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The response of a site to a seismic solicitation depends on local topographical and geomechanical characteristics. This paper deals with the evaluation of seismic site effects due to the local topographical and geomechanical characteristics and tries to contribute to establishment of a simple method to evaluate site effects. The amplification of surface motions is calculated by a numerical tool, HYBRID software, combining finite elements in the near field and boundary elements in the far field (FEM/BEM). In this paper, horizontal ground movements in various points of 2D empty valleys with irregular configurations subjected to synthetic SV waves of vertical incidence are calculated. Parametric studies are done on slopes, ridges and different shapes of canyons to characterize topographical site effects. The second part deals with sedimentary valleys. The complexity of the combination of geometrical and sedimentary effects is underlined. Extensive parametrical studies are achieved to discriminate the topographical and geotechnical effects on seismic ground movement amplifications in two-dimensional irregular configurations. The results are also shown in the form of pseudo-acceleration response spectra. For the empty valleys, we can classify the spectral response according to a unique geometric criterion: the “surface/angle” ratio, where surface is the area of the valley opening, and angle denotes the angle between the slope and horizontal line in the above coin. To assess the influence of the two dimensional effect on the spectral response of filled valleys, the response of alluvial basins are compared with the response of one-dimensional columns of soil. Finally, an offset criterion is proposed to choose a relevant computation method for the spectral acceleration at the surface of alluvial basins. The accuracy of this quantitative evaluation technique is tested and discussed.

Keywords

hybrid numerical technique time truncation poroelastodynamics seismic amplification 2D site effects topographical irregularities seismic risk 

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References

  1. Gatmiri, B. and Arson, C. (2008) Seismic site effects by an optimized 2D BE/FE method. II. Quantification of site effects in two dimensional sedimentary valleys, Int. J. Soil Dynamics Earthquake Eng. 28, 646–661.CrossRefGoogle Scholar
  2. Gatmiri, B., Arson, C., and Nguyen, K. V. (2008) Seismic site effects by an optimized 2D BE/FE method. I. Theory, numerical optimization and application to topographical irregularities, Int. J. Soil Dynamics Earthquake Eng. 28, 632–645.CrossRefGoogle Scholar
  3. Gatmiri, B. and Dehghan, K. (2005) Applying a new fast numerical method to elasto-dynamic transient kernels in HYBRID wave propagation analysis. In Proc. 6th Conf. on Structural Dynamics (EURODYN 2005), Paris, France, pp. 1879–1884, Rotterdam, Millpress.Google Scholar
  4. Gatmiri, B. and Jabbari, E. (2005a) Time-domain Green's functions for unsaturated soils. Part I: Two dimensional solution, Int. J. Solid Structure 42, 5971–5990.zbMATHMathSciNetGoogle Scholar
  5. Gatmiri, B. and Jabbari, E. (2005b) Time-domain Green's functions for unsaturated soils. Part II: Three dimensional solution, Int. J. Solid Structure 42, 5991–6002.zbMATHMathSciNetGoogle Scholar
  6. Gatmiri, B. and Kamalian, M. (2002a) On the fundamental solution of dynamic poroelastic boundary integral equations in the time domain, Int. J. Geomechanics 2, 381–398.CrossRefGoogle Scholar
  7. Gatmiri, B. and Kamalian, M. (2002b) Two-dimensional transient wave propagation in anelas-tic saturated porous media by a Hybrid FE/BE method. In Proc. 5th European Conf. on Numerical Methods in Geotechnical Engineering, Paris, France, pp. 947–956.Google Scholar
  8. Gatmiri, B. and Nguyen, K. V. (2005) Time 2D fundamental solution for saturated porous media with incompressible fluid, Int. J. Comm. Num. Meth. Eng. 21, 119–132.zbMATHCrossRefMathSciNetGoogle Scholar
  9. Gatmiri, B. and Nguyen, K. V. (2007) Evaluation of seismic ground motion induced by topographic irregularity, Int. J. Soil Dynamics Earthquake Eng. 27, 183–188.CrossRefGoogle Scholar
  10. Gatmiri, B., Nguyen, K.-V., and Dehghan, K. (2007) Seismic response of slopes subjected to incident SV wave by an improved boundary element approach, Int. J. Num. Anal. Meth. Geomechanics 31, 1183–1195.CrossRefGoogle Scholar
  11. Kamalian, M., Jafari, M. K., Sohrabi-Bidar, A., Razmkhah, A., and Gatmiri, B. (2006) Time-domain two-dimensional site response analysis of non-homogeneous topographic structures by a Hybrid FE/BE Method, Int. J. Soil Dynamics Earthquake Eng. 26, 753–765.CrossRefGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2009

Authors and Affiliations

  • Behrooz Gatmiri
    • 1
  1. 1.Ecole Nationale des Ponts et Chaussées, ParisChamps-Sur-MarneFrance

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