Abstract
This paper presents the identification of the time-variant modal properties of a full-scale fivestory RC building tested on a shake table. The building was tested under fixed-base (FB) and base-isolated (BI) configurations and was subjected to a suite of earthquake motions of various intensities. The deterministic-stochastic subspace identification method is employed to estimate the variations of the modal properties of the BI building during the seismic tests by employing a short-time windowing approach. The changes of the modal parameters are tracked, analyzed, and compared to those previously identified from ambient vibrations data and low-amplitude whitenoise base excitation tests. In addition, observed and measured responses of the structure are studied and correlated with the variation of the identified modal parameters. For the base-isolated configuration, the nonlinear behavior of the isolators generates the variation of the identified natural frequencies and equivalent damping ratios of the building, which change in agreement with the input motion intensity. A high correlation between the effective stiffness of the isolators and the instantaneous frequency of the first mode is found. The effective damping ratio of the isolation system and the instantaneous damping ratio of the fundamental mode of the building are highly correlated.
| Original language | English |
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| Title of host publication | 11th National Conference on Earthquake Engineering 2018, NCEE 2018 |
| Subtitle of host publication | Integrating Science, Engineering, and Policy |
| Publisher | Earthquake Engineering Research Institute |
| Pages | 6155-6164 |
| Number of pages | 10 |
| ISBN (Electronic) | 9781510873254 |
| State | Published - 2018 |
| Event | 11th National Conference on Earthquake Engineering 2018: Integrating Science, Engineering, and Policy, NCEE 2018 - Los Angeles, United States Duration: 25 Jun 2018 → 29 Jun 2018 |
Publication series
| Name | 11th National Conference on Earthquake Engineering 2018, NCEE 2018: Integrating Science, Engineering, and Policy |
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| Volume | 10 |
Conference
| Conference | 11th National Conference on Earthquake Engineering 2018: Integrating Science, Engineering, and Policy, NCEE 2018 |
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| Country/Territory | United States |
| City | Los Angeles |
| Period | 25/06/18 → 29/06/18 |
Bibliographical note
Funding Information:The author is very grateful to Professors Tara C. Hutchinson, Joel P. Conte, and José I. Restrepo from the University of California, San Diego for making these data available. R. Astroza acknowledges the financial support from the Universidad de los Andes, Chile through the research grant FAI and from the Chilean National Commission for Scientific and Technological Research (CONICYT), FONDECYT project No. 11160009.
Funding Information:
The author is very grateful to Professors Tara C. Hutchinson, Joel P. Conte, and Jos? I. Restrepo from the University of California, San Diego for making these data available. R. Astroza acknowledges the financial support from the Universidad de los Andes, Chile through the research grant FAI and from the Chilean National Commission for Scientific and Technological Research (CONICYT), FONDECYT project No. 11160009.
Publisher Copyright:
Copyright © 2018 Earthquake Engineering Research Institute. All rights reserved.