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language
eng
Author
Okada, Keiichi Institute of Technology, Shimizu Corporation, Tokyo, Japan
Description
The seismic isolation mechanism of the core-suspended isolation (CSI) system comprises a double layer of inclined rubber bearings installed on top of a reinforced core structure. A multilevel structure is then suspended from a hat truss or umbrella girder constructed on the seismic isolation mechanism. The first building to use the CSI system was the Safety and Security Center in Tokyo, Japan, whose structural health monitoring system has detected and recorded 231 earthquake motions since 2006, including the 2011 Tohoku Pacific Earthquake (2011-TPE). The present study estimates the dynamic characteristics of this CSI-equipped building in earthquakes, and the effects of the CSI system are revealed via the observed earthquake records. The temporal changes of the fundamental period and damping factor are estimated from the 2011-TPE; the fundamental period increases with the deformation of the isolation level, whereas the fundamental damping factor is only related weakly to that deformation. The 231 observed earthquake records reveal that the CSI system performs seismic isolation by reducing the response acceleration of the suspended structure by roughly a half for peak ground accelerations exceeding 30 cm/s2. Daily microtremor observations are used to diagnose earthquake damage; the fundamental frequencies in each direction remain almost constant and were not changed by the 2011-TPE.
Volume
50
Issue
9
Start Page
2259
End Page
2276
ISSN(Online)
1096-9845
Published Date
2021-07-21
DOI
Publisher
John Wiley & Sons, Inc
NII Type
Journal Article
Format
PDF
Text Version
著者版
Gyoseki ID
39167
OAI-PMH Set
Faculty of Science and Engineering