A foundation is defined as the part of a building or a public works structure which ensures the transmission in the ground of the loads (self-weight, climatic forces, seismic and operating loads) of this one.

The foundations vary according to the quality of the ground on which the building is to be located, as well as according to the nature and size of the building. It is strongly recommended that this soil be of good bearing capacity and little subject to settlement.

Shallow foundations form a type of foundation that can be placed on soils with good bearing capacity, that is to say capable of taking up the loads of the building by causing minimum settlement. Their simplicity of construction and their low cost make this type of foundation the most common structures.

Deep and semi-deep foundations are structures that allow a building to be found in depth when the surface layer of soil is not strong enough to use shallow foundations: the load is then taken up by the resistance of the soil under the base. of the foundation (bearing capacity) to which is added the lateral friction exerted by the soil on the foundation (resistance to sinking).

The transverse movements of the ground during an earthquake can create very significant shear forces between the foundations and the framework of the building. Instead of opting for very resistant and therefore very expensive foundations, earthquake engineering seeks to reduce soil-structure interactions by using materials that dampen vibrations (low insulation): rubber rollers, neoprene supports (stacking of neoprene sheets and steel plates), etc.