Piles are used when vertical loadings are high. Besides this, piles are also used to take up lateral loads and tensions in some other cases. The dynamic formula and the application of wave mechanics in pile capacity determination are described in this chapter. While the former type includes H-piles bearing on rock, there are some common types of piles known as socketed H-piles and mini-piles belonging to the latter type. Broadly speaking, the determination of a single pile's capacity for a vertical load is by 'static' and 'dynamic' formula. Cheng has developed a similar programme using a faster numerical technique for the settlement of a single pile and pile group with the moment, which can be obtained from Cheng for education purposes. Besides static load test on the vertical compression and tension capacity of the pile, lateral load tests are sometimes carried out on piles taking up a very large lateral load.