Day 1 Mon, July 28, 2014最新文献

{"title":"Uncertainty in 100 and 10,000 Year Ice Loads on Offshore Structures","authors":"R. McKenna, Mark Fuglem, G. Crocker","doi":"10.5957/icetech-2014-167","DOIUrl":"https://doi.org/10.5957/icetech-2014-167","url":null,"abstract":"The ISO 19906 arctic structures standard specifies that ice loads be calculated at the extreme level (100 year return period) for verifying ultimate limit states and at the abnormal level (10,000 years) for accidental/abnormal limit states. Since ice load measurements on structures have only been made over much shorter time periods, concerns are often expressed about the accuracy to which 10,000 year values can be estimated.\u0000 In this paper, the uncertainties in 100 and 10,000 year loads are considered through examples based on experience with calculations of loads on structures in different iceberg and sea ice environments. For icebergs, it is necessary to consider the size distribution of icebergs (including the potential presence of extremely large icebergs and ice islands) as well as drift velocities and shapes that can govern high return- period loads for fixed structures. With sea ice, abnormal-level loads can be governed either by the presence and geometrical properties of large discrete features (e.g. first-year ridges and stamukhi, or in the arctic, multi-year floes with thick ridges), or by very thick ice as a result of thermal growth. It is demonstrated how errors in key contributing ice parameters can influence extreme-level loads, and the relationship between level/rafted ice loads at the abnormal level and the factored (1.35) extreme-level values, and how these uncertainties might be considered in the design process.","PeriodicalId":113144,"journal":{"name":"Day 1 Mon, July 28, 2014","volume":"400 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120892182","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Short History on Ice Expeditions in the Russian Federation","authors":"G. Wilkman","doi":"10.5957/icetech-2014-165","DOIUrl":"https://doi.org/10.5957/icetech-2014-165","url":null,"abstract":"In the field of ice expeditions, we have three main branches of activity where people go to test, observe, measure and map the ice conditions or performance of certain ship. The practices for conducting such exercise are different depending on the country and region. To organize an expedition or ship testing trip in the Russian Federation and former Soviet Union has always been a challenge. Preparations and planning needs to be started well in advance for getting the permits, and even then when you have all the paperwork done you cannot be sure that the expedition will come true. You need to cross the border to Russia and it may happen that you and the customs officer do not come along in a perfect way. This paper will tell the story of how things should or should not be arranged in the changing legislative atmosphere of Russian Federation. Russian Federation is here only as one example as similar practices can be found also elsewhere on this globe.","PeriodicalId":113144,"journal":{"name":"Day 1 Mon, July 28, 2014","volume":"90 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116156427","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Challenges Implementing ISO 19906 for Probabilistic Assessment of Multi-year Sea Ice Loads on Sloping Structures","authors":"Mark Fuglem, M. Richard, Jan Thijssen","doi":"10.5957/icetech-2014-154","DOIUrl":"https://doi.org/10.5957/icetech-2014-154","url":null,"abstract":"The ISO standard ISO 19906:2010 provides guidance for determining design loads for offshore structures in arctic and sub-arctic regions, using both deterministic and probabilistic approaches. References are provided for models of both first and multi-year ice loads on both vertically-faced and sloping structures.\u0000 ISO 19906 indicates that consideration should be given to limit stresses at the ice structure interface based on the dominating ice failure mechanisms, limit forces associated with the available driving force that can act on the interacting ice floe due to wind, currents and surrounding ice, and the kinetic energy of the impacting feature. Analyses show that the kinetic energy of an impacting multi-year floe driven by surrounding ice will result in larger loads than those from driving forces alone. In order to determine penetrations and maximum loads, it is then necessary to consider the variation in load with penetration during an impact.\u0000 In the case of multi-year ice loads on sloping structures, full-scale data to properly validate models is lacking. Several models are available that estimate maximum loads for level ice interactions with sloping structures. These models can partially account for rubble forming on the structure during the interaction thereby increasing loads, though the ability to estimate rubble heights for different structure shapes and ice conditions at present is limited. In the case of multi-year ridges, several models are available that estimate the maximum load during the interaction of a prismatic beam shaped ridge contacting a conical structure. Data and model for loads from more realistic multi-year ridge shapes are lacking. Additionally, the influence of rubble existing on the structure at the time the ridge impacts is not explicitly considered.\u0000 This paper examines issues in determining probabilistic design loads for multi-year interactions with sloping structures and presents sensitivity results for key assumptions and parameters. The analyses were carried out using the Sea Ice Loads Software (SILS) developed by C-CORE as part of a Joint Industry Project (JIP) to implement ice load models referenced in ISO 19906 within a probabilistic framework for the purpose of determining design loads. Interpretation was required where ISO 19906 does not provide explicit details on the models and probabilistic implementation. Monte-Carlo simulation was selected for carrying out probabilistic calculations of design loads as this approach is robust.","PeriodicalId":113144,"journal":{"name":"Day 1 Mon, July 28, 2014","volume":"142 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123401611","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Detailed Ice Ridge Loading Events on the Norströmsgrund Lighthouse","authors":"L. Poirier, D. Sudom, R. Frederking","doi":"10.5957/icetech-2014-138","DOIUrl":"https://doi.org/10.5957/icetech-2014-138","url":null,"abstract":"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.","PeriodicalId":113144,"journal":{"name":"Day 1 Mon, July 28, 2014","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126708556","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}