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Suspension bridge facts for kids

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Suspension bridge
A suspension bridge can be made out of simple materials such as wood and common wire rope.

A suspension bridge is a type of bridge that has been made since ancient times as early as 100 AD. Some simple suspension bridges, for use by pedestrians and livestock, are still constructed, based upon the ancient Inca rope bridge.

Suspended from two high locations over a river or canyon, simple suspension bridges follow a shallow downward arc and are not suited for modern roads and railroads.

The design of the modern suspended-deck suspension bridge was developed in the early 19th century. It can cross a longer span than other kinds of bridges.

The Akashi Kaikyō Bridge is the world's longest suspension bridge.

Advantages

  • Longer main spans are achievable than with any other type of bridge.
  • Less material may be required than other bridge types, even at spans they can achieve, leading to a reduced construction cost.
  • Except for installation of the initial temporary cables, little or no access from below is required during construction and so a waterway can remain open while the bridge is built above.
  • They may be better able to withstand earthquake movements than heavier and more rigid bridges.
  • Bridge decks can have deck sections replaced in order to widen traffic lanes for larger vehicles or add additional width for separated cycling/pedestrian paths.

Disadvantages

  • Considerable stiffness or aerodynamic profiling may be required to prevent the bridge deck from vibrating under high winds.
  • The relatively low deck stiffness compared to other (non-suspension) types of bridges makes it more difficult to carry heavy rail traffic in which high concentrated live loads occur.
  • Some access below may be required during construction to lift the initial cables or to lift deck units. That access can often be avoided in cable-stayed bridge construction.

Longest spans

Suspension bridges are typically ranked by the length of their main span. These are the ten bridges with the longest spans, followed by the length of the span and the year the bridge opened for traffic:

Bridge Country Length Year
Çanakkale 1915 Bridge  Turkey 2023 m (6637 ft) 2022
Akashi Kaikyō Bridge  Japan 1991 m (6532 ft) 1998
Yangsigang Bridge  China 1700 m (5577 ft) 2019
Xihoumen Bridge  China 1650 m (5413 ft) 2009
Great Belt Bridge  Denmark 1624 m (5328 ft) 1998
Osman Gazi Bridge  Turkey 1550 m (5085 ft) 2016
Yi Sun-sin bridge  South Korea 1545 m (5069 ft) 2012
Runyang Bridge  China 1490 m (4888 ft) 2005
Fourth Nanjing Yangtze Bridge  China 1418 m (4652 ft) 2012
Humber Bridge  United Kingdom 1410 m (4626 ft) 1981
Yavuz Sultan Selim Bridge  Turkey 1408 m (4619 ft) 2016

Other examples

(Chronological)

  • Union Bridge (England/Scotland, 1820), the longest span (137 m) from 1820 to 1826. The oldest suspension bridge in the world still carrying road traffic.
  • Roebling's Delaware Aqueduct (USA, 1847), the oldest wire suspension bridge still in service in the United States.
  • John A. Roebling Suspension Bridge (USA, 1866), then the longest wire suspension bridge in the world at 1,057 feet (322 m) main span.
  • Brooklyn Bridge (USA, 1883), the first steel-wire suspension bridge.
  • Bear Mountain Bridge (USA, 1924), the longest suspension span (497 m) from 1924 to 1926. The first suspension bridge to have a concrete deck. The construction methods pioneered in building it would make possible several much larger projects to follow.
  • Benjamin Franklin Bridge (USA, 1926), replaced Bear Mountain Bridge as the longest span at 1,750 feet between the towers. Includes an active subway line and never-used trolley stations on the span.
  • San Francisco–Oakland Bay Bridge (USA, 1936). This was once the longest steel high-level bridge in the world (704 m). The eastern portion (a cantilever bridge) has been replaced with a self-anchored suspension bridge which is the longest of its type in the world. It is also the world's widest bridge.
  • Golden Gate Bridge (USA, 1937), the longest suspension bridge from 1937 to 1964. It was also the world's tallest bridge from 1937 to 1993, and remains the tallest bridge in the United States.
  • Mackinac Bridge (USA, 1957), the longest suspension bridge between anchorages in the Western hemisphere.
  • Si Du River Bridge (China, 2009), the highest bridge in the world, with its deck around 500 meters above the surface of the river.
  • Rod El Farag Bridge (Egypt, 2019), a modern Egyptian steel wire-cables based suspension bridge crossing the river Nile, which was completed in 2019 and holds the Guinness World Record for the widest suspension bridge in the world with a width of 67.3 meters, and with a span of 540 meters.

Notable collapses

  • Broughton Suspension Bridge (England) – Iron chain bridge built in 1826. One of Europe's first suspension bridges, it collapsed in 1831 due to mechanical resonance induced by troops marching in step. As a result of the incident, the British Army issued an order that troops should "break step" when crossing a bridge.
  • Silver Bridge (USA) – Eyebar chain highway bridge, built in 1928, that collapsed in late 1967, killing forty-six people. The bridge had a low-redundancy design that was difficult to inspect. The collapse inspired legislation to ensure that older bridges were regularly inspected and maintained. Following the collapse a bridge of similar design was immediately closed and eventually demolished. A second similarly-designed bridge had been built with a higher margin of safety and remained in service until 1991.
  • Tacoma Narrows Bridge, (USA), 853 m – 1940. The Tacoma Narrows bridge was vulnerable to structural vibration in sustained and moderately strong winds due to its plate-girder deck structure. Wind caused a phenomenon called aeroelastic fluttering that led to its collapse only months after completion. The collapse was captured on film. There were no human deaths in the collapse; several drivers escaped their cars on foot and reached the anchorages before the span dropped.
  • Yarmouth suspension bridge (England) – Built in 1829 and collapsed in 1845, killing 79 people.
  • Peace River Suspension Bridge (Canada) The north anchor's soil support for the suspension bridge, which was completed in 1943, failed over a few days in October 1957, and the entire bridge subsequently collapsed.
  • On 30 October 2022, Jhulto Pul, a pedestrian suspension bridge over the Machchhu River in the city of Morbi, Gujarat, India collapsed, leading to the deaths of at least 141 people.

Images for kids

See also

Kids robot.svg In Spanish: Puente colgante para niños

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