Akashi-Kaikyo Suspension Bridge

akashi kaikyo bridgeThe Akashi-Kaikyo suspension bridge in Japan currently holds the distinction as the world’s longest spanning suspension bridge. Also known as the Pearl Bridge, its main span is 1,991 meters long (equivalent to four Brooklyn Bridges).

Not only that, the bridge’s two towers are also extremely tall. At 928 feet, they are higher compared to any other bridge towers in the world. The Akashi-Kaikyo Bridge opened for traffic on April 5, 1998 to join Maiko in Kobe and Iwaya on Awaji Island.

History

Before the construction of the bridge, passengers take ferries to cross the dangerous Akashi Strait, known for its severe storms. Two ferries sank in the waterway during a storm in 1955, killing hundreds of people. The ensuing public outrage forced the Japanese government to build a bridge to cross the strait.

Originally, the plan was the construction of a mixed railway-road bridge. However, when construction started in April 1986, it was restricted to road with six lanes. The actual construction began in May 1986 and was completed in April 1998.

Architecture

The Akashi-Kaikyo Bridge has three spans. Its central span measures 1,991 meter long and the other sections each measures 960 meters long. Originally, the central span was only 1,990 meters long, but the destructive January 1995 Kobe earthquake significantly moved the two towers. Engineers then made some critical adjustments and increased the span by a meter. Each anchorage have 350,000 tons of concrete and its steel cables have 300,000 km of wire. Each cable measures 112 cm in diameter and is composed of around 36,830 strands of wire.

The design features a two-hinged stiffening girder system, which allows the entire structure to endure earthquakes (8.5 on the Richter scale), 286 kph winds, and extreme sea currents. The Akashi-Kaikyo Bridge also has pendulums designed to damp forces. The bridge expands up to 2 meters a day because of heating.

Head-to-head comparison

By comparison, the Akashi-Kaikyo Bridge is 366 meters longer than the former record holder, Denmark’s StoreBaelt (East Bridge), which also officially opened in 1998. It is also 580 meters longer than England’s Humber Bridge, which was constructed in 1981.

The Akashi-Kaikyo Bridge is also 692 meters longer than New York’s Verrazano-Narrows Bridge (constructed in 1964), the longest suspension bridge in the United States. It is 710 meters longer than the San Francisco’s world-famous Golden Gate Bridge, built in 1937.

 
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