Monopiles are the most common foundation type in the offshore wind industry. Their design is largely dependent on the ability to accurately model the soil-structure response of the foundation, with more refined modelling approaches enabling significant reductions in required embedment depth, fabrication cost and installation risk. The PISA joint industry project (JIP) has been completed in recent years with the objectives of developing a more refined soil-structure response modelling method compared to other available methods such as the API p-y curve approach. The scope of this paper is to detail how the PISA recommendations have been implemented on a real offshore wind farm project located in the UK North Sea, identifying how the findings can be incorporated into a combined geotechnical and structural analysis approach to enable efficient serial design of multiple foundations for wind turbines. The paper presents how existing design processes and criteria can be modified to take into account the recommendations of the PISA JIP for use in design. Discussion will be provided on the following procedures: calibration of the PISA 1-D soil response formulations to site specific conditions; the combination of the homogeneous sand and clay formulations to accurately model soil-structure response in layered soil profiles; and, consideration of the effects of cyclic loading in conjunction with the use of the PISA monotonic soil response formulations. Results will be presented to demonstrate the calibration of the PISA 1-D soil response formulations to a layered soil site. Discussion will also be provided on the significant monopile lengths savings achieved when using a PISA approach compared to an API p-y curve approach. The monopile mass reduction will be illustrated against trends derived from installed monopiles. Observations will be provided on how the use of a PISA based approach can affect the governing design cases and how this is likely to impact on monopile design for future projects. Discussions and conclusions will also be presented on the challenges of implementing the PISA recommendations in monopile design for real projects and what additional work is required to enable further costs savings in implementing the new design approach. The PISA JIP recommendations are the cutting edge in monopile foundation design. The paper will provide discussion on how these recommendations can be effectively implemented in design based on experience from the foundation design for a real offshore wind farm. The wind farm in question will be one of the first constructed for which foundations have been designed using a PISA based method, demonstrating the significant CAPEX savings possible using the PISA approach.
{"title":"Application of the Findings of the PISA Joint Industry Project in the Design of Monopile Foundations for a North Sea Wind Farm","authors":"S. Manceau, R. Mclean, Anna Sia, M. Soares","doi":"10.4043/29557-MS","DOIUrl":"https://doi.org/10.4043/29557-MS","url":null,"abstract":"\u0000 Monopiles are the most common foundation type in the offshore wind industry. Their design is largely dependent on the ability to accurately model the soil-structure response of the foundation, with more refined modelling approaches enabling significant reductions in required embedment depth, fabrication cost and installation risk. The PISA joint industry project (JIP) has been completed in recent years with the objectives of developing a more refined soil-structure response modelling method compared to other available methods such as the API p-y curve approach. The scope of this paper is to detail how the PISA recommendations have been implemented on a real offshore wind farm project located in the UK North Sea, identifying how the findings can be incorporated into a combined geotechnical and structural analysis approach to enable efficient serial design of multiple foundations for wind turbines.\u0000 The paper presents how existing design processes and criteria can be modified to take into account the recommendations of the PISA JIP for use in design. Discussion will be provided on the following procedures: calibration of the PISA 1-D soil response formulations to site specific conditions; the combination of the homogeneous sand and clay formulations to accurately model soil-structure response in layered soil profiles; and, consideration of the effects of cyclic loading in conjunction with the use of the PISA monotonic soil response formulations.\u0000 Results will be presented to demonstrate the calibration of the PISA 1-D soil response formulations to a layered soil site. Discussion will also be provided on the significant monopile lengths savings achieved when using a PISA approach compared to an API p-y curve approach. The monopile mass reduction will be illustrated against trends derived from installed monopiles. Observations will be provided on how the use of a PISA based approach can affect the governing design cases and how this is likely to impact on monopile design for future projects. Discussions and conclusions will also be presented on the challenges of implementing the PISA recommendations in monopile design for real projects and what additional work is required to enable further costs savings in implementing the new design approach.\u0000 The PISA JIP recommendations are the cutting edge in monopile foundation design. The paper will provide discussion on how these recommendations can be effectively implemented in design based on experience from the foundation design for a real offshore wind farm. The wind farm in question will be one of the first constructed for which foundations have been designed using a PISA based method, demonstrating the significant CAPEX savings possible using the PISA approach.","PeriodicalId":11149,"journal":{"name":"Day 1 Mon, May 06, 2019","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81440485","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}
T. A. Masters, P. Juszkiewicz, A. Mandolini, H. Christian
Soil stiffness is a key criterion in the design of OWT foundations. The necessity for the development of accurate in-situ small strain moduli profiles has led to an increased interest in using Seismic CPT (SCPT) and P-S Suspension logging. This paper describes both methods, weighs up the relative benefits (and limitations) and identifies the obstacles experienced in the data processing in order to gain reliable results. The accuracy of the techniques is evaluated through the site investigations for wind farm developments and compared against shear moduli derived from advanced laboratory tests on the soil element. The relative performance is made more complicated by the location of the investigation, often including placing additional equipment on the seafloor (in the case of SCPT) and having to work with heave compensated systems. P-S waves were found to be affected by the borehole conditions in terms of borehole diameter, irregularity of its walls (rugosity and/roughness), cavitation issues, fractures and ambient noises (especially at shallow depth), as well as borehole stability. The analysis of the results confirmed that both in-situ testing methods have promising potential in the evaluation of soil stiffness with higher characteristic values being derived than those by laboratory testing, leading to potential foundation cost reduction. There are distinct benefits achievable by performing seismic tests in-situ.
{"title":"A Critical Appraisal of the Benefits of and Obstacles to Gaining Quality Data with Offshore Seismic CPT and P-S Logging.","authors":"T. A. Masters, P. Juszkiewicz, A. Mandolini, H. Christian","doi":"10.4043/29485-MS","DOIUrl":"https://doi.org/10.4043/29485-MS","url":null,"abstract":"\u0000 Soil stiffness is a key criterion in the design of OWT foundations. The necessity for the development of accurate in-situ small strain moduli profiles has led to an increased interest in using Seismic CPT (SCPT) and P-S Suspension logging. This paper describes both methods, weighs up the relative benefits (and limitations) and identifies the obstacles experienced in the data processing in order to gain reliable results. The accuracy of the techniques is evaluated through the site investigations for wind farm developments and compared against shear moduli derived from advanced laboratory tests on the soil element. The relative performance is made more complicated by the location of the investigation, often including placing additional equipment on the seafloor (in the case of SCPT) and having to work with heave compensated systems. P-S waves were found to be affected by the borehole conditions in terms of borehole diameter, irregularity of its walls (rugosity and/roughness), cavitation issues, fractures and ambient noises (especially at shallow depth), as well as borehole stability. The analysis of the results confirmed that both in-situ testing methods have promising potential in the evaluation of soil stiffness with higher characteristic values being derived than those by laboratory testing, leading to potential foundation cost reduction. There are distinct benefits achievable by performing seismic tests in-situ.","PeriodicalId":11149,"journal":{"name":"Day 1 Mon, May 06, 2019","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82899667","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}
M. Gassert, V. Calabrese, G. Paccagnella, A. Fazio, Nicola Galisai, F. Argento, T. Castellitto, S. Magi, G. Citi, Lorenzo Infusino, F. Rollo
The scope of the paper is to further present and discuss, in continuation of OTC-28839-MS paper, the results of our technology development program regarding very long oil tiebacks architectures (50-100km) and enabling technologies. It is arrived the time when long tieback solutions are considered for real development projects. The paper will describe how those technological solutions compare with more conventional development schemes in concept selection phases and how our Operating Company is getting prepared for potential implementation. The paper will review key enabling technologies, together with their readiness level and discuss drivers for integration and operation. Sizing references will be presented as a result of Front End Engineering and Design activities developed for real project development opportunities. Technical performances will be discussed and technical-economic indicators will be provided. Risks during development and production will be analyzed and mitigation will be evaluated. A combination of heated high thermal performance flowlines, subsea multiphase boosting, subsea power management, innovative preservation procedures, newest subsea production components together with a reliable integrated control system and digital technologies are the key enablers of a very long tieback solution that may work as kind of highways to bring back production of a whole area to a production hub. Technically the way to go and the gap to cross appear manageable in mid to short terms opening new opportunities for deepwater asset development. It appears now possible to reduce deepwater development costs by increasing the distance between new assets and existing production hubs, shallow water areas or even connecting those assets to shore.
{"title":"Deepwater Opportunities Extra Long Oil Tiebacks Developments","authors":"M. Gassert, V. Calabrese, G. Paccagnella, A. Fazio, Nicola Galisai, F. Argento, T. Castellitto, S. Magi, G. Citi, Lorenzo Infusino, F. Rollo","doi":"10.4043/29265-MS","DOIUrl":"https://doi.org/10.4043/29265-MS","url":null,"abstract":"\u0000 \u0000 \u0000 The scope of the paper is to further present and discuss, in continuation of OTC-28839-MS paper, the results of our technology development program regarding very long oil tiebacks architectures (50-100km) and enabling technologies. It is arrived the time when long tieback solutions are considered for real development projects. The paper will describe how those technological solutions compare with more conventional development schemes in concept selection phases and how our Operating Company is getting prepared for potential implementation.\u0000 \u0000 \u0000 \u0000 The paper will review key enabling technologies, together with their readiness level and discuss drivers for integration and operation. Sizing references will be presented as a result of Front End Engineering and Design activities developed for real project development opportunities. Technical performances will be discussed and technical-economic indicators will be provided. Risks during development and production will be analyzed and mitigation will be evaluated.\u0000 \u0000 \u0000 \u0000 A combination of heated high thermal performance flowlines, subsea multiphase boosting, subsea power management, innovative preservation procedures, newest subsea production components together with a reliable integrated control system and digital technologies are the key enablers of a very long tieback solution that may work as kind of highways to bring back production of a whole area to a production hub. Technically the way to go and the gap to cross appear manageable in mid to short terms opening new opportunities for deepwater asset development.\u0000 \u0000 \u0000 \u0000 It appears now possible to reduce deepwater development costs by increasing the distance between new assets and existing production hubs, shallow water areas or even connecting those assets to shore.\u0000","PeriodicalId":11149,"journal":{"name":"Day 1 Mon, May 06, 2019","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75101219","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}
Emerging inspection technologies, tools and platforms such as unmanned aerial vehicles (UAVs), remotely operated vehicles (ROVs), robotic crawlers, and wearable/handheld devices are creating actionable data to help enable more informed decision making and improve process efficiency during survey and inspection related activities. This paper will discuss ABS’ initiatives to further understand and help define the use of and the integration of these tools and technologies to support the evolution of the maritime industry's transition to digitalization. ABS, in conjunction with technology equipment manufacturers and service providers, has been conducting feasibility trials to evaluate the pragmatic application and implementation of these technologies to support Class surveys. These trials have focused on areas such as the detection of coating breakdowns using high-definition optics to aid in close-up visual inspections (CVI) and leveraging mobile platforms (wearable and handheld devices) in conjunction with a collaborative software platform to execute survey activities virtually in real-time (connected) or near real-time (disconnected), capturing data as required by Class Rules. In support of these trials, ABS is actively involved in a joint development project (JDP) with academia focusing on the realization of image recognition (artificial Intelligence [AI]) into the survey decision-making process. As part of this JDP, an AI software was developed incorporating thousands of damaged structural coating images. These images were used for the training, testing and evaluation of the software's image recognition capabilities. This paper discusses the results of the feasibility trials and the next steps in the digital evolution for Classification Society activities. Potential applications include but are not limited to: condition-based/remote surveys, evaluation of maintenance programs, development of 3D models with 3D scanning/image data capture, documentation auditing, and corrosion mapping of steel plates.
{"title":"Emerging Inspection Technologies – Enabling Remote Surveys/Inspections","authors":"Feng Wen, J. Pray, K. McSweeney, Hai Gu","doi":"10.4043/29450-MS","DOIUrl":"https://doi.org/10.4043/29450-MS","url":null,"abstract":"\u0000 Emerging inspection technologies, tools and platforms such as unmanned aerial vehicles (UAVs), remotely operated vehicles (ROVs), robotic crawlers, and wearable/handheld devices are creating actionable data to help enable more informed decision making and improve process efficiency during survey and inspection related activities. This paper will discuss ABS’ initiatives to further understand and help define the use of and the integration of these tools and technologies to support the evolution of the maritime industry's transition to digitalization.\u0000 ABS, in conjunction with technology equipment manufacturers and service providers, has been conducting feasibility trials to evaluate the pragmatic application and implementation of these technologies to support Class surveys. These trials have focused on areas such as the detection of coating breakdowns using high-definition optics to aid in close-up visual inspections (CVI) and leveraging mobile platforms (wearable and handheld devices) in conjunction with a collaborative software platform to execute survey activities virtually in real-time (connected) or near real-time (disconnected), capturing data as required by Class Rules.\u0000 In support of these trials, ABS is actively involved in a joint development project (JDP) with academia focusing on the realization of image recognition (artificial Intelligence [AI]) into the survey decision-making process. As part of this JDP, an AI software was developed incorporating thousands of damaged structural coating images. These images were used for the training, testing and evaluation of the software's image recognition capabilities.\u0000 This paper discusses the results of the feasibility trials and the next steps in the digital evolution for Classification Society activities. Potential applications include but are not limited to: condition-based/remote surveys, evaluation of maintenance programs, development of 3D models with 3D scanning/image data capture, documentation auditing, and corrosion mapping of steel plates.","PeriodicalId":11149,"journal":{"name":"Day 1 Mon, May 06, 2019","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79573820","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}
Jack Vincent, Nazli Deniz Sevinc, Neil Andrew Herbst
Autonomous Underwater Vehicles (AUVs) have shown promise to disrupt Inspection, Maintenance, and Repair (IMR) activities typically performed by Remotely Operated Vehicles (ROVs) tethered to large, expensive vessels on the surface. There are many concepts and projects within oil and gas that are focused in utilizing the efficiencies of these AUVs in novel deployment framework. A novel autonomous vehicle platform in this domain is being developed called uROV (untethered ROV). The uROV vision has three main elements to bring to the IMR market. The first is to develop efficient deployment solutions such that IMR vessel expenditure is reduced or removed. The second is to bring next generation sensing technology to the market and integrate into the uROV platform. This is aimed at collecting better and more insightful data to use for integrity evaluation. The third main element is to bring digital enablement to the market through connectivity, data process automation, and visualization.
{"title":"uROV – The Next Generation IMR Platform Utilizing Supervised Autonomy","authors":"Jack Vincent, Nazli Deniz Sevinc, Neil Andrew Herbst","doi":"10.4043/29586-MS","DOIUrl":"https://doi.org/10.4043/29586-MS","url":null,"abstract":"\u0000 Autonomous Underwater Vehicles (AUVs) have shown promise to disrupt Inspection, Maintenance, and Repair (IMR) activities typically performed by Remotely Operated Vehicles (ROVs) tethered to large, expensive vessels on the surface. There are many concepts and projects within oil and gas that are focused in utilizing the efficiencies of these AUVs in novel deployment framework.\u0000 A novel autonomous vehicle platform in this domain is being developed called uROV (untethered ROV). The uROV vision has three main elements to bring to the IMR market. The first is to develop efficient deployment solutions such that IMR vessel expenditure is reduced or removed. The second is to bring next generation sensing technology to the market and integrate into the uROV platform. This is aimed at collecting better and more insightful data to use for integrity evaluation. The third main element is to bring digital enablement to the market through connectivity, data process automation, and visualization.","PeriodicalId":11149,"journal":{"name":"Day 1 Mon, May 06, 2019","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79296575","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}
Corrosion protection is a key aspect of all subsea developments. Indeed the complexity of subsea pipe maintenance and repair makes it necessary to provide solutions suitable for the full life time of the field. Though sensitive applications such as production lines transporting corrosive compounds, CO2 and H2S for instance, immediately comes to mind when mentioning corrosion, other applications, though seemingly less demanding, also require to be properly addressed from a corrosion perspective. One of these applications is water injection lines. Corrosion in these lines is usually tackled with using a wide range of approaches depending on operation philosophy: topside treatment, corrosion allowance, cladding or plastic liners. A balance usually has to be found between how extensively the injected water is processed topsides and what other corrosion mitigations methods are deployed. This assessment should be carefully conducted the selected approach will impact procurement and installation costs. For instance, increasing the pipe wall thickness to cope with corrosion would results in higher lay vessel installation capabilities as well as longer welding time while relying on clad pipes would negatively impact procurement costs and require more complex NDT methods to be implemented. Plastic liners offer a relevant alternative though their implementation has to be carefully assessed so as to ensure it remains cost competitive. To that extent, the Fusion Bonded Joint has been developed and qualified. This system ensures the continuity of the plastic layer at carbon steel weld locations while limiting the offshore cycle time thus preserving lay rates of the installation vessel. This paper includes an overview the technology itself as well as a summary of the extensive qualification campaign that has been carried out. A global overview of the testing campaign will be provided from the early stages of the development to the full scale testing of the technology in an environment representative of its actual operating conditions. Topics discussed will include: prototyping of the system and associated tools, qualification of the electro-fusion welding process as well as its control and qualification of the carbon steel welding process. The main challenges and outcomes of tests performed will be presented and discussed. A focus on the specificities of the fatigue testing campaign will be presented including fatigue string design as well as fatigue performance of plastic electro-fusion weld. Eventually, the applicability of the FBJ to reeling will be discussed.
{"title":"The Fusion Bonded Joint: A New Way of Joining HDPE Lined Pipes for Reeling and Fatigue Sensitive Applications","authors":"F. Lirola","doi":"10.4043/29592-MS","DOIUrl":"https://doi.org/10.4043/29592-MS","url":null,"abstract":"\u0000 Corrosion protection is a key aspect of all subsea developments. Indeed the complexity of subsea pipe maintenance and repair makes it necessary to provide solutions suitable for the full life time of the field. Though sensitive applications such as production lines transporting corrosive compounds, CO2 and H2S for instance, immediately comes to mind when mentioning corrosion, other applications, though seemingly less demanding, also require to be properly addressed from a corrosion perspective. One of these applications is water injection lines.\u0000 Corrosion in these lines is usually tackled with using a wide range of approaches depending on operation philosophy: topside treatment, corrosion allowance, cladding or plastic liners. A balance usually has to be found between how extensively the injected water is processed topsides and what other corrosion mitigations methods are deployed. This assessment should be carefully conducted the selected approach will impact procurement and installation costs. For instance, increasing the pipe wall thickness to cope with corrosion would results in higher lay vessel installation capabilities as well as longer welding time while relying on clad pipes would negatively impact procurement costs and require more complex NDT methods to be implemented.\u0000 Plastic liners offer a relevant alternative though their implementation has to be carefully assessed so as to ensure it remains cost competitive. To that extent, the Fusion Bonded Joint has been developed and qualified. This system ensures the continuity of the plastic layer at carbon steel weld locations while limiting the offshore cycle time thus preserving lay rates of the installation vessel.\u0000 This paper includes an overview the technology itself as well as a summary of the extensive qualification campaign that has been carried out. A global overview of the testing campaign will be provided from the early stages of the development to the full scale testing of the technology in an environment representative of its actual operating conditions. Topics discussed will include: prototyping of the system and associated tools, qualification of the electro-fusion welding process as well as its control and qualification of the carbon steel welding process. The main challenges and outcomes of tests performed will be presented and discussed. A focus on the specificities of the fatigue testing campaign will be presented including fatigue string design as well as fatigue performance of plastic electro-fusion weld. Eventually, the applicability of the FBJ to reeling will be discussed.","PeriodicalId":11149,"journal":{"name":"Day 1 Mon, May 06, 2019","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85546609","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}
Defense POW/MIA Accounting Agency's (DPAA) mission, the fullest possible accounting of our nation's defense personnel lost in action, drives all agency direction. This includes novel applications of multidisciplinary solutions towards maximizing agency capabilities. By building collaborations and harnessing applications for advancing technology, DPAA's Partnerships and Innovations Directorate has been a key facilitator for implementing this imperative and has proven the benefit to challenging the operational status quo. The partnership paradigm represents a game-changing model that forces stakeholders to think differently and creatively, and ultimately deviate from traditional operations.
{"title":"Implementing Innovation: Partnerships and Problem-Solving in the Defense POW/MIA Accounting Agency","authors":"Kara E Davis, Jeneva Wright","doi":"10.4043/29388-MS","DOIUrl":"https://doi.org/10.4043/29388-MS","url":null,"abstract":"\u0000 Defense POW/MIA Accounting Agency's (DPAA) mission, the fullest possible accounting of our nation's defense personnel lost in action, drives all agency direction. This includes novel applications of multidisciplinary solutions towards maximizing agency capabilities. By building collaborations and harnessing applications for advancing technology, DPAA's Partnerships and Innovations Directorate has been a key facilitator for implementing this imperative and has proven the benefit to challenging the operational status quo. The partnership paradigm represents a game-changing model that forces stakeholders to think differently and creatively, and ultimately deviate from traditional operations.","PeriodicalId":11149,"journal":{"name":"Day 1 Mon, May 06, 2019","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90168169","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}
This study describes the purpose, scope, and acceptance criteria for wind load assessments that are used in the Classification of offshore units and installations. Wind loadings are applied as external environmental forces when evaluating afloat stability, structural strength, and mooring system integrity for mobile offshore units and site-specific installations. Existing criteria in the Rules and industry standards are identified to show the usage of the wind loads and their varying characterization depending on purpose, such as time averaging period and vertical speed distribution. The current requirements are placed in historical context based on the development of the offshore Classification Rules over the last 50 years, and the evolution of tools and technology to carry out the computations over that period are discussed. Practical aspects of calculation and independent analysis are illustrated by applying the standard methodologies in example calculations, using a geometric model that is of similar layout and complexity compared to existing offshore units. Sample calculations are presented as typically performed by Class in an independently developed model, and sensitivity analysis is used to point out areas where results may diverge depending on the approach by the assessor. The effect of these modeling decisions to evaluate wind moment is put in perspective by showing the change in the allowable vertical center of gravity, which relates directly to the deck load capacity of the platform. The result is a consolidated illustration of the Classification methodology for wind load analysis, which has been uniformly applied to a large number of offshore units and installations over a significant period of time. The importance of common assumptions and approach is highlighted, based on the effect that varying certain parameters has on overall results of the wind load calculation. The resulting impact of wind load changes on the stability, mooring, or structural analysis will be further shown. This will assist in providing visibility to industry on what constitutes a complete report of the wind loads for Classification purposes, how detailed a model should be for basic and detail design purposes, and how to improve confidence in the submission and approval process during design.
{"title":"A Class Perspective for Wind Load Assessment","authors":"A. Guha, S. Boppudi, J. Rousseau","doi":"10.4043/29465-MS","DOIUrl":"https://doi.org/10.4043/29465-MS","url":null,"abstract":"\u0000 This study describes the purpose, scope, and acceptance criteria for wind load assessments that are used in the Classification of offshore units and installations. Wind loadings are applied as external environmental forces when evaluating afloat stability, structural strength, and mooring system integrity for mobile offshore units and site-specific installations. Existing criteria in the Rules and industry standards are identified to show the usage of the wind loads and their varying characterization depending on purpose, such as time averaging period and vertical speed distribution. The current requirements are placed in historical context based on the development of the offshore Classification Rules over the last 50 years, and the evolution of tools and technology to carry out the computations over that period are discussed.\u0000 Practical aspects of calculation and independent analysis are illustrated by applying the standard methodologies in example calculations, using a geometric model that is of similar layout and complexity compared to existing offshore units. Sample calculations are presented as typically performed by Class in an independently developed model, and sensitivity analysis is used to point out areas where results may diverge depending on the approach by the assessor. The effect of these modeling decisions to evaluate wind moment is put in perspective by showing the change in the allowable vertical center of gravity, which relates directly to the deck load capacity of the platform.\u0000 The result is a consolidated illustration of the Classification methodology for wind load analysis, which has been uniformly applied to a large number of offshore units and installations over a significant period of time. The importance of common assumptions and approach is highlighted, based on the effect that varying certain parameters has on overall results of the wind load calculation. The resulting impact of wind load changes on the stability, mooring, or structural analysis will be further shown. This will assist in providing visibility to industry on what constitutes a complete report of the wind loads for Classification purposes, how detailed a model should be for basic and detail design purposes, and how to improve confidence in the submission and approval process during design.","PeriodicalId":11149,"journal":{"name":"Day 1 Mon, May 06, 2019","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90603857","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}
Amy E. Gusick, J. Maloney, Roslynn B. King, T. Braje
As applications for offshore renewable energy projects increase, state and federal land managers have become concerned over potential impacts to cultural heritage resources along submerged landscapes. Identification, documentation, and management of historical shipwrecks have been relatively common, but methods for identifying submerged pre-contact archaeological deposits are developing in many coastal regions of the continental United States. Permitting agencies in certain regions along the Gulf of Mexico and the Atlantic Ocean typically require management plans that include mitigation measures for submerged archaeological sites. Over the last decade, resource managers along Pacific Coast regions have become increasingly aware of the need for submerged archaeological site protection. This is especially important since the eastern Pacific continental shelf has become a focal point in the search for late Pleistocene migrations into the Americas and other evidence of pre-contact habitation in coastal regions since the Last Glacial Maximum (LGM). Integral to this search is the identification of submerged Pleistocene landforms that may favor preservation of pre-contact archaeological sites. Stemming from this, our multidisciplinary and multi-institutional effort includes marine geologists, marine biologists, and archaeologists synthesizing existing data using GIS models, and collecting new side scan sonar, CHIRP, and multibeam bathymetry data ground truthed with marine sediment cores. This methodology for the identification of submerged archaeological deposits is not new; however, the landscape approach that defines our research, and our focus on understanding paleolandscapes using modeling, sonar survey, and marine coring is the first of its kind on the eastern Pacific continental shelf. The goal of our project is to develop an archaeological sensitivity model, which the Bureau of Ocean Energy Management can consult in the offshore energy permitting process. As such, we are building our model using data from California’s Northern Channel Islands and testing the model along Oregon’s central coast. Results suggest that with the right technologies, sensitive landscape features such as paleochannels, paleoestuaries, and offshore tar seeps – all features used by Native American communities during the late Pleistocene and Holocene along the Pacific Coast – can be identified and used to model sensitive archaeological landscapes. We also are testing the efficacy of controlled-source marine electromagnetic methods in conjunction with sonar survey data for the identification of tar seeps, paleochannels, and buried archaeological shell midden deposits. This combined methodological approach is unique to North America’s Pacific Coast and represents a pioneering effort in the search for submerged archaeological deposits, which will help identify, document, and preserve underwater cultural heritage resources.
{"title":"Emerging Technologies in the Search for the Submerged Cultural Landscapes of the Pacific Continental Shelf","authors":"Amy E. Gusick, J. Maloney, Roslynn B. King, T. Braje","doi":"10.4043/29221-MS","DOIUrl":"https://doi.org/10.4043/29221-MS","url":null,"abstract":"\u0000 As applications for offshore renewable energy projects increase, state and federal land managers have become concerned over potential impacts to cultural heritage resources along submerged landscapes. Identification, documentation, and management of historical shipwrecks have been relatively common, but methods for identifying submerged pre-contact archaeological deposits are developing in many coastal regions of the continental United States. Permitting agencies in certain regions along the Gulf of Mexico and the Atlantic Ocean typically require management plans that include mitigation measures for submerged archaeological sites. Over the last decade, resource managers along Pacific Coast regions have become increasingly aware of the need for submerged archaeological site protection. This is especially important since the eastern Pacific continental shelf has become a focal point in the search for late Pleistocene migrations into the Americas and other evidence of pre-contact habitation in coastal regions since the Last Glacial Maximum (LGM). Integral to this search is the identification of submerged Pleistocene landforms that may favor preservation of pre-contact archaeological sites.\u0000 Stemming from this, our multidisciplinary and multi-institutional effort includes marine geologists, marine biologists, and archaeologists synthesizing existing data using GIS models, and collecting new side scan sonar, CHIRP, and multibeam bathymetry data ground truthed with marine sediment cores. This methodology for the identification of submerged archaeological deposits is not new; however, the landscape approach that defines our research, and our focus on understanding paleolandscapes using modeling, sonar survey, and marine coring is the first of its kind on the eastern Pacific continental shelf.\u0000 The goal of our project is to develop an archaeological sensitivity model, which the Bureau of Ocean Energy Management can consult in the offshore energy permitting process. As such, we are building our model using data from California’s Northern Channel Islands and testing the model along Oregon’s central coast. Results suggest that with the right technologies, sensitive landscape features such as paleochannels, paleoestuaries, and offshore tar seeps – all features used by Native American communities during the late Pleistocene and Holocene along the Pacific Coast – can be identified and used to model sensitive archaeological landscapes. We also are testing the efficacy of controlled-source marine electromagnetic methods in conjunction with sonar survey data for the identification of tar seeps, paleochannels, and buried archaeological shell midden deposits. This combined methodological approach is unique to North America’s Pacific Coast and represents a pioneering effort in the search for submerged archaeological deposits, which will help identify, document, and preserve underwater cultural heritage resources.","PeriodicalId":11149,"journal":{"name":"Day 1 Mon, May 06, 2019","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90631170","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}
1. Review the effectiveness of existing technology for identifying and characterizing submerged and buried prehistoric archaeological sites.2. Critique and suggest changes to existing technology to improve the effectiveness for the identification and characterization of submerged prehistoric archaeological sites.3. Examine the "why" this is important to offshore technology regulation and management. The process can easily be paraphrased as "sound, software, and three inch pipes" - the sound being the pulse from sonar or sub-bottom instruments, the software being the methods by which those pulses are processed and display, and the three-inch pipes, of course, denoting the coring tubes used to sample targets identified in using sound and software. In fairness to the methods discussed herein, their application has been, at best, uneven. The use of the first two technologies - sound/acoustic and post-processing software programs have been in regular use by geophysical contractors. The latter technology - sediment coring - has been utilized far less. How effective has this methodology proven to be over the past thirty years? That is open to some debate and this paper will examine some reasons why this is so and suggest some possible alternatives. The overarching goal of this paper is to push beyond this methodology to potentially more effective technologies or at least improved usage of the current technology. Submerged prehistoric archaeological sites are "hard problems" in terms of their discovery and characterization. Compared to submerged historic archaeological sites - primarily shipwrecks - those are "easy." This comparison of the use and effectiveness of technology is novel and additive.
{"title":"Submerged Archaeological Resources: Sound, Software and Three Inch Pipes - A Recipe for Finding Submerged Prehistoric Archaeological Sites?","authors":"Garrison G Ervan","doi":"10.4043/29597-MS","DOIUrl":"https://doi.org/10.4043/29597-MS","url":null,"abstract":"\u0000 \u0000 \u0000 1. Review the effectiveness of existing technology for identifying and characterizing submerged and buried prehistoric archaeological sites.2. Critique and suggest changes to existing technology to improve the effectiveness for the identification and characterization of submerged prehistoric archaeological sites.3. Examine the \"why\" this is important to offshore technology regulation and management.\u0000 \u0000 \u0000 \u0000 The process can easily be paraphrased as \"sound, software, and three inch pipes\" - the sound being the pulse from sonar or sub-bottom instruments, the software being the methods by which those pulses are processed and display, and the three-inch pipes, of course, denoting the coring tubes used to sample targets identified in using sound and software. In fairness to the methods discussed herein, their application has been, at best, uneven. The use of the first two technologies - sound/acoustic and post-processing software programs have been in regular use by geophysical contractors. The latter technology - sediment coring - has been utilized far less.\u0000 \u0000 \u0000 \u0000 How effective has this methodology proven to be over the past thirty years? That is open to some debate and this paper will examine some reasons why this is so and suggest some possible alternatives. The overarching goal of this paper is to push beyond this methodology to potentially more effective technologies or at least improved usage of the current technology.\u0000 \u0000 \u0000 \u0000 Submerged prehistoric archaeological sites are \"hard problems\" in terms of their discovery and characterization. Compared to submerged historic archaeological sites - primarily shipwrecks - those are \"easy.\" This comparison of the use and effectiveness of technology is novel and additive.\u0000","PeriodicalId":11149,"journal":{"name":"Day 1 Mon, May 06, 2019","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89855224","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}
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