Physical Forces on Buried Pipeline Coatings

2000 ◽  
Author(s):  
Graeme King
Keyword(s):  
Operating Conditions ◽  
Buried Pipeline ◽  
Buried Pipelines ◽  
Design Work ◽  
Physical Forces

Physical forces activated when buried pipelines move relative to the soil can damage coatings. The problem is most common near bends and areas with poor backfill compaction. Most solutions are best implemented early in the design work when pipeline routes, alignments, and operating conditions are being selected. Solutions, in addition to the obvious one of increasing toughness and adhesion of coatings, include increasing radius of bends, avoiding unstable slopes, improving backfill operations, stabilizing operating conditions, and reducing operating pressures and temperatures.

scholarly journals Experimental Research on Bearing Characteristics of the Asphalt Pavement Containing Buried Pipeline

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Hailiang Xu ◽  
Jining Qin ◽  
Hehuan Ren ◽  
Jindou Sun ◽  
Lian He
Keyword(s):  
Shear Strain ◽  
Experimental Research ◽  
Asphalt Pavement ◽  
Vertical Displacement ◽  
Operating Conditions ◽  
Test Method ◽  
Buried Pipeline ◽  
Buried Pipelines ◽  
Digital Speckle ◽  
Pavement Structure

The bearing characteristics of the asphalt pavement structure are greatly influenced by buried pipelines. Improper treatment of buried pipelines would cause early damage to pavement structure. By the digital speckle correlation method (DSCM), the experimental research on bearing characteristics of the asphalt pavement containing buried pipe was carried out. The mechanical characteristics of the asphalt pavement structure are studied under four different pipeline burial conditions. The vertical displacement and strain values of each layer of the asphalt pavement structure are obtained under four operating conditions. The results showed that (1) the digital speckle observation test method can accurately obtain the displacement and strain values of each layer of asphalt pavement structure containing buried pipeline, and the application effect is good. Compared with the traditional contact strain measurement method, this method is simple and accurate and can provide effective analysis data for experimental research. (2) There exists an interlayer effect of the asphalt pavement structure. The vertical displacement value and the strain value are discontinuities and can suddenly change between two adjacent layers. At the same time, the vertical strain and the shear strain concentration phenomenon appear at the bottom of each layer, especially at the bottom of the upper layer and the subbase layer of asphalt. (3) Affected by the buried pipelines, the vertical displacement value of the asphalt pavement structure reduces, and the tensile and shear strain values of asphalt pavement structure increase. The subbase layer of asphalt is most affected by the buried pipelines, which accelerated the destruction of the asphalt pavement structure.

Designing CO2 Transmission Pipelines Without Crack Arrestors

2010 ◽  
Author(s):  
Graeme G. King ◽  
Satish Kumar
Keyword(s):  
Wall Thickness ◽  
Carbon Capture ◽  
Power Plants ◽  
Oil And Gas ◽  
Cost Optimization ◽  
Operating Conditions ◽  
Operating Pressure ◽  
Design Work ◽  
Industrial Facilities ◽  
Pipeline Network

Masdar is developing several carbon capture projects from power plants, smelters, steel works, industrial facilities and oil and gas processing plants in Abu Dhabi in a phased series of projects. Captured CO2 will be transported in a new national CO2 pipeline network with a nominal capacity of 20×106 T/y to oil reservoirs where it will be injected for reservoir management and sequestration. Design of the pipeline network considered three primary factors in the selection of wall thickness and toughness, (a) steady and transient operating conditions, (b) prevention of longitudinal ductile fractures and (c) optimization of total project owning and operating costs. The paper explains how the three factors affect wall thickness and toughness. It sets out code requirements that must be satisfied when choosing wall thickness and gives details of how to calculate toughness to prevent propagation of long ductile fracture in CO2 pipelines. It then uses cost optimization to resolve contention between the different requirements and arrive at a safe and economical pipeline design. The design work selected a design pressure of 24.5 MPa, well above the critical point for CO2 and much higher than is normally seen in conventional oil and gas pipelines. Despite its high operating pressure, the proposed network will be one of the safest pipeline systems in the world today.

Comparison of Buried Pipeline Crossing Assessments Using API RP 1102, Analytical Method and Finite Element Approach

2020 ◽  
Author(s):  
Nikhil Joshi ◽  
Pritha Ghosh ◽  
Jonathan Brewer ◽  
Lawrence Matta
Keyword(s):  
Finite Element ◽  
Analytical Method ◽  
Rapid Assessment ◽  
Buried Pipeline ◽  
The Finite Element Method ◽  
Buried Pipelines ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Element Approach ◽  
Multiple Loading

Abstract API RP 1102 provides a method to calculate stresses in buried pipelines due to surface loads resulting from the encroachment of roads and railroads. The API RP 1102 approach is commonly used in the industry, and widely available software allows for quick and easy implementation. However, the approach has several limitations on when it can be used, one of which is that it is limited to pipelines crossing as near to 90° (perpendicular crossing) as practicable. In no case can the crossing be less than 30° . In this paper, the stresses in the buried pipeline under standard highway vehicular loading calculated using the API RP 1102 method are compared with the results of two other methods; an analytical method that accounts for longitudinal and circumferential through wall bending effects, and the finite element method. The benefit of the alternate analytical method is that it is not subject to the limitations of API RP 1102 on crossing alignment or depth. However, this method is still subject to the limitation that the pipeline is straight and at a uniform depth. The fact that it is analytical in nature allows for rapid assessment of a number of pipes and load configurations. The finite element analysis using a 3D soil box approach offers the greatest flexibility in that pipes with bends or appurtenances can be assessed. However, this approach is time consuming and difficult to apply to multiple loading scenarios. Pipeline crossings between 0° (parallel) and 90° (perpendicular) are evaluated in the assessment reported here, even though these are beyond the scope of API RP 1102. A comparison across the three methods will provide a means to evaluate the level of conservatism, if any, in the API RP 1102 calculation for crossing between 30° and 90° . It also provides a rationale to evaluate whether the API RP 1102 calculation can potentially be extended for 0° (parallel) crossings.

Reliability of Buried Pipeline Using a Theory of Probability of Failure

2006 ◽  
Vol 110 ◽  
pp. 221-230 ◽  
Author(s):  
Ouk Sub Lee ◽  
Dong Hyeok Kim ◽  
Seon Soon Choi
Keyword(s):  
Failure Probability ◽  
Probability Of Failure ◽  
Operating Conditions ◽  
Reliability Estimation ◽  
Design Parameters ◽  
Buried Pipeline ◽  
Safety Level ◽  
First Order ◽  
Reliability Method ◽  
Corrosion Defects

The reliability estimation of buried pipeline with corrosion defects is presented. The reliability of corroded pipeline has been estimated by using a theory of probability of failure. And the reliability has been analyzed in accordance with a target safety level. The probability of failure is calculated using the FORM (first order reliability method). The changes in probability of failure corresponding to three corrosion models and eight failure pressure models are systematically investigated in detail. It is highly suggested that the plant designer should select appropriate operating conditions and design parameters and analyze the reliability of buried pipeline with corrosion defects according to the probability of failure and a required target safety level. The normalized margin is defined and estimated accordingly. Furthermore, the normalized margin is used to predict the failure probability using the fitting lines between failure probability and normalized margin.

Prestressing Buried Pipelines by Heating With Air

1993 ◽  
Vol 115 (4) ◽  
pp. 223-228
Author(s):  
G. King
Keyword(s):  
Elevated Temperatures ◽  
Lateral Stability ◽  
Buried Pipeline ◽  
Heating Equipment ◽  
Buried Pipelines ◽  
Thermally Induced ◽  
Hot Air ◽  
Compressive Stresses ◽  
Liquid Sulphur ◽  
Surrounding Soil

Buried pipelines operating at elevated temperatures experience high longitudinal compressive stresses because the surrounding soil prevents thermal expansion. At high operating temperatures, buried pipelines can push through the soil at bends and buckle catastrophically. In soft soils they can lose lateral stability, and they can develop plastic failures. Thermally induced problems can be prevented with varying degrees of success by using thicker wall pipe, higher strength steel, longer radius bends, deeper burial, better backfill compaction, and/or prestressing during construction. Prestressing is most appropriate for pipelines operating at temperatures more than 80°C above ambient. One technique for prestressing a buried pipeline, that has been found to be both easy and economical for a liquid sulphur pipeline in Alberta, is to heat it with hot air and bury it while it is still hot. Pipe diameter and prestressing temperature both have a significant impact on the kind of heating equipment that is required.

scholarly journals Additional Stress on a Buried Pipeline under the Influence of Coal Mining Subsidence

2018 ◽  
Vol 2018 ◽  
pp. 1-16 ◽  
Author(s):  
Ping Xu ◽  
Minxia Zhang ◽  
Zhibin Lin ◽  
Zhengzheng Cao ◽  
Xu Chang
Keyword(s):  
Coal Mining ◽  
Surface Deformation ◽  
Analytical Calculation ◽  
Mining Subsidence ◽  
Ground Subsidence ◽  
Additional Stress ◽  
Buried Pipeline ◽  
Buried Pipelines ◽  
Probability Integral Method ◽  
Coal Mining Subsidence

Buried pipelines influenced by coal mining subsidence will deform and generate additional stress during surface deformation. On the basis of the coordinating deformation relationship between buried pipeline and its surrounding soils, a stress analysis method of a buried pipeline induced by mining was proposed. The buried pipeline additional stresses were analyzed; meanwhile, a corresponding analysis process of the pipeline stresses was also presented during mining subsidence. Furthermore, based on the ground subsidence along the pipeline predicted in advance by the probability integral method, the additional stresses and Von Mises equivalent stresses and their distributions along the buried pipeline induced by the exploitation of a coal mining working face named 14101 were obtained. Meanwhile, a comparative analysis of additional stresses between simulation and analytical calculation was performed for the deep analysis and reliability of the results presented by the proposed methodology in this paper. The proposed method provides references for analysis of the additional stress and safety of buried pipelines under the influence of mining subsidence.

Upheaval Buckling Analysis of Partially Buried Pipeline Subjected to High Pressure and High Temperature

2011 ◽  
Author(s):  
Jason Sun ◽  
Han Shi ◽  
Paul Jukes
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Soil Cover ◽  
Resistance Force ◽  
Soil Resistance ◽  
Buried Pipeline ◽  
Buried Pipelines ◽  
Lateral Buckling ◽  
Upheaval Buckling ◽  
Global Buckling

Offshore industry is now pushing into the deepwater and starting to face the much higher energy reservoir with high pressure and high temperature. Besides the significant impacts on the material, strength, and reliability of the wellhead, tree, and manifold valve; high Pressure (HP) also leads to thicker pipe wall that increases manufacturing and installation cost. High Temperature (HT) can have much wider impact on operation since the whole subsea system has to be operated over a greater temperature range between the non-producing situations such as installation, and long term shut down, and the maximum production flow. It is more concerned for fact that thicker wall pipe results in much greater thermal load so to make the pipeline strength and tie-in designs more challenging. Burying sections of a HPHT pipeline can provide the advantages of thermal insulation by using the soil cover to retain the cool-down time. Burial can also help to achieve high confidence anchoring and additional resistance to the pipeline axial expansion and walking. Upheaval buckling is a major concern for the buried pipelines because it can generate a high level of strain when happens. Excessive yielding can cause the pipeline to fail prematurely. Partial burial can have less concern although it may complicate the pipeline global buckling behavior and impose challenges on the design and analysis. This paper presents the studies on the upheaval buckling of partially buried pipelines, typical example of an annulus flooded pipe-in-pipe (PIP) configuration. The full-scale FE models were created to simulate the pipeline thermal expansion / upheaval / lateral buckling responses. The pipe-soil interaction (PSI) elements were utilized to model the relationship between the soil resistance (force) and the pipe displacement for the buried sections. The effects of soil cover height, vertical prop size, and soil resistance on the upheaval and lateral buckling response of a partially buried pipeline were investigated. This paper presents the latest techniques, allows an understanding in the global buckling, upheaval or lateral, of partially buried pipeline under the HPHT, and assists the industry to pursue safer but cost effective design.

Beam-Mode Buckling of Buried Pipeline Subjected to Seismic Ground Motion

2012 ◽  
Author(s):  
Masaki Mitsuya ◽  
Takashi Sakanoue ◽  
Hiroyuki Motohashi
Keyword(s):  
Finite Element ◽  
Ground Motion ◽  
Critical Strain ◽  
Peak Load ◽  
Earthquake Resistance ◽  
Past Study ◽  
Buried Pipeline ◽  
Buried Pipelines ◽  
Seismic Ground Motion ◽  
Beam Mode

During seismic events, buried pipelines are subjected to deformation by seismic ground motion. In such cases, it is important to ensure the integrity of the pipeline. Both beam-mode and shell-mode buckling may occur in the event of compressive loading induced by seismic ground motion. In this study, the beam-mode buckling of a buried pipeline that occurred after the 2007 Niigataken Chuetsu-oki earthquake in Japan is investigated. A simple formula for estimating the critical strain, which is the strain at the peak load, is derived, and the formula is validated by finite-element analysis. In the formula, the critical strain increases with the pipeline diameter and hardness of the surrounding soil. By comparing the critical strain derived in this study for beam-mode buckling with the critical strain derived in a past study for shell-mode buckling, the formula facilitates the selection of the mode to be considered for evaluating the earthquake resistance of a pipeline. In addition to the critical strain, a method to estimate the deformation caused by seismic ground motion is proposed; the method can be used to evaluate the earthquake resistance of buried pipelines. This method uses finite-element analyses, and the soil–pipe interaction is considered. This method is used to reproduce the actual beam-mode buckling observed after the Niigataken Chuetsu-oki earthquake, and the earthquake resistance of a buried pipeline with general properties is evaluated as an example.

scholarly journals Methods for estimating the durability of the needle bearing of the piston head of the connecting rod of a transportation diesel

2021 ◽  
pp. 55-60
Author(s):  
Vadym Mychaylovich Petuhov ◽  
Alexandr Vasilyevich Orobinsky ◽  
Natalya Anatolyevna Aksenova
Keyword(s):  
Diesel Engine ◽  
Service Life ◽  
Test Procedure ◽  
Operating Conditions ◽  
Accelerated Tests ◽  
Connecting Rod ◽  
Design Work ◽  
Engine Operation ◽  
Piston Head ◽  
Rolling Elements

The article presents the results of an experimental study and analytical evaluation calculations to check service life and increase durability of the needle bearing of piston head of connecting rod of a transport diesel engine. The primary reasons for the violation of the nominal operation of the main units of this mechanism have been established. Corresponding recommendations are proposed for carrying out accelerated tests for durability, reducing the thermal loads of the bearing operation and, as a consequence, improving the quality and service life of its entire piston group. Theoretical and experimental methods for determining the nominal life of the needle bearing of the piston head of the connecting rod (PHCR) of a transport diesel engine are proposed. The theoretical methodology allows obtaining reliable values of durability, taking into account the distribution of the working load over the rolling elements, as well as the mobility of the piston pin and sleeve. The performed calculations make it possible to correct and clarify the standard mathematical model for determining the nominal life of the PHCR needle bearing, depending on the distribution of loads on the rolling elements (rollers) under different operating conditions. This experimental technique with an acceleration factor of 10 is based on a twofold increase in the force effect on the elements of the PHCR needle bearing. This was achieved by assembling the bearing using a special technology, which is described in detail in the work. A significant decrease in the thermal effect and a decrease in radial loads on working rollers have been established. For ensure the regular oil supply into bearing during engine operation, a technique was developed to increase the load on the roller in contact zone, which significantly influenced durability and made it possible to conduct accelerated tests with a reliable yield. Its results of operational research and experience in design work correlate and are sufficiently explained by the developed methods, which allows them to be used for the improvement and modernization of connecting rods with needle bearings in PHCR. That is a permission to use these methodic for doing perfect and modern the needle bearing of the connecting-rod piston. Keywords: diesel, test procedure, needle bearing, rollers, piston head of the connecting rod, durability.

Research on Analytic Calculation Method of the Dynamic Response of Buried Pipelines under Indirect Ground Shock

2013 ◽  
Vol 477-478 ◽  
pp. 77-80 ◽  
Author(s):  
Guo Fu Xu ◽  
Zheng Dong Deng ◽  
Chong Ji ◽  
Jing Jing Jia
Keyword(s):  
Solution Method ◽  
Static Load ◽  
Analytic Solution ◽  
Engineering Application ◽  
Buried Pipeline ◽  
Buried Pipelines ◽  
Equivalent Static Load ◽  
Conventional Weapons ◽  
Ground Shock ◽  
Dynamic Damage

Buried pipelines are important lifeline engineering. During war conventional weapons blasting in the air would induce indirect ground shock, and the shock to the buried pipeline can lead to the paralyzed of urban economic and social function. And the numerical simulation of the dynamic damage of buried pipeline is complicated and time consuming, so this article using the equivalent static load method proposes analytic solution method of stress calculation of buried pipeline under ground shock. Through comparing the results calculated by analytic solution method and numerical solution, it shows that the analytical solution is feasible in engineering application.

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