Buried Continuous and Segmented Pipelines Subjected to Longitudinal Permanent Ground Deformation

In responding to the need for improved technologies to accommodate permanent ground deformation imposed by earthquakes, landslides, and other sources, a new family of segmented pipelines has emerged employing joints that displace axially and deflect before locking up and restraining further movement. Other than employing finite-element modeling, there is no existing procedure allowing practicing engineers to efficiently evaluate displacements and strains that develop along segmented pipelines consistent with those of continuous pipelines at equivalent levels of potential ground movement. A methodology is presented that allows continuous and segmented pipelines of any defined material in the elastic range to be evaluated consistently using a single set of equations for block ground deformations moving parallel to the longitudinal pipe axis. The equations reduce to previously recognized solutions for continuous pipelines as the segmented pipe joints reach their allowable displacement. Results show how the hybrid-segmented pipelines have lower axial strains than continuous pipes for equivalent levels of block deformation. The proposed model provides a fundamental basis for engineering design selection of continuous and segmented pipelines in hazard-prone regions.