Wednesday, October 8, 2008

Akashi Kaikyo

Japan greatest engineering feet, Akashi Kaikyo, is a landmark in the history of bridges. It is world’s largest suspension bridge that has a record main span of 1991 meters. It took 10 years of hardcore struggle to get to build this excellent piece of engineering and April 5, 1998 was the day when it was officially inaugurated.
The other name for Akashi Kaikyo is pearl bridge that very well suits the concept. In comparison with other bridges, it is by far the most magnificent piece of architecture. Being constructed in 110 meter- deep water with tidal current of 4.5 meters per second, it was quiet challenging. Moreover, wind speed of 80 meters per second was a lot more to bear for the bridge. All these and earthquake of 8.5 magnitude at rector scale, were well kept in mind to form a safe and secured base for this bridge.
The name Akashi Kaikyo is derived from the geological site of the bridge. Basically, the site includes layered alluvium and diluvium deposits over what is called Akashi or Kobe layer. Getting onto its features would definitely provide you a man-made miracle. The main span being 1990 meters is supported by two side spans of 960 meters each. This bridge links city of Kobe with Awaji-Shima Island with a record length of 3,911 meters.
However, the construction of such a massive structure was not a child’s play. It took 2 million workers, 10 years, 181000 tonnes of steel, and 1.4 million cubic meters of concrete and whole lot of expert’s brain to have the way it is. Akashi Kaikyo has six lanes witnessing millions of people passing thereby.

Construction of Akashi Kaikyo was a challenge for engineers. To bear the fast swirling tidal currents in the narrow strait the foundations were securely laid in 60 ft under water, on the seabed. To do this, huge steel cylinder with a diameter of about 80 meter, stretching its height to 70 meters was sunk to the bottom of sea. It was through this cylinder, concrete was poured to form a solid base for this heavy, massive structure.
Also, this structure was designed and tested in a large-scale wind tunnel to ensure that it will withstand with the wind flows and water currents including massive earthquakes.

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