Tenjou Bridge


Photo above:Completion forecast photo montage of Tenjou Bridge (right side is current Tenmon Bridge).

A bridge that harmonizes with its surrounding environment, yet gives a sense of technological progress for more than 40 years 

The current Tenmon Bridge was completed as the first bridge of Amakusa Gokyo Bridge connecting the main island of Kyushu and Amakusa Islands in 1966 and plays an important role in promoting local industry and improving the living environment. At the time of completion, the maximum span of 300 meters crossing the Misuminoseto Strait was the world’s largest continuous truss bridge, and it was awarded the first Japan Society of Civil Engineers Tanaka Prize.

Alongside the Tenmon Bridge with its history as described above, the newly built Tenjo Bridge is for cars only, and was constructed as part of improvements to the Kumamoto Amakusa trunk road. We undertook the preliminary design work with the concept of “A bridge that harmonizes with its surrounding environment yet gives a sense of technological progress for more than 40 years.”

Based on the advice of the “Shin-Tenmon Bridge Technical Review Committee” consisting of experts including university professors, Steel PC Composite Arch Bridge (Center Road Type) was selected by comparison of truss bridges, extradosed and arch bridges.

Model for review
Model for review

  • Excellent in economic efficiency as well as blending beautifully with the topography.

  • The appearance of crossing the Misuminoseto Strait harmonizes with the current Tenmon bridge as a “form that fits the topographical situation,” and technical progress can be seen through the long span of the bridge.

  • For the composite structure part, further study is necessary, but it can be judged to have a comparative advantage in terms of maintenance and management.

General view.
General view.

The selected proposal was to fix both ends with steel box arch ribs with a span length of 348 m (Japan’s largest span length for a solid rib type), with stiffened girders for the steel box girders and PC box girders for the side spans. The detailed design of the main bridge was completed in March 2010 and the procedures for ordering construction are currently under way. Construction is scheduled to start from FY2013.

You can see details of the project on the Kumamoto Prefecture website “new sky gate bridge.”

Location Oyano Cho, Kamiamakusa City, Kumamoto Prefecture to Misumimachi, Uki City, Kumamoto Prefecture
Ordering institution Kumamoto Prefecture Civil Engineering Department