In recent years, sufficient measures to prevent vibration-noise along our country's roads have been in highdemand. One of the measures implemented to help prevent this problem occurring, uses a method of construction in which the floor slab of a bridge is extended onto the topsoil at the back of an abutment pier, and has been carried out by the former JH. This measure, named the' extension floor slab' method of construction, can reduce the vibration-noise by separating the joints along which most vibration occurs. An independent administrative agency; the Public Works Research Institute (PWRI), and a corporate judicial body; Japan Bridge Association (JBA), performed a collaboration study for several years about this method of construction. PWRI and JBA applied this method of construction to the existing Tokonami Bridge, along National Highway No.49. In this article, we report on the application of our new method of construction and its design.
