Foundation

Article By:

Reynolds, Gardner M. Dames & Moore, Los Angeles, California.

Last reviewed:April 2020

DOI:https://doi.org/10.1036/1097-8542.270400

Structures or other constructed works are supported on the earth by foundations. The word “foundation” may mean the earth itself, something placed in or on the earth to provide support, or a combination of the earth and the elements placed on it. The foundation for a multistory office building could be a combination of concrete footings and the soil or rock on which the footings are supported. The foundation for an earth-fill dam would be the natural soil or rock on which the dam is placed. Concrete footings or piles and pile caps are often referred to as foundations without including the soil or rock on which or in which they are placed. The installed elements and the natural soil or rock of the earth form a foundation system; the soil and rock provide the ultimate support of the system. Foundations that are installed may be either soil-bearing or rock-bearing. The reactions of the soil or rock to the imposed loads generally determine how well the foundation system functions. In designing the installed portions, the designer must determine the safe pressure which can be used on the soil or rock and the amount of total settlement and differential settlement which the structure can withstand. For a discussion of soil as a part of the foundation system See also: Soil mechanics .

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