Reconstruction of the Daiichi Shinden-gawa bridge -Design and construction of a PC hybrid Langer bridge-

摘要

The Daiichi Shinden-gawa bridge on the JR Ou-honsen line crosses a class 2 river, Shinjo-gawa, in Aomori prefecture. It was reconstructed in the scope of a river improvement project of this prefecture. The old bridge was modified in 2000 into a new girder carrying double-track, with a single span of 48.8 m. A prestressed concrete (PC) hybrid through-girder Langer design was selected for the new bridge. The main members of its superstructure, that is, arch and hanger members, are composed of hot-dip galvanized cold-pressed rectangular steel tubes. This was the first attempt in railway bridge projects in Japan. The main study themes in the design were; 1) ensuring the toughness of cold-bent portions of rectangular steel tubes, 2) anchoring system at the joints of the hybrid structure. This paper focuses upon the measures taken in relation to these points and study results.