phase 4 report - DNV

RN02: DESIGN OF FLOATING STRUCTURES IN ICE // PART 3 ANNEX ABarents 2020extreme ice conditions. Due to this, the distributions fitted to data from the icebreaker scenarios are only valid upto the probability level where they cross the initial distribution (i.e., no management).Figure 3.2. Illustration of cumulative distribution function for actioneffects with different ice-management scenarios. The level correspondingto an annual exceedance probability of 10 −4 is indicated. Modified fromEik (2011).TFY= Traditional First-Year Icebreaker. (examples: Vidar Viking,Terry Fox, B≈20m−P≈15MW).TMY= Traditional Multiyear Icebreaker. (examples: Krasin,USCGC Healy, B≈25m−P≈25MW).AMY= Azimuth Multi-Year Icebreaker. (examples: Fennica, YuriTopchev).To quantitatively demonstrate that the intended level of IM success is achieved is more or less the same as todetermine the level of system reliability (requirement in Clause 17.2.1). As stated above it must be clear how toassess the reliability of the Ice management.More information may be found in Fuglem, (1997) and Eik and Gudmestad (2010) in addition to Eik (2011).A.17.2.2 Ice management to reduce ice actionsGiven the lack guidance on how to estimate ice actions from managed ice, it seems prudent to add somereferences.A.17.2.3 Characterization of ice management performanceThere is no requirement in the present text for systematic documentation of future IM activities. ISO 19906states in this clause that the actual full scale experience of IM performances is limited and that systematicdocumentation of future ice management activities is highly recommended. The information required in order toevaluate the overall reliability of structural resistance combined with IM operations will never be available unlessfuture operators put some efforts in documenting experiences in a systematic manner.The information required in order to evaluate the overall reliability of structural resistance combined with IMoperations will never be available unless future operators put some efforts in documenting experiences in asystematic manner.Examples of environmental conditions that might be monitored in order to characterize the performance of thephysical ice manage system include but are not limited to the factors described in Table 3.1:Report no 2012-0690 57