Rocking Damping of Arbitrarily Shaped Embedded Foundations

Abstract

A simple analytical model is developed for estimating the rocking radiation damping coefficients of arbitrarily shaped rigid foundations embedded in an elastic homogeneous halfspace. The model, based on sound physical approximations that respect fundamental principles of dynamics and wave propagation, is calibrated with the help of rigorous numerical results from boundary element and finite element formulations. Results and comparisons are presented for a variety of basemat shapes (including the circle, rectangles with aspect ratio of up to ten, the strip, and T‐shapes), for a wide range of embedment depths, and for complete, as well as partial, symmetric and nonsymmetric contact between the vertical sidewalls and surrounding soil. Valuable insight is gained into the mechanics of radiation damping, and it is demonstrated quantitatively that, in practice, separation and slippage between side‐walls and soil would appreciably affect damping for rocking only in the lateral direction (i.e., about the long axis of the basemat).