Earthquake response of underground pipelines

Seismic response of underground pipelines is investigat́ed theoretically considering dynamic soil‐pipe interaction. A lumped mass model of the pipe is employed with the soil reactions derived from static and dynamic continuum theories. The soil is supposed to be homogeneous or composed of two different media separated by a vertical boundary. Axial and bending stresses in the pipe due to travelling waves are examined. An extensive parametric study indicates that the axial stresses in the pipe are much higher than bending stresses. In a homogeneous medium, soil‐pipe interaction reduces the stresses in the pipe compared to those calculated ignoring interaction. In a soil composed of two different media, the pipe stresses are highest close to the boundary and can exceed those predicted neglecting interaction.