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INSTRUCTORS:
Sandesh Adhikari
Guohua Li
Mark S. Salvatore, PE
Purpose and Background
These presentations were recorded at the UESI Pipelines 2025 Conference.
Assessing the Impact of Network Topology on Seismic Resilience in Gas Pipeline Networks (14 minutes)
This presentation examines how network topology affects the seismic resilience of gas pipeline systems. Using a benchmark network and statistical modeling, over 50,000 simulated scenarios were analyzed to assess pipeline failures under earthquake conditions. Key resilience metrics such as robustness, reliability, and vulnerability were quantified and correlated with topological attributes, including link density, node degree, and modularity. Results show that loop-like networks exhibit greater resilience than tree-like configurations due to improved connectivity and redundancy. The study highlights the potential for surrogate models based on topology to complement or reduce the need for computationally intensive hydraulic simulations. Findings provide valuable insights for designing more resilient gas pipeline networks in seismically active regions.
Effectively Purging a Decommissioned Natural Gas Distribution Network (20 minutes)
This presentation addresses the challenges and methodologies of purging decommissioned natural gas distribution networks to ensure safety and regulatory compliance. The process involves isolating the pipeline, achieving sufficient flow velocity to displace natural gas with air, and preventing the formation of flammable gas mixtures. Factors such as minimum purging velocity, pipe geometry, and network configuration significantly influence purge effectiveness. Diffusion in dead-end sections presents a particular hazard, potentially creating flammable gas slugs that persist over time. Mitigation strategies, including adjusting vent pressure, adding air inlets, and balancing flow distribution, are discussed to reduce risks. A systematic purge procedure is outlined to safely abandon pipelines in place while minimizing residual hazards.
Grout Filling and Pipeline Abandonment: A Comprehensive Approach to Nearly 50 Miles of Gas Pipeline at Southern Company/Nicor Gas Dubuque Line (21 minutes)
This presentation reviews a large-scale pipeline abandonment project where nearly 50 miles of decommissioned gas pipeline were filled with low-density cellular concrete (LDCC). The project demonstrated the advantages of LDCC over traditional controlled low-strength materials (CLSM), including longer pumping distances, reduced excavation, and faster project completion. The material’s lightweight nature, high pumpability, and consistent strength made it suitable for long abandonment sections, with some runs exceeding 5,000 feet. The presentation highlights logistical planning, quality control practices, and lessons learned from multiple project phases, including supplier selection and cement shortages. The approach resulted in significant cost and time savings while enhancing safety and reliability in pipeline abandonment.
Benefits and Learning Outcomes
Upon completion of this course, you will be able to:
- Explain how network topology influences the seismic resilience of gas pipeline systems.
- Discuss the differences in resilience between tree-like and loop-like network configurations.
- Describe the principles and risks involved in purging natural gas pipelines during decommissioning.
- Identify mitigation strategies to prevent incomplete purging and the formation of hazardous gas concentrations.
- List the benefits of using low-density cellular concrete for large-scale pipeline abandonment projects.
- Discuss key lessons learned from executing long-distance grout filling operations, including logistics, material performance, and supplier coordination.
Assessment of Learning Outcomes
Students' achievement of the learning outcomes will be assessed via a short post-test assessment (true-false, multiple choice, and/or fill in the blank questions).
Who Should Attend?
- Utility and Pipeline Engineers
- Design and Consulting Engineers
- Construction Contractors
- Project Managers
- Academic and Professional Researchers
- Early Career and Pipeline Professionals
How to Earn Your CEUs/PDHs and Receive Your Certificate of Completion
To receive your certificate of completion, you will need to complete a short post-test and receive a passing score of 70% or higher within 1 year of purchasing the course.
How do I convert CEUs to PDHs?
1.0 CEU = 10 PDHs [Example: 0.1 CEU = 1 PDH]