For the purpose of carrying different fluids to its operating units, generally a pipe rack structure having pipes of various sizes laid on it is used in an industrial refinery plant. Sudden opening or closing of pipe valves leads to water hammer effect. Also at pipe bends, this phenomenon is prevalent. A soil structure (pipe-rack) interaction is carried out. By coupling the infinite elements (H.R. Yerli, B. Temel and E.Kiral 1998) with standard finite elements, an ordinary finite element procedure is used for simulation of wave propagation in an unbounded foundation due to external forces. Example studied here indicates that the present approach can be useful for analyzing the transient response of soil-structure interaction problems.