| Abstract | A Joint Industry Project (JIP) was conducted in 2007 to determine the degree of consensus of leading ice mechanics experts on the loads exerted by multi-year ice on offshore platforms. Seven international experts on multi-year ice loads were asked to predict loads for three different ice loading scenarios involving multi-year ice floes: isolated floe, a multi-year floe in pack ice, and a multi-year hummock field in a sheet of first-year ice. The Experts were asked to calculate the loads from these three ice conditions interacting with a 150 m wide vertical caisson structure and a 45 degree conical-shaped structure. There were significant differences in the methodologies used and the assumptions made to estimate the loads. Load predictions varied considerably for each scenario with estimates differing by a factor of 4.6 for the vertical caisson and 3.5 for the conical structure. In spite of the lower ratio of predicted loads for the conical structure, the Experts were more confident with loads on the vertical caisson. The key areas for further research were identified and these include improved knowledge of the ice thickness and its variation for Old Ice, new and innovative techniques for obtaining ice loads, improved knowledge of pack ice driving forces, and better understanding of the failure behavior of multi-year ice. This paper provides an overview of the loading scenarios, details of the load predictions, and outlines the areas identified for future research to help to provide more reliable load predictions. |
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