This document provides an overview of foundations for civil engineering structures. It defines foundations as the substructure below ground level that supports the superstructure above. Foundations distribute structural loads over a large area of soil to prevent excessive settlement. There are two main types of foundations: shallow foundations, which are less than the width in depth; and deep foundations, which extend deeper. Shallow foundations include isolated footings for columns and combined footings for groups of columns. Deep foundations include pile foundations, which transfer loads using friction or bearing on a hard stratum, and pier foundations. Piles can be made of concrete, steel, or timber and installed using methods like driving, jacking, or drilling.