- Author
- Phan, L. T. | Hendrickson, E. M. | Marshall, R. D.
- Title
- Measurement of Structural Response Characteristics of Full-Scale Buildings: Analysical Modeling of the San Bruno Commercial Office Building.
- Coporate
- National Institute of Standards and Technology, Gaithersburg, MD
- Report
- NISTIR 4782, March 1992, 50 p.
- Distribution
- Available from National Technical Information Service
- Keywords
- earthquakes | accelerations | ambient vibration | analytical modeling | autocorrelation | buildings | damping | Fourier spectrum | frequencies | instrumentation | Loma Prieta | measurement | model analysis | structural response | transient analysis | dynamic characteristics
- Abstract
- A 6-story commercial office building in San Bruno, California, which experienced the Loma Prieta earthquake of October 17, 1989 and sustained no visible damage, was subjected to ambient vibration tests in September 1990. Ambient vibration data were recorded from the 13 accelerometers installed prior to the Loma Prieta earthquake. Comparison of dynamic characteristics revealed that the first-mode response frequency deduced from the Loma Prieta records is significantly lower than that deduced from ambient vibration tests, and the damping ratio for strong motion is substantially higher than that obtained from ambient vibration. A computer model of the building was developed and applied using two different boundary conditions; fixed-base and spring-supported conditions. The fixed-base condition was used to simulate the building response to ambient vibration, and the spring-supported condition was used to incorporate soil-structure interaction and thus simulate realistic building response to the Loma Prieta earthquake. Results of analyses showed that the first-mode response frequencies for the two cases differ by essentially the same factor observed from measurements. This suggests that the difference in first-mode response frequencies between ambient vibration and strong motion in this building was due largely to soil-structure interaction.