Isolation story structure of Umeda Tower, Osaka, Japan

• Published in: Structural engineering international : journal of the International Association for Bridge and Structural Engineering (IABSE) 2003-11, Vol.13 (4), p.225-227
• Main Authors: Yamane, K, Tsubaki, H, Tanaka, T, Sumi, A
• Format: Article
• Language: English
• ISSN: 1016-8664
• DOI: 10.2749/101686603777964351

The Hyogo-ken Nanbu Earthquake (Great Hanshin Earthquake) (Magnitude 7.8) in 1995 resulted in devastating damage to the Kansai area of Japan. For buildings, many cases of collapse and of other major damage to structures were reported. Although the super high-rise buildings were not subject to major structural damage, interior damage caused by furniture movement, cracks to the interior finish material, and/or damage to equipment/ facilities were reported. The earthquake left behind it, the lesson that building functions must be maintained as well as the building itself following an earthquake. Story isolation can reduce not only the force but also the acceleration when a building is subject to an earthquake. Because of this, the isolation story structure is attracting much attention. The Umeda DT Tower is a super high-rise office building extending 130 m above ground. The construction of the building commenced in 1991, but was interrupted in 1993 after installation of the underground columns, piles, 1st floor, and a part of B1 and B2 floors. Subsequently, the building use and plans were reviewed and the working drawing phase started in 1999. Finally, in November 2000, the construction work recommenced and the building was completed in January 2003. The structural features of the building are the mega-frames on the 1st through to the 3rd floors and the story isolation on the intermediate floor immediately beneath the 3rd floor. These features enable the use of existing already-installed structures on site, to realize the building's safety requirements against earthquakes and to maintain the building functions following the earthquake. The details of the features are described in the following paragraphs.