R. Frederking

R. Frederking
National Research Council Canada | NRC

About

257
Publications
38,193
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2,457
Citations
Citations since 2017
7 Research Items
575 Citations
2017201820192020202120222023020406080100120
2017201820192020202120222023020406080100120
2017201820192020202120222023020406080100120
2017201820192020202120222023020406080100120
Introduction
Review of NRC measurements of ice forces on a dock structure.

Publications

Publications (257)
Conference Paper
Full-text available
Climate change and its potential impacts upon northern coastal infrastructure are pressing concerns. Changing patterns of sea ice formation, movement and break-up may impact design criteria for such infrastructure. The National Research Council (NRC) with the help of the Department of National Defence, Defence Construction Canada and their contract...
Conference Paper
Full-text available
In the summer of 2015, the Department of National Defense's began construction of a new deep water refueling station in Nanisivik In October of 2017, two load panels were installed on the outward face of one of three cylindrical cells making up the wharf. In June of 2018, a field team performed a short measurement program to validate the pressure p...
Article
The Molikpaq drilling platform, a steel annulus filled with sand, 90 m wide, was deployed at the Amauligak I-65 location in the Beaufort Sea during the 1985–1986 winter. It was heavily instrumented for measurement of ice loads, using strain gauges, extensometers, and Medof panels. The original calibrations of the Medof panels were used to estimate...
Article
A probabilistic model for ice forces on a caisson platform in the Beaufort Sea was used to evaluate two different approaches for describing pack ice pressure. The ridge-building equation in the ISO Arctic offshore structures standard was compared to a more recently derived exceedance curve (EC) approach. The results indicated that the EC approach y...
Chapter
Ice forms in water bodies under the influence of climate, oceanography, and the geography of the surrounding land. It grows as a result of thermal processes and mechanical processes. First-year level sea ice can grow thermally to a maximum thickness of about 2 and 2.5 m in extreme winters. Ice floes interacting with each other can build accumulatio...
Article
This paper provides the details of ice loading events that can be used to further the understanding of pack ice driving forces in the Beaufort Sea. Several methods have been reviewed and employed including in situ stress measurements, loads on the Molikpaq offshore caisson, shoreline pile-up events, pile-ups and rubble fields on offshore shoals and...
Technical Report
Full-text available
There are a large number of bridges in Canada which cross water expanses that freeze in the winter. Ice loads on bridge piers, which depend on floe size as well as ice strength, thickness and temperature, have to be factored in the design of these structures. Climate change is affecting ice growth patterns, in response to changes both in the wat...
Conference Paper
In northern regions, ice forces, or actions, must be considered in the design of structures such as light piers, bridge piers, and offshore platforms. Estimates of ice forces in Canadian waters are usually obtained by consulting design standards such as those developed by the International Organization for Standardization (ISO) and the Canadian Sta...
Conference Paper
This paper describes the work done by the Canadian Academy of Engineering in reviewing past and current activities in Canada's Northern Oceans and in developing some ideas for strategic programs and projects to further enhance engineering knowledge and capabilities for operation in northern waters.
Article
Full-text available
We have examined the ice loading forces on two piers of the Confederation Bridge during the 2012-13 ice season using the updated NRC ice load monitoring system. The new system allows better time synchronization of the tiltmeter and video data from each pier as well as the anemometer. The new system has allowed for the analysis of two large ice load...
Conference Paper
Full-text available
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...
Conference Paper
Full-text available
The ISO 19906 Arctic offshore structures standard presents a means for designing offshore platforms in ice-covered waters. This paper uses the Standard to predict loads for two simple scenarios. The predictions were made by an experienced ice engineer and an experienced engineer with no background in ice mechanics. Their predictions are compared to...
Article
Full-text available
Ice interactions with the Confederation Bridge for the winters 2008, 2009 and 2010 have been studied. Ice conditions for these winters were characterized as two average winters and one very mild winter. 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...
Article
Full-text available
As part of the ColdTech program, the Norwegian Coastguard vessel KV Svalbard has been equipped with an inertial measurement device (MRU) to record global ship motions in six degrees of freedom during ramming of heavy ice features. The objective of the measurement campaign was to look further into the possibility of using recorded whole-ship motions...
Article
Full-text available
Flexural strength from dedicated beam tests and ramming of multi-year floes has been compared. Flexural strength of multi-year ice from beam tests indicates the strength decreases as the size of the beams increases and this is important in comparing flexural strength data from various sources. In terms of relative flexural strength; from strongest...
Technical Report
Bureau Veritas has an interest in expanding the Guidelines for ‘Ice Reinforcement Selection in Different World Navigation Areas’ to include a chapter on Greenland Waters. This report contains the chapter for the guidelines and includes: 1) typical ice conditions, 2) selection of appropriate ice class, 3) legislation to be followed and 4) additional...
Conference Paper
Full-text available
Port structures in cold regions generally take the form of large caisson structures or piled structures. There are limited standards for such structures, so the following standards for highway bridges and offshore structures were assessed for application in specifying ice forces on port structures; CSA-S6 Canadian Highway Bridge Design Code, ISO 19...
Article
Ice force predictions using the ISO 19906 Arctic offshore structures standard and three national standards have been compared for structures offshore Sakhalin. A multi-leg structure with leg diameters 18 and 24 m subjected to several design ice conditions, level ice 1.2 m, rafted ice 3.5 m and a first year ridge keel 21 m deep was evaluated. ISO 19...
Technical Report
The CCGS Terry Fox field trials produced impacts with growlers, bergy bits and a small iceberg over a range of velocities. Ice mass ranged from 30 t to 22,000 t and velocity from 0.1 m/s to 6.6 m/s. Results have been analysed looking at the effect of speed and ice mass on the measured impact force. There was considerable scatter in the results unti...
Article
Eighteen ice experts from nine countries were actively involved in the development of new guidelines for ice actions that are an essential part of the new standard ISO 19906. This paper provides an overview of the methods that are recommended for ice action determination. This standard is based on the limit states design method. Therefore, guidelin...
Article
Full-text available
The present paper describes a recalibration of the loading side of all the design check equations in the Canadian offshore structures standard CAN/CSA-S471, General requirements, design criteria, the environment, and loads (offshore structures). The recalibration was prompted by concerns about changing or improved load–load effect models and new lo...
Article
Full-text available
Ice pressure ridges in the southern Beaufort Sea near Tuktoyaktuk were surveyed in April 1986. Sail cross-section profiles and ice-block dimensions of ridges of extreme heights were measured at several locations along the outer edge of the landfast ice. Statistical distributions of sail heights as well as correlations between sail dimensions and be...
Article
Full-text available
During the period December 1979 to June 1980, five visits were made to observe and measure ice behaviour around the wharf at Nanisivik, on Baffin Island. The measurements included ice thickness, temperature, salinity, and density, as well as horizontal movements of the ice cover. In March 1980, additional measurements and observations were made of...
Article
Full-text available
Field observations have been made over three winters at a vertically faced wharf in an area of limited horizontal ice movement but substantial vertical movement due to tides. Ice thickness was profiled and vertical ice movements were measured. A reasonably consistent pattern of ice behaviour adjacent to the wharf was established, characterized by t...
Article
Full-text available
The implications of a design criterion for the static load problem, which limits the maximum vertical deflection to the freeboard, are considered. An expression relating strain and deflection is developed. Field results for a static loading case were analyzed and indicated that the time dependent deflected shape of the ice cover could be represente...
Article
Full-text available
An ice feature comprising ice blocks ranging from football size to 0.6 m cubes to 1.2 m X 3.6 m X 0.6 m slabs was observed on the surface of a frozen lake. Site investigations revealed the source of the blocks to be an ice mound that had formed along the shore of the lake. A model, supported by local meteorological, geological, and hydrological inf...
Article
Full-text available
Laboratory tests on piles made of different materials ( polyethylene, polyvinylchloride, steel, wood, concrete, and Inerta 160-coated steel) were used to investigate their adhesion to an ice cover at high rates of loading. Steel, wood, and concrete piles had adhesive strengths from 0.4 to 0.5 MPa; failure at these stresses occurred in the ice. Poly...
Article
A Joint Industry Project (JIP) has been carried out from 2007-2010 to revisit the original data of the 1985-86 Amauligak I-65 deployment of the Molikpaq in the Beaufort Sea. The JIP focused on loads from multi-year ice, and took a fresh look at the instrumentation, ice conditions and analysis methods. The Molikpaq was equipped with various ice load...
Article
Estimates of ice loads and pressures on the Molikpaq structure during the 1986 deployment at the Amauligak I-65 location in the Beaufort Sea, have been based on Medof panels attached to the outer steel surface, strain gauges installed on the steel structure, extensometers measuring the deformation of the caisson, as well as inferences from the geot...
Article
Full-text available
This paper describes a study of first-year ice conditions that the new Canadian Coast Guard Polar Icebreaker is likely to encounter. About 50 years of ice thickness, snow depth and air temperatures at 10 stations in the Arctic were analyzed for average and extreme values. The maximum annual ice thickness at 8 of the 10 stations was less than 2.5 m....
Conference Paper
Full-text available
The impact of a large ice floe with the Molikpaq on May 12, 1986 resulted in some of the highest measured loads on this offshore structure. Video data from the event have been studied to produce refined estimates of ice thickness, rubble height and rubble extent. Ice load estimates are made based upon instrumentation as well as an analysis of the f...
Article
Local pressures are generally determined based on extreme pressures obtained in measurements. The exposure of structural components is an issue that needs attention. Exposure can be considered in everyday terms as “the longer you fish, the bigger the fish you catch.” In the case of design of offshore structures for ice environments, the more numero...
Article
The impact of a large ice floe with the Molikpaq on May 12, 1986 resulted in some of the highest measured loads on this offshore structure. Video data from the event have been studied to produce refined estimates of ice thickness, rubble height and rubble extent. Ice load estimates are made based upon instrumentation as well as an analysis of the f...
Technical Report
Ice interactions with the Confederation Bridge for the winters 2008, 2009 and 2010 have been studied. 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 int...
Article
A finite element analysis of various geometries of on ice edge was carried out. The analysis showed that high tensile stresses were generated at interior corners which would lead to tensile failure of the ice at those locations before compressive failure under the indentor. Suggestions were made on the positioning of a stress relief slot to encoura...
Article
Full-text available
Strength and deformation behaviour of horizontally oriented specimens of granular and columnar-grained ice were measured in the field. Cylindrical specimens were loaded on compliant platens and prismoidal specimens on steel platens to provide a range of loading system stiffness. Loading system stiffness proved to have a significant effect on streng...
Article
Full-text available
One method of thickening an ice sheet is "free flooding": ice is built up by successive flooding and freezing of sea water layers. The salinity of the built-up ice is of great interest because it plays an important role in establishing mechanical properties. Detailed observations on salinity of flooded water and built-up ice were carried out during...
Article
Full-text available
Data are presented on ice salinity, density, grain size and morphology, uniaxial compressive strength and failure modulus for old sea and brackish ice specimens from Ward Hunt Ice Shelf, Ellesmere Island, Canada. Brackish ice mean salinity (0.3 %) is an order of magnitude less than that of sea ice (1.59 %), and brackish ice structure is much more v...
Article
Full-text available
Ice property measurements were carried out during ice breaking trials of the "CANMAR KIGORIAK" during the winter of 1979-80, primarily in landfast ice in the Southern Beaufort Sea in the vicinity of McKinley Bay. They included crystallographic analysis to establish ice type and structure, temperature and salinity profiles, and uniaxial compression...
Article
Full-text available
The confined compressive strength has been measured for both vertical (A-type) and lateral (B-type) confinement conditions for sea ice from the Beaufort Sea. The results show that the confined compressive strength is extremely sensitive to the structure of the ice. For granular ice, the confined compressive strength for both A and B type confinemen...
Article
Full-text available
Pack-ice driving forces are synonymous with the limiting forces that can be transmitted through pack ice. Knowledge of this topic is important in relation to: ice loads on structures (the limiting driving force approach); ice motion modelling and forecasting; arctic ship routing. Until recently, limiting pack-ice forces had been speculated upon but...
Article
Full-text available
First-year sea ice pressure ridges are modelled as two- dimensional wedges of a Mohr-Coulomb material and the passive stress distribution is obtained using a similarity solution and approximate polynomial forms of the dependent variable. Analysis gives the horizontal forces in ice covers associated with formation of floating pressure ridges and som...
Article
For Phase 2 of INSROP Project I.1.7, Large Scale Hull Loading of First-Year Sea Ice, a series of tests in first-year brackish ice were carried out Tuktoyaktuk in the Canadian Arctic to simulate ice loading on a ship hull. Loading was generated by hydraulic actuators impressing a rigid indentor against an ice edge. A finite element analysis of the t...
Article
Full-text available
Stresses were measured in the rubble field surrounding a caisson-retained island in the southern Beaufort Sea. The rubble movements, geometry and composition were examined. The maximum stress, near the edge of the rubble field, was approximately 200 kPa, apparently caused by thermal expansion of the ice between the shore and the island. Stresses me...
Article
Information on the morphology and properties of first-year ice ridges in the Sea of Okhotsk is required for design of offshore structures. Data have been compiled to provide a picture of Okhotsk sea ice ridges. The data include sail heights, keel depths, consolidated layer thickness, porosity and ridge width. The data from the Sea of Okhotsk are co...
Article
Full-text available
Ice stresses and environmental factors at Nanisivik wharf on Strathcona Sound in the Canadian Arctic are reported for the winter 1985/86. The ice regime is that of landfast first- year sea ice that attains a maximum thickness of 1.6 m in May. The primary mechanism of generating ice loads at this location appears to be temperature-induced strains in...
Article
Full-text available
Finite element analysis of beams subjected to four-point asymmetric loading has been used to calculate the internal stress fields for different specimen and loading geometries. The shear stresses determined from these stress fields were significantly different from those calculated from simple beam theory. Laboratory experiments done on samples of...
Article
This paper discusses three years of property measurements that were made on decaying first-year sea ice in the Canadian Arctic. Data were collected on five, level, landfast first-year ice sites in Parry Channel. Measurements, made from May to July/August, included the snow and ice thickness, ice temperature and salinity, and the in situ confined co...
Article
Full-text available
The performance characteristics of two cold rooms operating since 1954 were evaluated with regard to temperature distribution throughout the rooms and temperature stability. One room is approximately 9 x 13 x 10 ft high, and the other is 10 x 12 x 10 ft high. Each room is conditioned with a 3.5 ton capacity compressor. An auxiliary compressor is sh...
Article
Full-text available
The first part of this paper considers the elastic theory of a beam on an elastic foundation. Various factors that affect the interpretation of cantilever beam tests are examined, i. e. , beam geometry, elastic foundation effect, and nonhomogeneity of elastic modulus through beam thickness. The second part of the paper presents results from in situ...
Article
Full-text available
Transducers for the measurement of in situ stresses in ice have application to the problem of determining ice forces on structures. The elastic theory of a thick walled tube in a host material under a biaxial stress state is developed and applied to the design of an in situ stress transducer. An aluminum tube of 50 mm diameter and 3 mm wall thickne...
Article
Field experiments on cylindrical and prismoidal specimens oriented in the plane of the ice cover and perpendicular to it are reported. Nominal strain rate was varied from 2 x 10[-5] s[-1] to 5 x 10[-4] s[-1]; both load and strain were monitored continuously. The strength of vertical specimens of unaligned columnar-grained ice was about three times...
Article
Full-text available
Ice load measuring sensors were installed on the Yamachiche Bend lightpier in the St. Lawrence River downstream from Montreal. Panels consisting of steel plates supported on load cells are used to measure static loads while accelerometers are used to monitor dynamic loads. Operation of the system over the winters of 1983-84 to 1985-86 is described...
Article
Full-text available
A review and comparison of calculation methods of ice ridging forces is presented. An overview of a new ridging model that predicts the limiting rubble height and depth is included. This model uses a diffusion equation to describe the normal stress spread in the bulk rubble. Results of calculation methods are compared to those of laboratory tests a...
Article
Full-text available
A program to determine ice forces and behaviour was carried out on a wharf at Strathcona Sound on Baffin Island during the winter 1975-76. Observations at the site revealed that tidal action resulted in the formation of an increasingly wide and thick zone of ice between the wharf and the natural ice cover. A qualitative model for developing ice pre...
Article
Full-text available
Observations on the nearshore movement of an ice cover were made at two locations in the North Baffin Area of the Canadian Arctic. These measurements were made at half hourly and hourly intervals for periods up to 24 hours. From these measurements, a consistent pattern of offshore ice cover movement has been observed. This has been related to a con...
Article
Full-text available
A considerable amount of information and knowledge was gained during the exploration phase of the Beaufort Sea during the 1970s through to the 1990s. However, this information can be difficult to locate. This report provides a broad summary of the oil and gas activities in the Canadian Beaufort Sea. Information is provided on the environment in thi...
Article
The CCGS Terry Fox bergy bit impact trials provided data on ice impact force, loaded area and local ice pressure, which have been used to analyse the nature of ice impact forces. The iceberg masses were 30 t to 22,000 t and impact velocities ranges from 0.2 m/s to 6.5 m/s. 178 impacts were measured, with the largest force being 5.2 MN. The measurem...
Article
Full-text available
Intensive oil and gas exploration activity took place in the Beaufort Sea during the 1970s and 1980s. There was a considerable amount of research performed and new, valuable knowledge was gained. However the information is spread over a wide range of locations. This paper provides a brief overview of the activity and provides guidance on the type a...
Article
As part of the environmental monitoring program that supported drilling operations from the Molikpaq at the Amauligak I-65 location during the winter of 1985-86, information about the ice conditions and movements round the structure were collected on an hourly basis. These observations included ice thickness, ice type, partial concentrations, floe...
Article
This paper presents an overview of bergy bit impact trials carried out on the CCGS Terry Fox off the northern tip of the island of Newfoundland in June 18–23, 2001 and is meant to accompany the five papers that follow. The trial consisted of impacting target iceberg ice masses ranging from roughly 100 t (growlers) to 22,000 t (bergy bits) on an ins...
Article
This paper describes the forces that were measured on the CCGS Terry Fox during just over 50 collisions with glacial ice. Global impact forces on the ship were estimated by an inertial measurement system called MOTAN, using two different approaches. The global force can be calculated at the point of impact (POI) from the POI Approach or, if the imp...
Article
A field test program was carried out with the CCGS Terry Fox off the northeast coast of Newfoundland in June 2001. During these trials, a total of 178 impacts occurred between the vessel and bergy bits whose sizes ranged from 20 t to 22,000 t, at ship speeds from 0.2 to 6.5 m/s.An area on the port bow was instrumented using 120 strain gauges. An in...
Article
Full-text available
Local pressure data from bergy bit impacts with the CCGS Terry Fox off the north east coast of Newfoundland in June 2001 have been compared with other data. These data sources include the USCGC Polar Sea from operations in the Beaufort Sea and Chukchi Sea, and bergy bit impacts at Grappling Island, They have been put on a common basis and compared...
Article
Full-text available
An existing pressure vs. area curve for determining local ice pressures on offshore structures and ship hulls was included in the CSA S-471 and API RP 2N standards for offshore structure design. The data comprising the original curve was based on multi-year ice obtained from medium scale impact tests, ship ramming tests, and ice load panels on the...
Article
Full-text available
Within the SAFEICE Project a database of forces and local pressures has been compiled for icebreakers and commercial ships operating in ice. The areas of operation include the Arctic Ocean with multi-year ice and first year ice in the Baltic and Bering Seas. This ice type has the greatest effect on ice loading. The maximum local pressure measured i...
Article
On April 12, 1986, the Molikpaq, a caisson-type offshore drilling structure, experienced a series of loading events when second-year and multi-year ice moved against the structure. The highest loads that the Molikpaq experienced during the 1985–86 season were during this day. Extensive ice thickness measurements had been taken in the ice around the...
Article
Full-text available
A large piece of shore fast ice approximately 5 by 10 km broke free and drifted through Northumberland Strait on April 4 2003, failing against the piers of the Confederation Bridge. The ice had been surveyed shortly before its break-up and its thickness was about 1 m with many ridges of about 4 m thick when averaged over a 20-m diameter. While the...
Article
Full-text available
This paper mainly focuses on establishing a probabilistic model to explore the relationship between local pressures and the global pressure. Both spatial and temporal correlations among the local pressures are considered in the study. A vector autoregressive model (VAR) is applied in this research to include these correlations. The global contact a...
Article
Full-text available
Compressive ice failure is an important aspect in the design of offshore structures in ice environments. The authors concentrate attention on the crushing failure mode. The scale effect is a phenomenon whereby the average pressure decreases with contact area. In classical elasticity, viscoelasticity and plasticity, there is no scale effect. In the...
Article
Full-text available
The Canadian Standards Association (CSA) developed a comprehensive Offshore Structures Standard in the early 1990s. The Code has had limited use in Canada, but S471 General Requirements, Design Criteria, the Environment, and Loads has seen international application. The Code is performance-based; setting overall targets for reliability and provides...
Article
Full-text available
In 1991 the ODEN made a voyage to the North Pole. An area in the starboard bow of the ship was instrumented with strain gauges to measure local ice pressures. The ship encountered various ice conditions in its voyage, and whenever a threshold strain was exceeded, a 6 to 12 second-long “event” record of strains was made. Based on a finite element an...
Article
During the 1980s extensive offshore geophysical surveys yielded over 100,000 measured ice thicknesses in one area of the Arctic Archipelago. The date and location of these measurements are known and can be compared with ice regime information on Canadian Ice Service ice charts from the same time period. Air temperature data are available from Arcti...
Article
Full-text available
The Amauligak I-65 deployment of the Molikpaq for the winter of 1985/86 provides a good source of local pressure data and a basis for estimating global loads on a wide structure. Data including Medof panel pressures and hourly ice conditions at Molikpaq have been extracted from the “Catalogue of Local Ice Pressures” (CLIP) database. Pressures as hi...
Article
A probabilistic analysis is made to predict the seasonal evolution of first-year ice loads on the Molikpaq offshore structure throughout a winter in the Canadian Beaufort Sea. The analysis is based solely on the failure modes of the ice, the ice thickness, and the number of weekly ice loading events. The paper illustrates the use of the probabilist...
Article
Full-text available
The Japan Ocean Industry Association made available to the IAHR Ice Crushing Working Group one data file from a field test conducted February 4, 1999. An indenter 1.5 m wide by 0.5 m high, penetrated a sea ice sheet 168 mm thick at a rate of 3 mm/s for a total penetration of 1000 mm. The entire indenter face was covered with “tactile” sensor elemen...
Article
Country-Specific Mortality and Growth Failure in Infancy and Yound Children and Association With Material Stature Use interactive graphics and maps to view and sort country-specific infant and early dhildhood mortality and growth failure data and their association with maternal
Article
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Local ice pressure data collected from the 1994 Polar transit of the Louis S. St. Laurent provides an excellent data set for determining local average ice pressures as a function of area. The voyage covered over 2000 nautical miles over a 35-day period. A probabilistic approach was used to determine an annual probability of exceedance of ice pressu...
Article
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This paper presents a review of the current state of knowledge on the in situ borehole strength of multi-year ice. Since very few data exist in the open literature, data from the private sector are combined with publicly available data to present a review of borehole measurements on second-year and multi-year ice. Data from six studies are compiled...
Article
This report provides documentation on the recently updated MOTAN system. The MOTAN uses measured whole-ship motions to obtain the global loads associated with transient ice impacts. Model-scale and full-scale data are used to demonstrate the feasibility of using the MOTAN system to provide reliable information on global loads. Whole-ship motions of...
Article
This paper introduces an inertial measurement system called MOTAN and discusses results from one of its full-scale installations. Recent measurements have shown that the MOTAN system offers a novel approach for determining ice-induced global loads on ships. The system consists of two parts: an instrument for measuring whole-ship motions, and softwa...
Article
Full-text available
A testing system has been devised to simulate the frictional behaviour between ice and a structure as the ice slows down and stops, and subsequently increases in speed again. This simulates the interaction behaviour often observed in nature between ice floes and a sloping structure. A test series was carried out to measure friction between sea ice...