In the recent years, there has been a trend to run metallic pipelines carrying petroleum products and high voltage AC power lines parallel to each other in a relatively narrow strip of land. The case of electromagnetic interference between high voltage transmission lines and metallic pipelines has been a topic of major concern since the early 60’s. The main reasons for that are: • The ever increasing cost of right-of-ways, suitable for power lines and pipelines, along with recent environmental regulations, aiming to protect nature and wildlife, has forced various utilities to share common corridors for both high voltage power lines and pipelines. Therefore, situations where a pipeline is laid at close distance from a transmission line for several kilometers have become very frequent. • The rapid increase in energy consumption, which has led to the adoption of higher load and short circuit current levels, thus making the problem more acute. Due to this sharing of the right-of-way, overhead AC power line field may induce voltages on the metallic pipelines running in close vicinity leading to serious adverse effects. This electromagnetic interference is present both during normal operating conditions as well as during faults. The coupling of the field with the pipeline takes place either through the capacitive path or through the inductive or conductive paths. In the present work, the induced voltages due to capacitive and inductive coupling on metallic pipelines running in close vicinity of high voltage power transmission lines have been computed.The conductor surface field gradients calculated for the various phaseconfigurations have been presented in the thesis. Also the electric fields under transmission lines, for both single circuit and double circuit (various phase arrangements) have been analysed. Based on the above results, an optimum configuration giving the lowest field under the power line as well as the lowest conductor surface gradient has been arrived at and for this configuration induced voltage on the pipeline has been computed using the Charge Simulation Method (CSM). For comparison, induced voltages on the pipeline have been computed for the various other phase configurations also. A very interesting result is that the induced voltage on the pipeline becomes almost negligible at a critical lateral distance from the center of the powerline and beyond which the induced voltage again increases.This critical distance depends on the conductor configuration. Hence it is suggested that the pipeline be located close to the critical distance so that the induced voltage would be close to zero. For calculating the induced voltage due to the inductive coupling, electromotive force (EMF),induced along the pipeline due to the magnetic field created by the transmission line has been calculated. The potential difference between the pipeline and the earth, due to the above induced EMFs, is then calculated. As the zones of influence are generally formed by parallelism, approaches, crossings as well as removals, the computation involves subdividing the zone into several sections corresponding to these zones. The calculation of voltages is carried out at both the ends of the sections. Each section is represented by an equivalent π electrical network, which is influenced by the induced EMF. The induced EMF is calculated during faulted conditions as well as during steady state conditions. Inductive coupling calculations have been carried out for the following cases: •Perfect parallelism between powerline and pipeline. •zone of influences formed by parallelism, approaches, crossings and removals. It has been observed that when the pipeline is approaching the HV transmission line at an angle, then running parallel for certain distance and finally deviating away, the induced voltage is maximum at the point of approach or removal of the pipeline from the transmission line corridor.The induced voltage is almost negligible near to the midpoint of the zone of influence. The profile of the induced voltage also depend on whether the pipeline is grounded or left open circuited at the extremities of the zone of influence. Effect of earth resistivity and anti-corrosive coatings on induced voltage has also been studied. For mitigating the induced voltage on the pipeline,numerous low resistive earthings have been suggested. Results show that significant reduction in induced voltage can be achieved as the number of earth points is increased.

[Truncated abstract] The hydrodynamic forces on a marine pipeline and the local scour around it are the most serious and important issues in designing and maintaining pipelines. This thesis explores the vortex shedding phenomena for the flow over smooth surface and rough surface isolated cylinders. This thesis also explores the two-dimensional and three-dimensional scour process beneath offshore pipelines numerically. A series of numerical models are proposed in this dissertation for the prediction of flow characteristics and the time development of local scour around pipelines. All the models presented in this thesis are deliberately developed based on novel lattice Boltzmann method (LBM), because in recent years it has been considered as a serious alternative to standard computational fluid dynamics (CFD) as it is ideally suited to massively parallel computations. The lattice Boltzmann method is described in details to reveal how it recovers the Navier- Stokes equations. Various grid refinement schemes available in literature are discussed and a slightly modified new scheme is proposed to remove oscillatory solutions at high velocity change regime. The proposed scheme is then validated against bench mark tests for low Reynolds number flow. A turbulent model based on LBM is developed in order to predict the vortex shedding flow around an isolated square smooth surface cylinder. The various local and global flow parameters and structure of vortices are validated against experimental and numerical data available in literature. The model is then extended to investigate the vortex shedding flow over an isolated rough surface cylinder as it has an engineering significance in the design process of pipelines. The model is employed to investigate the influence of pipe roughness on various local and global parameters of flow. ... Significant part of this thesis is aimed at modelling flow and local scour around pipelines employing LBM and cellular automata (CA) methods. The erosion mechanism of the CA method available in literature for sand particles is improved by defining the threshold of sediment entrainment on bed in a similar manner to that employed in the traditional scour models. The predicted scour profiles for various incoming flow conditions are found to compare well with the experimental results reported in the literature. The existence of lee wake erosion due to continuous generation of vortex shedding in the lee of the pipelines is revealed. The time development of the maximum scour depth below the pipe is also found to be in good agreement with the experimental measurements reported in literature Finally, a three-dimensional flow and scour model is developed in order to explore the scour process beneath pipelines. It is revealed that the three-dimensionality effects are more pronounced near the span shoulder. On the other hand, there exists a two-dimensional scour regime in the vicinity of the middle section of the suspended pipe. It is found that the propagation speed of the scour hole in the sapnwise direction remains almost constant at all stages of scour process.

Thesis (MA)--University of Stellenbosch, 2002. / ENGLISH ABSTRACT: A major concern for Energex, Australia's largest energy utility in South East Queensland, is the escape of natural gas out of their reticulation systems. Within many of the older areas in Brisbane, these networks operate primarily at low and medium pressure with a significant percentage of mains being cast iron or steel. Over many years pipes in these networks have been replaced, yet reports show that unaccounted for gas from the same networks remain high. Furthermore, operation and maintenance budgets for these networks are high with many of these pipes close to the end of their economic life. When operation and maintenance costs exceed the costs of replacement, the Energex gas utility initiates projects to renew reticulation networks with polyethylene pipes. Making decisions about pipe renewal requires an evaluation of historical records from a number of sources, namely: • gas consumption figures, • history of leaks, • maintenance and other related cost, and • the loss of revenue contributed by unaccounted for gas. Financial justification of capital expenditure has always been a requirement for renewal projects at the Energex gas utility, however the impact of a deregulation in the energy utility market has necessitated a review of their financial assessment for capital projects. The Energex gas utility has developed an application that evaluates the financial viability of renewal projects. This research will demonstrate the role of GIS integration with the Energex financial application. The results of this study showed that a GIS integrated renewal planning approach incorporates significant benefits including: • Efficient selection of a sub-network based on pipe connectivity, • Discovery of hidden relationships between spatially enabled alphanumeric data and environmental information that improves decision making, and • Enhanced testing of proposed renewal design options by scrutinizing the attributes of spatial data. / AFRIKAANSE OPSOMMING: 'n Groot bron van kommer vir Energex, Australië se grootste energieverskaffer in Suidoos- Queensland, is die verlies van natuurlike gas uit hul gasdistribusie netwerke. In 'n groot deel van ouer Brisbane opereer hierdie netwerke hoofsaaklik teen lae en medium druk, met 'n aansienlike persentasie van hoofpyplyne wat uit gietyster of staal bestaan. Al is sommige pyplyne in hierdie netwerke met verloop van tyd vervang, maak verslae dit duidelik dat 'n groot deel van die gas in hierdie netwerke steeds langs die pad verlore gaan. Die operasionele - en onderhoudsbegrotings vir hierdie netwerke is boonop hoog, met 'n groot persentasie van die pyplyne wat binnekort aan die einde van hulle ekonomiese leeftyd kom. Wanneer operasionele- en onderhoudsonkostes die koste van vervanging oorskry, beplan Energex se gasvoorsienings-afdeling projekte om verspreidingsnetwerke te hernu met poli-etileen pype. Om sinvolle besluite te neem tydens pyplynhernuwings, word verskeie historiese verslae geraadpleeg, insluitend: gasverbruikvlakke, lekplek geskiedenis rekords, onderhoud- en ander verwante onkostes, asook die verlies van inkomste weens verlore gas. Alhoewel finansiële stawing van kapitale uitgawes nog altyd 'n voorvereiste was tydens hernuwingsprojekte by Energex, het die impak van privatisering op die energieverskaffingsmark dit noodsaaklik gemaak om hulle finansiële goedkeuringsproses vir kapitaalprojekte te hersien. Energex het dus 'n sagteware toepassing ontwikkel wat die finansiële gangbaarheid van hernuwingsprojekte evalueer. Hierdie navorsing sal die moontlike integrasie van geografiese inligtingstelsels (GIS) met dié van Energex se finansiële evalueringspakket demonstreer. Die resultate van hierdie studie toon dat die integrasie van GIS in die hernuwingsproses aansienlike voordele inhou, insluitende: • die effektiewe seleksie van sub-netwerke, gebaseer op pyp konnektiwiteit, • die ontdekking van verskuilde verwantskappe tussen geografies-ruimtelike alfanumeriese data en omgewingsinligting, wat besluitneming vergemaklik, en • verbeterde toetsing van voorgestelde hernuwingsopsies deur die indiepte-nagaan van geografiesruimtelike elemente.

Orientador: João Batista Fogagnolo / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-23T06:53:34Z (GMT). No. of bitstreams: 1 Alcatrao_MaurodosSantos_M.pdf: 3580618 bytes, checksum: b8c15735174b64bdbb58cb26181043c5 (MD5) Previous issue date: 2013 / Resumo: A grande expansão da malha de duto terrestre que vem ocorrendo nos últimos anos no Brasil, principalmente com a construção de linhas únicas para o escoamento de gás natural, representa um novo desafio às equipes de manutenção. A interrupção do fornecimento de gás, devido à parada para manutenção pode representar o colapso de muitas cidades. Situações programadas de paradas operacionais são muito comuns porem envolve recursos humanos e financeiros vultosos, nem sempre disponíveis. Os riscos envolvidos no preparo e condicionamento para a retirada de operação de um gasoduto ou oleoduto, alem dos mesmos cuidados ao retorno normal às atividades requer planejamento minucioso. Nas aplicações envolvendo processos de soldagem sobre o duto em operação, isto é , com fluxo interno na forma gás ou liquido, é necessário garantir a ausência de vazamento de produto, ou seja, onde se tenha o produto totalmente confinado no interior da linha, viabilizando a execução de soldagem e, portanto, não ocorrendo à possibilidade de ignição do produto nela contido. Em uma soldagem executada diretamente sobre uma tubulação com fluxo interno é necessário considerar-se dois tipos de riscos de origem antagônica: Perfuração e trincas a frio. O objetivo deste trabalho é discutir a aplicação do processo de soldagem MAG mecanizado com transferência metálica por curto-circuito com controle de corrente, alternativo ao comumente utilizado, eletrodo revestido, com intuito de obtenção de maior segurança nas aplicações para baixas espessuras na parede do duto, além de almejar maior produtividade e qualidade das soldagens / Abstract: The great expansion of the onshore pipeline grid that has been occurring in recent years in Brazil, especially with the construction of single lines for the flow of natural gas, represents a new challenge to the maintenance teams. The interruption of gas supply due to maintenance downtime can represent the collapse of many cities. Scheduled stops operating situations are very common however involve financial and human resources heavily, not always available. The risks involved in the preparation and conditioning for the withdrawal of operation of a pipeline or pipeline, besides the same care to return to normal activities require careful planning. In applications involving welding process on the pipe in operation, ie, internal flow with the gas or liquid form, it is necessary to ensure no leakage of product, ie, where the product has completely confined within the line, allowing performing welding and therefore not occurring the possibility of ignition of the product contained therein. In welding performed directly on a pipe with internal flow is necessary to consider two types of risks antagonistic source: Drilling and cracking cold. The objective of this study and discuss the application of mechanized MAG welding process with metal transfer short-circuit with current control, alternative to the commonly used electrode coated with the aim of achieving greater safety in applications for low thicknesses in the duct wall , and aim for higher productivity and quality of the welds / Mestrado / Materiais e Processos de Fabricação / Mestre em Engenharia Mecânica

Buried pipelines are tubular structures that are used for transportation of important liquid materials and gas in order to provide safety for human life. During an earthquake, imposed loads from soil deformations on concrete pipelines may cause severe damages, possibly causing disturbance in vital systems, such as cooling of nuclear power facilities. The high level of safety has caused a demand for reliable seismic analyses, also for structures built in the regions that have not traditionally been considered as highly seismically active. The focus in this study is on areas with seismic and geological conditions corresponding to those in Sweden and Northern Europe. Earthquakes in Sweden for regions with hard rock dominated by high-frequency ground vibrations, Propagation of such high-frequency waves through the rock mass and soil medium affect underground structures such as pipelines. The aim of this project is investigating parameters that affect response of buried pipelines due to high-frequency seismic excitations. The main focus of the study is on reinforced concrete pipelines. Steel pipelines are also studied for comparison purposes. The effects of water mass, burial depth, soil layer thickness and non-uniform ground thickness caused by inclined bedrock are studied. The results are compared to those obtained for low-frequency earthquakes and the relationship between strong ground motion parameters and pipelines response is investigated. It is shown that, especially for high frequency earthquake excitations, non-uniform ground thickness due to inclined bedrock significantly increase stresses in the pipelines. For the conditions studied, it is clear that high-frequency seismic excitation is less likely to cause damage to buried concrete pipelines. However, the main conclusion is that seismic analysis is motivated also for pipelines in high-frequency earthquake areas since local variation in the ground conditions can have a significant effect on the safety. / Nedgrävda rörledningar (pipelines) är rörformiga strukturer som används för transport av viktiga flytande material och gas för att säkerhetsställa samhälleliga funktioner. Denna typ av infrastruktursystem korsar stora områden med olika geologiska förhållanden. Under en jordbävning kan markdeformationer påverka rörledningar av betong vilka kan få allvarliga skador som i sin tur kan leda till störningar i vitala system, såsom till exempel kylning av kärnkraftsanläggningar. Den höga säkerhetsnivå som eftersträvas ger upphov till ett behov av tillförlitliga seismiska analyser, även för strukturer som byggs i regioner som traditionellt inte har ansetts som seismiskt aktiva. Fokus i denna licentiatuppsats ligger på områden med seismiska och geologiska villkor som motsvarar de i Sverige och norra Europa. Jordbävningar i Sverige klassas som händelser inom en tektonisk platta som för regioner med hårt berg kan resultera i jordbävningar som domineras av högfrekventa markvibrationer. Sådana högfrekventa vågor propagerar genom bergmassa och jordmaterial och kan där påverka underjordiska strukturer såsom rörledningar. Syftet med detta projekt är att undersöka vilka parametrar som har stor påverkan på nedgrävda rörledningar som utsätts för högfrekventa seismiska vibrationer. Tyngdpunkten i studien är på rörledningar av armerad betong men stålledningar studeras också i jämförande syfte. Två-dimensionella finita elementmodeller används, utvecklade för dynamisk analys av rörledningar belastas av seismiska vågor som propagerar från berggrunden genom jorden. Modellerna beskriver båda längsgående och tvärgående snitt av rörledningar. Samspelet mellan rörledningar och omgivande jord beskrivs av en icke-linjär modell. De studerade rörledningarna antas vara omgivna av friktionsjord med stor, medel eller liten styvhet. Effekterna av vattenmassa i rören, grundläggningsdjup, jordlagrens tjocklek och varierande jordtjocklek på grund av lutande berggrund studeras. Det visas hur två-dimensionella modellerbaserade på plan töjning kan användas för seismisk analys av rörledningar med cirkulära tvärsnitt. Resultaten jämförs med de som erhållits för lågfrekventa jordbävningar och förhållandet mellan markrörelseparametrar och responsen hos rörledningar undersöks. Det visas att den naturliga frekvensen för modellerna beror av jordtyp, tjocklek och variation hos jordlagret. Det visas att, särskilt för högfrekventa jordbävningar, olikformigt varierande markdjup på grund av lutande berggrund avsevärt ökar spänningarna i rörledningarna. För de förhållanden som studerats är det klart att det är mindre sannolikt att högfrekvent seismisk belastning ska orsaka skador på nedgrävda rörledningar av betong. Dock är den viktigaste slutsatsen att seismisk analys ändå motiveras, även för rörledningar i områden där jordbävningar med högt frekvensinnehåll förekommer eftersom lokala variationer i markförhållanden kan ha en betydande inverkan på säkerheten. / <p>QC 20161014</p>

This thesis applies energy measurements to the domain of continuous integration (CI) and continuous delivery (CD) pipelines. The goal is to conduct transparent and fine-granular energy measurements of these pipelines, increasing awareness and allowing optimizations regarding their energy efficiency. CI and CD automate processes like compilation, running tests, and code analysis tools and can improve the software quality and developer experience and enable more frequent releases. Initially, the applicability of existing energy measurement approaches for these tasks is analyzed. Afterward, a generic framework consisting of a pipeline run analyzer, a resource consumption collector, and an energy calculator is proposed. A representative implementation for a state-of-the-art infrastructure is devised to demonstrate its functionality, enabling the collection, analysis, and interpretation of data from real-world examples. Finally, it is examined whether this data aligns with the theoretical considerations and can be used to optimize the pipelines. The overall goal is to contribute to the sustainability of DevOps processes and therefore counteract the disastrous consequences of unrestrained climate change. / Denna avhandling tillämpar energimätningar på området kontinuerlig integration (CI) och kontinuerlig leverans (CD). Målet är att genomföra transparenta och finkorniga energimätningar av dessa pipelines, vilket ökar medvetenheten och möjliggör optimeringar av deras energieffektivitet. CI och CD automatiserar processer som kompilering, testkörning och kodanalysverktyg och kan förbättra programvarukvaliteten och utvecklarens upplevelse samt möjliggöra tätare lanseringar. Inledningsvis analyseras tillämpligheten av befintliga metoder för energimätning för dessa uppgifter. Därefter föreslås ett generiskt ramverk som består av en analysator för pipelinekörning, en insamlare av resursförbrukning och en energikalkylator. För att demonstrera dess funktionalitet utarbetas en representativ implementering för en modern infrastruktur som möjliggör insamling, analys och tolkning av data från verkliga exempel. Slutligen undersöks om dessa uppgifter stämmer överens med de teoretiska övervägandena och kan användas för att optimera rörledningarna. Det övergripande målet är att bidra till hållbarheten i DevOpsprocesser och därmed motverka de katastrofala konsekvenserna av ohämmade klimatförändringar.

Call number: LD2668 .T4 1965 R649 / Master of Science

Submitted in fulfillment of the requirements of the Degree of Magister Technologiae: Civil Engineering, Durban University of Technology, 2013. / The urgent need to rehabilitate or replace ageing deteriorated buried potable water pipeline networks is one of the many critical service utility provision challenges faced within the municipalities in South Africa. The majority of these unreliable deteriorated pipeline networks consist of un-dipped (not coated with bitumen) AC piping which have long passed their planned economic and technical lifespan. Traditionally, the open trenching method has been utilised for the replacement of aged and deteriorated piping. However, this traditional open trenching method has shown to be expensive and difficult to implement, particularly in congested high traffic use urban areas. The need to rehabilitate or replace the ageing deteriorated buried potable water pipelines in South Africa, taking into account the above mentioned expensive factors has a solution. This solution is termed ‘trenchless technology’ and sometimes also termed ‘no dig’. Recent advancements in trenchless technologies now include innovative methods such as pipe bursting, close-fit lining and sliplining. Close-fit compact pipe manufactured by Wavin Overseas B.V. was newly introduced in South Africa in 2010 for the rehabilitation of deteriorated pipelines. These trenchless methods require further research into their technical application merits, drawbacks and costs in relation to the traditional open trenching method in order to determine which method is more expensive and also least suitable. Traditionally, the ‘total cost’ associated with pipe rehabilitation or replacement projects consisted only of the direct costs. The indirect and socio-economic inconvenience costs were often ignored and resulted in costly expenses to the municipalities. However, this research will show that these indirect and socio-economic inconvenience costs must form part of the total cost of a project as it assists with the successful completion of the project without expensive unforeseen costs to the municipalities. In addition, this research will provide insight as to which indirect and socio-economic inconveniences are dominantly experienced by the public. To achieve this, a quantitative socio-economic survey questionnaire was developed. This questionnaire was aimed at residents and business owners who were affected during a project of this nature. This research study will serve as a support tool to municipalities of South Africa when selecting a pipe rehabilitation or replacement method. This support tool will provide key technical merits and drawbacks of the traditional open trenching method, pipe bursting method, close-fit compact pipe method and sliplining method. In addition, this research study will compare the ‘total cost’ of the traditional open trenching method against the trenchless pipe bursting method. The decision making process lies in the hands of the municipal technical managers. Therefore, their knowledge and experience of up to date information on trenchless methods (as well as the traditional open trenching method) is vitally important. This research provides insight as to the knowledge and experience of technical municipal staff on trenchless methods, its application and use in South Africa. A quantitative survey questionnaire was developed by the researcher. This questionnaire was aimed at technical staff in the water departments of district and local municipalities of South Africa. The results of the above questionnaire surveys formed part of the eThekwini Water and Sanitation (EWS) Feasibility study funded by the Dutch Government. When comparing the costs of the trenchless pipe bursting method against the traditional open trenching method, the results revealed that trenchless methods are undoubtedly cheaper and far less disruptive to the public. The results of the socio-economic survey revealed that trenchless methods were preferred by the public since it was less disturbing and the hindrances experienced were also far less than the traditional open trenching method. The results of the technical municipal survey questionnaire revealed that at least 50% of municipal technical staff of South Africa are not adequately informed about trenchless methods, its application and technical merits and drawbacks respectively. This survey questionnaire revealed that South Africa may be advancing over the years on the use of trenchless methods, however, more educating in the form of training, seminars and other methods of marketing must be undertaken starting at a municipal level.

Pipelines used for the transportation of oil and gas products offshore are often buried beneath the seabed for protection from mechanical damage and for thermal insulation. During high temperature and high pressure operations, these pipelines are susceptible to resurfacing behaviour known as upheaval buckling, a structural response that is strongly influenced by the resistance of the surrounding soil. Despite much previous research on pipe uplift, the influence of the initial soil state – particularly in loose and liquefiable soil conditions – on the uplift resistance and corresponding buckling behaviour of the pipe is not well understood. This thesis presents research that examines the implications of these backfill conditions in the context of the global behaviour of the pipeline. The work consists of plane-strain monotonic uplift experiments focusing on density, rate, and stress level effects on the initial pipe-soil response. This is followed by numerical modelling of the global buckling behaviour using the experimental data as inputs. Finally, plane-strain cyclic experiments examine the possibility of progressive upward displacements over a number of cycles causing eventual upheaval buckling. A key finding from the uplift tests is that very loose backfill conditions may result in a localised flow-around failure mechanism, associated with lower peak resistance and a softer force-displacement response than with the sliding block mechanism that is typically assumed. This leads to lower peak buckling loads/temperatures than those predicted by current design guidelines. High quality data from both the monotonic and cyclic experiments was used to assess and suggest improvements to design guidance for these conditions.

published_or_final_version / Applied Geosciences / Master / Master of Science