Foundation structures, their testing and modelling their behavior is a wide area to research. Analysis of interaction between the subsoil and the foundation structures has been developed for many years. For the determination of stress in foundation structure is needed to determine the influence of the stiffness respectively pliability of subsoil to structural internal forces, and vice versa, how the stiffness of the foundation structure affects the resulting subsidence. A lot of different elements are tested or modeled in the world. Previous researches on loading of reinforced slabs have shown a number of phenomena significantly influencing their strength and behaviour. However, no general agreement is yet found on a physical theory (either in codes of practice or in design models) suitably describing the interaction between the subsoil and the foundation structures.