Reassessment and life extension of offshore structures

Dato: 11-05-2016-12-05-2016 | Påmeldingsfrist: 02-05-2016

Dette kurset er avlyst pga for få deltakere
- Petroleum Safety Authorities (PSA/Ptil) regulations
- NORSOK N-006 and DNVGL-RP-0001
- Basic principles - Fatigue and fracture mechanics
- Life extension & repair methods
- Risk based inspection planning
- Life extension based on Inspection

Lecturers: Prof. P. J. Haagensen, NTNU; Prof. G. Ersdal, UiS/Petroleum Safety Authority (PSA); I. Lotsberg, DNV GL; Arne Fjeldstad, DNV GL; Prof. T. Lassen, U i Agder and Sen. Eng. O.T. Vårdal, Axess, Bergen.

Aging and life extension of offshore platforms is an area of increasing focus in the North Sea. Offshore structures intended for use within an extended life time must be documented to satisfy the required safety level by the PSA authority.This requires that more of ULS,ALS,FLS, SLS analyses must be performed including the effects of degradation and changes in loading during operation. Relevant factors influencing the service life of steel structures will be discussed, based on Norsok N-006 and other relevant rules.
Life extension of structures with low remaining life can in principle be obtained in two ways, either by repair or by increased inspection. Corrosion and fatigue are the two major mechanisms affecting existing structures. In many cases structures have the required static strength, but the effects of fatigue and corrosion need to be demonstrated for further operation, hence updated analysis are required.
The course gives an introduction to the causes of the damages resulting in fracture or other types of loss of fitness for service in structures.
An introduction to theory and methods for life extension and inspection will be provided. NORSOK N-006 and the new DNV GL- RP -0001 will also be discussed in detail during the course. Examples on relevant cases will be given.


Wednesday  11th May  2016

08.30 Registation and refreshments

09.00  Ageing and life extension - principles and regulations
Gerhard Ersdal, UiS/Ptil
- Introduction to ageing and life extension
- Damage, degradation and other ageing mechanisms for offshore structures and other maritime systems
- Life extension – the process
- Rules (PSA) and industry practice (OLF GL 122 and - NORSOK N-006)
- Robustness and barrier control
- Maintenance control for structures (SIM)
- Examples of examples of life extension

10.30 Coffee break

10.45 Fracture and fatigue – basics; fatigue life assessment
Per J. Haagensen, NTNU
- Crack initiation and growth
- Factors influencing crack initiation and crack propagation- fracture mechanics
- Fatigue strength of welded structures – influence of material and fabrication methods
- S-N curves – classification of welded joints
- Life assessment methods

12.00 Lunch

13.00 Life extension & repair methods
Per J. Haagensen, NTNU
- Fatigue life extension methods – applied in design, during fabrication and service
- Revised standards, DNV GL–RP-0001 (ex DNV RP-C-203), BS 7608 and BS 7910
- Examples of repair and upgrading methods: Troll C and Veslefrikk B platforms

1400 Break – refreshments

14.15 Risk based inspection planning - introduction
Tom Lassen, UiA
- Risk based inspection – introduction
- Basic principles of inspection planning
- Probabilistic fracture mechanics
- Crack growth development and crack detection
- Scatter in crack growth data – causes and statistical treatment

17.00 End of day one


Thursday 12th May  

08.30 Risk based inspection planning applications
Tom Lassen, UiA
- Probability of Detection (POD) curves
- Methods of crack detection
- Monte Carlo simulation of uncertainties
- Risk based inspection planning – examples
- Software and exercises

09.30 Probabilistic fracture mechanics assessment
Inge Lotsberg/Arne Fjeldstad, DNV-GL
- Principles for documentation of ULS and ALS when assessing existing structures
- Definition of characteristic loads
- Definition of characteristic resistance
- Norsok N-006 Background and application    

10.15 Coffee break

10.30 Probabilistic based methods for fatigue crack inspection –new guidelines
Inge Lotsberg/Arne Fjeldstad, DNV-GL
- Background for DNVGL-RP 0001 - the  joint industry project (JIP)
- Fatigue analysis methods for purpose of planning in-service inspection.
- Basic distributions of parameters required for calculation of stochastic properties for load effects and capacity.
- Methodology for probabilistic analyses for planning inspection for fatigue cracks.
- Target reliability level in relation to consequence of a fatigue failure.

12.00 Lunch

13.00 Life extension assessments based on inspection results
Ole Tom Vårdal, Axess 
Practical experience:
- Veslefrikk B
- Aker H3 rigs

14.00 Fatigue damage - observations and experience
Ole Tom Vårdal, Axess 
- Jackets structures  
- Semisubmersibles
- Correspondence between analyses and observations

14.30 Break – refreshments

14.45 The prosess of assuring structural integrity
Ole Tom Vårdal, Axess 
- Inspection data
- Requirements to inspection programs

15.45 Discussion - summary

16.00 End


Praktiske opplysninger

Tid: 11 - 12. mai 2016

Sted: Felix konferansesenter, Aker brygge, Oslo

kr. 9 200 for medlemmer i NFS og Norsk Stålforbund
kr. 9 700 for ikke-medlemmer

Det gis 10 % kvantumsrabatt ved minimum 4 påmeldte

Hotell: Den enkelte må selv bestille hotellrom

Dokumenter: Kurset inkluderer e-kurskompendium

Administrasjon: Norsk Stålforbund, tel: 41 02 15 98

NB! Påmeldingsfrist 2. mai 2016

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