Earthquake loads are applied to the foundation mainly through shear waves in the underlying soil. A method is presented for analyzing the alteration in the response of a structure by adding piling to the foundation. The method of computation consists of a series of transfer matrices which are used to form a stiffness matrix of the foundation system. Central to the computation is the modelling mode for the soil-pile interaction; several alternatives are presented. Observations regarding the effect of several design parameters, based on a numerical example, are discussed
