Simple superposition approach for dynamic analysis of piled embedded footings

L. A. Padrón*, G. Mylonakis, D. E. Beskos

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

7 Citations (Scopus)

Abstract

The effectiveness and accuracy of the superposition method in assessing the dynamic stiffness and damping coefficients (impedance functions) of embedded footings supported by vertical piles in homogeneous viscoelastic soil is addressed. To this end, the impedances of piled embedded footings are compared to those obtained by superposing the impedance functions of the corresponding pile groups and embedded footings treated separately, with the magnitude of the relative average differences being around 10-30%. The results are presented in a set of dimensionless graphs and simple expressions that can be used to estimate the dynamic stiffness and damping of piled embedded footings, provided that the impedance functions of the two individual components are known. This is precisely the reason why the superposition approach studied here is appealing, because such impedance functions for both embedded footings and pile groups are available for a wide range of cases. How to estimate the kinematic response functions of the system when those of the individual components are known is also discussed. To address the problem, parametric analyses performed using a 3D frequency-domain elastodynamic BEM-FEM formulation are presented for different pile-soil stiffness contrasts, embedment depths, pile-to-pile separations and excitation frequencies. Vertical, horizontal, rocking, and cross-coupled horizontal-rocking impedance functions, together with translational and rotational kinematic response functions, are discussed. The results suggest that the superposition concept, in conjunction with a correction strategy as that presented herein, can be employed in geotechnical design. For kinematic effects, the response functions of the embedded footing are found to provide reasonable estimates of the system's behaviour.

Original languageEnglish
Pages (from-to)1523-1534
Number of pages12
JournalInternational Journal for Numerical and Analytical Methods in Geomechanics
Volume36
Issue number12
DOIs
Publication statusPublished - 25 Aug 2012

Keywords

  • Boundary element method
  • Dynamic stiffness
  • Embedded foundations
  • Kinematic response
  • Pile groups
  • Piled embedded footings
  • Soil-structure interaction

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