Seismic Isolation Retrofit of a Medical Complex by Integrating Two Large-Scale Buildings
Yoe Masuzawa* and Yoshiaki Hisada**
*Risk Management Department, Engineering and Risk Services Corporation, Japan, Akasaka Kikyo Bldg., 3-11-15 Akasaka, Minato-ku, Tokyo 107-0052, Japan
**Department of Architecture, Faculty of Engineering, Kogakuin University, Japan, 1-24-2 Nishi-Shinjuku, Shinjuku-ku, Tokyo 163-8677, Japan
We developed a methodology of seismic isolation retrofit integrating adjacent buildings using prestressed concrete slabs, and applied it to two large-scale buildings in Hamamatsu City in Shizuoka Prefecture in Japan. It is the first seismic isolation retrofit of hospital in Japan. The two steel-reinforced concrete buildings were nine stories high with one basement, and had been constructed in 1973 and 1975 based on an old structural design code. The two buildings were integrated into one building by connecting individual floors using post-tensioned prestressing cables through slabs. A comparison of microtremors before and after the integration confirmed that the integration worked well. Seismic isolation devices were set up mainly in basement columns using temporary support involving steel brackets and prestressing cables to install devices safely and economically (Masuzawa et al., 2004 ). In the seismic design phase, broadband-generated earthquake ground motions for a hypothetical Magnitude 8 earthquake near the site were simulated using a hybrid method (Hisada, 2000 , etc.). Safety and functionality were verified by evaluating structural seismic performance based on time-history seismic response analysis.
-  Y. Masuzawa and Y. Hisada, “Seismic Isolation Retrofit of a Prefectural Government Office Building,” Proc. of the 13th World Conference on Earthquake Engineering, CD-ROM, 2004.
-  Y. Hisada, “A Hybrid Method for Predicting Strong Ground Motions at Broad-frequencies Near M8 Earthquakes in Subduction Zones,” Proc. of the 12th World Conference on Earthquake Engineering, CD-ROM, 2000.
-  “Report on the Damage Investigation of the October 23, 2004 Mid Niigata Prefecture Earthquake,” Architectural Institute of Japan, 2006.8. (in Japanese).
-  T. Toshinawa and Y. Masuzawa, “Vibration Characteristics of 9-Story SRC Buildings Connected with Expansion Joints,” Summaries of Technical Papers of Annual Meeting, Architectural Institute of Japan, B-2, pp. 73-74, 2005.9. (in Japanese).
-  Y. Masuzawa and T. Toshinawa, “Vibration Characteristics of 9-Story SRC Buildings Connected with Expansion Joints, Part 2: Vibration Characteristics After Integrating Two Buildings,” Summaries of Technical Papers of Annual Meeting, Architectural Institute of Japan, B-2, pp. 157-158, 2008.9. (in Japanese).
-  Y. Masuzawa and Y. Hisada, “Development a Temporary Supporting Method for Seismic Isolation Retrofit and Evaluation of Vertical Load Support Capacity Based on Full Scale Tests,” Journal of Structural and Construction Engineering, Architectural Institute of Japan, Vol.74, No.638, pp. 701-710, 2009.4. (in Japanese).
-  “The 7th material of Special Investigation Committee for a Tokai earthquake,” Central Disaster Management Council secretariat, Cabinet Office, Government of Japan, 2001.8. (in Japanese).
-  “Digital Strong-Motion Seismograph Network (KiK-net),” National Research Institute for Earth Science and Disaster Prevention.
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