Foundation (engineering)
Foundations are designed to have an adequate load capacity depending on the type of subsoil/rock supporting the foundation by a geotechnical engineer, and the footing itself may be designed structurally by a structural engineer. The primary design concerns are settlement and bearing capacity. When considering settlement, total settlement and differential settlement is normally considered. Differential settlement is when one part of a foundation settles more than another part. This can cause problems to the structure which the foundation is supporting. Expansive clay soils can also cause problems.
Shallow foundation
These foundations are common in residential construction that includes a basement, and in many commercial structures.
But for high rise buildings they are not sufficient. A spread footing that changes elevation in a series of vertical steps so that it follows the contours of a sloping site or accommodates changes in soil strata, is called a "stepped footing".