ICE FORCE DESIGN CONSIDERATIONS FOR CONICAL OFFSHORE STRUCTURES

Arctic offshore structures may be exposed to a variety of ice features including sheet ice, unconsolidated ridges, ice rubble fields, and consolidated multiyear ridges. The interaction of these ice features with conical structures is the subject of investigations that consist of a combination of model tests and analytical studies. Analytical and model basin studies of sheet ice failure against conical structures have been previously discussed in the literature. The analytical work was based on a linear elastic description of ice deformation, with a brittle failure criterion, and was found to underestimate the model basin data. A new analysis has been developed that considers a floating ice sheet to be an elastic-plastic plate resting on an elastic-plastic foundation. The upper bound procedure of plastic limit analysis leads to a mathematical model for both sheet ice failure and rideup on a conical structure. Multiyear ridges are an important design consideration for offshore structures in the deeper waters of the Beaufort Sea. The forces required to break these ridges have been estimated using published theories that approximate the ridge as a beam on an elastic foundation. This approach implies that short, rather than long, multiyear ridges may impose the greatest ice forces on structures that are designed to fail ice in flexure. There is a need for confirmation with model tests and perhaps the development of nonlinear analytical models.

• Supplemental Notes:
  • Proceedings of the 4th International Conference on Port and Ocean Engineering under Arctic Conditions (POAC 77), Newfoundland Memorial University, Canada, September 26-30, 1977.
• Corporate Authors:

  POAC Conference 77

  ,    
• Authors:
  • Ralston, T D
• Publication Date: 1977

Media Info

• Features: References;
• Pagination: 12 p.

Subject/Index Terms

• TRT Terms: Elastic analysis; Flexural strength; Force; Ice; Ice phenomena; Offshore structures; Plastic analysis; Strength of materials
• Old TRIS Terms: Ice deformation; Ice forces on structures; Ice ridges; Ice strength
• Subject Areas: Bridges and other structures; Marine Transportation;

Filing Info

• Accession Number: 00167679
• Record Type: Publication
• Source Agency: Memorial University of Newfoundland, Canada
• Report/Paper Numbers: Proceeding
• Files: TRIS
• Created Date: Jan 13 1978 12:00AM