The frictional behavior of soil-construction material interfaces is of significant importance in geotechnical engineering applications such as retaining structures, pile foundations, geosynthetic liners, and trenchless technologies. Since most failures initiate and develop on the interfaces, special attention is required to predict the capacity of these weak planes in the particular application. Pipe-jacking and microtunneling technologies are being more widely used over the past decade and there is significant interest to predict the jacking forces and jacking distances achievable in order to achieve more efficient design and construction. This study focuses on the evaluation of the frictional characteristics and factors affecting the shear strength of pipe-soil interfaces. Eight different pipes made from fiber reinforced polymer (FRP), polycrete, steel, concrete, and vitrified clay were tested in the experimental program. For this purpose, a new apparatus was designed to conduct conventional interface direct shear testing on pipes of different curvature. This device allows coupons cut from actual conduits and pipes to be tested in the laboratory under controlled conditions. The apparatus includes a double-wall shear box, the inner wall of which is interchangeable to allow for testing against surfaces of different curvatures. By considering a narrow width section, the circular interface of pipes was approximated with a surface along the axial direction and the boundary is defined by the inner box. Roughness tests were performed using a stylus profilometer to quantify the surface characteristics of the individual pipes and relate these to the interface shear behavior. The surface topography showed different degrees of variability for the different pipes. To extend the range of roughness values tested and force the failure to occur in the particulate media adjacent to the interface, two artificial pipe surfaces were created using rough sandpapers. Interface shear tests were performed using the new apparatus with air-pluviated dense specimens of Ottawa 20/30 sand. Additional tests were performed using Atlanta blasting sand to evaluate the effect of particle angularity. The effect of normal stress and relative density were also examined. The interface strength was shown to increase with surface roughness and finally reach a constant value above a certain critical roughness value, which corresponded to the internal strength of the soil itself. This represented the failure location moving from the interface into the soil adjacent to the interface. Both the strength and the shearing mechanism were thus affected by the surface topography. It was also shown that the interface shear strength was affected by particle angularity, relative density and normal stress.

Die Arbeit ist der Weiterentwicklung der Formgebungs- und Verdichtungsausrüstungen zur Herstellung von Beton- und Stahlbetonrohren gewidmet. Es werden die Grundlagen für eine schwingungstechnische Auslegung von Betonrohrfertigern mit stehendem und steigendem Kern geschaffen. Den Ausgangspunkt bildet die Untersuchung des Verdichtungsprozesses in Rohrfertigern und der Einflußgrößen auf die Vibrationsverdichtung des Betongemenges. Es werden experimentelle Untersuchungen an einem Versuchsstand und praktische industrielle Erfahrungen dargestellt. Für die schwingungstechnische Auslegung der Verdichtungseinrichtung von Rohrfertigern werden diskrete Modelle mit analytischen Lösungen sowie Modelle zur numerischen Simulation auf der Basis der Mehrkörperdynamik und der Finite-Elemente-Methode gebildet. Es erfolgen Empfehlungen zur Auslegung und Ansätze zur Weiterentwicklung von Rohrfertiger.

Polymer pipes, typically high density polyethylene (HDPE), can be pulled-into-place, avoiding traditional cut-and-cover construction, using pipe bursting and horizontal directional drilling (HDD) pipe installation techniques. Of particular interest, are the ground displacements, induced by cavity expansion, associated with these techniques and the strains that develop in existing pipes in response to these displacements. Further, the axial stress-strain response of the new HDPE pipe during and after the cyclic pulling force history required to pull the pipe into place is of interest. Surface displacements and strains in an adjacent polyvinyl chloride (PVC) pipe induced by static pipe bursting were measured during the replacement of a new unreinforced concrete pipe. For the pipe bursting geometry tested, the maximum vertical surface displacement measured at the ground surface was 6 mm, while the distribution of vertical surface displacements extended no more than 2 m on either side of the centreline. The maximum longitudinal strain measured in the PVC pipe was less than 0.1% and its vertical diameter decreased by only 0.5%, suggesting that pipe bursting did not jeopardize the long-term performance of the water pipe tested. In addition, results from identical stress relaxation and creep tests performed on whole pipe samples and coupons trimmed from a pipe wall were compared, and these demonstrated that the coupons exhibited higher modulus than the pipe samples. Therefore, isolated pipe samples, as opposed to coupons, were tested to quantify the stress-strain response of HDPE pipe during the simulated installation, strain recovery, and axial restraint stages of HDD. Axial strains were found to progressively accumulate when an HDPE pipe sample was subjected to the cyclic stress history used to simulate an HDD installation. It was shown that existing linear and nonlinear viscoelastic models can serve as predictive design tools for estimating the cyclic strain history of HDPE pipe during installation. For the specific conditions examined, the tensile axial stresses redeveloped in the pipe samples, once restrained, were not large enough to lead to long-term stress conditions conducive to slow crack growth even when the short-term performance limits were exceeded by a factor of 1.5. / Thesis (Ph.D, Civil Engineering) -- Queen's University, 2009-04-01 18:19:24.434

Solving for energy losses in pipe junctions has been a focus of study for many years. Although pipe junctions and fittings are at times considered "minor losses" in relation to other energy losses in a pipe network, there are cases where disregarding such losses in flow calculations will lead to errors. To facilitate these calculations, energy loss coefficients (K-factors) are commonly used to obtain energy losses for elbows, tees, crosses, valves, and other pipe fittings. When accurate K-factors are used, the flow rate and corresponding energy at any location in a pipe network can be calculated. K-factors are well defined for most pipe junctions and fittings; however, the literature documents no complete listings of K-factors for crosses. This study was commissioned to determine the K-factors for a wide range of flow combinations in a single pipe cross and the results provide information previously unavailable to compute energy losses associated with crosses. To obtain the loss coefficients, experimental data were collected in which the flow distribution in each of the four cross legs was varied to quantify the influence of velocity and flow distribution on head loss. For each data point the appropriate K-factors were calculated, resulting in over one thousand experimental K-factors that can be used in the design and analysis of piping systems containing crosses.

In the welding of more sensitive metals such as stainless steel, titanium and some specific nickel alloys, the presence and application of a protective gas is essential. Without the use of a nonreactive shielding gas, defects occur in or adjacent to the weld joint, which vary from light discoloration of the weld bead to the direct onset and propagation of cracks. The supply of shielding gas is usually via the welding tool. Unfortunately, when it comes to welding pipes, the problem arises when the root bead comes into contact with the oxygen present within the pipe. Since the shielding gas supplied from the welding tool has no possibility of penetrating into the pipe and protecting the melt from the oxygen, the result consequence will be defects in the weld bead. To prevent this from happening, the pipes are sealed before welding and the oxygen in the pipe is purged and replaced with protective gas. Due to the fact that pipe welding operations concern a vast spectrum of pipe dimensions, complications arise for the welding operator as the solutions available have a low degree of adaptability. Thus, the purpose of this project is to investigate the possibility of designing and developing a new method of supplying root gas protection that can be adapted to several pipe diameters. Field studies at welding companies resulted in the clarification of which diameter spans the root gas protection solution should comply with, the pipe diameter span to cater for was identified as 25-100 mm in diameter. Requests were also made regarding the robustness of the product, with expressed desire for the product to withstand the strenuous working environment often encountered during welding operations. Solution proposals were produced which later developed into six separate concepts. From these six concepts, one was selected as the foremost solution and further developed for construction. The concept was sketched out and reproduced using CAD and a model was made using 3D printers. The model showed a need for modifications as it was not of a sufficiently adaptable nature. A modified model was thus developed and manufactured using a 3D printer, this modified model showed better results of adaptation to different pipe diameters. Furthermore, a flow analysis of the gas as it enters via the root gas plug and into the pipe was conducted, to verify total distribution of the gas within the pipe. The material with which to construct the concept with will be silicone infused with additives to make it more heat resistant and more resistant to wear. However, the exact mixture of silicone and additives in question was not available for this project but is something that is intended for future work. The concept meets the specified requirements of being applicable to multiple pipe diameters, more specifically so meeting the wishes of those active within the industry, covering a pipe span of 25- 100 mm. / Vid svetsning av mer känsliga metaller såsom rostfritt stål, titan och vissa specifika nickellegeringar är närvaron och tillämpningen av en skyddsgas väsentligt. Utan nyttjandet av en icke reaktiv skyddsgas uppkommer defekter i eller intill svetsfogen, vilka varierar från lätta missfärgningar av svetssträngen till den direkta uppkomsten och propageringen av sprickor. Tillförseln av skyddsgas sker vanligtvis via svetsverktyget. När det kommer till svetsning av rör uppstår dessvärre problemet att rotsträngen kommer i kontakt med syret som finns på insidan av röret. Eftersom att den skyddsgas som tillförs från svetsverktyget inte har någon möjlighet att tränga sig in i röret och skydda smältan från syret kommer det resultera i en svetssträng med defekter. För att förhindra detta från att ske tätas rören innan svetsning och syret i röret ersätts med skyddsgas. Eftersom att de rör som skall sammanfogas förekommer i flera dimensioner uppstår komplikationer för svetsoperatören ty de lösningar som finns tillgängliga har låg anpassningsgrad. Därmed är syftet med detta projekt att undersöka möjligheten att designa och utveckla ett nytt rotgasskydd som kan anpassas till flera diametrar. Fältstudier hos svetsföretag resulterade i ett tydligt spann för vilka diametrar som bör tillgodoses med sagda rotgasskydd, detta spann av rördiametrar var 25-100 mm. Det uppgavs även önskemål om säkerställning av att produkterna är robusta nog att klara den påfrestande arbetsmiljö som ofta förekommer vid svetsning. Lösningsförslag lades fram vilket senare utvecklades till sex separata koncept. Från dessa sex koncept utsågs en som den främsta lösningen och togs vidare till konstruktion. Konceptet skissades upp i CAD och en modell gjordes i 3D-skrivare. Modellen visade upp behov på modifieringar då den inte var av tillräckligt anpassningsbar karaktär. En modifierad modell togs därmed fram och tillverkades i en 3D-skrivare, denna modifierade modell visade bättre prov på anpassning till olika  rördiametrar. Vidare gjordes en flödesanalys av gasen då den färdas in via rotgaspluggen, vilket visade att gasen fyller röret som önskat. Materialet som konceptet kommer tillverkas i är silikon med tillförda additiv för att göra det mer värmebeständigt och mer resistent mot slitage. Den exakta blandningen av silikon och additiv i fråga var dock inte tillgängliga till detta projekt utan är något som får gå till vidare arbete. Konceptet uppfyller kraven på anpassning till flera rördiametrar och möter mer specifikt även önskemålet från branschaktiva med dess spann på 25-100 mm.

No description available.

Yes / In this study, large-scale fully instrumented laboratory tests were conducted to investigate the behaviour of buried flexible high-density polyethylene (HDPE) pipes, in sand beds with and without voids subjected to incrementally increasing cyclic loading. Voids with a predetermined size were created at one side of the springlines of the pipes, which were buried at variable depths, H, of 1.5, 2.0 and 2.5 times the diameter of the pipe, D. Results showed that increasing the pipe burial depth, H/D, contributed to decreasing the settlement of the footing, deformation of the pipe crown and invert, lateral displacement of the spring-line, and the stress and strain generated along the pipe crown and invert. Void presence led to a significant increase in the footing settlement, which ranged from 3 % up to 18 %, according to H/D. Furthermore, void presence led to a sharp increase in the crown, invert, and spring-line settlements, which ranged from 34 % to 52 %, 10 %–12.5 %, and 13 %–38 %, respectively. Increasing pipe burial depth was found to be highly effective in protecting buried pipes, minimising inevitable consequences of the presence of voids. However, this was combined with an increase in the pressure at the pipe spring-line that led to a positive horizontal support at the pipe’s spring-lines resulting in reducing pipe deformation.

No description available.

Elastomer seals are used in a variety of industries that require flow isolation. The characterization of the behavior of these seals remains largely unexplored and hence, this study is focused on simulating and validating the axial-compressive behavior of an annular rubber seal constrained concentrically in a pipe. The elastomer material composing the seal, was experimentally characterized for its mechanical, frictional, and viscoelastic properties and modelled using models developed by Yeoh, Thirion, and Prony respectively. A 2D axisymmetric finite-element model was developed using ANSYS 16 and used alongside the material models to simulate an axial load versus displacement curve, a contact pressure distribution, and a pipe hoop strain gradient. The results for quasi-static loading and viscoelastic effects agreed within 7% and 18% of the experimental results, respectively. It was observed that pipe geometry, rubber chemistry, frictional properties, and viscoelastic effects have significant effect on the compressive behavior of the seal. / October 2016

Made available in DSpace on 2016-12-23T14:08:10Z (GMT). No. of bitstreams: 1 Marcelo Aiolfi Barone - cap 00 - 01 - 02 - 03 - 04.pdf: 1483841 bytes, checksum: f4e05e25d485e179dfceea82acfc06b7 (MD5) Previous issue date: 2012-10-29 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Este trabalho utiliza um protótipo de escala laboratorial do medidor primário pipe prover de modo a avaliar a sua conformidade com os requisitos estabelecidos por normas técnicas e examinar a incerteza da medição da vazão realizados, além de verificar a reprodutibilidade das medições, testes com esferas de diferentes diâmetros, a influência de parâmetros operacionais tais como a variação da pressão de operação e comparação com o teste gravimétrico. O protótipo é feito de tubos plástico com dimensões definidas estatisticamente. Dentro do tubo, uma esfera de elastômero interferente é impulsionada por um escoamento fornecido por uma bomba centrífuga. O sistema de detecção usa sensores de luz infravermelha capaz de detectar a passagem das esferas sem causar interferência ou bloqueio na tubulação. O sistema de aquisição de dados é automático e registra o tempo de trânsito da esfera através de cada pulso de sinal detectado bem como os pulsos gerados por um medidor calibrado tipo turbina, como comparação da avaliação das incertezas de processo utilizando o desempenho da técnica dos sensores infravermelhos / The work uses a laboratory scaled prototype of primary pipe prover flowmeter in order to assess conformity with the requirements established by technical standards and examine the uncertainties of flow measurement performed, besides to check the reproducibility of measurements, tests with spheres of different diameters, the influence of operating parameters such as operating pressure variation and comparison with gravimetric test. The prototype is plastic tubing and considering statically defined dimensions. Inside tubing, an interfering elastomer sphere is driven by flow provided by a centrifugal pump. The detection system uses infrared light sensors able to detect the spheres passage causing pipeline interference or blockage. The acquisition data system is automatic and records the sphere transit time through each pulse signal detected as well as the pulses generated by a calibrated turbine meter, as comparison of the evaluation of process uncertainties using the technique performance with infrared sensors