Location: Between Kurashiki City, Okayama Pref. and Sakaide City, Kagawa Pref.   Construction Period: October 10, 1978 to April 10, 1988.   Total length of the bridges over the sea: 9.4 km (5.8 mi)   Steel materials used: 700,000 ton   Cable for suspension bridges: 1.06 m (3.48 ft) in diameter.   Shimotsui Seto Bridge:   Between Kurashiki City and Hitsuishijima Island  Bridge type: Single span truss-stiffened suspension bridge with overhanging  Total length: 1,447 m (4,747 ft)  Center span: 940 m (3,150 ft)   Hitsuishijima Bridge:  Between Hitsuishijima and Iwakurojima Islands.  Bridge type: Tandem 3-span continuous truss cable-stayed bridge  Total length: 790 m (2,592 ft)  Center span: 420 m (1,378 ft)   Iwakurojima Bridge:  Between Iwakurojima and Wasashima Islands.  Bridge type: Tandem 3-span continuous truss cable-stayed bridge  Total length: 790 m (2,592 ft)  Center span: 420 m (1,378 ft)   Yoshima Bridge:  Between Wasashima and Yoshima Islands  Bridge type: 2-span and 3-span continuous truss bridge  Total length: 877 m (2,877 ft)   Kita Bisan Seto Bridge  Between Yoshima and Mitsugoshima Islands.  Bridge type: Tandem 3-span continuous truss-stiffened suspension bridge  Total length: 1612 m (5,289 ft)  Center Span: 990 m (3,248 ft)   Minami Bisan Seto Bridge  Between Mitsugoshima Island and Sakaide City.  Bridge type: Tandem 3-span continuous truss-stiffened suspension bridge  Total length: 1723 m (5,653 ft)  Center Span: 1100 m (3,609 ft)

 

The route via the Seto Ohashi Bridge was the first of the three routes linking Honshu and Shikoku opened to traffic. In an area studded with many islands, this route hops from one island to another across the Seto Inland Sea. Joining the city of Kurashiki in Okayama Prefecture on the Honshu side with Sakaide City in Kagawa Prefecture on the Shikoku side, the complete route was opened in 1988. Stretching across a total distance of 9.4 kilometers (5.8 miles) there are six bridge sections that span the gaps between islands that lie between the two cities, as well as four viaducts on the islands themselves. The whole route is a double-decker construction, with an expressway running above a railway. In terms of scale, it is the largest combined road and rail bridge system in the world. Among all, the 1100-meter (3,609-foot) central span of the 1,723-meter (5,653-foot) long Minami Bisan Seto Ohashi Bridge at the southernmost end is on its own the world's longest combined road and rail bridge.  

Construction began in October, 1978. A total of over 1 trillion yen (7,692 million dollars; $1=\130) was spent on this huge project, and it took ten years to be completed in April 1988. At present only normal trains are accommodated, but for future integration into the national high-speed railway network, the railway section is also designed to accommodate Shinkansen "bullet" trains. Due consideration has been given to the forces of nature, and the structure can withstand winds of up to 65 meters per second (146.25 m.p.h.) and earthquakes of magnitude 8.5.  

Photo: Seto Ohashi Bridges viewed from the Shikoku side (Kagawa Prefecture). 

Unauthorized reproduction of the photos in this page is prohibited. 

Related Links:

• Honshu-Shikoku Bridge Authority