Vibrations and fatigue cracking have occurred for some years, in flare boom structures on a number of platforms on the Norwegian continental shelf. This paper describes the vibration and its characteristics on Statfjord A and Heimdal which had the largest vibrations. The vibrations cannot be predicted by vortex induced vibrations of individual members but could be caused by wake effects, local frame vibrations or global dynamic effects. The evaluation of cracks if other flare boom structures is reviewed. The work was based on DIN 4133 and includes vibrations of both individual members and frames. Also reviews is the design practice and operational experience with design parameters especially measurements of damping on individual tubular members and observed vibrations of individual members and frames. Possible limitations of the DIN standard are discussed. A device for reducing the vibrations is described. The problems have mainly been caused by the methods used in design, however, evidence of welding defects initiating fatigue cracks has also been found. A review of the existing methods has led to the recommendation of using German DIN 4133 code for design purposes. This code is to a large extent similar to the proposed Eurocode-1. A design procedure based on DIN 4133 is proposed including additional parametric boundaries for avoiding resonant vibration.

  • Supplemental Notes:
    • OMAE 1995, 14th Intl Conf on Offshore Mechanics & Arctic Engng; 18-22 June 1995; Copenhagen, Denmark. Sponsored by ASME et al. Procs. Publ by ASME, ISBN 0-7918-1307-X. Vol I, Pt B, p 341 [14 p, 22 ref, 1 tab, 13 fig]
  • Authors:
    • Oppen, A N
    • Kvitrud, A
  • Publication Date: 1995


  • English

Subject/Index Terms

Filing Info

  • Accession Number: 00718535
  • Record Type: Publication
  • Source Agency: British Maritime Technology
  • Files: TRIS
  • Created Date: Mar 27 1996 12:00AM