A Macro-Element for Dynamic Soil-Structure Interaction Analyses of Shallow Foundations

TL;DR

This paper develops a macro-element model for dynamic soil-structure interaction analysis of shallow foundations, simplifying complex nonlinearities into a point-based approach using multi-mechanism plasticity theory, and presents initial results on seismic bearing capacity.

Contribution

It introduces a novel macro-element framework that reduces soil-structure interaction to a point model incorporating nonlinearities via multi-mechanism plasticity.

Findings

Initial model for seismic bearing capacity developed

Nonlinearities incorporated through multi-mechanism plasticity

Simplified interaction domain facilitates analysis

Abstract

The scope of the paper is to present some aspects of the development of a "macro-element" for dynamic soil-structure interaction analyses of shallow foundations. Initially the concept of "macro-element" is introduced and is illustrated with the aid of a very simple example originating from structural engineering. Then the link is made with the modeling of the dynamic response of shallow foundations and the objectives and structure of such a tool are described with reference to the specific configuration of a circular footing resting on the surface of a heterogeneous purely cohesive soil. The principal features of the "macro-element" are then presented; the soil-structure interaction domain is reduced to a point that coincides with the center of the footing and all the (material and geometric) non-linearities are lumped at this point. A discussion on the most appropriate way to treat these non-linearities is undertaken based on experience gained with earlier works. It is suggested that the non-linearities be incorporated in the model within a unified formalism making use of the theory of multi-mechanism plasticity. Initial results concerning the definition of the ultimate surface for such a plasticity model, corresponding to the seismic bearing capacity of the foundation, are finally presented.