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On the reliability of long‐period response spectral ordinates from digital accelerograms
Author(s) -
Paolucci Roberto,
Rovelli Antonio,
Faccioli Ezio,
Cauzzi Carlo,
Finazzi Daniela,
Vanini Manuela,
Di Alessandro Carola,
Calderoni Giovanna
Publication year - 2007
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.781
Subject(s) - waveform , spurious relationship , displacement (psychology) , ordinate , broadband , acceleration , noise (video) , spectral shape analysis , cutoff frequency , geology , seismology , engineering , mathematics , spectral line , statistics , computer science , telecommunications , physics , electrical engineering , geometry , artificial intelligence , psychology , radar , classical mechanics , astronomy , image (mathematics) , psychotherapist
Using records from co‐located broadband and digital strong motion (SM) instruments, it is first shown that the displacement waveforms obtained by double integration of the accelerogram need not be free of unrealistic baseline drift to yield reliable spectral ordinates up to at least 10 s. Secondly, to provide objective criteria for selecting reliable digital SM records for ground motion predictions at long periods, a set of synthetic accelerograms contaminated by random long‐period noise has been used, and the difference between the original accelerograms and the spurious ones in terms of response spectra has been quantified, by introducing a noise index that can be easily calculated based on the velocity waveform of the record. The results of this study suggest that high‐pass filtering the digital acceleration record from a cutoff period selected to suppress baseline drifts on the displacement waveform appears to be in most cases too conservative and unduly depletes reliable information on long‐period spectral ordinates. Copyright © 2007 John Wiley & Sons, Ltd.