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Akashi Kaikyo Bridge

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Projects > Bridges
Port hole view of the Akashi Kaikyo Bridge
The Akashi Kaikyo Bridge, also known as the Pearl Bridge[1], is the longest, tallest, and most expensive suspension bridge ever built[2]. Located in Kobe City, Japan, the Akashi Kaikyo spans 2.4 miles (4 km) across the Akashi Straits. The bridge connects the Kobe area to Awaji Island, Japan's sixth largest island[3].

Contents

[edit] Construction History

The Akashi Kaikyo Bridge was originally designed to allow for both cars and trains. However in 1986, when bridge designs were being finalized, the rail portion of the bridge was scrapped.[4]

The bridge is located in an area known to be susceptible to natural disasters.[5] Powerful tides, strong winds, frequent earthquakes, and extreme depths required special attention from the bridge's engineers. To test the bridge under various environmental conditions, a miniature replica was built at a scale of 100:1.[6] The bridge was built to withstand winds up to 180mph (288kmph) and an earthquake measuring 8.5 on the Richter Scale.[7] A design utilizing a 116.5 foot-wide (35.5m) truss girder system to support the roadway was chosen to allow wind to pass through gaps between the trusses, improving aerodynamics while maintaining structural integrity.[8] The bridge is located in seas measuring 360ft (110m) deep, with tidal currents measuring 10mph (16.2kmph). To overcome these obstacles, a gigantic 263ft by 230ft (80m by 70m) steel cylinder was sunk to the sea bottom to provide a stable foundation from which to build.[9]

Construction began in May 1988.[10] The bridge was originally designed to be 12,825 feet (3909m) in length. However on January 17, 1995 the Great Hanshan Earthquake struck, increasing the distance from shore-to-shore by three feet, and necessitating an extension to the bridge deck of the same length.[11] After ten years of construction and a cost of $3.6 billion USD, the Akashi Kaikyo Bridge opened to traffic on April 5, 1998.[12] When it was completed, it overtook the Humber Bridge as the longest suspension bridge in the world, with a centre span of 6532 feet (1991m).[13][14]

[edit] Unique Facts

  • 181,400 metric tonnes of steel were used in the superstructure
  • 1.42 million cubic meters of concrete
  • A new variety of concrete was designed for the project. Called "underwater nondisintegration concrete", it was developed for improved fluidity and consistency, and is able to be transported long distances without a solid layer forming on its surface.[15]

[edit] Bridge

  • Main span: 6532ft (1991m)
  • Side spans: 3150ft (960m)
  • Total length: 12831ft (3911m)

[edit] Towers

  • Tower height: 283m (928ft)
  • Tower height above water: 213ft (65m)

[edit] Cables

  • Number of main cables: 2
  • Diameter of each cable: 3.7ft (1.12m)
  • Total length of cables: 186411 miles (300,000 kilometers)

[edit] References

  1. World's Longest Suspension Bridge Opens in Japan. US Department of Transportation Federal Highway Administration [January 5, 2010].
  2. Akashi Kaikyo Bridge. PBS.org [January 5, 2009].
  3. World's Longest Suspension Bridge Opens in Japan. US Department of Transportation Federal Highway Administration [January 5, 2010].
  4. Akashi-Kaikyo Bridge - Japan Suspension Bridge. Japan-101.com [January 5, 2010].
  5. Akashi Kaikyo Bridge. PBS.org [January 5, 2009].
  6. Akashi Kaikyo Bridge. Roadsbridges.com [January 5, 2010].
  7. Akashi Kaikyo Bridge. PBS.org [January 5, 2009].
  8. World's Longest Suspension Bridge Opens in Japan. US Department of Transportation Federal Highway Administration [January 5, 2010].
  9. A Suspension Bridge that Spans a Vision of the 21st Century. Web-Japan.org [January 5, 2009].
  10. Akashi-Kaikyo Bridge - Japan Suspension Bridge. Japan-101.com [January 5, 2010].
  11. Akashi Kaikyo Bridge. PBS.org [January 5, 2009].
  12. World's Longest Suspension Bridge Opens in Japan. US Department of Transportation Federal Highway Administration [January 5, 2010].
  13. A Suspension Bridge that Spans a Vision of the 21st Century. Web-Japan.org [January 5, 2009].
  14. Akashi Kaikyo Bridge. Roadsbridges.com [January 5, 2010].
  15. Akashi Kaikyo Bridge. Roadsbridges.com [January 5, 2010].