2015.2.3
The opening ceremony of Irabu Bridge, which connects Miyako-jima and Irabu-jima was held on January 31st. Yohei Matsumoto, Parliamentary Secretary of the Cabinet Office, Governor Takeshi Onaga, Mayor Toshihiko Shimoji and other invited guests took part in the grand opening ceremony on this day. Because Miyako-jima and Irabu-jima are separated by the sea, they are forced to suffer great disadvantages and inconveniences in medical care, education, welfare, etc., and were faced with various problems unique to remote islands such as progressing depopulation and industrial decline. Some 41 years after the former Irabu Village first asked the Japanese Government to build a bridge, local newspapers used many pages to express their joy on the completion of the bridge.
Together with the Chuo Kensetu Consultants, Co., Ltd., Nippon Engineering Consultants took charge of the detailed design of the ship passage section and the landscape design for the whole bridge. Irabu Bridge is located in a strong wind environment where many typhoons pass nearby, and is also a severe salt damage environment. The central section with the total length of 3,540 m (project extension 6,500 m) is the route for 2000 t class cargo and passenger ships. Based on these conditions, a steel deck box girder bridge with an unusual cross section, which is wider than the width of the roadway, was chosen for its excellent performance in terms of durability, economy, reliability and quality of construction, ease of maintenance and management. By eliminating protrusions on the main girder surface, the bridge is planned and designed to improve durability and to ensure quality is easily achieved in the construction environment.
