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    <title>Transport Research International Documentation (TRID)</title>
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    <copyright>Copyright © 2026. National Academy of Sciences. All rights reserved.</copyright>
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    <managingEditor>tris-trb@nas.edu (Bill McLeod)</managingEditor>
    <webMaster>tris-trb@nas.edu (Bill McLeod)</webMaster>
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      <title>MODEL AND FIELD EXPERIMENTS FOR DEVELOPMENT OF ICE RESISTANT OFFSHORE STRUCTURES</title>
      <link>https://trid.trb.org/View/166111</link>
      <description><![CDATA[In order to meet the demand for offshore oil development in the Sub-arctic and Arctic, Mitsui Engineering & Shipbuilding Co., Ltd. has conducted research to establish technology to predict the ice loads applied on various shapes of ice resistant structures as a basis for designing optimum structures.  The ice force measuring experiments have included laboratory tests performed by Arctec Inc., U.S.A., outdoor tests using medium size models in a lagoon and field tests on a large size tower specially installed in the Okhotsk Sea.  This large tower was built in August 1976, 600 m off Mombetsu in Hokkaido at a water depth of 6.5 m and had a cylindrical shape of 9.5 m in height and 2.5 m in diameter.  This tower was converted the next year to a conically shaped structure of 11 m in height and 5.5 m diameter at the water line.  In winter the site was covered with pack ice ranging from 30 to 60 cm in thickness. The ice loads were sensed by measuring bending strains at the tower root and transmitted through sub-sea cable to land, and observations of ice behavior around the tower were conducted.  Model tests of a mono-cone, mono-pod, four-legged conical structures, and four-legged cylindrical structures were conducted in an ice model basin of Arctec Inc.  These were tested in unconsolidated and semiconsolidated first-year pressure ridges and rafted ice. Also, outdoor tests have been conducted at the Saroma Lagoon near Mombetsu since 1976 using medium sized models on various types of ice-resistant structures.  The phenomena of vibratory crushing were also investigated.  In this paper the outline of these tests including the correlation of ice loads on cone-shaped structure between the different tests is presented as well as some design consideration for ice-resistant structures.]]></description>
      <pubDate>Wed, 15 Apr 1981 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/166111</guid>
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      <title>THE ARCTIC ENVIRONMENT AND THE ARCTIC SURFACE EFFECT VEHICLE</title>
      <link>https://trid.trb.org/View/43766</link>
      <description><![CDATA[This report summarizes the advances in understanding of the Arctic which have come about since the inception of the ARPA Arctic Surface Effect Vehicle Program in 1970, primarily as the result of CRREL's participation.  Major efforts to increase knowledge of sea ice, terrestrial, and coastal topographic features are described.  Special emphasis is placed upon the quantitative understanding of pressure ridging.  Other areas of major interest are atmospheric characteristics and ecological effects.  A list of publications generated is included.  /Author/]]></description>
      <pubDate>Thu, 16 Sep 1976 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/43766</guid>
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      <title>ARCTIC ICE DYNAMICS JOINT EXPERIMENT. AIDJEX BULLETIN NO. 12</title>
      <link>https://trid.trb.org/View/9968</link>
      <description><![CDATA[AIDJEX Bulletin No. 12 reports the preliminary results of several projects which were carried out during the 1971 AIDJEX Pilot Study (March-April 1971, in the Beaufort Sea 550 km north of Tuktoyaktuk, NWT, Canada).  These projects include a study of a multiyear pressure ridge; 25 cm coherent, synthetic-aperture radar observations of sea ice from aircraft; measurements of (atmospheric) turbulence in the near-ice layer; and water stress and ocean current measurements.  Also included in the Bulletin are: a paper on water and ice motion during the 1970 AIDJEX Pilot Study (March-April 1970, Beaufort Sea); two papers on the study of sea-ice pressure ridge statistics; and the table of contents of Trudy (Proceedings) of the Arctic and Antarctic Research Institute, Leningrad, Vol. 303 (1971) (translation to appear in AIDJEX-72-16 and AIDJEX-72-17, AIDJEX Bulletin Nos. 16 and 17, TT 72-50022).]]></description>
      <pubDate>Wed, 14 Nov 1973 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/9968</guid>
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      <title>STATISTICAL ASPECTS OF SEA-ICE RIDGE DISTRIBUTION</title>
      <link>https://trid.trb.org/View/12175</link>
      <description><![CDATA[A theoretical distribution function for pressure-ridge sail heights and keel depths is derived from fundamental assumptions about the randomness of the ridges.  It is shown that the distribution function for ridge spacings (distance between ridges) can also be predicted from the assumption of spatially random occurrence.  The suggested distribution functions are, in form, negative exponentials of the ridge height (or depth) squared and the ridge spacing, respectively.  Extremely good fits were achieved to extensive data collected from sonar profiles of the lower surface of the pack ice and to laser profiles, as well as visual roughness data from the upper ice surface.  Using these models, it is possible to completely characterize the ridging, in a one-dimensional sense, by two parameters: (N), the mean number of ridges per unit length, and (h), the mean ridge height (or depth).  In addition, there is a linear correlation between (N) and (h).  This suggests that maps showing the distribution of (N) or (h) over an ocean covered with pack ice can be used to statistically characterize both the spacing and the height distribution of the ridges.]]></description>
      <pubDate>Fri, 27 Apr 1973 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/12175</guid>
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    <item>
      <title>MARINE TRANSPORTATION IN ICE COVERED WATERS: AN ESTIMATE OF FUTURE CAPABILITY</title>
      <link>https://trid.trb.org/View/8033</link>
      <description><![CDATA[The purpose of this paper is to provide an estimate of the capability of future marine transportation systems in ice covered waters and is based on the assumption that the economic justification for developing the required technology will exist.  This paper is presented in three sections.  The first section describes some recent technical efforts that have been conducted in ice covered waters.  The second section presents an estimate of future capability of marine vehicles and offshore structures in ice.  The final section summarizes the paper and discusses the type of programs which will have to be undertaken if these forecasts are to be realized.]]></description>
      <pubDate>Fri, 02 Mar 1973 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/8033</guid>
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      <title>PRESSURE RIDGE CHARACTERISTICS IN THE ARCTIC COASTAL ENVIRONMENT</title>
      <link>https://trid.trb.org/View/2432</link>
      <description><![CDATA[Pressure ridges and hummocks, which are the largest of the ice relief features, present formidable problems to design of off-shore facilities and to the operation of surface and subsurface shipping.  The mechanics of ridge and hummock formation are reviewed and it is shown that several distinct types of ice formation features occur depending upon whether the formation mechanism is marginal crushing, overthrusting or shearing.  Between 1969 and the present a number of both free-floating and grounded ridges have been examined by the authors in the Bering, Chukchi and Beaufort Seas.  Profiles of the upper and lower surfaces of the ridges were determined by leveling and by drilling and sonar, respectively, and the internal structure of the ridges was investigated by coring.  Ice temperatures, salinities, and densities were obtained and brine volumes were computed from the temperatures and salinities. Representative profiles are presented.  The present results of this program are:  1. The degree of bonding between ice blocks and, therefore, the overall structural integrity of ridge keels would appear to be variable, presumably changing with the age of the ridge and the initial temperature of the ice being incorporated into the ridge.  It can be shown that during the winter the cold reserve of ice blocks being incorporated into a ridge can be sufficient to cause significant inter-block ice growth.  2. Lack of local isostatic adjustment is common in ridges.  In new ridges a significant portion of the surface load is supported by the surrounding plate ice resulting in its deflection.  When ridges form by thrusting, their upper and lower portions may be laterally separated by tens of meters.  This obviously results in a nonisostatic condition which is compensated by deflections of the local plate ice.  3. A representative salinity for the ice in the ridges we examined was 4 percent.  Temperature profiles were reasonably linear except in the lower parts of ridges with pronounced keels where temperatures were roughly constant at near freezing values.  The brine volume of the ice blocks in the keels varied between 40 and 120 percent.  4. Present information indicates that the average slope angle of the above-water portion of a ridge (24 degrees) is less than that of the underwater portion (33 degrees).  5. Ridges act as effective snow fences, causing large amounts of snow to accumulate both in and around their upper parts. 6. It appears doubtful that the cross-section profiles of all ridges can adequately be represented by any one geometric model.  Current data bearing on the general distribution of deformation features in time and space over the Arctic Ocean are also summarized.  The data sources include the Birdseye flights, recent special laser profilometer flights, and sonar traces of the lower ice surface.  Prime attention is paid to the ridging characteristics in the Coastal and Offshore Sea Ice Provinces where the ice is clearly more highly deformed than the ice in the Central Arctic Basin Province.  Winter and summer distributions of both sail heights and keel depths as well as the number of ridges per nautical mile are presented.]]></description>
      <pubDate>Tue, 28 Mar 1972 00:00:00 GMT</pubDate>
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