Akashi-Kaikyo Bridge
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Akashi-Kaikyo Bridge on April 27, 2003. |
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Akashi-Kaikyo Bridge at night |
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View from a tower. |
The , 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
Honshu-
Shikoku Highway. It is the
longest suspension bridge in the world to date, both in terms of total length (3,911 m or 12,826 ft) and in terms of its center span (
1991 metres or 6532 ft). It was planned to be one of three
Honshu-Shikoku connecting bridges, annexing two borders of the
Inland Sea.
Before the Akashi-Kaikyo Bridge was built, ferries carried passengers back and forth across the Akashi Strait in Japan. This dangerous waterway often experiences severe storms, and in 1955, two ferries sank in the strait during a storm, killing 168 children. The ensuing shock and public outrage convinced the Japanese government to draw up plans for a suspension bridge to cross the strait. The original plan was for a mixed
railway-
road bridge but when the bridge was begun in April
1986 it was restricted to road only, with six
lanes. Actual construction did not begin until May
1988 and the bridge was opened for traffic on
April 5,
1998. The Akashi Strait is an international
waterway and required a 1500 metre wide shipping lane.
The bridge has three
spans. The central span is 1991 metres, with the two other sections each 960 metres. The bridge is 3911 metres long overall. The central span was originally only 1990 metres but was stretched by a further metre in the
Kobe earthquake on
January 17,
1995. It was designed on a two-hinged stiffening girder system, allowing it to withstand 286 kilometres per hour (178 mph) winds, earthquakes measuring up to 8.5 on the
Richter scale, and harsh sea currents. The bridge also contains
pendula which operate at the
resonant frequency of the bridge to dampen forces on it.
The total cost is estimated at 500 billion (≈USD 5 billion). This cost is expected to be defrayed by charging commuters a toll to cross the bridge. However, the toll is so high (2,300 Yen or 20US$) that, ironically, very few drivers actually use the expensive bridge, preferring instead to use the slower-but-cheaper ferries.
Two parks in proximity of the bridge have been built for tourists, one in Maiko (including a small museum) and one in Asagiri. Both are accessible by the coastal train line.
The Akashi-Kaikyo Bridge has a total of 1737 illumination lights: 1084 for the main
cables, 116 for the main
towers, 405 for the
girders, and 132 for the anchorages. On the main cables three high light discharged tubes are mounted in the colors
red,
green, and
blue. The
RGB model and
computer technology make for a variety of combinations. Currently, 28 patterns are used for such occasions as national or regional
holidays, memorial days or festivities.
*
Honshu-Shikoku Bridge Project*
Kurushima-Kaikyo Bridge*
Great Seto Bridge*
List of largest suspension bridges*
Megaprojects*
Structurae: Akashi Kaikyo Bridge*
Satellite photograph from
Google Maps
