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Norman Allyn - One of the best experts on this subject based on the ideXlab platform.
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Reliability Calibration of a Waves–Icebergs Interaction Load Combination Factor
23rd International Conference on Offshore Mechanics and Arctic Engineering Volume 1 Parts A and B, 2004Co-Authors: Ricardo O Foschi, Michael Isaacson, Norman AllynAbstract:The Canadian Standards Association [1] has developed and published a code for the design and construction of fixed offshore structures. One of the limit states relates to the combined effects of waves and iceberg collision Loading. The Code uses a Load Combination Factor to determine the design Load effect. The present paper describes a recent study on the appropriateness of the recommended value of the Combination Factor. The study involves a numerical analysis in which Loads have been calculated, at different probability levels, for a range of iceberg and wave parameters, considering waves alone, an iceberg alone, and an iceberg and waves in Combination. The paper thereby makes recommendations for the Load Combination Factor as a function of iceberg and sea state parameters.Copyright © 2004 by ASME
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reliability calibration of a waves icebergs interaction Load Combination Factor
23rd International Conference on Offshore Mechanics and Arctic Engineering Volume 1 Parts A and B, 2004Co-Authors: Ricardo O Foschi, Michael Isaacson, Norman AllynAbstract:The Canadian Standards Association [1] has developed and published a code for the design and construction of fixed offshore structures. One of the limit states relates to the combined effects of waves and iceberg collision Loading. The Code uses a Load Combination Factor to determine the design Load effect. The present paper describes a recent study on the appropriateness of the recommended value of the Combination Factor. The study involves a numerical analysis in which Loads have been calculated, at different probability levels, for a range of iceberg and wave parameters, considering waves alone, an iceberg alone, and an iceberg and waves in Combination. The paper thereby makes recommendations for the Load Combination Factor as a function of iceberg and sea state parameters.Copyright © 2004 by ASME
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assessment of the wave iceberg Load Combination Factor
International Journal of Offshore and Polar Engineering, 1997Co-Authors: Ricardo O Foschi, Michael Isaacson, Norman Allyn, Ibrahim SaudyAbstract:The present paper describes an extension to a recent study (Foschi et. al., 1996), which was undertaken to determine the appropriateness of the recommended value of the Load Combination Factor relating to the combined effects of wave and iceberg Loads, as described in the Canadian Standards Association (1992) code for the design and construction of fixed offshore structures. The study examines the sensitivity of the Load Combination Factor to various iceberg and wave parameters typical of three sites off the East Coast of Newfoundland. The methodology is based on a numerical analysis in which Loads due to waves alone, an iceberg alone, and an iceberg and waves in Combination, have been calculated for a range of iceberg and wave parameters, with the results applied to a first-order reliability analysis to study force levels corresponding to specified annual exceedence probabilities. The results indicate that the Load Combination Factor is most sensitive to the wave angle relative to the current direction, and to the wave climate during the iceberg season therefore, the Load Combination Factor is site dependent. The Load Combination Factor has been calculated as 0.25 on average, with a conservative value of 0.33. This compares with the Code values of 0.8 or 0.4, for icebergs and waves which are taken to be stochastically dependent or independent, respectively.
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Combined wave – iceberg Loading on offshore structures
Canadian Journal of Civil Engineering, 1996Co-Authors: Ricardo O Foschi, Michael Isaacson, Norman AllynAbstract:The Canadian Standards Association has developed and published a code for the design and construction of fixed offshore structures. This code has been subjected to a comprehensive verification process which has identified several issues warranting further study. One of these relates to the combined effects of wave and iceberg collision Loading. At present, this Combination is treated by the use of a Load Combination Factor specified in the Code. The present paper describes a recent study which was undertaken to determine the appropriateness of the recommended value of the Load Combination Factor. The study involves a numerical analysis in which Loads due to waves alone, an iceberg alone, and an iceberg and waves in Combination have been calculated for a range of iceberg and wave parameters. These results have been applied to a first-order reliability analysis in order to study the force levels corresponding to an annual probability of 10−4 or to the onset of global sliding with an annual probability of 10...
Ricardo O Foschi - One of the best experts on this subject based on the ideXlab platform.
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Reliability Calibration of a Waves–Icebergs Interaction Load Combination Factor
23rd International Conference on Offshore Mechanics and Arctic Engineering Volume 1 Parts A and B, 2004Co-Authors: Ricardo O Foschi, Michael Isaacson, Norman AllynAbstract:The Canadian Standards Association [1] has developed and published a code for the design and construction of fixed offshore structures. One of the limit states relates to the combined effects of waves and iceberg collision Loading. The Code uses a Load Combination Factor to determine the design Load effect. The present paper describes a recent study on the appropriateness of the recommended value of the Combination Factor. The study involves a numerical analysis in which Loads have been calculated, at different probability levels, for a range of iceberg and wave parameters, considering waves alone, an iceberg alone, and an iceberg and waves in Combination. The paper thereby makes recommendations for the Load Combination Factor as a function of iceberg and sea state parameters.Copyright © 2004 by ASME
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reliability calibration of a waves icebergs interaction Load Combination Factor
23rd International Conference on Offshore Mechanics and Arctic Engineering Volume 1 Parts A and B, 2004Co-Authors: Ricardo O Foschi, Michael Isaacson, Norman AllynAbstract:The Canadian Standards Association [1] has developed and published a code for the design and construction of fixed offshore structures. One of the limit states relates to the combined effects of waves and iceberg collision Loading. The Code uses a Load Combination Factor to determine the design Load effect. The present paper describes a recent study on the appropriateness of the recommended value of the Combination Factor. The study involves a numerical analysis in which Loads have been calculated, at different probability levels, for a range of iceberg and wave parameters, considering waves alone, an iceberg alone, and an iceberg and waves in Combination. The paper thereby makes recommendations for the Load Combination Factor as a function of iceberg and sea state parameters.Copyright © 2004 by ASME
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assessment of the wave iceberg Load Combination Factor
International Journal of Offshore and Polar Engineering, 1997Co-Authors: Ricardo O Foschi, Michael Isaacson, Norman Allyn, Ibrahim SaudyAbstract:The present paper describes an extension to a recent study (Foschi et. al., 1996), which was undertaken to determine the appropriateness of the recommended value of the Load Combination Factor relating to the combined effects of wave and iceberg Loads, as described in the Canadian Standards Association (1992) code for the design and construction of fixed offshore structures. The study examines the sensitivity of the Load Combination Factor to various iceberg and wave parameters typical of three sites off the East Coast of Newfoundland. The methodology is based on a numerical analysis in which Loads due to waves alone, an iceberg alone, and an iceberg and waves in Combination, have been calculated for a range of iceberg and wave parameters, with the results applied to a first-order reliability analysis to study force levels corresponding to specified annual exceedence probabilities. The results indicate that the Load Combination Factor is most sensitive to the wave angle relative to the current direction, and to the wave climate during the iceberg season therefore, the Load Combination Factor is site dependent. The Load Combination Factor has been calculated as 0.25 on average, with a conservative value of 0.33. This compares with the Code values of 0.8 or 0.4, for icebergs and waves which are taken to be stochastically dependent or independent, respectively.
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Combined wave – iceberg Loading on offshore structures
Canadian Journal of Civil Engineering, 1996Co-Authors: Ricardo O Foschi, Michael Isaacson, Norman AllynAbstract:The Canadian Standards Association has developed and published a code for the design and construction of fixed offshore structures. This code has been subjected to a comprehensive verification process which has identified several issues warranting further study. One of these relates to the combined effects of wave and iceberg collision Loading. At present, this Combination is treated by the use of a Load Combination Factor specified in the Code. The present paper describes a recent study which was undertaken to determine the appropriateness of the recommended value of the Load Combination Factor. The study involves a numerical analysis in which Loads due to waves alone, an iceberg alone, and an iceberg and waves in Combination have been calculated for a range of iceberg and wave parameters. These results have been applied to a first-order reliability analysis in order to study the force levels corresponding to an annual probability of 10−4 or to the onset of global sliding with an annual probability of 10...
Michael Isaacson - One of the best experts on this subject based on the ideXlab platform.
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Reliability Calibration of a Waves–Icebergs Interaction Load Combination Factor
23rd International Conference on Offshore Mechanics and Arctic Engineering Volume 1 Parts A and B, 2004Co-Authors: Ricardo O Foschi, Michael Isaacson, Norman AllynAbstract:The Canadian Standards Association [1] has developed and published a code for the design and construction of fixed offshore structures. One of the limit states relates to the combined effects of waves and iceberg collision Loading. The Code uses a Load Combination Factor to determine the design Load effect. The present paper describes a recent study on the appropriateness of the recommended value of the Combination Factor. The study involves a numerical analysis in which Loads have been calculated, at different probability levels, for a range of iceberg and wave parameters, considering waves alone, an iceberg alone, and an iceberg and waves in Combination. The paper thereby makes recommendations for the Load Combination Factor as a function of iceberg and sea state parameters.Copyright © 2004 by ASME
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reliability calibration of a waves icebergs interaction Load Combination Factor
23rd International Conference on Offshore Mechanics and Arctic Engineering Volume 1 Parts A and B, 2004Co-Authors: Ricardo O Foschi, Michael Isaacson, Norman AllynAbstract:The Canadian Standards Association [1] has developed and published a code for the design and construction of fixed offshore structures. One of the limit states relates to the combined effects of waves and iceberg collision Loading. The Code uses a Load Combination Factor to determine the design Load effect. The present paper describes a recent study on the appropriateness of the recommended value of the Combination Factor. The study involves a numerical analysis in which Loads have been calculated, at different probability levels, for a range of iceberg and wave parameters, considering waves alone, an iceberg alone, and an iceberg and waves in Combination. The paper thereby makes recommendations for the Load Combination Factor as a function of iceberg and sea state parameters.Copyright © 2004 by ASME
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assessment of the wave iceberg Load Combination Factor
International Journal of Offshore and Polar Engineering, 1997Co-Authors: Ricardo O Foschi, Michael Isaacson, Norman Allyn, Ibrahim SaudyAbstract:The present paper describes an extension to a recent study (Foschi et. al., 1996), which was undertaken to determine the appropriateness of the recommended value of the Load Combination Factor relating to the combined effects of wave and iceberg Loads, as described in the Canadian Standards Association (1992) code for the design and construction of fixed offshore structures. The study examines the sensitivity of the Load Combination Factor to various iceberg and wave parameters typical of three sites off the East Coast of Newfoundland. The methodology is based on a numerical analysis in which Loads due to waves alone, an iceberg alone, and an iceberg and waves in Combination, have been calculated for a range of iceberg and wave parameters, with the results applied to a first-order reliability analysis to study force levels corresponding to specified annual exceedence probabilities. The results indicate that the Load Combination Factor is most sensitive to the wave angle relative to the current direction, and to the wave climate during the iceberg season therefore, the Load Combination Factor is site dependent. The Load Combination Factor has been calculated as 0.25 on average, with a conservative value of 0.33. This compares with the Code values of 0.8 or 0.4, for icebergs and waves which are taken to be stochastically dependent or independent, respectively.
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Combined wave – iceberg Loading on offshore structures
Canadian Journal of Civil Engineering, 1996Co-Authors: Ricardo O Foschi, Michael Isaacson, Norman AllynAbstract:The Canadian Standards Association has developed and published a code for the design and construction of fixed offshore structures. This code has been subjected to a comprehensive verification process which has identified several issues warranting further study. One of these relates to the combined effects of wave and iceberg collision Loading. At present, this Combination is treated by the use of a Load Combination Factor specified in the Code. The present paper describes a recent study which was undertaken to determine the appropriateness of the recommended value of the Load Combination Factor. The study involves a numerical analysis in which Loads due to waves alone, an iceberg alone, and an iceberg and waves in Combination have been calculated for a range of iceberg and wave parameters. These results have been applied to a first-order reliability analysis in order to study the force levels corresponding to an annual probability of 10−4 or to the onset of global sliding with an annual probability of 10...
Jun Kanda - One of the best experts on this subject based on the ideXlab platform.
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simplified Load Combination Factor for snow Load
Structural Safety, 1993Co-Authors: Jun KandaAbstract:Abstract The Load Combination Factor for snow Load is formulated by a simplified development based on Turkstra's rule for Load Combination and the Gumbel distribution for the snow Load model. The probability of exceedance expression is compared with an existing probabilistic Load model. The Load Combination Factor is expressed in terms of the period of snow duration and the ratio between the standard deviation of the principal Load effect and the accompanying snow Load effect. Numerical examples are presented and discussed with the Load Combination Factor used in Japanese current practice.
Martin Häglund - One of the best experts on this subject based on the ideXlab platform.
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Load Combination of moisture induced eigenstresses in timber
2020Co-Authors: Martin Häglund, Fredrik CarlssonAbstract:This paper presents and suggests a Load Combination Factor for moisture induced stress (MIS) when MIS and snow Load are combined. It is argued that MIS may be considered as an ordinary Load to be combined with other structural actions, for example snow Load. This outlook is not new but till now the Load Combination Factor issue has not been investigated. Based on measured snow depths and calculated MIS at four different locations in Sweden it is suggested that the Load Combination Factor for MIS is set to 0.2.
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Moisture Induced Stress Perpendicular to Grain in Timber Structures
2020Co-Authors: Martin HäglundAbstract:Timber structures and wooden element are in general affected by moisture and moisture variation in different ways. Their hygroscopic properties result in adsorption of water when wetted and in desorption when dried. Because the volume of wood is not constant but varies with the moisture content, uneven distribution of moisture will result in induced eigen-stresses because of internal restraint hygroexpansion. Since cross-sectional forces must self-balance, drying causes tensile and compressive stresses near the surface and the middle of a beam, respectively; the opposite applies for wetting. In the design of timber structures today, effects of moisture are considered in a rather summary way. A structural element is assigned to a certain service class and each class has its specific constant strength reduction Factor (i.e. the wetter the climate, the larger the reductions). Nevertheless, one concern with such a method it that noting is said about the moisture variation—the selection of service class is only based on anticipated moisture equilibrium levels. It is verified by experiment that moisture induced eigen-stress, which adds to the mechanical stress from external Loading, may cause stress fields that significantly reduce the Load bearing capacity. In view of the significant importance of moisture on the behavior of wood structures, there is an apparent lack of precise characterization of the climatic condition as a basis for design of timber structures. In order to improve design codes it has been suggested that moisture effects should may be considered as an action to be combined with other ordinary Loads (such as snow and live Load) instead of being recognized in form of strength reduction Factors. In order to further explore this line of suggestion, investigation of climatic conditions and determination of moisture and stress profiles were performed, and the outcome was evaluated by application of e.g. statistical extreme value analysis. This thesis presents background and new findings on moisture induced stress perpendicular to grain. The five appended papers address climate modeling, moisture penetration, development of eigen-stresses and consideration of moisture as an action. In short, some of the findings are: higher stress-levels are induced in larger cross-sections than in smaller ones, summer seasons cause more induced eigen-stresses than winter seasons, induced tensile stress can reach well above the characteristic strength (0.5 MPa), proper surface coating effectively reduces moisture gradients (and thus hinder potential stresses to fully develop), and finally, it is suggested that a Load Combination Factor for moisture induced stress should be equal to 0.2. (Less)