Iceberg management and impact on design of offshore structures

A methodology is presented for the systematic evaluation of the need for an iceberg management system and the efficiency of various components such as detection, deflection and disconnection. The approach involves the numerical modelling of iceberg drift and probabilistic analysis. Experiences from the Canadian iceberg detection studies and iceberg deflection operations have been incorporated into the approach.The methodology describes the concept: an offshore installation and an iceberg management system, as a traditional industrial system, i.e. a system which is designed so that it works well under normal conditions. Under some circumstances, an event occurs which stops the operation of the system. In order to prevent such a stop, different types of safety functions may be considered in order to increase the redundancy in the system and thereby increase the operability. In the present work, the iceberg management means are treated as such safety functions.For a selected site in the Barents Sea, it was found that the maximum impact load corresponding to a 10 000 year event was 85 MJ for a concept without any iceberg management capabilities. An alternative system with iceberg detection, iceberg deflection and disconnection capabilities including emergency disconnect indicated a corresponding abnormal load of about 1.8 MJ.