Mutual interactions between soil and foundation play a fundamental role in the overall behaviour of constructions. Therefore, it is not surprising that soil-structure interaction has been the subject of numerous research works. This doctoral thesis is a theoretical contribution in this field.

Despite the available knowledge, the fact that specific studies on the behaviour of foundation structural elements and soil masses progressed independently constrained the understanding of the governing mechanisms, especially close to failure. This constitutes a serious limitation to the development of a consistent performance-based design strategy.

The first part of this dissertation presents an attempt in this direction. The limit state of surface footings subjected to centred and vertical loads is investigated considering simultaneously the structural failure and the soil bearing capacity. The relevance of the employed theoretical methods with respect to the real materials is critically reviewed. A simplified procedure for quantifying soil-structure interaction effects is presented. Despite the analysis deals with surface footings, the concepts can easily be extended to other conditions and geotechnical works.

The second part of the thesis focuses on the behaviour of thermoactive deep foundations. They are an innovative and environmentally friendly technology that couples the role of ground heat exchanger to that of structural support. An extensive numerical parametric analysis defines the main effects of the presence of a flexible raft cast directly on the ground. The potential benefits of considering reinforced concrete non-linear behaviour are discussed, and guidelines are provided for the performance-based design of energy piles.