Osaka Station City South Gate Building

The long-cycle ground motion that was a problem in the Great East Japan Earthquake greatly amplifies shaking through resonance, particularly in super high-rise buildings. This project is an expansion of ACTY Osaka in the Osaka Terminal Building, our design, which was completed in 1983. In expanding the building, which had become structurally non-compliant with the amendment of the Building Standards Act, we used the coupled vibration control approach, which connects the expanded structural frame and the existing structural frame, which have differing vibration characteristics, through oil dampers(coupling dampers). This method enabled us to minimize earthquake resistance reinforcement of the existing structural frame. Furthermore, we were able to keep the dimensions of the expansion joints between the new and old structural frames within 450mm, which is within the range of common dimensions. This enabled us to raise the vibration damping performance of the building as a whole against various predicted ground motions, including long-cycle ground motion.Our design takes into consideration the sense of surrounding unity and presence projected by the open space in front of the station, the stance and “face” of the station, provision of lines of sight from the station to the city, and integration between the older building and its extension. The characteristic facade, and the sight of pedestrians making their way into and out of the city through the station, speaks of the close relationship between the station and the city.