The force-resultant modelling of the interaction of rigid foundations and soil under combined loading is described using a framework based on energy principles. The general formulation allows idealization of the problem using two continuous model systems. In the first system, referred to as "uni-continuous", the global foundation behaviour can be described by defining a continuous field of stress-displacement elasto-plastic models along the interface of the problem. By replacing each of these elasto-plastic models to be continuous along an internal coordinate a "bi-continuous" system can be constructed. With physical interpretation of the underlying properties in each stress-displacement model, force-resultant behaviour of the entire foundation can be calibrated. Though applicable to monotonic loading, the approach is particularly appealing to the formation of models describing cyclic loading conditions. In this paper, the framework will be applied to the modelling of both monotonic and cyclic loading of strip footings. However, the methodology could be easily expanded to account for changes in geometry (for instance between strip and circular footings) or footing types. (c) 2005 Elsevier Ltd. All rights reserved.