My first Magazine dsi-info-23-en | Page 54

Construction—APAC—Japan—Bridges Efficiency with DYWIDAG Strand Tendons: The Gunkai-gawa Bridge on the New Tomei Expressway in Japan The New Tomei Expressway on Japan’s main island of Honshu connects Japan’s 3 largest cities with each other. Located between the cities of Toyota and Okazaki in the Aichi Prefecture, the Gunkai-gawa Bridge also forms part of this route. The 740m long, 7 span bridge was built as a continuous rigid frame box girder using prestressed reinforced concrete. The bridge is a rigid frame structure with only two bearings, thus eliminating the need for complex intermediate bearings. The superstructure of the Gunkai-gawa Bridge was built taking advantage of light weight concrete construction. 54 For this purpose, high-strength concrete was used in some parts of the girder in order to reduce slab and web thicknesses. Additionally, 650t jacks were used near both end piers in the hollow box girder in order to transfer horizontal loads before closing the girder at the center span. This way, the bending moment acting on the end piers was reduced. This method allows a more compact design of the end pier foundations, minimizing adverse environmental impact in the area of the jobsite. Furthermore, the method was the most economic approach. Caisson foundations were constructed for all bridge piers. In some cases, an angle cut cylinder earth retaining method was adopted in order to reduce the excavation area.