RESPONSE BASED DESIGN CRITERIA FOR WEST OF SHETLANDS

Compliant structures, such as TLPs and compliant towers, hold promise as permanent structures for long-term production facilities in the deep water West of Shetlands. Being compliant instead of rigid, the response of these structures to wave frequency loading is largely mass-dominated, while slow drift forces, current and wind loadings assume increasing importance in the strength design of critical structural components. The oceanographic focus of previous decades, primarily on wave spectra, must therefore be broadened to include currents. To calculate a satisfactory 100 year response- based design criteria for such scenarios, a total of 11 parameters must be considered. Dealing directly with the joint probabilities of these 11 parameters would be complex. Taking a simpler response based approach, one response parameter at a time is focused on, eg broadside base shear. The first step is to reconstruct the history of all severe sea states at the site for region of interest in an oceanographic database. Then a simple generic or typical structure model of the type for which design criteria are needed is analyzed. After the analysis has been done for all the sea states, statistics of the desired response are assembled, from which the 100 year response is readily determined. Finally, a design recipe or set of criteria, a reasonably likely combination of wave height, wind speed and current, together with the associated rules for kinematics and force computeration, is found, which reproduced the target response.

  • Supplemental Notes:
    • J Offshore Technology, v 3 n 2, May 1995, p 42 [4 p, 1 ref, 2 tab, 1 fig]
  • Authors:
    • MARSHALL, P
    • Rezvan, M
    • Gunatunga, A
  • Publication Date: 1995

Language

  • English

Subject/Index Terms

Filing Info

  • Accession Number: 00710902
  • Record Type: Publication
  • Source Agency: British Maritime Technology
  • Files: TRIS
  • Created Date: Aug 14 1995 12:00AM