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.
Ring ground
A ring ground is typically constructed from a fairly large wire that is buried at least a few feet underground. The ring ground will usually encircle the entire building that it is trying to protect. The ring ground is used as the base of the entire building's ground system, and all components of the building's ground system, including the building structure, are connected to the ground ring. In the U.S., the National Electrical Code specifies that ring grounds must be constructed from #2 or thicker wire, must be buried at least 2 1/2 feet underground, and must have at least 20 feet of exposed copper to ensure good electrical contact with the earth. Ring grounds should be installed beyond the building's drip line to prevent corrosion of the ring's metal.