Seismic Considerations for Piping at Marine Terminals Subject to Large Movements During Earthquakes

Abstract: Pipelines at Marine Oil Terminals, used to conduct bulk liquid transfers between vessels and shore, present unique challenges in design and analysis. Large seismic displacements between marine structures and shore create unique challenges in providing adequate restraint for inertial loads while at the same time providing adequate flexibility for seismic anchor motion and thermal loads. Additionally, these problems can be compounded by the pipeline being supported on separate marine structures with different responses and relative movements. Codes such as ASME B31E provide limited guidance on how to handle these scenarios.

This paper will highlight the following unique challenges facing stress analysis of pipelines at high-seismicity terminals:

• How to accommodate large seismic MOT displacements with simultaneous inertial loading.
• Consideration of piping codes, local and international codes, and their effect on seismic evaluation of pipelines at MOTs.
• Consideration of nonlinearities (e.g. friction, support gaps, etc) in seismic analysis of pipelines at MOTs.
• The impact seismic analysis of pipelines has on operational considerations and vice-versa.

The authors will highlight lessons learned based on several case studies throughout California, including approaches in minimizing stresses on piping during earthquakes. The authors will provide information on lessons learned on general approaches to pipe stress analysis that includes large displacements and solutions to reduce pipe stress to within allowable limits.

How does this project / topic contribute to the advancement of the industry and profession?: The topic addresses challenges unique to bulk liquid cargo transfer operations in seismic areas subject to large displacements.

Does the project / topic implement new and innovative techniques, materials, technologies, and delivery methods?: The presentation will discuss the latest pipe stress analysis software, limitations in the analysis, and best practices in pipe stress analysis.

What was the most challenging aspect of your project / topic and how did you handle it to ensure success?: Balancing separate design requirements for piping subject to high seismic loads and seismic anchor motion with operational loads.

Who is the target audience for this paper?: Engineers, designers, owners and operators.