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Evaluation of Accuracy of Modified Equivalent Linear Method  

Jeong, Chang-Gyun (한양대학교 공과대학 건설환경공학과)
Kwak, Dong-Yeop (UCLA 공과대학 토목환경공학과)
Park, Duhee (한양대학교 공과대학 건설환경공학과)
Kim, Kwangkyun (한양대학교 공과대학 건설환경공학과)
Publication Information
Journal of the Korean GEO-environmental Society / v.11, no.6, 2010 , pp. 5-20 More about this Journal
Abstract
One-dimensional equivalent linear site response analysis is widely used in practice due to its simplicity, requiring only few input parameters, and low computational cost. The main limitation of the procedure is that it is essentially a linear method, in which the time dependent change in the soil properties cannot be modeled and constant values of shear modulus and damping is used throughout the duration of the analysis. Various forms of modified equivalent linear analyses have been developed to enhance the accuracy of the equivalent linear method by incorporating the dependence of the shear strain with the loading frequency. The methods are identical in that it uses the shear strain Fourier spectrum as the backbone of the analysis, but differ in the method in which the strain Fourier spectrum is smoothed. This study used two domestically measured soil profiles to perform a series of nonlinear, equivalent linear, and modified equivalent linear site response analyses to verify the accuracy of two modified procedures. The results of the analyses indicate that the modified equivalent linear analysis can highly overestimate the amplification of the high frequency components of the ground motion. The degree of overestimation is dependent on the characteristics of the input ground motion. Use of a motion rich in high frequency contents can result in unrealistic response.
Keywords
Modified equivalent linear analysis; Frequency dependency; Strain Fourier spectrum; High frequency;
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Times Cited By KSCI : 1  (Citation Analysis)
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