L51620 Pipeline Monitoring--Limit State Criteria

With the growing emphasis on extending the useful operation of existing pipelines and reducing the operating costs, the pipeline industry is sensitive to keeping pipelines in service and having a rational basis for doing so. When pipelines undergo fault displacement, mining subsidence, thaw settlement, or landslide induced soil loading, monitoring of pipeline strains and/or displacements must protect their integrity. Currently, there is little information available to indicate when remedial action is necessary for such a pipeline. This report focuses on assisting pipe-monitoring programs by providing data and criteria for monitoring intervention. The objective of the work reported herein was to compile data and define criteria for monitoring intervention for local buckling, denting, and tensile failure, based upon data and experience from the pipeline industry. It was established that three separate quantities might be defined for each loading condition; a limit state criterion, a damage state criterion, and an intervention criterion.