Seismic response of transamerica building. II. System identification

Journal of Structural Engineering
By:  and 



A detailed analysis of the recorded seismic response of the Transamerica Building during the October 17, 1989 Loma Prieta earthquake is presented. The system identification algorithm used for the analysis is based on the discrete-time linear filtering approach with least-squares approximation, and assumes a multi-input, single-output model for the building. Fifteen modes in the north-south direction, and 18 modes in the east-west direction are identified from the records. The analysis shows that the building's response to the earthquake was dominated by a coupled mode of vibration at 0.28 Hz in the southwest-northeast direction, which is almost parallel to one of the diagonals in the building's square cross section. The reason for this behavior is the symmetry of the building's structural characteristics, as well as the strong polarization of the S-waves of the earthquake. Several higher modes of the building were excited during the strong-motion part of the earthquake. The results also show a significant amount of rocking in the building at a frequency of 2.15 Hz.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Seismic response of transamerica building. II. System identification
Series title Journal of Structural Engineering
DOI 10.1061/(ASCE)0733-9445(1991)117:8(2405)
Volume 117
Issue 8
Year Published 1991
Language English
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Journal of Structural Engineering
First page 2405
Last page 2425
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