A simplified procedure for torsional impedance functions of embedded foundations in a soil layer

Abstract A simplified calculation procedure for torsional impedance functions of circular embedded foundations in a soil layer with rigid base is presented. The solution is constructed by means of linear combinations of natural modes of propagation and participation factors. The unknown coefficients of such expansions are obtained from the continuous treatment of appropriate boundary conditions in the least-squares sense. The influence of soil material damping is investigated by using hysteretic and viscous models. Dynamic stiffnesses of soil-foundation systems are computed for different foundation embedments and soil layer depths. Finally, the practical importance of introducing viscous instead of hysteretic damping in linear interaction analyses in the time domain is discussed.

[1]  Milos Novak,et al.  Torsional and coupled vibrations of embedded footings , 1973 .

[2]  E. Kausel,et al.  On the effect of the rigid sidewall on the dynamic stiffness of embedded circular footings , 1983 .

[3]  R. D. Woods.  Measurement and use of shear wave velocity for evaluating dynamic soil properties : proceedings of a session , 1985 .

[4]  Milos Novak,et al.  Vertical Vibration of Embedded Footings , 1972 .

[5]  J. W. Meek,et al.  CONE MODELS FOR HOMOGENEOUS SOIL. I , 1992 .

[6]  J. W. Meek,et al.  Insights on cutoff frequency for foundation on soil layer , 1991 .

[7]  J. Avilés,et al.  A boundary method for elastic wave diffraction: Application to scattering of SH waves by surface irregularities , 1982 .

[8]  Robert D. Stoll.  Computer-Aided Studies of Complex Soil Moduli , 1985 .

[9]  J. Wolf.  Soil-structure-interaction analysis in time domain , 1988 .

[10]  Eduardo Kausel,et al.  Dynamic Stiffness of Circular Foundations , 1975 .

[11]  Eduardo Kausel,et al.  Elements for the numerical analysis of wave motion in layered strata , 1983 .

[12]  J. Achenbach.  Wave propagation in elastic solids , 1962 .

[13]  J. Luco.  Torsion of a Rigid Cylinder Embedded in an Elastic Half Space , 1976 .

[14]  J. W. Meek,et al.  CONE MODELS FOR EMBEDDED FOUNDATION , 1994 .

[15]  J. Luco,et al.  Impedance functions for foundations embedded in a layered medium: An integral equation approach , 1987 .

[16]  Akira Mita,et al.  Dynamic response of embedded foundations: a hybrid approach , 1987 .

[17]  Y. O. Beredugo,et al.  Coupled Horizontal and Rocking. Vibration of Embedded Footings , 1972 .

[18]  J. W. Meek,et al.  Cone models for a soil layer on a flexible rock half-space , 1993 .