The Akashi-Kaikyo Bridge, also known as the Pearl Bridge, has the longest central span of any suspension bridge, at 1,991 metres (6,532 ft). It is located in Japan and was completed in 1998. The bridge links the city of Kobe on the mainland of Honshū to Iwaya on Awaji Island by crossing the busy Akashi Strait. It carries part of the Honshū-Shikoku Highway. (wikipedia)
The Akashi Kaikyo Suspension Bridge is the longest suspension bridge in the world and it is probably Japan’s greatest engineering feat.
It took two million workers ten years to construct the bridge, 181,000 tonnes of steel and 1.4million cubic metres of concrete. The steel cable used would circle the world seven times.
The Akashi Straits is four miles wide at the bridge site with sea depths of one hundred metres and currents averaging fourteen kmph. The Akashi Straits is one of the busiest sea lanes in the world with over a thousand ships per day travelling through it. Furthermore, the bridge is in a typhoon region in which winds can reach speeds of 290 kmph.
The construction of a suspension bridge involves the use of two main cables stretching between two towers. The roadway beneath these is suspended by more cables. To stop the towers, roadway and cables collapsing, they are held at either end by large anchor blocks (the Akashi anchor blocks weigh 350 000 tonnes). In the case of the Akashi-Kaikyo Bridge, suspension bridge technology was pushed to the limit.