridge, and usually a footbridge. The deck is flexible and lies on the main cables, which are anchored to the earth. Bridge-suspension-simple.svg
Underspanned suspension bridge : an early 19th-century descendant of the simple suspension bridge. The deck is raised on posts above the main cables. Micklewood-bridge-x2.svg
Stressed ribbon bridge : a modern descendant of the simple suspension bridge. The deck lies on the main cables, but is stiff, not flexible. Pont-catenaire.svg
Suspension bridge (more precisely, suspended-deck suspension bridge): the most familiar type. Though technically all the types listed here are suspension bridges, when unqualified with adjectives the term commonly refers to a suspended-deck suspension bridge. This type is suitable for use by heavy vehicles and light rail. The main cables are anchored to the earth. The deck is carried below the main cables by "suspenders" and usually is stiff. Bridge-suspension-anchorages.svg
Self-anchored suspension bridge : a modern descendant of the suspension bridge, combining elements of a cable-stayed bridge. The main cables are anchored to the ends of the decks. Bridge-self-anchored.svg
Taper suspension bridge : a 19th century variant of the suspension bridge where the suspenders pull at an angle to the ground, nearly tangent with the main cable Railway Bridge in Whin Park - geograph.org.uk - 2476236.jpg

A pure suspension bridge is one without additional stay cables and in which the main cables are anchored in the ground. [2] This includes most simple suspension bridges and suspended-deck suspension bridges, and excludes self-anchored suspension bridges.

Hybrid types

Some suspension bridges are of unusual hybrid types. Among these are suspension bridges that have an "intermediate deck". [3] These bridges have a portion of deck that resembles an underspanned suspension bridge. Some of the earliest suspended-deck suspension bridges were of this type, and they continue to be constructed. Examples constructed in the 20th century include a viaduct over the river Oberargen near Wangen, Germany. A 258-metre (846 ft) span of the viaduct has a cable support below the deck, with one end of the cable anchored at a pier and the other end tied into a conventional cable stay. The underspanned portion of the span is 172-metre (564 ft) long and has three vertical members. [3]

The Akashi Kaikyō Bridge, one of the longest suspension bridges in the world, is a suspended-deck suspension bridge with a stiff truss girder deck. [4] Its main span is 1,991 m (6,532 ft) long. [4]

Construction

Unlike other types of bridge, suspension bridges can usually be built without use of falsework or even any access from below the bridge. In many cases, the main cables are constructed first, often with a pilot cable. Construction then proceeds by hanging components and equipment from the main cables. The articles about each type of bridge have further specific construction details.

Suspension bridges are suitable for the longest spans, provided the cables and their anchorage are of sufficient strength. Their construction cost is high, so usually they are less economical than other bridges for spans less than 1,000 ft (300 m). However, shorter spans have been constructed for aesthetic reasons.

All types of suspension bridges have less rigidity than other bridges. Because of their greater flexibility, these bridges are more suitable as road bridges than railroad bridges. [2]

See also

Related Research Articles

<span class="mw-page-title-main">Suspension bridge</span> Type of bridge

A suspension bridge is a type of bridge in which the deck is hung below suspension cables on vertical suspenders. The first modern examples of this type of bridge were built in the early 1800s. Simple suspension bridges, which lack vertical suspenders, have a long history in many mountainous parts of the world.

<span class="mw-page-title-main">Cable-stayed bridge</span> Type of bridge with cables directly from towers

A cable-stayed bridge has one or more towers, from which cables support the bridge deck. A distinctive feature are the cables or stays, 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 modern suspension bridge, where the cables supporting the deck are suspended vertically from the main cable, anchored at both ends of the bridge and running between the towers. The cable-stayed bridge is optimal for spans longer than cantilever 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.

<span class="mw-page-title-main">Viaduct</span> A multiple span bridge crossing an extended lower area

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

<span class="mw-page-title-main">Arch bridge</span> Bridge with arch-shaped supports

An arch bridge is a bridge with abutments at each end shaped as a curved arch. Arch bridges work by transferring the weight of the bridge and its loads partially into a horizontal thrust restrained by the abutments at either side. A viaduct may be made from a series of arches, although other more economical structures are typically used today.

<span class="mw-page-title-main">Millau Viaduct</span> Cable-stayed bridge in Creissels, France; tallest bridge in the world

The Millau Viaduct is a multispan cable-stayed bridge completed in 2004 across the gorge valley of the Tarn near Millau in the Aveyron department in the Occitanie Region, in Southern France. The design team was led by engineer Michel Virlogeux and English architect Norman Foster. As of October 2023, it is the tallest bridge in the world, having a structural height of 336.4 metres (1,104 ft).

<span class="mw-page-title-main">Rio–Antirrio Bridge</span> Bridge

The Rio–Antirrio Bridge, officially the Charilaos Trikoupis Bridge, is one of the world's longest multi-span cable-stayed bridges and longest of the fully suspended type. It crosses the Gulf of Corinth near Patras, linking the town of Rio on the Peloponnese peninsula to Antirrio on mainland Greece by road. It opened one day before the Athens 2004 Summer Olympics, on 12 August 2004, and was used to transport the Olympic flame.

<span class="mw-page-title-main">Ting Kau Bridge</span> Bridge in New Territories, Hong Kong

Ting Kau Bridge is a 1,177-metre (3,862 ft) long cable-stayed bridge in Hong Kong that spans from the northwest of Tsing Yi Island and Tuen Mun Road. It is near the Tsing Ma Bridge which also serves as a major connector between the Hong Kong International Airport on Lantau Island and the rest of Hong Kong. It was completed on 5 May 1998. The bridge is toll-free.

<span class="mw-page-title-main">Self-anchored suspension bridge</span>

A self-anchored suspension bridge is a suspension bridge type in which the main cables attach to the ends of the deck, rather than directly to the ground or via large anchorages. The design is well-suited for construction atop elevated piers, or in areas of unstable soils where anchorages would be difficult to construct.

<span class="mw-page-title-main">Beam bridge</span> Type of bridge

Beam bridges are the simplest structural forms for bridge spans supported by an abutment or pier at each end. No moments are transferred throughout the support, hence their structural type is known as simply supported.

<span class="mw-page-title-main">Through arch bridge</span> Type of bridge

A through arch bridge, also known as a through-type arch bridge, is a bridge that is made from materials such as steel or reinforced concrete, in which the base of an arch structure is below the deck but the top rises above it. It can either be lower bearing or mid-bearing. Thus, the deck is within the arch, and cables or beams that are in tension suspend the central part of the deck from the arch.

<span class="mw-page-title-main">Simple suspension bridge</span> Type of bridge

A simple suspension bridge is a primitive type of bridge in which the deck of the bridge lies on two parallel load-bearing cables that are anchored at either end. They have no towers or piers. The cables follow a shallow downward catenary arc which moves in response to dynamic loads on the bridge deck.

<span class="mw-page-title-main">Kap Shui Mun Bridge</span> Overpass in western Hong Kong

The Kap Shui Mun Bridge (KSMB) in Hong Kong, part of Lantau Link of Route 8, is one of the longest cable-stayed bridges in the world that transports both road and railway traffic, with the upper deck used for motor vehicles and the lower deck used for both vehicles and the MTR. It has a main span of 430 metres (1,410 ft) and an overall length of 750 metres (2,460 ft). It spans the Kap Shui Mun marine channel between Ma Wan and Lantau and has a vertical clearance of 47 metres (154 ft) above sea level. The bridge was completed in 1997.

<span class="mw-page-title-main">Eastern span replacement of the San Francisco–Oakland Bay Bridge</span> Seismic stabilization megaproject in California (2002–2013)

The eastern span replacement of the San Francisco–Oakland Bay Bridge was a construction project to replace a seismically unsound portion of the Bay Bridge with a new self-anchored suspension bridge (SAS) and a pair of viaducts. The bridge is in the U.S. state of California and crosses the San Francisco Bay between Yerba Buena Island and Oakland. The span replacement took place between 2002 and 2013, and is the most expensive public works project in California history, with a final price tag of $6.5 billion, a 2,500% increase from the original estimate of $250 million, which was an initial estimate for a seismic retrofit of the span, not the full span replacement ultimately completed. Originally scheduled to open in 2007, several problems delayed the opening until September 2, 2013. With a width of 258.33 ft (78.74 m), comprising 10 general-purpose lanes, it is the world's widest bridge according to Guinness World Records.

<span class="mw-page-title-main">Nordhordland Bridge</span> Bridge in Vestland county, Norway

The Nordhordland Bridge is a combined cable-stayed and pontoon bridge which crosses Salhusfjorden between Klauvaneset and the island of Flatøy in Vestland county, Norway. It is 1,614 meters (5,295 ft) long, of which the pontoon section is 1,246 meters (4,088 ft) long. The cable-stayed section consists of a single 99-meter (325 ft) tall H-pylon which has a length of 368 meters (1,207 ft) and a main span of 172 meters (564 ft). This allows for a clearance of 32 meters (105 ft).

<span class="mw-page-title-main">Hampden Bridge, Kangaroo Valley</span> Bridge in New South Wales, Australia

Hampden Bridge is a heritage-listed single-span suspension bridge that carries Moss Vale Road (B73) across the Kangaroo River, in Kangaroo Valley, in the City of Shoalhaven local government area of New South Wales, Australia. The bridge was designed by Ernest de Burgh and built by Loveridge and Hudson. The property is owned by Transport for NSW. It was added to the New South Wales State Heritage Register on 2 August 2019.

<span class="mw-page-title-main">Orthotropic deck</span> Welded steel segmented construction technique for bridge decks

An orthotropic bridge or orthotropic deck is typically one whose fabricated deck consists of a structural steel deck plate stiffened either longitudinally with ribs or transversely, or in both directions. This allows the fabricated deck both to directly bear vehicular loads and to contribute to the bridge structure's overall load-bearing behaviour. The orthotropic deck may be integral with or supported on a grid of deck framing members, such as transverse floor beams and longitudinal girders. All these various choices for the stiffening elements, e.g., ribs, floor beams and main girders, can be interchanged, resulting in a great variety of orthotropic panels.

<span class="mw-page-title-main">Extradosed bridge</span>

An extradosed bridge employs a structure that combines the main elements of both a prestressed box girder bridge and a cable-stayed bridge. The name comes from the word extrados, the exterior or upper curve of an arch, and refers to how the "stay cables" on an extradosed bridge are not considered as such in the design, but are instead treated as external prestressing tendons deviating upward from the deck. In this concept, they remain part of the main bridge superstructure.

<span class="mw-page-title-main">Bandra–Worli Sea Link</span> Bridge connecting Bandra Basitt and Worli, Mumbai, India

The Bandra-Worli Sea Link is a 5.6 km long, 8-lane wide cable-stayed bridge that links Bandra in the Western Suburbs of Mumbai with Worli in South Mumbai. It is the longest sea bridge, as well as the 5th longest bridge in India after Mumbai Trans Harbour Link, Bhupen Hazarika Setu, Dibang River Bridge and Mahatma Gandhi Setu. It contains pre-stressed concrete-steel viaducts on either side. It was planned as a part of the proposed Western Freeway that would link the Western Suburbs to Nariman Point in Mumbai's main business district, but is now planned to become part of the Coastal Road to Kandivali.

<span class="mw-page-title-main">Tied-arch bridge</span>

A tied-arch bridge is an arch bridge in which the outward horizontal forces of the arch(es) caused by tension at the arch ends to a foundation are countered by equal tension of its own gravity plus any element of the total deck structure such great arch(es) support. The arch(es) have strengthened chord(s) that run to a strong part of the deck structure or to independent tie-rods below the arch ends.

<span class="mw-page-title-main">Rama VIII Bridge</span> Bridge in Bangkok, Thailand

The Rama VIII Bridge is a cable-stayed bridge crossing the Chao Phraya River in Bangkok, Thailand. It was built to alleviate traffic congestion on the nearby Phra Pinklao Bridge. Construction of the bridge took place from 1999 to 2002. The bridge was opened on 7 May 2002 and inaugurated on 20 September, the birth anniversary of the late King Ananda Mahidol, after whom it is named. The bridge has an asymmetrical design, with a single pylon in an inverted Y shape on the west bank of the river. Its eighty-four cables are arranged in pairs on the side of the main span and in a single row on the other. The bridge has a main span of 300 metres (980 ft), and was one of the world's largest asymmetrical cable-stayed bridges at the time of its completion.

References

  1. Tom F. Peters (1987-01-01). Transitions in Engineering: Guillaume Henri Dufour and the Early 19th Century Cable Suspension Bridges. Birkhauser. p. 260. ISBN   3-7643-1929-1.
  2. 1 2 R. L. Brockenbrough, Frederick S. Merritt (2005). Structural Steel Designer's Handbook: AISC, AASHTO, AISI, ASTM, AREMA, and ASCE-07 Design Standards (4 ed.). McGraw-Hill Professional. p. 800. ISBN   0-07-143218-3. page 15.7
  3. 1 2 Leonardo Fernández Troyano (2003-11-30). Bridge Engineering: A Global Perspective. Thomas Telford. p. 775. ISBN   0-7277-3215-3. pages 517-520
  4. 1 2 James D. Cooper (July–August 1998). "World's Longest Suspension Bridge Opens in Japan". Public Roads. 62.