Fatigue of offshore structures - Advanced course

Date: 3 - 4. December 2014
Venue: Felix Conference Centre, Aker Brygge, Oslo

. The course is held in English


Main topics in this course are : Assessment methods for floating and fixed structures; mooring systems, design of pipelines and riser systems, developments in materials for severe environmental conditions. Methodologies for assessments of remaining life and life extension of aging structures. Standards and recommedations.
Target group: Practicing engineers in the offshore industry.


Day 1

09.00 - 09.15 Opening

09.15 – 10.00 Design standards – an overview
• International Institute of welding - IIW
• ISO 19902
• NORSOK N-004 and N-006
• BS 7608 and BS 7910
Per J Haagensen, NTNU

10.00 -10.45 Modelling of weather conditions for fatigue calculations of fixed and floating structures
• Basics of fatigue load estimation
• Fatigue methodology - overview
• Scatter and statistical analysis
• Examples
Sverre K. Haver, Statoil/NTNU

10.45 – 11.00 Coffe break

11.00-11.45 Wave and wind loads – response analysis
• Fatigue loads and response
• Wave loads
• Wind loads
Sverre K. Haver, UiS/NTNU

11.45 -12.30 Fatigue methodology
• Simplified approach
• FE analyses for hot spot stress fatigue assessment
• Modelling principles
Arne Fjeldstad, DNV GL

12.30 – 13.30 Lunch

13.30-14.15 Life ssessment of offshore structures
• Special consideration for FPSOs – selection of details
• Fatigue of unwelded components, e.g. wellheads
• Developments in DNV-RP-C203 (now DNVGL-RP-0005 Fatigue Design of offshore steel structures) and other DNV guidance
Arne Fjeldstad, DNV GL

14.15-15.00 Fracture mechanics – theory and practice
• Basic aspects
• Crack growth under fatigue loading
• Crack growth in welded structures
Tom Lassen, University of Agder

15.00 - 15.15 Coffee break

15.15 - 16.00 Applied fracture mechanics
• Marine structures
• Applications of BS 7910
• Welded structures and mooring systems
• Examples
Tom Lassen, University of Agder

16.00 - 16.30 Inspection and life extension
- Probilistic fracture mechanics and inspection planning
- Examples
Tom Lassen, University of Agder

16.30 Closure

Day 2

08.30 -09.00 Butt welded pipes– S-N curves and stress analysis
• Stresses used in design codes
• Effects defects and misalignment in pipes
Per J Haagensen, NTNU

09.00 -09.45 Fatigue of pipelines, risers and umbilicals
• Free-spanning pipelines and risers
• Fracture mechanics vs. S-N approach to life assessment
• Developments in standards and guidance - IIW, BS 7910:2013 and BS 7608:2014
Per J Haagensen, NTNU

09.45–10.30 Integrity issues - pipelines and risers
• Girth welds:
- Welding processes – defects and residual stresses
Quality control (QA) and quality assurance (QA) issues.
• Engineering critical assessment (ECA)
- Initiation and propagation phase
Example/Case study: Comparison of S-N fatigue and crack growth
Agnes Marie Horn, DNV GL

10.30– 11.00 Coffee break

11.00 -12.00 Arctic conditions and developments in assessment methods
• Developments in materials for arctic conditions
• Strain based methods
• Research activities
• Examples
Agnes Marie Horn, DNV

Kl. 12.00 Lunch

Kl. 13.00 – 13.45 Improvement for higher fatigue strength
- Improved detail design
- Geometry improvement methods
- Residual stress methods
- Recent developments in rules and standards
Per J Haagensen, NTNU

13.45 -14.00 Coffeee break

14.15 -15.00 Materials, fabrication and methods for life extension
- Higher strength steels
- Cast and forged parts
- Materials for sour service
- Materials for arctic conditions
- Testing and validation of new S-N curves
Per J Haagensen, NTNU

15.00 -16.00 Examples of life extension
- Veslefrikk B
- Troll C
Per J Haagensen, NTNU

16.00 - 16.30 Summary and discussion

16.30 End

Practical information & registration

Tid: 3 - 4. December 2014


Registration fee: incl. lunch and coffee breaks
Nkr. 9.200 for members of NFS and/or Norsk Stålforbund
Nkr. 9.500 for members of Tekna
Nkr. 9.700 for non-members

The course includes e-cours compendium
The folloing standards can be useful for the course:
* NORSOK N-004 and N-006 er free to download here 
* DNV-RP-C203 (Fatigue of offshores structures) free to download here

Administration: Tekna, servicekontoret, Postboks 2312 Solli, 0201 Oslo
Tel: 22947560/61 Fax: 22947501 e-mail: 

Cansellation: If cancellation is done after final date of registration, the full fee has to be paid. Only written cancellation, that is confirmed received by Tekna, will be approved. Cancellation due to illness has to be confirmed by the doctor`s written approval.Otherwise, a full fee has to be paid.

Online registration (coming soon)  

NB! Final date for registration 28. November 2014



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