Tuesday, September 25, 2007

LONGEST SUSPENSION BRDIGE


The Akashi-Kaikyō Bridge (明石海峡大橋, Akashi Kaikyō Ō-hashi?), also known as Pearl Bridge, is a suspension bridge in Japan that crosses the Akashi Strait; it links Maiko in Kobe and Iwaya on Awaji Island as part of the Honshū-Shikoku Highway. It is the longest suspension bridge in the world to date, as measured by the length of its center span 1,991 metres (6,532 ft), substantially longer than the second longest suspension bridge, the Danish Great Belt Bridge. Its total length is 3,911 metres (12,831 ft). It was planned to be one of three Honshū-Shikoku connecting bridges, annexing two borders of the Inland Sea.


Architecture
The bridge has three spans. The central span is 1,991 metres (6,532 ft), with the two other sections each 960 metres (3,150 ft). The bridge is 3,911 metres (12,831 ft) long overall. The central span was originally only 1,990 metres (6,529 ft) but was stretched by a further metre in the Kobe earthquake on January 17, 1995.
The bridge was designed with a two-hinged stiffening girder system, allowing the structure to withstand winds of 286 kilometres per hour (178 mph), earthquakes measuring to 8.5 on the Richter scale, and harsh sea currents. The bridge also contains pendulums that operate at the resonant frequency of the bridge to dampen forces. The two main supporting towers are 298 metres (978 ft) above sea level, and the bridge can expand up to two meters in one day.(wikipedia)

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