Brash ice channels are frequently created during ship navigation. To improve the understanding of the brash ice channel development experimental tests have been conducted. The tests were performed by repeated passage of a model ship in a ship channel. Channel profile measurements, temperature profiles, salinity of cores were taken from consolidated brash ice edges and centre of the channel, as well as measurements of the ship model parameters. The results provide insight into the processes in the brash ice channel during freezing and breaking. The paper presents an overview of the tests, measurements and results. The findings from these tests provide an improved understanding of the process in brash ice channel development which can be incorporated into modelling techniques for marine design and operations.@en

Ice encroachment is the accumulation of ice atop a platform and results when ice drifts against a platform. Most often this occurs in shallow water but in principle can occur in deep water if the ice drift length is long enough. As the ice drifts against the platform it is broken and generates rubble and ice piles in front of the platform, and with sufficient drift duration blocks of ice can be pushed up and onto the platform. This must be taken into account when designing structures in the Caspian Sea and other shallow water areas where there is significant ice drift. Ice can encroach on the structure by ice ride-up and pile-up. Consequently, the height and extent of the ice piling up on top of the structures must be taken into account in designing the layout, and often a protective ice encroachment zone is made all around the structure. The aim of this paper is to provide an outline of various approaches and parameters to consider where ice encroachment may occur. The study is supported by analysis of dedicated ice model test data, numerical simulations using Discrete Element Models, and full scale data of ice encroachment events. The intent is to give an understanding of the physics of ice encroachment and support in the design of shallow water offshore structures. In particular, the results indicate the importance of ice strength in the process and especially the maximum pile height. If the ice is weaker, the pile grows horizontally in a seaward direction in front of the structure, and conversely, stronger ice forms ice encroachment with greater vertical and also horizontal extent on the platform. The results also show that once the maximum pile height is established subsequent drift enlarges the seaward extent of the rubble pile in front of the structure.@en

The safety philosophy for floating oil and gas production systems in arctic and cold regions has been enhanced in the recent revision to the ISO 19906 (2019) arctic structures standard. Important changes since the initial publication of the ISO 19906 (2010) standard include the identification of different facility types, depending on whether ice management and disconnection/move-off capabilities are part of the design concept. Because operational procedures are such an important consideration for floaters, additional requirements include operating envelopes and non-physical barriers to ensure that these procedures are conducted safely and in a way that human life, structural reliability levels and the environment are preserved. Arctic standards dealing with physical environmental data requirements (ISO 35106, 2017) and ice management (ISO 35104, 2018) have also been published since 2010. The new data requirements include verifiable data streams, particularly when dealing with weather and ice forecasts. Much of the material relating to ice management in the initial version of ISO 19906 (2010) has been moved to the new standard as well as numerous enhancements related to detection systems and performance requirements. Both ISO 35104 (2018) and the revised ISO 19906 (2019) provide increased focus on ice alert systems under which ice management activities are conducted.

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Accumulations of broken ice can pose challenges for ice engineering applications, such as rubble accumulations around offshore structures and brash ice in ports. It is thus important to understand the properties to enable reliable assessments of the impact they might have on facilities or to ship navigation. To improve the understanding of the different brash ice parameters, and especially those involved in the consolidation process, a series of experimental tests have been conducted. The tests included variations in parameters including the porosity, salinity and thickness of the brash ice. A series of measurements were made over the consolidation period. Namely those were salinity and compressive strength measurements of cores taken from consolidated brash ice and temperature profiles within the brash ice. The results provide insight into the processes in the brash ice during freezing. The paper presents an overview of the tests, measurements and results. The findings from these tests provide an improved understanding of the consolidation process which can be incorporated into modelling techniques for marine design and operations.

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Arctic environmental parameters form the basis for the design and operation of ships and offshore platforms, and as the understanding of climate change evolves this knowledge needs to be reflected in the processes and methods that developing the environmental design basis. This paper provides a review of the applicable Rules and Regulations for Arctic regions with focus on the environmental parameters impacted by climate change, such as air temperature, ice properties, wind, snow, and wave states, etc. Scenarios of parameter variations are presented and the applicability of probabilistic models for trend analysis and extreme events are discussed. The influence of environmental parameters on the evolution on design are discussed including the hull strength, steel grade, and stability, as well as operational parameters such as ship speed, crew procedures and maintenance. The paper highlights the importance of a risk analysis approach to evaluate the impact of climate change on the design and operation of the ship and offshore platforms in the Arctic. For offshore platforms in ice, ISO 19906 recommends that probabilistic methods be used to determine ice actions. Such an approach can also be used to assess the effects of different climate change scenarios based on either temperature trends or future temperature assumptions. It is important to note that ice loads may reduce under various future climate change scenarios. Whether or not to take advantage of such potential reductions will be a key issue for future projects. The risk analysis approach could be helpful in this regard. The analysis has shown that the climate change may have an optimistic influence on some design or operational parameters but others may have a negative influence on some of these parameters. It is clear that the issue is complex and requires in depth research, and that the industry needs to cooperate in further development as climate change plays an important role.

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Ice action on ships and offshore structures is commonly determined by calculating the contact ice pressure. The aim of this paper is to describe the empirical background for determining the ice pressure. This review article describes six different test series where ice edge indentation and contact ice pressure have been investigated. These test series are ice pressure measurements onboard IB Sisu in the Baltic in 1977, pendulum tests carried out at Arctec in Ottawa, Canada, in 1979, laboratory and full scale ice crushing tests at WARC in 1988 and onboard IB Sampo 1989, medium scale indentation tests on Hobson's Choice Ice Island 1990, ice crushing tests at NRC, Ottawa 1992 and the JOIA tests in Hokkaido 1996-1999. These tests were selected as at each series a new phenomenon was observed. The aim of the paper is to introduce the main features for ice-structure contact empirically through the description of tests. The paper is concluded with a short description of the existing models for ice pressure, especially to gain an insight and highlight the main observations in each test series and how the models for ice pressure have developed based on the observations.

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Low temperatures can have a significant impact on the design and construction of marine and offshore structures as the performance and functions can be severely reduced. Compliance with relevant rules and regulations forms a prerequisite along with the specific design considerations to be taken into account. This paper provides an overview of the influence that the specification of the air temperature has on the materials selection used in design codes and standards. The paper focuses on the standards and the definitions used for the ambient air temperature and contributing parameters. To highlight the impact, analysis of air temperature data is presented for low temperature regions of the Russian Arctic, and observations from application to design standards for ships and offshore structures are provided based on this. From the analysis it is clear that the design temperature needs to be carefully selected to ensure the reliability of fracture toughness of structures.

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