Empirical design of foundations

The ability to choose reasonable sizes for the elements of the substructure of a building is a critical skill for a designer. Although a complete and detailed design of foundations requires sufficient understanding of the engineering properties of soils and of the design of the reinforced concrete elements of the foundation, even in design by engineers, foundation design often includes empirical decisions. For most conventional foundations, especially for foundations for light structures, the sizes of the elements are practically predetermined according to empirical rules. In this chapter, we will review the empirical rules necessary to determine the type and extent of a foundation for conventional buildings of limited height (8–10 stories or fewer). We will introduce the major types of deep foundations used in contemporary practice, and identify the conditions under which each of these foundation types is used.