Showing papers in "Journal of Pipeline Systems Engineering and Practice in 2013"
TL;DR: In this paper, the authors proposed a method of detecting distributed deterioration by investigating the time-domain water hammer response trace from a single pipe with a deteriorated section, where a theoretical square-shaped perturbation is found in the transient pressure trace as a result of distributed deterioration.
Abstract: A number of different methods that use signal processing of fluid transients (water hammer waves) for fault detection in pipes have been proposed in the past two decades. However, most of them focus solely on the detection of discrete deterioration, such as leaks or discrete blockages. Few studies have been conducted on the detection of distributed deterioration, such as extended sections of corrosion and extended blockages. This is despite the fact that they commonly exist and can have a severe negative impact on the operation of pipelines. The research reported here proposes a method of detecting distributed deterioration by investigating the time-domain water hammer response trace from a single pipe with a deteriorated section. Through wave analysis using a step pressure input, a theoretical square-shaped perturbation is found to exist in the transient pressure trace as a result of distributed deterioration. The hydraulic impedance of this section can be derived from the magnitude of the reflected pressure perturbation, while the location and length of the corresponding deteriorated section can be determined by using the arrival time and duration of the perturbation. The proposed method has been validated by analyzing experimental data measured from a pipe with a section of wall thickness change.
52 citations
TL;DR: In this paper, a hybrid model PSO-GA is presented to effectively utilize local and global search capabilities of particle swarm optimization (PSO) for optimal pipe sizing in a water distribution network.
Abstract: In modern civilization, water distribution network has a substantial role in preserving the desired living standard. It has different components such as pipe, pump, and control valve to convey water from the supply source to the consumer withdrawal points. Among these elements, optimal sizing of pipes has great importance because more than 70% of the project cost is incurred on it. Unfortunately, optimal pipe sizing falls in the category of nonlinear polynomial time hard (NP-hard) problems. Hence, solid research activities march on because of two facts, namely, importance and complexity of the problem. The literature revealed that the stochastic optimization algorithms are successful in exploring the combination of least-cost pipe diameters from the commercially available discrete diameter set, but with the expense of significant computational effort. The hybrid model PSO-GA, presented in this paper aimed to effectively utilize local and global search capabilities of particle swarm optimization (...
49 citations
TL;DR: An acoustic emission (AE) method was used to detect leaks and discern their location under flow conditions in a 304.8m-long, 305mm-diameter buried steel pipeline at the New Jersey Institute of Technology/U.S. Environmental Protection Agency (NJIT/USEPA) Buried Pipeline Test Facility in Edison, New Jersey as mentioned in this paper.
Abstract: An acoustic emission (AE) method was used to detect leaks and discern their location under flow conditions in a 304.8-m-long, 305-mm-diameter buried steel pipeline at the New Jersey Institute of Technology/U.S. Environmental Protection Agency (NJIT/USEPA) Buried Pipeline Test Facility in Edison, New Jersey. A 16.2 mL/s leak was successfully detected, and its discernible location was indicated to within 0.3 m, with a sensor separation of 65.5 m, and with water in the pipeline flowing at 11.4 L/s. Encouraging results were also obtained for a 1.3 mL/s leak that was discernible at a sensor separation of 21.3 m under the same flow conditions. Previous static pressure leak testing on this pipeline detected a 12.6 mL/s leak at sensor separations of up to 192.9 m, and it is expected that mitigating the effects of both externally produced and flow-induced background noise will allow for the detection of smaller leak rates under greater flow conditions. These results demonstrated that effective AE leak ...
46 citations
TL;DR: In this paper, a semi-empirical technique is proposed to model the increase in lateral stress and soil kneading during compaction, which takes into account the increase of lateral stress in compaction and provides an upper limit for the pipe deformations and stresses.
Abstract: Compaction of the soil placed beside culverts (the side-fill) can have a significant effect on the behavior of flexible and rigid structures. This is particularly true for shallow buried structures when the stresses resulting from compaction represent a greater proportion of the total stresses present. Different techniques have been reported in the literature to model soil compaction during finite-element analyses. A new semiempirical technique is proposed, which takes into consideration the increase in lateral stress and soil kneading during compaction. A simple procedure is discussed to incorporate the compaction of granular material in finite-element analysis. The new technique is used to model five different pipe products composed of different materials and dimensions, and the results are compared to measured values reported in the literature. A new factor is proposed to account for soil kneading during compaction to provide an upper limit for the pipe deformations and stresses that result dur...
44 citations
TL;DR: In this paper, the authors proposed a data-driven approach in determining an optimal inspection interval for a petroleum pipeline system, which accounts for the determination of both the probability of failure and its associated consequences.
Abstract: This paper proposes a data-driven approach in determining an optimal inspection interval for a petroleum pipeline system. The approach accounts for the determination of both the probability of failure and its associated consequences. The probability of failure is estimated by fitting the historical data of failure of the pipeline into either a homogenous Poisson process or non-homogenous Poisson process (power law). The analysis of historical data reveals the Poisoneous form that gives better description of the failure process. The consequences of failure are calculated in terms of economic loss, environmental damage and loss of human life. Both the failure probability and consequences are utilized to estimate the total loss of an operating pipeline system. A risk based integrity maintenance optimization of the pipeline is achieved by minimizing the economic loss, while taking the human risk and maintenance budget as constraints. The proposed framework is utilized in the maintenance planning of a very long cross country petroleum pipeline system. The outcomes are robust and well validated. The framework can be applied to any engineering system that requires inspection and maintenance planning.
32 citations
TL;DR: In this paper, the three-dimensional flow velocity components at the span shoulder, which is located at the junction of a submarine pipeline and the associated scour hole, are measured in unidirectional steady current in order to investigate the flow structure and mechanics of the lateral propagation of a 3D pipeline-scour hole.
Abstract: The three-dimensional flow velocity components at the span shoulder, which is located at the junction of a submarine pipeline and the associated scour hole, are measured in unidirectional steady current in order to investigate the flow structure and mechanics of the lateral propagation of a three-dimensional pipeline-scour hole. A naturally formed three-dimensional scour hole around a modeled pipeline is immobilized using adhesive, giving a steady flow field around the fixed boundary. A three-dimensional down-looking acoustic Doppler velocimeter is then used to measure the flow velocities at several critical sections. Combined with the measured data and observations made in the study, the flow characteristics and other factors that affect propagation of the three-dimensional pipeline-scour hole in steady current are discussed.
28 citations
TL;DR: In this paper, a series of large-scale model tests were carried out with soft clay chosen as the supporting medium in view of Bohai Sea geotechnical conditions, and pipe segments with diameters of 30, 50, and 80 mm were used.
Abstract: Under high thermal stress, buckling of submarine pipelines may occur to release the stresses accumulated in the walls of the pipelines. The likelihood that buckling occurs is largely determined by the capability of the soil to resist pipeline movements. Therefore, it is very important to determine the soil resistance in upheaval buckling when designing submarine pipelines. A series of large-scale model tests were carried out with soft clay chosen as the supporting medium in view of Bohai Sea geotechnical conditions. Pipe segments with diameters of 30, 50, and 80 mm were used. The pipes were buried in different depth-to-diameter ratios between 1 and 9. The uplift, lateral, and axial resistances were recorded during the tests. The test results have shown that the soil resistance depends on the pipe’s diameter and cover depth. According to the uplift test results, the load-displacement relationships with smaller depth of cover differ greatly from those with larger depth of cover. The results of the ...
28 citations
IBM1
TL;DR: In this article, the authors reviewed large crater-forming pipeline explosive ruptures in the past 25 years and explored the explosive ignition of accumulated gas leaks from pipeline defects into surrounding air spaces.
Abstract: Large crater-forming pipeline explosive ruptures in the past 25 years are briefly reviewed in this paper. The National Transportation Safety Board reports on these accidents have found the mechanical failure of damaged or defective pipe to be the rupture cause. An alternative cause explored and discussed here is the explosive ignition of accumulated gas leaks from pipeline defects into surrounding air spaces. Remedial actions augmented to address the added risks associated with pipeline leaks and nearby air spaces could improve public safety.
27 citations
TL;DR: In this paper, the authors investigated the feasibility of continuous monitoring techniques using piezoelectric transducers (PZTs) permanently installed on steel pipes, and applied pattern recognition techniques to detect a mass scatterer (a proxy for damage) under ambient variations primarily due to varying internal pressure of a pipe.
Abstract: This paper presents the preliminary results of a research project that investigates the feasibility of continuous monitoring techniques using piezoelectric transducers (PZTs) permanently installed on steel pipes. The ultrasonic waves generated by PZTs are multimodal and dispersive. Therefore, it is difficult to detect changes created by the presence of damage, and it is even more difficult to differentiate changes produced by damage from benign changes produced by variation in environmental and operational conditions. In this paper, the results are reported of applying pattern recognition techniques to detect a mass scatterer (a proxy for damage) under ambient variations primarily due to varying internal pressure of a pipe. Using wavelet methods, 303 features are extracted, and adaptive boosting, modified adaptive boosting, and support vector machines for damage detection are employed. The performances of the three classifiers are evaluated over 41 trials with different combinations of training and testing data, resulting in the average accuracies of 85, 89, and 94%, respectively. Finally, the effectiveness of wavelet processing and features selected are discussed.
21 citations
TL;DR: In this article, an adaptive neuro-fuzzy inference system (ANFIS) and Gene Expression Programming (GEP) models are developed for the estimation of critical velocity.
Abstract: One of the important trends of development of hydromechanization in hydraulic engineering is the transport of solids in the form of slurries. Slurry is a thick suspension of solids in a liquid. Clogging of the pipeline carrying slurry will not occur if the velocity of the slurry is more than some critical value. Critical flow velocity, which is the minimum velocity to maintain all solid particles in a suspension condition, is the important design parameter in slurry transport through pipelines. Gene-expression programming (GEP) and adaptive neuro-fuzzy inference system (ANFIS) models are developed in this study for the estimation of critical velocity. The estimated critical velocity by GEP and ANFIS models are compared with existing empirical equations and it is found that the ANFIS model produces better results compared with GEP and other existing equations.
15 citations
TL;DR: The main indicator of physical integrity is frequency of water main breaks, but reducing these is difficult because of the complexity and scale of the problem and the lack of incentives for pipeline replacement.
Abstract: Replacement to sustain the integrity of water mains in the United States is on a cycle of approximately once in 200 years, a slow rate that contributes to the current grade of D- on the Infrastructure Report Card. The main indicator of physical integrity is frequency of water main breaks, but reducing these is difficult because of the complexity and scale of the problem and the lack of incentives for pipeline replacement. This paper draws from current research to explain the risk formulation of the decision process for pipeline replacement, the current rates of renewal, and the reasons why utilities renew pipes at low rates. Recommended solutions in the face of a financial crisis focus on analysis and management tools, data systems, standardized reporting, incentive structures, modest rate increases, and voluntary industry reforms. Improving integrity of water distribution systems and reducing main breaks are important to the long-term viability of public water systems, the costs to future generations, and to public health. Solutions will require enlightened and committed professional and political leadership, and optimized life-cycle asset management that includes maintenance, replacement, and realistic cost models and design lives.
TL;DR: In this article, the authors investigate the behavior of lead-caulked cast-iron pipe joints and estimate the degree of settlement that two or more contiguous segments of a pipe can tolerate before failure.
Abstract: Bell split, in which a shard is separated from the bell end of a bell-spigot joint, is a predominant failure mode (in addition to longitudinal facture) that is observed in lead-caulked bell-spigot joints of large-diameter cast-iron pipes installed between 1850 and the early 1960s. This paper addresses three specific issues related to this type of failure of lead-caulked bell-spigot joints: (1) the extent to which cast-iron pipe joints can rotate without inducing stress in the bell; (2) the behavior of the bell–spigot lead-caulked joints; and (3) an estimate of the degree of settlement that two or more contiguous segments of jointed cast-iron pipe can tolerate before failure. The procedures described in this paper were motivated by the need to understand and explain the circumstances that lead to this failure mode in large-diameter cast-iron pipes. A mechanistic model accounts for lead material nonlinearity, wet and dry joint conditions encountered in water and gas pipelines, respectively, and exis...
Journal Article•
TL;DR: In this article, the authors investigated the effect of antisliding piles on the stability of a pipeline crossing a typical landslide in western China and evaluated the safety of a typical underground pipeline crossing the landslide area.
Abstract: Long-distance natural gas transmission pipelines are planned to pass through the mountain area of midwest China, portions of which are threatened by severe landslide hazards. Therefore, the protection plan and control scheme for pipelines traversing and/or exiting landslide areas are of increasing interest and importance. A typical landslide in western China was used as an example to implement the strategy and evaluate the safety for a typical underground pipeline crossing the landslide area. The investigation and resulting control measures are based on the engineering geological study, and the numerical (finite-difference) interactive model of the pipeline and landslide, including the effect of soil arching. The effect of key design factors, including the spacing of antisliding piles, is determined by three-dimensional finite-difference numerical modeling. This technique also calculates the stability coefficient by use of the strength reduction method and calculation of stress and displacement fields. The results show that the recommended deployment of the antisliding piles can dramatically improve stability by reducing the effect of the landslide, thereby maintaining the displacement and stress of the pipeline within acceptable limits.
TL;DR: In this article, the authors discuss the possibility of vertical buckling of subsea pipelines. But, they do not consider the possibility that the axial compressive forces caused by the constrained expansions set up by thermal and internal pressure actions can lead to either lateral buckling in the plane of the seabed or vertical plane.
Abstract: Since the early seventies, pipelines have become one of the main means of transporting oil and gas offshore in many parts of the world. In-service hydrocarbons must be transported at high temperature and pressure to ease the flow and prevent solidification of the wax fraction. The buckling of subsea pipelines occur because of the introduction of axial compressive forces caused by the constrained expansions set up by thermal and internal pressure actions. Such compressive forces can lead to either lateral buckling in the plane of the seabed or buckling in a vertical plane. To ensure minimal interference with other marine activities, the pipelines can be buried in a trench. In such cases, the lateral soil restraint exceeds the vertical uplift restraint created by the pipe’s submerged weight. Therefore, vertical buckling is of particular interest with respect to entrenched subsea pipelines. The possibility of upheaval buckling in subsea pipelines has been appreciated in the pipeline industry for over...
TL;DR: In this paper, the authors compared the performance of the USLE and MMF models in terms of soil degradation along the corridor of oil and gas pipelines, and concluded that the USE model is more sensitive to elevation change than the MMF model.
Abstract: The main goal of this study is to assess the Morgan-Morgan-Finney (MMF) and the universal soil loss equation (USLE) erosion models in the prediction of soil degradation along the corridor of oil and gas pipelines. In the comparative analysis, the MMF model revealed a larger coefficient of variation (COV) in predicted soil loss rates. Based on the pair-sample t-test, the predictions of the two models were significantly different in the spatial distribution of soil loss along the rights-of-way (RoW) of the pipelines. Sensitivity of the MMF and USLE models to terrain morphometric elements was also assessed. Slope gradient was one of the controlling factors of erosion processes, but not of the soil loss rates. The MMF and USLE models did not reveal any sensitivity to slope aspects. In terms of elevation, the MMF model revealed higher soil loss rates in the lower elevations than with the USLE model, leading to the conclusion that the USLE model is more sensitive to elevation change than the MMF model. The USLE model revealed higher sensitivity to the terrain curvature than the MMF model because it had larger variations within concave and flat terrain curvature types. Both models were sensitive to increasing vegetation cover (VC) percentage. Both models revealed different sensitivities; therefore, better understanding of these sensitivities may contribute to the selection of the most suitable model, depending on the terrain, to yield the highest soil loss prediction accuracy. Qualitative validation of the spatial distribution of USLE- and MMF-predicted erosion-prone areas was performed using 6 years of ongoing surveillance and measurement of erosion occurrences. Quantitative validation of the predicted soil loss was performed using 3 years of monitoring of field erosion plots. The USLE model performed better than the MMF model in terms of the frequency ratio of erosion occurrences within the critical erosion classes (soil loss > 10 t/ha). The USLE-predicted soil loss rates were more reliable than the MMF rates not only in terms of spatial distributions of critical erosion classes, but also in quantitative terms of soil loss rates because of the high correlation with the soil loss measurements of field erosion plots. The number of erosion-prone pipeline segments realistically predicted by the USLE model, e.g., soil loss more than 10 t/ha, was 88, whereas the MMF model predicted only 76 erosion-prone pipeline segments. The regression analysis between the total of 354 USLE and MMF erosion-prone segments revealed an R2 equal to 0.33, which means that the predictions by the USLE and MMF erosion models are significantly different on the level of pipeline segments.
TL;DR: In this article, the impact of auto power spectrum density, pipe cross-sectional radius, and wall thickness, local effect, and coherency effect on pipeline responses are analyzed by calculating the longitudinal and lateral seismic responses of continuous pipelines in a homogeneous medium using a pseudoexcitation algorithm of the random vibration theory.
Abstract: Analyses on the basis of seismic array records have confirmed that spatially distributed earthquake ground motions are neither fully coherent nor independent, but partially coherent. It has not yet been fully addressed how the partially coherent nature of seismic ground motions affect the seismic response of underground pipelines. In this paper, the impact of auto power spectrum density, pipe cross-sectional radius, and wall thickness, local effect, and coherency effect on pipeline responses are analyzed by calculating the longitudinal and lateral seismic responses of continuous pipelines in a homogeneous medium using a pseudoexcitation algorithm of the random vibration theory. A numerical integration technique is developed by converting infinite integration into a series with limited terms. Sufficient precision is achieved when integration steps are sufficiently small. The method provides a simplified way for practical professionals to analyze response of underground pipelines to earthquakes.
TL;DR: In this article, the authors present full-scale testing results of a 1,370mm (54in.) nominal diameter prototype rolled groove joint incorporated into a bar-wrapped concrete pressure pipe manufactured to A...
Abstract: This paper presents full-scale testing results of a 1,370-mm (54-in.) nominal diameter prototype rolled groove joint incorporated into a bar-wrapped concrete pressure pipe manufactured to A...
TL;DR: In this article, the authors describe the in situ monitoring of the installation of a gas pipeline during HDD construction by using a gyroscope position-detection system and fiber optic sensing technique.
Abstract: Horizontal directional drilling (HDD) is an important technology for the placement of municipal pipelines, including water and sewer lines. This paper describes the in situ monitoring of the installation of a gas pipeline during HDD construction by using a gyroscope position-detection system and fiber optic sensing technique. The three dimensional (3D) spatial coordinates of the overall pipeline have been measured, allowing calculation of the product pipe strains and corresponding axial forces and moments during the installation. The results verify that the longitudinal strains and the section moments are sharply increased as the pipe traverses the bore path, with a simultaneous bend in the horizontal and vertical planes. The recorded data is available for the further theoretical analysis, as desired, and the monitoring strategy can be adopted for other similar projects.
TL;DR: In this paper, a procedure to utilize photogrammetry in the measuring of ground movements and examines its precision and accuracy in simulated field conditions is presented, and the results are compiled and analyzed to determine the accuracy and precision of photogrammetric measurements in measuring ground movements.
Abstract: A primary concern of owners specifying trenchless installation and rehabilitation methods are surface movements during construction. Surface heave or settlement can occur as a result of contractor methodology, design, or geotechnical conditions. Performing quality assurance during and after construction provides owners with an understanding of what surface movements have occurred and if remedial action may be required. Traditional methods utilized to measure ground surface movements include surveying triangulation, geometric leveling, and global positioning system (GPS) surveying. This paper presents a procedure to utilize photogrammetry in the measuring of ground movements and examines its precision and accuracy in simulated field conditions. Utilizing consumer-grade digital single lens reflex (SLR) cameras, photogrammetry does not require highly trained personnel, takes less time, and costs less money than traditional methods. Accuracy is determined by comparing measurements taken with photogrammetry to those taken with traditional rod and level. The results are compiled and analyzed to determine the accuracy and precision of photogrammetry in measuring ground movements.
TL;DR: In this article, the authors present results and analysis of pressure tests performed on carbon steel pipes with external defects repaired using composite materials and demonstrate that the load was transferred from the steel pipe into the composite material.
Abstract: This paper presents results and analysis of pressure tests performed on carbon steel pipes with external defects repaired using composite materials. These results are part of a broader study on the structural health monitoring of the use of composite repairs to rehabilitate damaged carbon steel pipework. The surface of pipe that contains the arc-shaped defects was appropriately prepared prior to installation of the composite repair, and monitoring of the performance was achieved through strain gauges. Rectangular strain gauge rosettes were installed beneath and on the outer surface of the composite repair, and the output strain data were acquired using the real-time Labview software and a Compact Rio system. The hoop and axial strains measured by each of these gauges showed a consistency in the strain distribution through the composite repair and demonstrated that the load was transferred from the steel pipe into the composite material.
TL;DR: In this paper, a quantitative analysis on sewage pipe damage is reported, based on this analysis, a quantification theory type II is proposed to describe the relationship between various factors that contribute to the damage of sewage pipe systems.
Abstract: The damage caused by the aging of sewage pipe systems has become one of the major rising problems in modern cities. The traditional method to search for damage points of sewage pipes is the use of cameras and human observation. However, the use of these methods to check all the sewage pipes in the city will require a great deal of time and money. In this paper, a quantitative analysis on sewage pipe damage is reported. This study utilized the results of the sewer investigation in Tokyo. Based on this analysis, a quantification theory type II is proposed to describe the relationship between various factors that contribute to the damage of sewage pipe systems. Thus, these factors, including pipe diameter, number of years since installation, type of road and foundation, overburden, and pipe slope, can be used to judge if the sewage pipe displays corrosion, cracks, or breakage. As a result, the diagnosis model can be used to determine the likely extent of damage to an existing sewage pipe system.
TL;DR: In this article, the hazardous exposure and self-burial of a submarine pipeline were studied based on the investigation of a sand wave area in the South China Sea, as well as on statistical data and mathematical calculations.
Abstract: The hazardous exposure and self-burial of a submarine pipeline were studied based on the investigation of a submarine pipeline in the sand wave area in the South China Sea, as well as on statistical data and mathematical calculations. The results indicate that the pipeline free span in the area was mainly induced by seabed erosion, sand wave movement, and human disturbance. Extreme weather events cause severe impacts on seabed topography and the pipeline condition. The burial status of the pipe is mainly controlled by the evolution of local seabed topographical conditions, i.e., the amount of sediment load and the movement of seabed sand waves. The migration of the continuous small-scale sand waves facilitates the self-burial of pipes, while the migration of isolated large-scale sand waves creates potential hazards for pipelines because of the existing free span continues to grow on both sides of the sand wave.
TL;DR: The web-based geospatial tool developed in this research enables the risk screening model results to be visualized and queried in a user-friendly, interactive environment for usefulness at the network level among water utilities.
Abstract: This paper focuses on the development of a web-based geospatial tool as a proof of concept to assist water utilities in performing a network-level risk screening of their buried water and wastewater pipeline infrastructure systems. This tool provides a preliminary risk screening at a high level to quickly identify problematic (hot spot) areas and help guide decisions about where to further analyze pipeline infrastructure systems. The tool employs a prototypical heuristic risk model developed with the involvement of five experts from the industry, with the primary intent of running the tool and assessing potential industry value. A case study of the tool results and utility feedback are presented. The web-based geospatial tool developed in this research enables the risk screening model results to be visualized and queried in a user-friendly, interactive environment for usefulness at the network level among water utilities.
TL;DR: In this article, microchips of a few millimeters in size and different shapes were embedded within small-scale polyethylene samples to assess their impact on the structural integrity of the pipes.
Abstract: One way to continuously monitor the whole water distribution system is to equip pipes with many small sensors. If these sensors are to be integrated within the pipe walls, it is important to assess their impact on the structural integrity of the pipes, but embedding pipes with these microchips for testing would allow limited control of the position and orientation of the microchips. Therefore, microchips of a few millimeters in size and different shapes were embedded within small-scale polyethylene samples. Pipes are subject to a range of different stresses during their lifetime including hoop, bending, and potentially local impact stresses, and long-term creep effects. This paper focuses on the bending, flexural creep, and impact stresses, with some examples from the tensile tests also presented. The key findings are that there is little effect of the microchips on the 50-year flexural moduli and the short-term flexural properties of the polymer, although there was a significant improvement in the toughness and a reduction in the tensile strength.