An inexpensive and realistic procedure is developed for estimating the lateral dynamic stiffness and damping of flexible piles embedded in arbitrarily layered soil deposits. Starting point is the determination of the pile deflection profile for a static force at the top using any reasonable method—beam‐on‐Winkler foundation, finite elements, well‐instrumented pile load tests in the field, etc. Material as well as radiation damping due to waves emanating at different depths from the pile‐soil interface are rationally taken into account; the overall equivalent damping at the top of the pile is then obtained as a function of frequency by means of a suitable energy relationship. The method is applied to study the dynamic behavior of three different piles embedded in two idealized and one actual layered soil deposit; the results of the method, obtained by hand computations, compare favorably with the results of three dimensional dynamic finite element analyses.

Horizontal Response of Piles in Layered Soils

Early history of soil–structure interaction

Nonlinear analysis for dynamic lateral pile response

Nonlinear lateral interaction in pile dynamics

Three-dimensional nonlinear analysis for seismic soil–pile-structure interaction

The semi‐analytical solution of the dynamic behavior of vertical pile groups is presented. The solution accounts for the pile‐soil‐pile dynamic interaction and is based on modeling the soil as a plane strain continuum and the piles as a set of finite elements. The method is generally enough to model any pile group geometry in a layered soil. The proposed method is simple since it needs no special soil modeling, accurate since its results compared well with the results of finite elements method, and cheaper to use than the finite element method. Some case studies are presented which show that the dynamic pile‐soil‐pile interaction is important for longer distances between the piles than the static case. It is shown also that correction factors due to dynamic pile‐soil‐pile interaction is frequency dependent.

Joseph A. Brennan

Papers

Dynamic Behavior of Pile Groups