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Stochastic subspace identification for output‐only modal analysis: application to super high‐rise tower under abnormal loading condition
Author(s) -
Liu YiCheng,
Loh ChinHsiung,
Ni YiQing
Publication year - 2012
Publication title -
earthquake engineering and structural dynamics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.218
H-Index - 127
eISSN - 1096-9845
pISSN - 0098-8847
DOI - 10.1002/eqe.2223
Subject(s) - subspace topology , tower , singular value decomposition , operational modal analysis , control theory (sociology) , identification (biology) , noise (video) , system identification , preprocessor , computer science , modal analysis , modal , projection (relational algebra) , algorithm , mathematics , engineering , structural engineering , data mining , artificial intelligence , finite element method , botany , control (management) , image (mathematics) , biology , measure (data warehouse) , chemistry , polymer chemistry
SUMMARY The objective of this paper is to develop an online system parameter estimation technique from the response measurements through using the recursive covariance‐driven stochastic subspace identification (SSI‐COV) approach. In developing the recursive SSI‐COV, to avoid time‐consumption of singular value decomposition in recursive SSI, the extended instrumental variable version of the projection approximation subspace tracking method is used in SSI‐COV. Besides, to reduce the effect of noise on the results of identification, the preprocessing of data using recursive singular spectrum analysis technique is also presented to remove the noise contaminant measurements to enhance the stability of data analysis. On the basis of the proposed method, both the ambient vibration and seismic response data of a tower (Canton Tower) are used to observe the time‐varying system natural frequencies of a tower from its operating condition. Results from using off‐line SSI‐COV method under normal operating condition are also presented. Comparison on the identified time‐varying dynamic characteristics of the tower under normal operating condition and earthquake response of distanced earthquake event is discussed. Copyright © 2012 John Wiley & Sons, Ltd.