The is a series of double deck bridges connecting

Okayama is the capital city of Okayama Prefecture in the Chūgoku region of Japan. The city was founded on June 1, 1889. , the city has an estimated population of 720,841 and a population density of 910 persons per km2. The total area is . The city is ...

and

Kagawa may refer to: * , the smallest prefecture of Japan by area, located on the island of Shikoku * , a district in Kagawa Prefecture * , a town located in Kagawa District * , train station in Chigasaki, Kanagawa Prefecture * Kagawa (surname) Kagawa (w ...

prefectures in Japan across a series of five small islands in the

Seto Inland Sea The , sometimes shortened to the Inland Sea, is the body of water separating Honshū, Shikoku, and Kyūshū, three of the four main islands of Japan. It serves as a waterway connecting the Pacific Ocean to the Sea of Japan. It connects to Osaka ...

. Built over the period 1978–88, it is one of the three routes of the Honshū–Shikoku Bridge Project connecting

Honshū , historically called , is the largest and most populous island of Japan. It is located south of Hokkaidō across the Tsugaru Strait, north of Shikoku across the Inland Sea, and northeast of Kyūshū across the Kanmon Straits. The island separa ...

and

Shikoku is the smallest of the four main islands of Japan. It is long and between wide. It has a population of 3.8 million (, 3.1%). It is south of Honshu and northeast of Kyushu. Shikoku's ancient names include ''Iyo-no-futana-shima'' (), '' ...

islands and the only one to carry rail traffic. The total length is , and the longest span, the Minami Bisan-Seto Bridge, is . Crossing the bridge takes about 20 minutes by car or train. The ferry crossing before the bridge was built took about an hour. The bridges carry two lanes of highway traffic in each direction (

Seto-Chūō Expressway The is a tolled Expressways of Japan, expressway that connects Okayama Prefecture, Okayama and Kagawa Prefecture, Kagawa prefectures in Japan across a series of five small islands in the Seto Inland Sea. Built between 1978 and 1988, it is one of t ...

) on the upper deck and one railway track in each direction (

Seto-Ōhashi Line The is a railway line operated by West Japan Railway Company (JR West) and Shikoku Railway Company (JR Shikoku) in Japan which links Okayama Station in Okayama Prefecture with Takamatsu Station in Kagawa Prefectu ...

) on the lower deck. The lower deck was designed to accommodate an additional set of

Shinkansen The , colloquially known in English as the bullet train, is a network of high-speed railway lines in Japan. Initially, it was built to connect distant Japanese regions with Tokyo, the capital, to aid economic growth and development. Beyond l ...

tracks for a proposed extension of the Shinkansen to Shikoku.

History

When in 1889 the first railway in Shikoku was completed between

Marugame is a city located in Kagawa Prefecture, Japan. , the city had an estimated population of 108,541 in 46101 households and a population density of 970 persons per km². The total area of the city is . Geography Marugame is located in north-ce ...

and

Kotohira is a town located in Nakatado District, Kagawa Prefecture, Japan. , the town had an estimated population of 8,105 in 3618 households and a population density of 960 persons per km². The total area of the town is . The town is best known as t ...

, a member of the Prefectural Parliament, , stated in his speech at the opening ceremony: "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." While it took a century for this vision of a bridge across the Seto Inland Sea to become reality, another of Ōkubo's 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!

The bridge idea lay dormant for about sixty years. In 1955, after 171 people died when Shiun Maru disaster, a ferry wrecked in dense fog off the coast of

Takamatsu 270px, Takamatsu City Hall 270px, Aerial view of Takamatsu city center 270px, View from Yashima to Takashima port is a city located in Kagawa Prefecture, Japan. , the city had an estimated population of 414,134 in 190120 households and a popul ...

, 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 Honshu-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 ferry disaster also led to the creation of the

Akashi Kaikyō Bridge The is a suspension bridge which links the city of Kobe on the Japanese island of Honshu to Iwaya on Awaji Island. It is part of the Kobe-Awaji-Naruto Expressway, and crosses the busy and turbulent Akashi Strait (''Akashi Kaikyō'' in Japanese ...

. The project took ten years to complete at a cost of US$7 billion; of concrete and 705,000 tons of steel were used in construction. Although nets, ropes and other safety measures were employed, the lives of 13 workers were lost during the 10 years of construction. The bridge opened to road and rail traffic on April 10, 1988.

Constituent bridges

JP-Okayama-Great-Seto-Bridge-Panoramic-View

Six of the eleven bridges are separately named, unlike some other long bridge complexes such as the

San Francisco–Oakland Bay Bridge The San Francisco–Oakland Bay Bridge, known locally as the Bay Bridge, is a complex of bridges spanning San Francisco Bay in California. As part of Interstate 80 in California, Interstate 80 and the direct road between San Francisco and Oakland ...

. The other five bridges are

viaduct A viaduct is a specific type of bridge that consists of a series of arches, piers or columns supporting a long elevated railway or road. Typically a viaduct connects two points of roughly equal elevation, allowing direct overpass across a wide v ...

s. The six named bridges from north to south are listed below. ;Shimotsui-Seto Bridge: The is a double-decked

suspension bridge A suspension bridge is a type of bridge in which the deck (bridge), deck is hung below suspension wire rope, cables on vertical suspenders. The first modern examples of this type of bridge were built in the early 1800s. Simple suspension bridg ...

with a center span of and a total length of which connects Honshū with the island of Hitsuishijima. It is the 45th largest suspension bridge in the world. It is the northernmost bridge of the

Seto-Chuo Expressway The 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 1978–88, it is one of the three routes of the Honshū–Shikoku Br ...

. ;Hitsuishijima Bridge: The is a double-decked

cable-stayed bridge A cable-stayed bridge has one or more ''towers'' (or ''pylons''), from which cables support the bridge deck. A distinctive feature are the cables or stays, which run directly from the tower to the deck, normally forming a fan-like pattern o ...

with a center span of and a total length of . It is immediately north of the identical Iwakurojima Bridge. ;Iwakurojima Bridge: The is a double-decked cable-stayed bridge with a center span of and a total length of . It is immediately south of the identical Hitsuishijima Bridge. ;Yoshima Bridge: The is a continuous double-decked

truss bridge A truss bridge is a bridge whose load-bearing superstructure is composed of a truss, a structure of connected elements, usually forming triangular units. The connected elements (typically straight) may be stressed from tension, compression, or ...

with a main span of and a total of five spans with a length of . It is immediately south of the Hitsuishijima and Iwakurojima Bridges. ;Kita Bisan-Seto Bridge: The is a double-decked suspension bridge with two sections linked by a common anchorage between them. The center span is and the total length is . It is the 19th largest suspension bridge in the world. The nearly identical Minami Bisan Seto Bridge is located immediately to the south. ;Minami Bisan-Seto Bridge: The is a double-decked suspension bridge with a center span of and a total length of . It is the 13th longest suspension bridge span in the world. It is the southernmost part of the Great Seto Bridge. The roadway of the bridge is above sea level.

Sister bridges

Golden Gate Bridge The Golden Gate Bridge is a suspension bridge spanning the Golden Gate, the strait connecting San Francisco Bay and the Pacific Ocean. The structure links the U.S. city of San Francisco, California—the northern tip of the San Francisco Pen ...

, San Francisco, California, United States ** Affiliated from April 5, 1988 *

Fatih Sultan Mehmet Bridge The Fatih Sultan Mehmet Bridge ("Sultan Mehmed the Conqueror Bridge"), also known as the Second Bosphorus Bridge (in Turkish: ''Fatih Sultan Mehmet Köprüsü'', ''F.S.M. Köprüsü'' or ''2. Köprü''), is a bridge in Istanbul, Turkey spannin ...

, Istanbul, Turkey ** Affiliated from July 3, 1988 *

Øresund Bridge The Öresund or Øresund Bridge ( da, Øresundsbroen ; sv, Öresundsbron ; hybrid name: ) is a combined railway and motorway bridge across the Øresund strait between Denmark and Sweden. It is the longest in Europe with both roadway and rai ...

, Malmo, Sweden and Copenhagen, Denmark ** Affiliated from May 24, 2008. JB本四高速 (

Honshu-Shikoku Bridge Expressway Company The , abbreviated as in Japanese or HSBE in English, operates the Kobe-Awaji-Naruto, Nishiseto, and Seto-Chūō expressways and their respective bridges between the islands of Honshu and Shikoku, Japan. It is headquartered in Chūō-ku, Kō ...

). Accessed February 24, 2010.

Notes

References

External links