Large ice rubble accumulations can occur adjacent to offshore structures in shallow water sea ice environments. Potential effects include ice load attenuation, impairment of EER systems and reduced vessel access. Drawing on measurements of rubble height and extent, an empirical approach has been developed for rubble characterization and modelling of these effects. A primary input is a series of events to represent the anticipated ice conditions and drift over the service life of the structure. The build-up of rubble against the structure during an event is modelled on a regular grid, with rubble extent and height based on measured data, thereby ensuring a realistic representation. The approach has been used to assess downtime based on access criteria for supply, or escape, evacuation and rescue (EER) and the ability to clear rubble by ice management vessels. The same methodology has also been used for incorporating load attenuation as a result of grounded rubble in probabilistic ice load assessments.

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