Strategies to Improve Large-Diameter Pipelines Seismic Resilience
The Metropolitan Water District of Southern California (MWD) is a regional wholesaler providing water for 26 member agencies to deliver to nearly 19 million people living in Southern California. Given that MWD’s service area covers one of the world’s most seismically active regions, improving seismic resilience is a critical task to ensure reliability of its water delivery system. A key component of this system is MWD’s 830 miles of pipelines that consists almost exclusively of large-diameter pipes. Factors such as exposing to multiple hazards (shaking, liquefaction, fault crossing and slope instability) and a lack of performance data from past earthquakes make seismic risk mitigation of large-diameter pipelines more challenging than that of other major assets. MWD has developed strategies and implemented mitigation measures to improve seismic resilience. These strategies include evaluating seismic risks, prioritizing mitigation efforts, developing mitigation measures, and planning for post-event restoration. The presentations will include three main topics – development of seismic resilience strategies for agencies with a large inventory of large-dimeter pipelines, methods to evaluate seismic risks of regional distribution systems, and mitigation measures to prevent seismic damage on large-diameter pipelines caused by permanent ground displacements. Examples will be provided to demonstrate proposed approaches and methodologies in the presentations. The session presents a comprehensive approach to achieve seismic resilience of a water distribution system from the initial assessment/development to the final implementation. Regional water agencies facing similar seismic risks will benefit from the accumulated knowledge which can facilitate the development of their own seismic resilience strategies.
Participants in this session will learn about three objectives:
- How one may develop a comprehensive approach to achieve seismic resilience of a regional water distribution system.
- Understand analytical tools available to evaluate seismic risks of reginal water distribution system, particularly those caused by shaking, liquefaction and fault crossing.
- Learn real examples of applying earthquake-resistant pipes and design/analytical tools to mitigate seismic risks of large-diameter pipelines caused by excessive permanent ground displacements (PGD) such as fault crossing and slope instability.