Full-Scale Measurement of Building Response to Ambient Vibration and the Loma Prieta Earthquake.
Full-Scale Measurement of Building Response to Ambient
Vibration and the Loma Prieta Earthquake.
Marshall, R. D.; Phan, L. T.; Celebi, M.
Earthquake Engineering Research Institute. Earthquake
Awareness and Mitigation Across the Nation. U.S.
National Conference, Fifth (5th). Proceedings. Volume
2. July 10-14, 1994, Chicago, IL, 661-670 pp, 1994.
earthquakes; vibration; data analysis; high rise
buildings; office buildings; commercial buildings
This paper describes the collection and analysis of
ambient vibration data from five buildings in the San
Francisco Bay area that experienced strong shaking
during the Loma Prieta earthquake of October 17, 1989.
Results of data analyses show that, while the lower
modes of vibration can be reliably identified from
ambient vibration records, the frequencies of these
modes are in each case higher than the frequencies
derived from strong-motion response records. When
soil-structure interaction is involved, the
strong-motion modal frequencies may range from 70 to 80
percent of the corresponding values extracted from
ambient vibration records. Estimates of structural
damping derived from ambient vibration data are
substantially smaller than those derived from
strong-motion data and are consistent with predictions
of a damping model based on forced vibration tests.
Where soil-structure interaction is a significant
factor, the overall damping for strong-motion response
may be 3 to 4 times the indicated lower bound.