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The seismic response of a pile foundation is usually analyzed by approximate methods in practice. These methods typically neglect one or more of the important factors that affect seismic response such as inertial interaction, kinematic interaction, seismic pore water pressures, soil nonlinearity, cross stiffness coupling and dynamic pile to pile interaction. A nonlinear 3-D analysis is used to show how all these factors affect pile response, to demonstrate some of the consequences of using various approximate methods and to provide a comprehensive overview of how pile foundations behave during earthquakes in liquefiable and non-liquefiable soils. [ABSTRACT FROM AUTHOR]

Presents a study that examined foundation factors in seismic codes to capture the amplification effects of local soil conditions on ground motions. Review of developments in categorizing site conditions for seismic codes; Analysis of approaches to foundation factors; Implications of the results for the proposed 2005 edition of the National Building Code of Canada.

Abstract In the current state of practice, static/seismic soil-pile interaction is included in design calculations by a set of one-dimensional (1D) uncoupled springs. The guidelines of American Petroleum Institute (API) are often adopted to develop backbone curves for the lateral springs. The purpose of the paper is to assess the reliability of this practice. Twenty-seven static field and laboratory tests, and two dynamic centrifuge tests are simulated to evaluate the performance of the springs. More detailed elaboration on the performance of the springs is provided by simulation of one of the static tests and both of the dynamic tests using also three-dimensional (3D) continuum approach. The evaluation results indicate that API springs do not capture the major mechanisms involved in soil-pile interaction, and this results in erroneous estimation of pile deflections and bending moments. It is shown that the observed errors stem not only from the insufficient characterization of the spring properties (API backbone curves), but also from the inadequate simulation method in which three-dimensional continuum configuration of the supporting soil is represented by a 1D uncoupled spring. Highlights • Measurements of 27 static and 2 dynamic tests on lateral loading of piles are used to assess the reliability of API p - y  springs. • 3D continuum method was used to provide better insight into soil-pile interaction mechanism. • Sources of error in the spring-based simulations are explored and discussed. • Detailed documentation of the limitations of p-y springs is insightful as they are used extensively in design practice. [ABSTRACT FROM AUTHOR]