Identification of Structural Matrices of Shear Buildings Using Ambient Vibration Tests with Incomplete Measurements

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System identification methods (SIMs) are powerful tools for structural health monitoring. SIMs are used either for identification of modal parameters or for extraction of structural characteristic matrices. The current study aims to identify the real matrices of a structure using structural dynamics theory and stochastic subspace identification based on realization theory. The study focuses on extraction of the condensed mass and stiffness matrices of shear buildings by means of ambient excitation responses for limited structural degrees of freedom. Realization theory states that there are minimal realizations for appropriate identification of the main real-system matrices. The present study shows that, by using values smaller than the minimal realization, condensed structural matrices can be correctly identified. This is accomplished by accurate estimation of the full real-system order. It is shown that successive repetitions of this approach can lead to complete structural matrices. The practical application of this procedure is examined using an experimental model and an analytical six-story shear model. Analysis revealed that, even in the presence of noise, this method can accurately identify structural matrices in all cases with high precision.

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One part of this study investigated free vibration of an experimental shear building model. This experiment was designed and performed by Dr. Khanlari under the supervision of Prof. Ashtiany at the Structural Engineering Research Center Laboratory of the International Institute of Earthquake Engineering and Seismology. We greatly appreciate their contribution and the sharing of their experimental experience.

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Correspondence to Omid Bahar.

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Khodayari, R., Bahar, O. & Ghafory-Ashtiany, M. Identification of Structural Matrices of Shear Buildings Using Ambient Vibration Tests with Incomplete Measurements. Iran J Sci Technol Trans Civ Eng (2020) doi:10.1007/s40996-019-00323-6

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  • System identification
  • Minimal realization
  • Ambient excitation
  • Incomplete measurement
  • Shear buildings