OPTIMISED INSPECTION SCHEDULING FOR OFFSHORE STRUCTURES A PROBABILISTIC APPROACH

A probabilistic method as the basis for the scheduling of the inspection of offshore jacket structures has been developed. A Monte-Carl simulation method for deriving reliability-time plots for an individual tubular joint is described. The derived fatigue life uncertainties and crack growth curves are combined with information relating to the past inspection history to obtain the plots for each joint. Methods for modelling future inspections and repairs are described and these models are used to derive the inspection intervals required to maintain a defined target reliability for each joint. Joints are assigned target reliability levels according to their influence on the overall failure of the structure. Inspection is scheduled when the probabilistic model shows that the reliability of a joint has fallen below the target level. A simplified method of estimating the system reliability of a structure using MATHCAD is described and the results are compared with those from a rigorous analysis using the RASOS software. The MATHCAD analysis is used to derive a set of target joint reliabilities to give an acceptable structure reliability.

  • Supplemental Notes:
    • BOSS '94, 7th Intl Conf on the Behaviour of Offshore Structures; 12-15 July 1994; Massachusetts, USA. Procs. Publ by Pergamon, ISBN 0 08 041915 1. Vol 3, p 101 [27 p, 12 ref, 5 tab, 15 fig]
  • Authors:
    • Oakley, A
    • Brown, M
  • Publication Date: 1994

Language

  • English

Subject/Index Terms

Filing Info

  • Accession Number: 00717051
  • Record Type: Publication
  • Source Agency: British Maritime Technology
  • Files: TRIS
  • Created Date: Mar 4 1996 12:00AM