A Transmitting Boundary in the Time Domain for Soil-Structure Interaction Problems

In this paper different transmitting and absorbing boundaries that have been applied in soil-structure interaction problems either in the frequency or in the time domain are briefly reviewed. A transmitting boundary derived from the well-known consistent transmitting boundary is also presented. This new boundary contrary to the consistent one can be used in time domain analysis and therefore its scope can be extended to the treatment of true nonlinear situations. As an application example the vertical vibrations of a rigid strip founded on one viscoelastic layer of uniform thickness is studied. The obtained results are compared with the ones reported in the technical literature. It has been observed from these results that the foundation stiffness derived from a transitory analysis may be different to the one found from a stationary analysis. In this example the importance of the time step used in the integration of the dynamic equilibrium equations is shown and some practical criteria for its selection are also given.