scholarly journals Solutions to enhance technology in the fabrication process and installation of marine pipelines

Author(s):  
Konstantin Nickolaevich Sakhno ◽  
Manh Do Tat ◽  
Hoang Bui Sy ◽  
Vladimir Muratovich Tsaloev ◽  
Peyvand Ahmad Saadati ◽  
...  

The article describes possible solutions of the problem connected with shortening shipbuilding construction time as well as reducing production costs. To reduce the total amount of labour involved in the manufacture and installation of ship piping systems, which is 20% compared to the total labour volume of shipbuilding, authors provide the research on the possibility of manufacturing straight pipe sections with permissible deviations in combination with free flanges, analysis of deviation compensation for pipelines through the use of straight pipe sections manufactured with permissible tolerance and proposing new theoretical solutions to improve manufacturing and installing ship piping systems. Introduction of these technologies contributes to reduction of cycles of building and decrease in labour-intensiveness of pipeline works when carrying out marine orders. The chart of modeling the system of pipelines is presented. A straight pipe manufactured with an allowable deflection on a flat support and a loose flange attached to the end of the welded pipe are shown. The scheme of a permissible deviation α at mounting the connections between pipes is considered. The possibility of assembling curved pipelines using straight pipe sections is described in detail. The compensation zone is illustrated using the rotation of two pairs of deflected straight pipes. A block diagram of the application of research results in manufacturing and mounting a pipeline system has been developed

Author(s):  
Supreedee Rittironk

Bamboo is the natural construction material that has become the trend for the sustainable architecture, due to its renewability. Bamboo connections are considered the most difficult process that consumes construction time. This study is the design experiment how innovative connections can expedite the fabrication and their performance. The study deals with the design of connection prototypes for bamboo framing and tests their performance in actual construction. Connectors are designed into the receivers and the nozzles. Receivers act like the female connector. They are receptors at foundation to transfer loads to ground. The nozzles are the male connector that looks like an extruder attached to the end of structural members to connect to the receivers. Nozzles are offered in both a single culm and split bundles. The experiment also designed the straps for bamboo splits, to wrap the split together into one bundle. Steel connectors are introduced to initiate the bamboo construction as pre-fabrication process, yet the strength of connections is maintained. These prototypes are also applied to actual construction to verify the constructability, performance, and architectural applications. It is found that connectors are effective to minimize construction time, but still have other limitation. The study took lesson learned to design more permanent connectors to solve all restricted issues. Finally, innovative connectors were created into many variety forms for fabrication. They can also perform greatly in strength and attractive look. These findings can motivate architects to explore possibility for bamboo architecture in pre-fabrication process, and to be more innovatively and effectively.


1967 ◽  
Vol 89 (2) ◽  
pp. 440-443
Author(s):  
B. L. Johnson ◽  
D. E. Wandling

This paper presents a method to determine the transfer function and input impedance of a pressurized fluid piping system. Distributed parameters are used to arrive at a transfer function of a single line, and then block-diagram feedback methods are used to model the system. The input impedance is derived from the feedback model, and methods are presented for finding the flow and pressure at any point in the system.


Author(s):  
G. J. Collie ◽  
I Black

Currently, there are two widely used methods for manufacturing corrosion-resistant, high-pressure pipework for oilfield applications: fabrication of the pipework from several, separate overlaid components joined by welding, or by combining fabrication and induction bending. The former is expensive and time consuming. The latter is less expensive but there are restrictions on the bend radii that can be achieved. This paper considers a range of possible alternatives in the production of complex, corrosionresistant, high-pressure piping systems for oilfield equipment. Some of the options (hot-rolled and seam-welded pipe, explosion-bonded and seam-welded pipe, and bi-metallic extrusions) result in an end product that is broadly comparable with that produced by fabrication. Others (epoxy coating, shape memory polymer, preformed plastic liner, cured-in-place plastic liner, and liquid coating) do not provide a metallic coating but are used in similar applications in different industries. Finally, there are technologies (such as plating, hot isostatic pressing, ceramic lining, and vapour deposition) that are proven processes but have no current application that may be considered directly relevant to high-pressure piping systems. One new concept under development by the authors is introduced - the use of a thin-walled liner manufactured from a corrosion resistant alloy, and expanded into a prebent carbon steel pipe.


Author(s):  
Debra Tetteh-Wayoe

The cost effective design and construction of liquid pipeline facilities traditionally necessitates the use of bolted joints as opposed to welds. Some of these bolted joints are frequently disassembled and reassembled as part of regular maintenance, while others are assembled at the time of construction and expected to retain a seal for the lifetime of the pipeline. Consequently, the design and installation practices employed for bolted connections are relied upon to produce the same operational life and integrity as welded pipe. In an effort to ensure that the bolted joints used on our pipeline system are as reliable as our welded joints, we investigated industry best practices for flange assembly and the root causes of joint failure. We have completed extensive research of technical literature, including the torquing procedures used in various industries, and performed field-testing on our own system. Generally we have found that: • Flange assembly failures and concerns about this issue are common in the oil and gas industry; • Practices for tightening flanges are inconsistent; and • To accomplish and retain an effective gasket seal, and thus minimize life cycle leaks, one has to consider many factors, including the amount of torque applied to nuts, the stud and nut friction, the type of gasket used, the size of the studs/nuts/flanges, the type of equipment used for tightening, the calibration of the torquing equipment, flange face alignment, and torquing sequence. Using the results of our investigation, we implemented several measures to enhance both the quality and the long-term integrity of our bolted flange connections. This paper describes the results of our investigations, as well as the practices implemented for flange assemblies required for maintenance and new construction activities.


Author(s):  
Wenxing W. Zhou ◽  
Ji Bao

The present study quantifies probabilistic characteristics of the wall thickness of welded pipe joints in onshore gas transmission pipelines based on about 5900 field-measured wall thicknesses collected from a pipeline system in Canada. The collected data cover a wide range of the pipe nominal wall thickness, from 3.18 to 16.67 mm. By considering the measurement error involved in the collected wall thickness data, statistical analyses indicate that the actual-over-nominal wall thickness ratio (AONR) follows a normal distribution with a mean of 1.01 and a coefficient of variation (COV) ranging from 1.6 to 2.2% depending on the nominal pipe wall thickness. The implications of the developed AONR statistics for the reliability analysis of corroded pipe joints are investigated. This study provides key input to the reliability-based design and assessment of pipelines with respect to various threats such as metal-loss corrosion and stress corrosion cracking.


Author(s):  
Bradley M. Jones ◽  
André-Michel Ferrari

Reliability, Availability and Maintainability (RAM) models were first developed in Enbridge Liquids Pipelines in 2006 and in the last 3 years have contributed over $200 Million in capital cost avoidance while maintaining or improving the reliable design and operation of the pipeline system. These models constitute a very effective, factual and dependable tool to assess the throughput performance of a pipeline system over its entire life cycle or a specified time of interest. In addition, the RAM model cost is a small fraction of the overall monetary benefit, in the order of 1%, hence making RAM models a highly leveraged activity. The concept of a RAM model stems from Reliability Block Diagram methods (also known as Dependent Diagrams). Interaction of large, complex and multi layered systems can then be analyzed using the Monte Carlo simulation methods (or Stochastic Discrete Event Simulation) hence quantifying the output of the entire system with greater accuracy than other estimating tools or methods. Over 10 years, Enbridge Liquids Pipelines has developed its own failure database for equipment and operational events consequently almost all model inputs are based on in-house data rather than industry generic data, making the model output more robust, accurate and appropriate for internal use. Initially, in Enbridge Liquids Pipelines, RAM models were mainly built to assess and confirm the design capabilities of future pipelines designs and assist in the optimal selection of specific design options. Because of the effectiveness of the tool combined with the current cost constrained business environment, the company is moving towards building RAM models for assets already in operation in order to optimize their performance. This is proving to be an extremely cost effective addition to internal decision making processes. The approach has been used in risk based budgeting, asset maintenance, design modifications and throughput optimization initiatives. In various industries including Oil and Gas, RAM models have proven their worth over time as an effective cost avoidance tool. This approach has now been successfully deployed in the Pipeline Industry at Enbridge. As an example, a RAM model conducted during the design phase of a pipeline project saved $28 million in capital by proving that an additional storage tank and significant new infrastructure was not required. Another benefit of RAM models has been their ability to confirm or counter stated assumptions by internal stakeholders. Equipment upgrades and equipment sparing decisions are often seriously debated and costly decisions may not always be based on complete economical foundations but rather on avoiding past negative experiences or by following basic guidelines that are less than optimal. When a project or operational team needs to find an alternative, a RAM model is a tool of choice to evaluate, and justify the best option. Because of its proven value, RAM models are now an integral part of Enbridge Liquids Pipelines Design Standards and are used on all large projects. Models recently built for operational pipelines delivered similar value so in the near future the work will be expanded to encompass the entire existing network of integrated pipelines to improve on performance and operational costs.


Author(s):  
Neda Stoeva ◽  
Timothy M. Adams ◽  
Tomas Jimenez ◽  
Scott Arnold ◽  
John Uhland

This paper presents the implementation of a Carbon Fiber Reinforced Polymer (CFRP) composite system as a long term replacement for a non-safety, non-seismic, non-QA, low pressure service water buried pipeline. The existing pipeline (to be replaced) consists of approximately 1800 feet of large diameter (primarily 54in.), carbon steel, spiral wound, seam welded pipe, which was built and installed using AWWA standards, but is maintained in accordance with the B31.1 Power Pipe Code [1]. The CFRP pipe installation is to be done as an internal repair, and designed to comply with ASME B31.1 as a stand-alone pipe (pressure boundary). In lieu of using the limited evaluation of PCC-2 [2], which is focused on local repairs; a complete design evaluation of the entire piping system to B31.1-2010 is conducted, which is consistent with and acceptable under PCC-2. Since B31.1 does not provide detailed guidance on the design of buried piping systems, the criteria presented in this paper use the base design requirements of B31.1 adjusted to include applied soil and surcharge loads. The selected CFRP repair is the TYFO® Fiberwrap® system which consists of a carbon fiber fabric (CFRP, TYFO SCH-41-2X), and glass fiber fabric (GFRP/dielectric barrier, TYFO SHE-51A), saturated with epoxy. This composite system is built up of unidirectional CFRP layers; thus, the presented design approach also considers anisotropic material behavior, and evaluates the hoop and axial loads and capacities separately. The criteria are presented for plants considering alternative repair and replacement techniques for buried and above ground non-safety pipes.


Author(s):  
R. Adibi-Asl

Piping systems in process industries and nuclear power plants include straight pipe runs and various fittings such as elbows, miter bends etc. Elbows and bends in piping systems provide additional flexibility to the piping system along with performing the primary function of changing the direction of fluid flow. Distinctive geometry of these toroidal shell components result in a structural behavior different from straight pipe. Hence, it would be useful to predict the behavior of these components with acceptable accuracy for design purposes. Analytical expressions are derived for stresses set up during loading and unloading in a toroidal shell subjected to internal pressure. Residual stresses in the component are also evaluated. The proposed solutions are then compared with three-dimensional finite element analysis at different locations including intrados, extrados and flanks.


2012 ◽  
Vol 134 (3) ◽  
Author(s):  
Bostjan Bezensek ◽  
Yinsheng Li ◽  
Kunio Hasegawa ◽  
Phuong H. Hoang

Piping systems in power plant may experience combined bending-torsion loads in the presence of planar crack-like flaws. ASME Boiler and Pressure Vessel Code Section XI nonmandatory Appendix C provides flaw evaluation procedures for pipes with flaws. These are currently limited to straight pipes under pressure and bending loads and no provision is made for torsion loading. The working group on pipe flaw evaluation is developing guidance for including the torsion load within the existing solutions provided in the Appendix C for bending loading on a straight pipe under fully plastic fracture regime. This paper reports on the finite element limit load analyses performed on the straight pipe containing a circumferential planar crack-like flaw. Pipe diameters were ranging from 4 in. (100 mm) to 24 in. (600 mm) nominal diameter (OD) and R/t ranging from 6 to 40. For the purpose of nonmandatory Appendix C flaw evaluation, it is concluded that the torsion loads can be combined with bending loads using the root of the sum of the squares (RSS) method of Section III of the ASME Boiler Code, without any additional weighting on torsion.


1984 ◽  
Vol 106 (3) ◽  
pp. 230-236 ◽  
Author(s):  
A. K. Dhalla

Explicit piping design procedures are not provided in theASME Code for structural evaluation of ovalization and fabrication effects at the butt-welded end of an elbow. This paper presents a conservative semi-analytical procedure that can be used with elastic as well as inelastic analysis to evaluate an elbow cross section welded to a straight pipe. The concept of carry-over factors is used to obtained ovalization stresses or strains at the elbow end. The stresses introduced by material and geometric nonuniformities in the fabrication process are then added to the ovalization stresses to complete structural evaluation of the girth butt-welded elbow joint.


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