Apparent Periods of a Building. I: Fourier Analysis
Publication: Journal of Structural Engineering
Volume 127, Issue 5
Abstract
This and the companion paper present an analysis of the amplitude and time-dependent changes of the apparent frequency of a seven-story reinforced-concrete hotel building in Van Nuys, Calif. Data of recorded response to 12 earthquakes are used, representing very small, intermediate, and large excitations (peak ground velocity, vmax = 0.6 − 11, 23, and 57 cm/s, causing no minor and major damage). This paper presents a description of the building structure, foundation, and surrounding soil, the strong motion data used in the analysis, the soil-structure interaction model assumed, and results of Fourier analysis of the recorded response. The results show that the apparent frequency changes form one earthquake to another. The general trend is a reduction with increasing amplitudes of motion. The smallest values (measured during the damaging motions) are 0.4 and 0.5 Hz for the longitudinal and transverse directions. The largest values are 1.1 and 1.4 Hz, respectively, determined from response to ambient noise after the damage occurred. This implies 64% reduction of the system frequency, or a factor ≈3 change, from small to large response amplitudes, and is interpreted to be caused by nonlinearities in the soil.
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References
1.
Biot, M. A. ( 1942). “Analytical and experimental methods in engineering seismology.” Proc. Am. Soc. Civ. Engrg., Paper No. 2183, 68, 356–409.
2.
Blume, J. A., et al. ( 1973). “Holiday Inn, chapter 29” San Fernando, California earthquake of February 9, 1971. Vol. I, Part A, U.S. Department of Commerce, National Oceanic and Atmospheric Administration, Washington, D.C.
3.
Goel, R. K., and Chopra, A. K. (1998). “Period formulas for concrete shear wall building.”J. Struct. Engrg., ASCE, 124(4), 426–433.
4.
Islam, M. S. ( 1996). “Analysis of the response of an instrumented 7-story non ductile concrete frame building damaged during the Northridge earthquake.” 1996 Ann. Meeting, Profl. Paper 96-9. Los Angeles Tall Buildings Structural Design Council, Los Angeles.
5.
Ivanović, S. S., Trifunac, M. D., Novikova, E. I., Gladkov, A. A., and Todorovska, M. I. ( 2000). “Ambient vibration tests of a seven-story reinforced concrete building in Van Nuys, California, damaged by the 1994 Northridge earthquake.” Soil Dyn. and Earthquake Engrg., 19(6), 391–411.
6.
Ivanović, S. S., Trifunac, M. D., Novikova, E. I., Gladkov, A. A., and Todorovska, M. I. ( 1999b). “Instrumented 7-story reinforced concrete building in Van Nuys, California: Ambient vibration surveys following the damage from the 1994 Northridge earthquake.” Dept. of Civ. Engrg., Rep. No. CE 99-03, University of Southern California, Los Angeles.
7.
Ivanović, S. S., Trifunac, M. D., and Todorovska, M. I. ( 1999a). “On identification of damage in structures via wave travel times.” Proc., NATO Workshop on Strong Motion Instrumentation for Civ. Engrg. Struct. Kluwer, Dordrecht, The Netherlands.
8.
Jacobsen, L. S., and Ayre, R. S. ( 1958). Engineering vibrations, McGraw-Hill, New York.
9.
Lee, V. W., and Trifunac, M. D. ( 1990). “Automatic digitization and processing of accelerograms using PC.” Dept. of Civ. Engrg. Rep. No. 90-03, University of Southern California, Los Angeles.
10.
Li, Y. R., and Jirsa, J. O. ( 1998). “Nonlinear analyses of an instrumented structure damaged in the 1994 Northridge earthquake.” Earthquake Spectra, 14(2), 265–283.
11.
Luco, J. E., Trifunac, M. D., and Wong, H. L. ( 1987). “On apparent changes in dynamic behavior of a nine-story reinforced concrete building.” Bull. Seismological Soc. Am., 77(6), 1961–1983.
12.
Luco, J. E., Wong, H. L., and Trifunac, M. D. ( 1986). “Soil-structure interaction effects on forced vibration tests.” Dept. of Civ. Engrg., Rep. No. 86-05, University of Southern California, Los Angeles.
13.
Sezawa, K., and Kanai, K. ( 1935). “Decay in the seismic vibration of a simple or tall structure by dissipation of their energy into the ground.” Earthquake Res. Inst., Tokyo University, Tokyo XIII(3), 681–697.
14.
Shakal, A., et al. ( 1994). “CSMIP strong motion records from the Northridge, California, earthquake of 17 January 1994.” Rep. No. OSMS 94-07, California Department of Conservation, Division of Minerology and Geology, Sacramento, Calif.
15.
Trifunac, M. D. ( 1974). “A three-dimensional dislocation model for the San Fernando, California, earthquake of February 9, 1971.” Bull. Seismological Soc. Am., 64(1), 149–172.
16.
Trifunac, M. D. (1997). “Relative earthquake motion of building foundations.”J. Struct. Engrg., ASCE, 123(4), 414–422.
17.
Trifunac, M. D. (1999). “Discussion of `Period formulas for concrete shear wall building,' by Rakesh K. Goel and Anil K. Chopra.”J. Struct. Engrg., ASCE, 125(7), 797–798.
18.
Trifunac, M. D. (2000). “Discussion of `seismic soil-structure interaction in buildings. I: Analytical methods, and II: Empirical findings,' by Jonathan P. Stewart, Raymond B. Seed, and Gregory L. Fenves.”J. Geotech. and Geoenvir. Engrg., ASCE, 126(7), 668–670.
19.
Trifunac, M. D., Brady, A. G., and Hudson, D. E. ( 1973). “Strong motion earthquake accelerograms, digitized and plotted data.” Rep. EERL-72-51, II(C), California Institute of Technology, Pasadena, Calif.
20.
Trifunac, M. D., Ivanović, S. S., and Todorovska, M. I. ( 1999a). “Seven story reinforced concrete building in Van Nuys, California: 1. Strong motion data recorded between 7 Feb. 1971 and 9 Dec. 1994, and 2. Description of damage following Northridge 17 Jan. 1994 earthquake.” Dept. of Civ. Engrg., Rep. No. 99-02, University of Southern California, Los Angeles.
21.
Trifunac, M. D., Ivanović, S. S., Todorovska, M. I., Novikova, E. I., and Gladkov, A. A. ( 1999b). “Experimental evidence for flexibility of a building foundation supported by concrete friction piles.” Soil Dyn. and Earthquake Engrg., 18(3), 169–187.
22.
Trifunac, M. D., Ivanović, S. S., and Todorovska, M. I. (2001). “Apparent periods of a building II: Time-frequency analysis.”J. Struct. Engrg., ASCE, 127(5), 527–537.
23.
Trifunac, M. D., and Lee, V. W. ( 1973). “Routine computer processing of strong motion accelerograms.” Earthquake Engrg. Res. Lab., Rep. EERL 73-03, California Institute of Technology, Pasadena, Calif.
24.
Udwadia, F. E., and Trifunac, M. D. ( 1974). “Time and amplitude dependent response of structures.” Earthquake Engrg. and Struct. Dyn., 2, 359–378.
25.
Wald, D. J., and Heaton, T. H. ( 1996). “The slip history of the 1994 Northridge, California, earthquake determined from strong-motion, telseismic, GPS and leveling data.” Bull. Seismological Soc. Am., 86(1B), S4–S70.
Information & Authors
Information
Published In
Journal of Structural Engineering
Volume 127 • Issue 5 • May 2001
Pages: 517 - 526
History
Received: Feb 22, 2000
Published online: May 1, 2001
Published in print: May 2001
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