Pile foundations are deep foundations. They are formed by long, slender, columnar elements typically made from steel or reinforced concrete, or sometimes timber. A foundation is described as 'piled' when its depth is more than three times its breadth.
The bearing capacity of a pile is determined by several factors, including the size, shape and type of pile, as well as the particular soil properties. The calculation method that is used as a means of testing pile foundations depends upon the magnitude of the work involved, the soil type, and the engineer’s specification. Methods of calculation include:
Dynamic pile formulae.
The integrity of, and presence of defects in, new and existing piles can be assessed by carrying out a pile integrity test.