City Research Online

Abstract

In this paper, the adaptive chirplet decomposition combined with the Wigner-Ville transform and the empirical mode decomposition combined with the Hilbert transform are employed to process various non-stationary signals (strong ground motions and structural responses). The efficacy of these two adaptive techniques for capturing the temporal evolution of the frequency content of specific seismic signals is assessed. In this respect, two near-field and two far-field seismic accelerograms are analyzed. Further, a similar analysis is performed for records pertaining to the response of a 20-story steel frame benchmark building excited by one of the four accelerograms scaled by appropriate factors to simulate undamaged and severely damaged conditions for the structure. It is shown that the derived joint time–frequency representations of the response time histories capture quite effectively the influence of non-linearity on the variation of the effective natural frequencies of a structural system during the evolution of a seismic event; in this context, tracing the mean instantaneous frequency of records of critical structural responses is adopted.

The study suggests, overall, that the aforementioned techniques are quite viable tools for detecting and monitoring damage to constructed facilities exposed to seismic excitations.

Publication Type:	Article
Publisher Keywords:	time-frequency representation, chirplets, empirical mode decomposition, intrinsic modes, accelerograms, non-linear structural response, damage detection, HILBERT SPECTRUM, INSTANTANEOUS FREQUENCY, DAMAGE DETECTION, TRANSFORM, WAVELET, SIGNAL, FORMULATION
Subjects:	G Geography. Anthropology. Recreation > GB Physical geography Q Science > QA Mathematics > QA75 Electronic computers. Computer science
Departments:	School of Science & Technology > Engineering
SWORD Depositor:	Symplectic Administrator

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