Urban Redevelopment, Akihabara, Tokyo, Japan

Epoxy-Coated Strands post-tension Pedestrian Bridge in the new "Akihabara Crossfield" Complex in Tokyo

Urban Redevelopment, Akihabara, Tokyo, Japan

Akihabara, a district of Tokyo, has changed its visual appearance several times in history. In the past few years, it has become known as "Electric town", as numerous shops for electronic devices settled there. In the main and side streets of Akihabara, the most modern electronic devices such as mobile phones, digital cameras and DVD players can be found.

At the beginning of the new millennium, plans for a renewed redevelopment of the Akihabara district were realized. The name of this project, "Akihabara Crossfield", is symbolic for the main purpose of this redevelopment measure. A new area is to be created amid the established IT industry featuring research, office and sales areas that serve as an interface with the public and provide adequate facilities for banquets, shows and IT workshops for children. For this purpose, two new multistory buildings, Akihabara Daibiru and Akihabara UDX, were built in the Akihabara district.

To provide a safe connection between the two new high-rise buildings and the railroad station, Kajima Corporation, Japan, had a new 63.8 m long and 8.0 m wide pedestrian bridge built. As regards the architectural design of the bridge, much importance was attached to a slim visual appearance so that the bridge design would harmonize with the IT center.

This objective was achieved by means of a twospan continuous prestressed concrete bridge using ultra high strength concrete. For the bridge construction, the newly developed selfcuring technology for artificial lightweight aggregates was applied for the very first time. Thus, low-shrinkage ultra high strength concrete was produced at reasonable cost that could be cast in place with a design strength of 120 N/mm2. The high-strength prestressing tendons are 20% stronger than the conventional type. The main girder of the bridge has a square cross-section consisting of an upper floor slab, a web and struts.

Within the framework of the inauguration of the new Akihabara Crossfield Center in March 2006, the bridge was opened to the public.