Prescriptive Approach to Design Buried Pipelines for Landslide Induced Permanent Ground Deformations

The American Society of Civil Engineers (ASCE) is currently developing a Manual of Practice (MOP) for the Seismic Design of Water and Wastewater Pipelines under the Pipeline Division of the Utility Engineering and Surveying Institute (UESI) in collaboration with ASCE’s Infrastructure Resilience Division (IRD). This MOP would include a prescriptive approach for seismic design of buried water and wastewater pipeline infrastructure that is potentially subjected to transient ground deformations (TGDs) and different types of permanent ground deformations (PGDs) such as those imposed by landslides, liquefaction-induced lateral spreads, and fault rupture. The work summarized in this paper pertains to an analysis framework being considered for the development of prescriptive design recommendations for PGDs from landslide hazards. These prescriptive design recommendations are presented in the form of design tables tabulated against primary seismic parameters such as site class and spectral acceleration for different pipeline criticality categories. A theoretical approach based on the simplified pseudo-static seismic slope stability evaluation approach has been adopted in developing the recommendations presented in these design tables. Data from either readily available landslide susceptibility maps, seismic slope stability hazard maps, and/or contour maps (i.e., steepness of the terrain) are being utilized to establish appropriate yield acceleration values in developing the design recommendations. This approach provides a mechanism to design commonly encountered water/wastewater pipelines against landslide hazards without undertaking significant and complex investigative, evaluative, and design efforts. However, critical pipelines located within high landslide hazard regions, especially those within very steep terrain and/or high seismic regions, will require site-specific analysis and design. Due to space limitations, this paper focuses on typical design tables and presents an example of how to use those design tables in a typical design.