Temporal variation in modal properties of a base-isolated building during an earthquake
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Temporal variation of dynamical modal properties of a base-isolated building is investigated using earthquake records in the building. A batch processing least-squares estimation method is applied to segment-wise time-series data. To construct an input-output system, an auto-regressive model with exogenous input (ARX) of second-order including a forgetting coefficient as a weighting coefficient is used for the estimation of modal parameters. The fundamental and second natural frequencies and the damping ratios of the fundamental and second natural modes of the base-isolated building are identified in the time domain. The identified results are consistent with the results obtained from the micro-tremor vibration data, forced-vibration test data and earthquake records in the present base-isolated building in the case of taking into account the amplitude-dependency of the isolators and viscous dampers. It is finally pointed out that several factors, e.g., amplitude dependency of the isolator and damper system and special characteristics of the series-type viscous damper system, may be related complicatedly with the temporal variation in modal properties of the above-mentioned system.
Key wordsSystem identification Shear building model Modal parameters Batch processing least-squares estimation method Forgetting coefficient Auto-regressive model with exogenous input (ARX) model
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- Davenport, A.G., Hill-Carroll, P., 1986. Damping in Tall Buildings: Its Variability and Treatment in Design. Proceedings of ASCE Spring Convention, Seattle, USA, p.42–57.Google Scholar
- Doebling, S.W., Farrar, C.R., Prime, M.B., Shevitz, D.W., 1996. Damage Identification and Health Monitoring of Structural and Mechanical Systems from Changes in Their Vibration Characteristics: A Literature Review. Report No. LA-13070-MS, Los Alamos National Laboratory, NM, USA.Google Scholar
- Hart, G.C., Vasudevan, R., 1975. Earthquake design of buildings: Damping. Journal of the Structural Division, ASCE, 101(ST1):11–30.Google Scholar
- Hart, G.C., Yao, J.T.P., 1977. System identification in structural dynamics. Journal of the Engineering Mechanics Division, ASCE, 103(EM6):1089–1104.Google Scholar
- Nakamura, M., Takewaki, I., 2002. System Identification Method for Interstory Stiffness and Damping through Limited Observation: Application to Ambient Vibration and Robustness for Noise. Summaries of Annual Meeting of AIJ, Structure II, p.291–292 (in Japanese).Google Scholar
- Nakamura, M., Takewaki, I., 2005. Evaluation of Time-variance of Dynamic Properties of a Base-isolated Building during an Earthquake. Summaries of Annual Meeting of AIJ, Structure II, p.675–676 (in Japanese).Google Scholar
- Nakamura, M., Takewaki, I., Yasui, Y., Uetani, K., 1998. System Identification Method for Interstory Stiffness and Damping through Limited Observation: Application to Ambient Vibration and Robustness for Noise. Summaries of Annual Meeting of AIJ, Structure II, p.291–292 (in Japanese).Google Scholar
- Nashif, A.D., Jones, D.I.G., Henderson, J.P., 1985. Vibration Damping. John Wiley & Sons, New York.Google Scholar