PROBLEMS IN THE DESIGN AND INSTALLATION OF OFFSHORE PILES

Offshore facilities supported on pile substructure foundations are becoming more frequent. The piles themselves are subject to high loads, requiring ultimate compressive capacities of up to 3500 tons and tension capacities of up to 2000 tons. Typical piles for offshore construction range in diameter from 30" to 48" and in length from 200' to 600' with embedment lengths on the order of 250' to 350'. Three methods available for determining pile capacity are load tests, dynamic formulas, and static method. The static method appears to be the most useful design approach in predetermining pile penetrations and predicting pile capacity despite its inherent limitations. Significant design uncertainties result from dependence on empirical data derived from short, lightly loaded piles driven and tested on land. This empirical data concerns itself with parameters which may be used to predict soil behavior in the presence of a structure, the selections of which are often subjective. A brief review of the characteristics of available pile hammers is presented. With pile leads increasing faster than the driving capacity of available pile hammers, pile placement techniques and equipment must be updated to assure adequate imbedment/lengths pile capacities. Wave equation analysis may aid selection of optimum pile wall thickness to improve drivability. Although design uncertainty is increased when utilizing pile installation aids such as jetting, drilling and grouting, development of controlled techniques will assist in installation of high-capacity piles when pile-driving alone is insufficient. Four case histories are presented to illustrate the problem of both design and installation of offshore piles.

  • Corporate Authors:

    American Society of Civil Engineers

    345 East 47th Street
    New York, NY  USA  10017-2398
  • Authors:
    • McClelland, B
    • Focht Jr, J A
    • Emrich, W J
  • Publication Date: 1969-11

Media Info

Subject/Index Terms

Filing Info

  • Accession Number: 00048058
  • Record Type: Publication
  • Source Agency: National Maritime Research Center, Galveston
  • Report/Paper Numbers: 6913 Proceeding
  • Files: TRIS
  • Created Date: Oct 31 1973 12:00AM