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The R.V. POLARSTERN carried out ice breaking trials in which ice forces were measured with special panels at two locations in the bow. Time series records of the ice forces for a 13-minute period were compared for differences in terms of magnitude and duration of loading for the two locations. Maximum force of 2800 kN was measured on a 1 m² panel. The nature of ice forces measured on the panels were very different in terms of frequency and duration compared to those measured with strain-gauged frames on the R.V. Polarstern and the CCGS Louis S. St-Laurent., 33rd International Ocean and Polar Engineering Conference (ISOPE 2023), June 19-23, Ottawa, Ontario, Canada, Series: International Ocean and Polar Engineering Conference

The wharf at Nanisivik was constructed over the winter 1974-75. It was the first deep-water wharf in the Canadian Arctic and there were questions on ice-structure interaction processes, ice loading and performance. This provided the impetus for a series of investigations at the site extending up to the present time. The wharf is located on Strathcona Sound, which is characterized by relatively land fast ice subject to vertical motions under tidal action. The nearby community and mine provided access and logistics which were very amenable for extensive on-site investigation. Early investigations extending over several winters showed the build-up of a zone of ice between the vertical wharf face and the adjacent level ice sheet. This ice behavior extends to the present. Various schemes of ice force measurement, directly on the wharf face and in the adjacent ice cover have been conducted and reported on at various conferences. Because of the mine, which the wharf was built to serve, extended season marine shipping occurred and also played a part in the ice investigations. This paper will provide an overview of ice investigations conducted at and around the Nanisivik wharf over an almost 50-year period and a summary of what has been learned., 26th IAHR International Symposium on Ice, June 19-23, 2022, Montréal, Québec, Canada

A project was carried out over the winter of 1985/86 to measure ice forces on the Nanisivik wharf and associated environmental factors. The ice regime was land-fast first year sea ice which attained a maximum thickness of 1.6 m in May. Five panel-type transducers 1-m wide and divided into 0.5-m vertical sections were frozen into the ice cover 40-m out from the vertical wharf face. Measured ice pressures in the panels indicated that the majority of the ice pressure was in the top 0.5 m of the ice cover and all panels responded in a similar/synchronous manner to temperature and tidal inputs. Major loading events were systematic associated with a large or rapid temperature increase. Superimposed on these events were ice pressure oscillations having a frequency twice the tidal frequency. Maximum measured ice pressure on one panel section was 450 kPa. Averaged ice pressure measurements reached a maximum of 155 kN/m. A conceptual model relating ice pressure to tide is proposed to guide interpretation., 26th International Conference on Port and Ocean Engineering under Arctic Conditions, June 15-18, 2021, Moscow, Russia

Indentation testing at medium scale has been carried out on four occasions, between 1984 and 1990, in the Canadian Arctic. Iceberg ice and multi-year ice were tested. Forces up to 16 MN were exerted on contact areas up to 3 m2 at rates up to 0.4 m/s. All testing was done with the same servo-hydraulic controlled system. Results of the test programs have been previously reported individually. Here the results have been compared in terms of force versus penetration, global pressure versus nominal contact area and volumetric specific crushing energy versus crushed volume of ice. Various geometries of indenter and ice face were used but the volumetric specific crushing energy was relatively independent of geometry of ice or the indenter for the cases examined. Specific energy is lower for lower penetration rates. There was a strong numerical similarity between volumetric specific energy (MJ/m3) and pressure (MPa) for the same test, whether plotted against crushed ice volume or nominal contact area. This paper explores whether volumetric specific crushing energy can provide helpful insights to defining global ice pressures on relatively small global areas, those less than 3 m2. While this linkage may provide an additional data source for global pressure-area relations needed for structural design, further understandings are needed before their application., 25th IAHR International Symposium on Ice, November 23-25, 2020, Trondheim, Virtual Conference

Many engineering problems require an estimate of ice thickness, either the maximum likely thickness or the thickness at some time during the winter. This can be for estimating ice forces on an offshore structure in the sea or a bridge pier in a river. Operation of icebreaking ships requires knowledge of ice thickness to establish the viability of transit to northern ports. Similarly, over-ice transportation on seas, lakes or rives depends on a knowledge of ice thickness. At some locations historical records can be used to estimate ice thicknesses, but with changing climate historical records have limited applicability. Having means for predicting ice growth during a winter is a helpful tool. In high Arctic regions it is assumed the primary factors affecting ice growth are air temperature and snow depth. Assessment of the equations against data from Arctic weather stations indicates that the incorporation of snow depth in terms of a mean annual snow depth is a simple means for improving their predictive capability. Modified equations including mean annual snow depth and freezing degree days as input parameters are proposed and tested against available data at two locations in the Canadian High Arctic; Resolute Bay in a marine coastal environment and Baker lake in an inland freshwater lake. These modified prediction equations are proposed for general application in the Arctic., 24th IAHR International Symposium on Ice, June 4-9, 2018, Vladivostok, Russia

The 25th International Conference on Port and Ocean Engineering under Arctic Conditions, June 9-13, 2019, Delft, The Netherlands

The story of offshore Arctic engineering. Dan Masterson. Cambridge Scholars Publishing; Unabridged edition (112015). (Hard cover), 195 pp. CDN$204.07. ISBN 978-1527518162. Dan Masterson enjoyed a 45-year career in which he was engaged in ice engineering aspects of a number of the major offshore petroleum exploration programs in the Canadian High Arctic Islands and the Canadian and Alaskan Beaufort Sea. This generously illustrated book recounts Dan’s own personal experiences in many of these projects. He writes well and his narration captures the spirit, enthusiasm, and optimism of the times. The book contains high level background information on the political and economic factors that set the scene or provide context for some of the projects he was involved in. This background information is factual and well researched, and clearly separated from his personal observations and opinions. The various problems and technical solutions described in the book are interspersed with some of the colourful experiences and characters he encountered.

International Conference on Performance of Ships and Structures in Ice (ICETECH), 28-31 July, 2014, Banff, Alberta

The lighthouse Norströmsgrund in the northern Baltic Sea was well instrumented to measure ice forces and ice thickness in the years 1999 to 2003. Load panel and tilt meter data have been analysed to assess global force on the lighthouse during several ice ridge or hummock field interaction events in 2002 and 2003. The size of the ridges, type of interaction, and level ice load are examined, and an attempt is made to assess keel load. The methods of the ISO 19906 Standard are applied to determine the range of ridge forces that may be predicted at the site., 11th International Conference and Exhibition on Performance of Ships and Structures in Ice (ICETECH), 28-31 July, 2014, Banff, Alberta

Three ridged ice loading events have been analyzed from the Norströmsgrund lighthouse, off the Swedish coast. Ice load data from 1999 and 2000 were collected as part of the LOLEIF project. The three events described in this paper occurred in March and April 2000. The ridges were relatively small, with maximum keels of less than 5 m depth and sails of less than 0.5 m height., International Conference on Performance of Ships and Structures in Ice (ICETECH), 28-31 July, 2014, Banff, Alberta

Although many studies have been carried out using field, laboratory and analytical methods, uncertainty remains in the magnitude of forces generated by ice ridges on offshore structures. Norstro msgrund lighthouse, located in the Bay of Bothnia in the Baltic Sea, is a cylindrical concrete structure with a sand filled caisson foundation and a waterline diameter of about 7.5 m. It was instrumented to measure ice forces from 1999-2000 for the LOLEIF project, and from 2001-2003 for the STRICE project. Instrumentation included load panels around one half of the structure for direct measurement of ice force, a tiltmeter for assessment of lighthouse tilt motion, and devices to record ice thickness at the site. Load panel and tilt meter data have been analysed to assess global force on the lighthouse during several first-year ice ridge or hummock field interaction events in late winter and early spring of the years 2000, 2002 and 2003. Ridges were encountered with maximum consolidated layer thicknesses of 1.1 to 1.5 m, and unconsolidated keels potentially of 8 m or greater draft. Global loads are calculated from the forces recorded by load panels, and are also interpreted from tilt data. The vertical and horizontal distribution of ice pressures is examined. Most previous publications have focused on the load panels, whose measurement area is limited by their height of 1.6 m. In the present analysis, an attempt was made to assess whether any keel load was measured by the tiltmeter. The forces generated by ridged ice are also compared to those from the surrounding level ice. The methods of the ISO 19906 Standard are applied to predict ice force using the geometry and assumed properties of ridges at Norstro msgrund. These force predictions are compared to the actual measurements, and reasons for discrepancies discussed. The variability in force estimates is examined with reference to the range of possible values for the assumed parameters, including thickness and strength of the consolidated layer, and porosity and cohesion of the keel rubble., International Conference on Cold Climate Technology, 26-28 May 2014, Narvik, Norway

Ice of many forms grows annually on rivers, lakes and the sea, and as a consequence can interact with hydrotechnical or coastal structures, generating forces on them. These forces must be appropriately assessed and accounted for in the design of structures in water bodies affected by ice. Ice conditions such as thickness, strength, morphology and floe size influence ice forces and must be characterized and suitable extreme values of these features determined. The environmental driving forces of wind, current and temperature must also be understood. Information on ice conditions and environmental factors are combined to provide guidance on calculating the magnitude of ice forces that a structure might be expected to withstand over its lifetime. Various national and international standards and codes that provide guidance on ice forces have been introduced and a high level overview of determining ice loads provided. Areas that would benefit from further research include; investigation of compressive strength of ice for rates greater than 10-3 s-1, the relation between rate effects in laboratory tests and rate in ice loading of structures, and analytical work to implement ice constitutive relations into the nonuniform stress states of ice indentation., 22nd IAHR International Symposium on Ice, August 11 to 15, 2014, Singapore

Ice interactions with the Confederation Bridge for the winters 2008, 2009 and 2010 have been studied. Ice conditions for these winters were characterized by two average and one very mild. Tilt data from piers P23 and P24 in response to ice and wind actions were recorded by a data acquisition system. Video records of ice interactions with pier P23 and overall ice conditions adjacent to piers P23 and P24 allowed ice conditions and interaction processes to be related to tilt measurements. Wind data were analysed to correct for the tilt caused by wind actions on the bridge. Limit stress and limit force events were identified. An ice loading scenario that transitioned from limit force to limit stress resulted in the highest ice forces measured over the three years of monitoring, with forces of 3.1 MN and 4.3 MN at P23 and P24, respectively. This loading event corresponded to a likwly adfreeze condition., 21st International Offshore and Polar Engineering Conference, ISOPE-2011, June 19-24, 2011, Maui, Hawaii