Use of probabilistic and deterministic measures to identify unfavorable earthquake records
This study introduces measures to identify resonant (concentration of energy in a single or a few frequencies) or unfavorable earthquake ground motions. Probabilistic measures based on the entropy rate and the geometric properties of the power spectral density function (PSDF) of the ground acceleration are developed first. Subsequently, deterministic measures for the frequency content of the ground acceleration are also developed. These measures are then used for identifying resonance and criticality in stochastic earthquake models and 110 acceleration records measured at rock, stiff, medium and soft soil sites. The unfavorable earthquake record for a given structure is defined as the record having a narrow frequency content and dominant frequency close to the structure fundamental natural frequency. Accordingly, the measures developed in this study may provide a basis for selecting records that are capable of producing the highest structural response. Numerical verifications are provided on damage caused to structures by identified resonant records.
Key wordsEntropy rate Dispersion index Power spectral density function (PSDF) Frequency content Unfavorable ground motion Resonant acceleration Critical accelerogram Energy Damage index
Unable to display preview. Download preview PDF.
- Abbas, A.M., 2002. Deterministic/Reliability-based Critical Earthquake Load Models for Linear/Nonlinear Structures. PhD Thesis, Indian Institute of Science, Bangalore.Google Scholar
- Arias, A., 1970. A Measure of Earthquake Intensity. Seismic Design of Nuclear Power Plants. MIT Press, Cambridge, MA, p.438–468.Google Scholar
- Kanai, K., 1957. Semi-empirical formula for the seismic characteristics of the ground. Bulletin of Earthquake Research Institute, University of Tokyo, 35:309–325.Google Scholar
- Lin, Y.K., 1967. Probabilistic Theory of Structural Dynamics. McGraw-Hill, NY.Google Scholar
- Moustafa, A., 2008. Discussion of a new approach of selecting real input ground motions for seismic design: the most unfavorable real seismic design ground motions. Earthquake Engineering and Structural Dynamics (in press). [doi:10.1002/eqe.885]Google Scholar
- Nigam, N.C., Narayanan, S., 1994. Applications of Random Vibrations. Narosa Publishing House, New Delhi.Google Scholar
- PEER, 2005. Pacific Earthquake Engineering Research Center. Available from: http://peer.berkeley.edu (Accessed 2008)
- Tajimi, H., 1960. A Statistical Method of Determining the Maximum Response of a Building Structure during Earthquakes. Proc. 2nd WCEE, Tokyo, 2:781–797.Google Scholar
- Trifunac, M.D, Brady, A.G., 1975. A study on the duration of strong earthquake ground motion. Bulletin of the Seismological Society of America, 65(3):581–626.Google Scholar
- Uang, C.M., Bertero, V.V., 1988. Implications of Recorded Earthquake Ground Motions on Seismic Design of Building Structures. Report No. UCB/EERC-88/13, Earthquake Engineering Research Center, Berkeley, CA.Google Scholar
- Vanmarcke, E.H., 1972. Properties of spectral moments with applications to random vibration. Journal of the Engineering Mechanics Division, 98(2):425–446.Google Scholar
- Vanmarcke, E.H., 1976. Structural Response to Earthquakes. Lomnitz, C., Rosenbluth, E. (Eds.), Seismic Risk and Engineering Decisions. Elsevier, NY.Google Scholar