Design and Construction of Kitasenju Station, Elevated Bridge Station

摘要

A new railway line("JOBAN NEW line") connecting Akihabara station in Tokyo and Tsukuba station in the Ibaraki prefecture has been planned. Kitasenju station, located in the northeast of Tokyo, is a station crowded with about 400,000 passengers per day, as four railway lines ride into it. A new 400 meter elevated bridge station for JOBAN NEW line is being planned to be constructed just above the existing platforms which experience more than 400 train stops per day. Considering that many passengers use this platform, the new station's columns on the platform have to be built in a short period of time and be shaped slender. Therefore, the CFT structure has been chosen for the new station's columns because of its high strength and ductility, as well as the socket type joint between CFT columns and RC piles due to its simplicity and low costs. The socket type joint is a simple sleeve joint in which a CFT column is inserted by the specific length to a RC pile whose top is covered with a steel pipe ("socket pipe"). A socket pipe is cheaper and easier to be built than conventional joints with anchor frames or melting. This type of joint has already proposed. And there are some structures which are built with socket type joints.''However, any destruction behavior of joint, for example, flow of bending moment and shear force, has not been made clear so far. So some model tests about joints of CFT structure have been carried out. And the destruction behavior was clearly described, and a calculation method about ultimate strength of joint was proposed. This paper describes a design method of socket joints that is proposed, as well as design and construction details about socket joints of the new elevated bridge at Kitasenju station.