Great Seto Bridge
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The Great Seto Bridge (瀬戸大橋, Seto Ō-hashi), or Seto-Ohashi Bridge, is a series of double deck bridges connecting Okayama and Kagawa prefectures in Japan across a series of five small islands in the Seto Inland Sea. Built over the period 1978–1988, it is one of the three routes of the Honshū-Shikoku Bridge Project connecting Honshū and Shikoku islands. At 13.1 km long, it ranks as the world's longest two-tiered bridge system.
Crossing the bridge takes about 20 minutes by car or train. The ferry crossing before the bridge was built took about an hour. The non-discounted toll from Kojima, Kurashiki (Okayama Prefecture on the Honshū side) to Sakaide (Kagawa Prefecture on the Shikoku side) is ¥3,500, and vice-versa.
The bridges carry two lanes of highway traffic in each direction (Seto-Chūō Expressway) on the upper deck and one railway track in each direction (Seto-Ōhashi Line) on the lower deck. The lower deck was designed to accommodate an additional Shinkansen rail line in each direction.
History
The bridge's history dates back to 1889 when a member of the Prefectural Parliament, Jinnojo Ōkubo (大久保諶之丞, Ōkubo Jinnojo, 1849–1891), suggested the idea of a bridge across the Seto Inland Sea. He aired his idea for the bridge in a speech made at the opening ceremony of the first railway in Shikoku between Marugame and Kotohira: "The four provinces of Shikoku are like so many remote islands. If united by roads, they will be much better off, enjoying the benefits of increased transportation and easier communication with each other." {{citation}}: Empty citation (help)
While it took a century for his vision to become a reality, another of his ideas, mentioned in a drinking song he composed, was accomplished twenty years sooner:
- I'll tell you, dear, don't laugh at me,
- a hundred years from now, I'll be seeing you
- flying to and from the moon in a space ship.
- Its port, let me tell you, dear,
- will be that mountaintop over there!
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The bridge idea lay dormant for about sixty years. In 1955, after 171 lives were lost when a ferry wrecked in dense fog off the coast of Takamatsu, a safer crossing was deemed necessary. By 1959, meetings were held to promote building the bridge. Scientists began investigations shortly after, and in 1970, the Honshū-Shikoku Bridge Construction Authority was inaugurated. However, work was postponed for five years by the "oil shock" of 1973; once the Environment Assessment Report was published in 1978, construction got underway.
The project took ten years to complete at a cost of US$7 billion; 3,646,000 cubic meters of concrete and 705,000 tons of steel were used in construction. {{citation}}: Empty citation (help) Although nets, ropes and other safety measures were employed, the lives of 13 workers were lost during the 10 years of construction. {{citation}}: Empty citation (help) The bridge opened to road and rail traffic on April 10, 1988.
Named bridges
Six of the eleven bridges are separately named, unlike some other long bridge complexes like the San Francisco – Oakland Bay Bridge (a suspension bridge, one tunnel, a cantilever span linked to five truss spans and a truss causeway). The other five bridges are viaducts. The six named bridges are:
- Shimotsui-Seto Bridge (下津井瀬戸大橋, Shimotsui Seto Ō-hashi): A suspension bridge with a center span of 940 meters which connects Honshū with the island of Hitsuishijima. The 22nd largest suspension bridge in the world.
- Hitsuishijima Bridge (櫃石島橋, Hitsuishijima-kyō) and Iwakurojima Bridge (岩黒島橋, Iwakurojima-kyō): Two identical cable-stayed bridges with center spans of 420 meters.
- Yoshima Bridge (与島橋, Yoshima-kyō): A continuous truss bridge with five spans and a total length of 847 meters.
- Kita Bisan-Seto Bridge (北備讃瀬戸大橋, Kita Bisan Seto Ō-hashi) and Minami Bisan-Seto Bridge (南備讃瀬戸大橋, Minami Bisan Seto Ō-hashi): A suspension bridge with two sections linked by a common anchorage between them. With center spans of 990 and 1,118 meters respectively they rank as the 19th and 11th largest suspension bridges. The roadway of the bridge is 93 m above sea level.[citation needed]
Sister bridges
- Golden Gate Bridge, San Francisco, California, United States
- Affiliated from April 5, 1988
- Fatih Sultan Mehmet Bridge, Istanbul, Turkey
- Affiliated from July 3, 1988
- Oresund Bridge, Malmo, Sweden and Copenhagen, Denmark
- Affiliated from May 24, 2008[1]
See also
References
- ^ 2008 Press Release (2008年プレスリリース Template:Ja icon). JB本四高速 (Honshū-Shikoku Bridge Expressway Company). Accessed February 24, 2010.
External links
