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Comfort G.,BMT Fleet Technology | Croasdale K.,KRCA Ltd.
International Conference and Exhibition on Performance of Ships and Structures in Ice 2012, ICETECH 2012 | Year: 2012

The ice load predictors in present codes tend to be empirical. The empirical relationships are heavily influenced by data from relatively small areas and thickness ranges. One uncertainty in applying the predictors is related to the effect of different contact zone geometries, as these variations tend to get "smeared" over the whole contact zone in the present empirical predictors. An approach (termed the Two-Zone Model) was developed to investigate the effect of various contact zone geometries on global loads and pressures. The contact zone was divided into two independent zones based on their proximity to a free edge. Lower pressures were prescribed for the Outer Zone on the presumption that these would be governed by spalling and flaking of the ice. Various approaches were explored to develop the Two-Zone Model to provide insights and identify sensitivities; and two Cases were used for sample analyses. The Two-Zone model was run for three scenarios producing significantly different contact zone geometries. Of course, the results are sensitive to the assumptions made regarding the pressures within, and the extents of, the Inner and Outer Zones. The work serves to highlight some of the uncertainties involved in estimating ice loads associated with severe ice-structure events. It is hoped that it will help to point a way forward for taking more direct account of the variations in contact zone geometries created by major ice-structure interaction scenarios. Further work in the form of both modelling improvements and large-scale measurements, would be beneficial to quantify the key inputs and relationships for the Two-Zone model. In fact, exercising this type of model helps to highlight the uncertainties and emphasizes the need for full-scale data at larger areas than measured to date and over a range of aspect ratios. Copyright ©2012 ICETECH 12. All rights reserved.


Pussegoda L.N.,BMT Fleet Technology | Tiku S.,BMT Fleet Technology | Tyson W.R.,CanmetMATERIALS | Park D.-Y.,CanmetMATERIALS | And 3 more authors.
Proceedings of the International Offshore and Polar Engineering Conference | Year: 2013

J-R and CTOD-R results were compared from multi-specimen and single-specimen procedures for toughness testing with SEN(T) specimens. Test procedures followed the multi-specimen method described in DNV-RP-F108, and a single-specimen recommended practice developed at CanmetMATERIALS. The latter uses CMOD unloading compliance to measure crack size. Tests were done in laboratories in Canada (BMT, CANMET) and in the UK (TWI). For Grade 483, BxB geometry with side grooves was adopted with the objective of comparison with results from the single-specimen method. The target fatigue precracking ao/W was about 0.5. The program employing Grade 690 used 2BxB geometry (DNV-RP-F108 & DNVOS- F101) for the multi-specimen tests and BxB geometry with side grooves for the single-specimen tests. The target ao/W was about 0.35. The paper describes experimental and analysis details, and compares results from the two techniques, using J expressions developed at CANMET for the BxB geometry. For the 2BxB geometry, comparison is made using both the CANMET and DNV-RP-F108 expressions for J. Copyright © 2013 by the International Society of Offshore and Polar Engineers (ISOPE).


Dinovitzer A.,BMT Fleet Technology | Fredj A.,BMT Fleet Technology | Sen M.,Enbridge Inc.
Proceedings of the Biennial International Pipeline Conference, IPC | Year: 2014

A major slope in southern Manitoba has been experiencing deep seated movements of approximately 60mm per year. This 24m high x 85m long slope contains a pipeline right of way with five large diameter crude oil lines that were constructed from 1950 - 1998. It is estimated that the slope has moved up to 3 meters since the pipeline installations. Management of the effects of this slope movement on the pipelines has involved cross-functional strategies that include geotechnical, integrity, and stress evaluations. A finite element analysis (FEA), which considers the interaction between the soil movement and pipeline, was generated to evaluate the pipeline stresses caused by the slope movements to date. The results indicated that the strain capacity on one of the pipelines may be near its limit. Correspondingly and in order to be conservative, a stress relief was conducted on three of the pipelines within the right-of-way. This mitigation involved excavating the pipelines 360 degrees which allowed for their decoupling from the surrounding soil, and the associated pipeline spring back was surveyed. Prior to backfilling, a low friction geotextile was installed around the excavated pipelines to help mitigate future movements. Drainage improvements and a toe berm were also installed to improve the slope stability. Several strain measurement technologies that have been the subject of previous Pipeline Research Council projects were also installed at the site. Stress probe measurements were taken before and after the stress relief; a fiber optic cable was installed; inline inspection bending strain measurements were analyzed; and the FEA analysis was used to model the strains before and after the stress relief. All of these technologies are compared to the measurements from strain gauges that were read both before and after the stress reliefs were conducted. Copyright © 2014 by ASME.


Pussegoda L.N.,BMT Fleet Technology | Semiga V.,BMT Fleet Technology
Proceedings of the Biennial International Pipeline Conference, IPC | Year: 2010

An in-service failure was associated with an NPS 12, 6.35 nominal wall API 5L X42 grade pipe. This segment of the pipeline had been in service since 1957 and had a tar coating. The pipe was manufactured by piercing followed by rolling/extrusion to produce a seamless pipe. The pipeline has always carried refined petroleum products. The rupture event was captured by pressure history records that recorded an overpressure experienced during a sudden valve closure event. The section of pipe removed included portions of the upstream and downstream pipe sections to carryout a failure investigation. The paper presents the findings from the investigation. The paper presents the observations from inspection and experimental testing carried out on the removed pipe section. These included NDE, fracture surface examinations and destructive examination such as metallography that helped in obtaining information on the reduction in the resistance of the material to withstand the in-service pressure conditions. The above observations together with results from mechanical testing was used to estimate failure pressures based on a "deterministic" primary flaw size, using assessment methods (ECA) applicable to the failure case under consideration. The investigation of the failure indicated that the major contributing factors were: (a) the corrosion feature at the failure site that reduced the remaining wall thickness below 2mm, and the overpressure caused by the valve closure down stream in the vicinity of the failure site. Pipe specification checks from material removed from the section of the failed pipe, indicate that the pipe meets the API 5L X42 specification requirements. Copyright © 2010 by ASME.


Fredj A.,BMT Fleet Technology | Dinovitzer A.,BMT Fleet Technology
Proceedings of the Biennial International Pipeline Conference, IPC | Year: 2010

Understanding the effect of soil-pipeline interactions in the event of large ground movement is an important consideration for pipeline designer. Both experimental investigation and computational analyses play significant roles in this research. As part of this effort, a framework incorporating continuum soil mechanics and advanced finite element approach (i.e., ALE and SPH method) for modeling soil pipe interaction is developed. The overall objective is to develop, validate and apply 3D continuum modeling technique to assess the performance of pipeline system subjected to large soil displacement. The numerical models than may be used to predict the wrinkle formation and post formation behavior of the pipeline considering the effect of the soil confinement, and develop a comprehensive wrinkle integrity assessment process. This is the second paper (Part II) in a series of two papers. In the first paper a three-dimensional Continuum models using MM-ALE (Multi-material Arbitrary Eulerian Lagrangian) and SPH (smooth particle hydrodynamics) approaches are developed and run using LS-DYNA. The results are compared with published experimental data of large-scale test to verify the numerical analysis methods. In this paper (Part II) the effects of soil restraint on the response of the pipe/soil systems (e.g., pipeline Wrinkle and buckle, strain demand) are discussed. Copyright © 2010 by ASME.


Fredj A.,BMT Fleet Technology | Dinovitzer A.,BMT Fleet Technology
Proceedings of the Biennial International Pipeline Conference, IPC | Year: 2010

Understanding the effect of soil-pipeline interactions in the event of large ground movement is an important consideration for the pipeline designer. Both experimental investigation and computational analyses play significant roles in soil-pipeline research. As part of this effort, a framework incorporating continuum soil mechanics and advanced finite element approach (i.e., ALE and SPH method) for modeling soil pipe interaction was constructed. The overall objective of this work is to develop, validate and apply 3D continuum modeling techniques to assess the performance of pipeline systems subjected to large soil displacements. The numerical models produced may subsequently be used to predict the wrinkle formation and post formation behavior of the pipeline considering the effect of the soil confinement. The aim is to develop a comprehensive wrinkle integrity assessment process. This is the first paper (Part I) in a series of two papers. In this paper a three-dimensional Continuum models using MMALE (Multi-material Arbitrary Eulerian Lagrangian) and SPH (smooth particle hydrodynamics) approaches are developed and employed using LS-DYNA. The results are compared with published experimental data of large-scale tests to verify the numerical analysis methods. In the second paper (Part II) the effects of soil restraint on the response of the pipe/soil systems (e.g., pipeline wrinkle and buckle, strain demand) are discussed. Copyright © 2010 by ASME.


Judson B.,BMT Fleet Technology
Proceedings of the International Offshore and Polar Engineering Conference | Year: 2010

Significant research on Arctic sea ice trends and the potential for resource development have been well documented and illustrated as drivers for changes to Arctic shipping traffic patterns. There is a strong awareness of the potential risks to the environment such as an oil spill in ice as well as impacts on traditional human activity. Similarly, there is awareness that there will be a demand for increased navigation services such as aids to navigation, charting and emergency response capacity. However, many questions remain about what impact sea ice trends and resource development have had on shipping and accidents. To date, the Arctic Marine Shipping Assessment (AMSA) project has provided a snapshot of Arctic shipping traffic patterns and activity for the year 2004 and suggests a further research opportunity exists to conduct a trend analysis of shipping activity. The AMSA report suggests that "As marine activity continues to expand in the Arctic, statistical trends indicate that the potential risk of vessel mishaps and marine pollution incidents also increases" (Arctic Council, 2009). However, this is not necessarily the case where risks are managed. Accident trends in the Canadian Arctic suggest that safety management, vessel design and navigation experience have had positive impacts and one must look more closely at specific areas of operation, vessel types and activity to identify opportunities to improve risk management including both prevention and response. So the question remains "What can we learn from recent trends in vessel traffic and accident rates to better understand potential navigation impacts in the future?" Using the AMSA Shipping Database (Arctic Council, 2009) and a spatial trend analysis of Canadian Arctic shipping traffic and vessel accident rates covering the period 1987 to 2008, this paper will report on preliminary findings, show where accident rates are increasing and decreasing, provide traffic trends for each Shipping Safety Control Zone, help to dispel a few myths, and possibly confirm other rumours. Copyright © 2010 by The International Society of Offshore and Polar Engineers (ISOPE).


Judson B.,BMT Fleet Technology
International Conference and Exhibition on Performance of Ships and Structures in Ice 2010, ICETECH 2010 | Year: 2010

Significant research on Arctic sea ice trends and the potential for resource development have been well documented and illustrated as drivers for changes to Arctic shipping traffic patterns. There is a strong awareness of the potential risks to the environment such as an oil spill in ice as well as impacts on traditional human activity. Similarly, there is awareness that there will be a demand for increased navigation services such as aids to navigation, charting and emergency response capacity. However, many questions remain about what impact sea ice trends and resource development have had on shipping and accidents. To date, the Arctic Marine Shipping Assessment (AMSA) project has provided a snapshot of Arctic shipping traffic patterns and activity for the year 2004 and suggests a further research opportunity exists to conduct a trend analysis of shipping activity. The AMSA report suggests that "As marine activity continues to expand in the Arctic, statistical trends indicate that the potential risk of vessel mishaps and marine pollution incidents also increases" (Arctic Council, 2009). However, this is not necessarily the case where risks are managed. Accident trends in the Canadian Arctic suggest that safety management, vessel design and navigation experience have had positive impacts and one must look more closely at specific areas of operation, vessel types and activity to identify opportunities to improve risk management including both prevention and response. So the question remains "What can we learn from recent trends in vessel traffic and accident rates to better understand potential navigation impacts in the future?" Using the AMSA Shipping Database (Arctic Council, 2009) and a spatial trend analysis of Canadian Arctic shipping traffic and vessel accident rates covering the period 1987 to 2008, this paper will report on preliminary findings, show where accident rates are increasing and decreasing, provide traffic trends for each Shipping Safety Control Zone, help to dispel a few myths, and possibly confirm other rumours. Copyright ©2010 ICETECH 10. All rights reserved.


Dinovitzer A.,BMT Fleet Technology
Engineering and Technology | Year: 2010

Welding has become a high-tech process that needs sophisticated procedures, strong technical back-up and a new way of thinking. The common weld is a much maligned beast. Despite the layman's preconception that welding is a rough, unsubtle industrial process, it is actually a complex procedure with many parameters affecting the result.


Fredj A.,BMT Fleet Technology | Dinovitzer A.,BMT Fleet Technology
Proceedings of the Biennial International Pipeline Conference, IPC | Year: 2014

Pipelines installed on active slopes can be exposed to slope failure mechanisms. The soil movement can introduce substantial axial and bending strains on buried pipeline, and possibly damage. The techniques to predict pipeline displacements, loads, stress or strains are not well described in design standards or codes of practice. The practice of using finite element analysis of soil-pipe interaction has developed in recent years and is proving to be a useful tool in evaluating the pipeline behavior in response to slope movement. A description of advanced pipe soil interaction modeling tools and their validation against full scale trails has been previously presented. This paper describes the ongoing work involved in a study investigating the mechanical behavior of buried pipelines interacting with active slope movement and evaluation of pipeline strain demand. Detailed pipe-soil interaction analyses were completed with a 3D continuum SPH (Smooth Particle Hydrodynamic) model to examine the pipeline behavior and evaluate the pipeline strain demand in relation to key parameters. This includes the effect of soil movement mechanism, pipeline geometry (D/t), material grade, pipeline burial depth and soil conditions and properties. Sample results of the application of the validated 3D continuum modeling process will be presented. The strain demand determined from the analyses were compared with calculated CSA-Z662 strain limit design, local FEA analyses and BS 7910. These results are being used to develop generalized trends in pipeline response to slope movements. Copyright © 2014 by ASME.

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