Achieving Resilient Water Networks – Experimental Performance Evaluation
Recognizing the need to improve the resilience of water distribution networks, water providers are seeking new technologies to accommodate ground deformation associated with seismically induced fault rupture, landslides, liquefaction-induced lateral spreading and settlement, and ground movements caused by other natural hazards, construction, mining, and regional dewatering activities. Pipeline manufacturers have responded to the need for improved resilience with innovative products designed to respond to significant levels of ground deformation through the use of improved materials and jointing mechanisms. Typical pipeline design is predicated on limiting relative displacements at pipe joints, or between the pipeline and surrounding soil. The new pipeline systems provide the capacity for large axial movements and deflections at joints, thus allowing pipelines to change shape, while maintaining pressure and flow, in response to complex patterns of ground displacement. To accompany new technologies and changes in design approaches, experimental procedures are proposed that assess the performance of hazard-resilient pipeline technologies under extreme loading conditions. Recommendations are provided based on best practices developed from more than sixty full-scale tests performed on pipes of various material and joint characteristics. Focus is given to the fundamental mechanics of pipeline response to externally applied movement: axial extension/compression and bending/joint deflection. Experimental evidence confirms that soil-pipeline interaction under large ground deformation can be decomposed into mechanical response parallel and perpendicular to the pipeline longitudinal axis, providing an effective means of understanding performance and developing hazard-resilient designs. Experimental methodologies, limit state assessment, instrumentation and load apparatus design, methods for interpreting and quantifying results, and classification of performance with respect to developing seismic design standards for water and wastewater pipelines are highlighted.