Probabilistic Evaluation of Design Iceberg Collision

Abstract

A probabilistic model has been developed for the selection of a design iceberg collision with an offshore structure. The design event is selected on the basis of global sliding force, which is likely to determine whether or not structural failure will occur during an iceberg collision. Hydrodynamic effects, including iceberg added mass, wave‐induced oscillatory iceberg motions, and the modification of currents by the presence of a structure, are considered in the evaluation of iceberg velocity and location of impact against a structure. A time‐stepping model is subsequently used for evaluating forces induced by ice crushing and friction during a collision. The application of the model to the selection of a design iceberg collision event is illustrated through two examples. Among the various parameters influencing collision severity, it appears that eccentricity of impact has a relatively small influence on design load levels. Wave‐induced oscillatory motions are shown to be significant for small icebergs.