In nonlinear soil-structure interaction analysis, the substructure method can be used in the time domain, where the interaction forces representing the contribution of the linear unbounded soil to the equation of motion are expressed in the form of convolution integrals. New numerical techniques for recursive evaluation of the interaction forces are presented using the dynamic stiffness in the frequency domain. These techniques are designed to enhance computational efficiency for application to practical nonlinear soil-structure interaction problems. Two applications are also presented. The effects of the frequency dependency of the dynamic stiffness on the nonlinear earthquake response are addressed.