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Technology
Assessment & Research (TA&R) Program
| Project Number |
434 |
| Date of Summary |
February 28, 2007 |
| Subject |
Strain-Based Design
of Pipelines |
| Performing Activity |
Edison Welding
Institute |
| Principal Investigator |
William Mohr |
| Contracting Agency |
Minerals Management Service |
| Estimated Completion |
Completed January 2007 |
| Description |
The majority of pipeline design codes are based on
stress-based design methods. Although conventional stress-based design
covers most pipeline applications, it does not cover the design of pipelines
that may experience high strains like those of the deepwater GOM and Arctic
regions. Similarly, high strains can occur to most any offshore pipeline due
to ground movement, unsupported spanning, and seismic loading therefore an
exacting site-specific analysis including loading conditions and material
mechanical properties is needed to maintain the acceptable level of pipeline
safety needed. This research project investigated the
use of strain-based design of pipelines and
provide a guidance document to better assure safe and pollution free
operations. |
| Progress |
Phase I was completed in 2003 and developed a
best practice Guidance Document on Strain Based Design of pipelines to cover
design, assessment, and testing guidelines for designers of pipelines that
may experience high strains in service. See Phase
I final reports AA and AB below.
Phase II, which began on July 28, 2004
and was completed in January 2007, refined
the Phase I Guidance Document by
providing further analysis and guidance in the areas of pipeline material
specifications, welding specifications, as well as determining
local stress-strain curves, provide material and welding guidance for strain
based design, and develop realistic choices in finite element models to
check the effects of combinations of soft regions, internal pressure, and
axial strain. Collaboration between EWI and Engineering Mechanics
Corporation (Emc2) of Columbus, OH was
highly effective in assessing
the effects of both softened HAZs and internal pressure on fracture
resistance for high-strain applications since Emc2 is conducting a parallel
project on fracture assessment of pipe girth welds.
See Phase II final reports AC and AD below. |
| Report |
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AA
(5,940 KB) |
Strain-Based Design of Pipelines, Phase I, Final
Report, William Mohr, Edison Welding Institute, Columbus OH, October 8,
2003. |
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AB
(31 KB) |
Guidance
Document on Strain Based Design, Final Report, William Mohr, Edison
Welding Institute, Columbus OH, July, 2004. |
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AC
(3,265 KB) |
Strain-Based Design: Strain Concentration at
Girth Welds, Phase II, Final Report, William Mohr, Edison Welding Institute,
Columbus, OH, January 2007, EWI Project No. 47447GTH. |
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AD
(64 KB) |
Guidance Document on Strain-Based Design, Phase
II, Final Report Appendix A, William Mohr, Edison Welding Institute,
Columbus, OH, January 2007, EWI Project No. 47447GTH. |
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