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Journal of Pipeline Systems Engineering and Practice

Journal of Pipeline Systems Engineering and Practice

Archives Papers: 138
The American Society of Civil Engineers
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Tribute to James Thomson: Pioneer in Trenchless Technology Development
Mohammad Najafi
Assessment of Stochastic Approaches in Prediction of Wave-Induced Pipeline Scour Depth
Ahmad Sharafati Reza Yasa Hazi Mohammad Azamathulla
Abstracts:Scouring phenomena below a pipeline exposed to waves is intrinsically a stochastic process. There is a huge level of uncertainty due to effective parameters on the scour depth prediction and mathematical shape of traditional equations for the scour depth prediction. With inspiration from previous investigations, Shields parameter ( θ ), Keulegan–Carpenter number ( K C ), and ratio of embedded depth to pipe diameter ( e / D ) were considered as effective parameters governing on this process. Furthermore, effective parameters mentioned in this study were taken into account as random variables and the general structure of empirical equations extracted from the literature have been regarded to develop stochastic methods such as generalized likelihood uncertainty estimation (GLUE) and sequential uncertainty fitting (SUFI). Having obtained statistical error indices values such as root-mean square error (RMSE), mean absolute percentage of error (MAPE), and agreement coefficient ( d ) from the training and testing phases, it was found that both improved stochastic methods have provided adequate accuracy for predicting pipeline scour depth. Moreover, performance of the developed stochastic models and genetic programing (GP) approach were compared with those obtained using deterministic techniques using the total improvement ( I M T ) index. Quantitative comparisons of the proposed stochastic models indicated that the GLUE method ( I M T = 21.5 and 24.73%) was the most efficient model in clear-water and live-bed conditions with large values of e / D . In terms of various conditions of scouring process, the highest and least improvement occurred in the clear-water and live-bed conditions with small values of e / D , respectively. Ultimately, the developed stochastic methods were more efficient compared with the deterministic models in prediction of wave-induced pipeline scour depth with consideration of uncertainty.
Application of GFRP for Unburied Submarine Pipeline in Shallow Water of Coral Islands
Saravanan Rajendran Jyothi Prakash Arkadu Shyamala Varthini Dinakaran Dhinesh Ganapathy Mallavarapu Venkata Ramana Murthy
Abstracts:Flexible pipelines such as high density polyethylene pipes (HDPE) and bonded pipes for seawater intake systems are often subjected to oscillations, due to the combined action of the wave and current in a shallow water region. Rigid pipe materials like aluminum or stainless steel are not economically viable for a seawater desalination project and steel pipes are susceptible to corrosion. This paper focuses on the application of glass fiber reinforced polymers (GFRP), considering their various merits for submarine pipelines in lieu of other pipe materials. The proposed GFRP pipe cannot be buried because of the coral seabed in the shallow water region and exposed to high marine environmental loads. A new methodology was developed to design the GFRP pipe drawing inference from various standards. A suitable winding angle of 30° and a 18.46-mm wall thickness of GFRP pipe were achieved. Pipe specimens were manufactured and tested to validate the design parameters. This paper mainly focuses on the design process for the GFRP pipeline in complex marine environment conditions, where direct methods and standards are not available for unburied submarine pipelines and qualification of GFRP pipe by conducting laboratory and prototype tests.
Finite-Element Analysis of the Installation Process of a Novel Corrosion Protective Kevlar-Reinforced Flexible Composite Liner
I. Barsoum J. Dymock R. Walters A. Seibi
Abstracts:Internal corrosion in pipelines is a persistent problem in the oil and gas industry. Available conventional rehabilitation techniques to stop corrosion losses and prolong the life of the pipeline use an internal lining system to isolate the corrosive medium from the host pipe’s inner surface. To overcome many of the shortcomings associated with conventional lining technologies, a Kevlar-reinforced flexible polymer composite liner has been recently developed. This flexible liner was installed in several stages and is of interest in understanding the mechanisms behind the installation process and, more specifically, in determining the forces and stresses at each stage of the installation process. Hence, the objective of the current study is to build a nonlinear finite element (FE) model to simulate the full installation process of this new liner. The FE model is further validated using physical tests, making it a reliable tool for simulating the entire installation process of this liner in an arbitrary pipeline network.
Defect-Based ArcGIS Tool for Prioritizing Inspection of Sewer Pipelines
Mohamed Elmasry Tarek Zayed Alaa Hawari
Abstracts:This paper presents a defect-based model for assessing risk of failure for sewer pipelines. The proposed model deploys a Sugeno fuzzy inference system to create a risk index from which inspection and replacement activities may be prioritized. To determine the likelihood of failure, dynamic Bayesian network (DBN) was used as an inference engine to predict the likelihood of sewer pipeline failure based on both probable defects that could occur and some pipeline characteristics. The consequences of failure were determined using an economic loss model that assumed both costs resulting from the failure of sewer pipelines and benefits from avoiding such failures. An ArcGIS tool was created using the Python programming language to perform the Sugeno fuzzy inference method and determine the risk of failure by combining both the likelihood and consequences of failure. Actual data for inspected sewer pipelines in Doha, Qatar, were used to validate the tool; in the validation, the pipelines from the model were compared with the inspected pipelines. It was found that, if deployed, the proposed tool could save more than 77% over the current inspection practices followed by municipalities. It is expected that the resulting risk map would help key personnel in municipalities to identify sewer pipelines that require immediate interventions and would assist in better planning for inspection programs, especially in cases of limited funds.
Scouring Damage to Buried Pipes Caused by Leakage Jets: Experimental Study
S. M. Pike J. E. van Zyl C. R. I. Clayton
Abstracts:This paper reports on an experimental study on the scouring of pipe materials on the outside of leaks caused by soil fluidization. A base experiment was designed consisting of a 3 mm diameter hole angled at 45° to the horizontal in a 110 mm diameter unplasticized polyvinyl chloride (uPVC) pipe. Five parameters were investigated in a sensitivity analysis: soil particle size, leakage flow rate, leak orientation, cover depth, and pipe material. The development of the scour patterns was measured at regular intervals. It was found that the leak jet orientation had the greatest impact on the scouring rate, followed by the leakage flow rate, sand particle size, pipe material, and cover depth.
Erratum for “Predicting the Numerical and Experimental Open-Channel Flow Resistance of Corrugated Steep Circular Drainage Pipes” by Zafer Gemici, Aliihsan Koca, and Kenan Kaya
Zafer Gemici Aliihsan Koca Kenan Kaya
Data Mining and Equi-Accident Zones for US Pipeline Accidents
Dayakar L. Naik Ravi Kiran
Abstracts:Data mining is performed on the last 21 years of United States pipeline accident data to illustrate the trends in different pipeline accident types and their consequences, namely financial losses, fatalities, and volume of oil spill. An objective ranking is introduced to identify the states with most pipeline accidents, losses, fatalities, and oil spills. The influence of meteorological season, temperature, and precipitation on pipeline accidents is investigated. The contiguous United States (excluding Alaska, Hawaii, and Puerto Rico) is partitioned into six accident zones with equal amounts of accidents (equi-accident zones) and the most frequent pipeline accident type in each zone is identified. Among all the pipeline accident types, material/equipment/weld failure is found to be the most frequent, expensive, and environmentally unfriendly pipeline accident type. Pipeline accidents due to natural force damage increase dramatically during winter season. Among the six equi-accident zones, Zone 2, located in the southern United States, is the smallest zone with the highest density of accidents.
Numerical Study of Restrained Joint and Pulling Load for Ductile Iron Pipe in Horizontal Directional Drilling
Shun Dong Xuefeng Yan Haifeng Zhang Baosong Ma
Abstracts:As an alternative pipe material, ductile iron pipe (DIP) has been more and more widely used in horizontal directional drilling (HDD) because of its excellent mechanical performance and corrosion resistance. The limited capacity of restrained joints to withstand pulling force severely constrains their application in long-distance crossing projects. The finite-element method (FEM) was used to study the mechanism of joint failure as well as the effect of slope angle, based upon which an approximate solution was developed to estimate the maximum pull capacity of joints. The authors found that joint failure started from the spigot and an appropriate increase of slope angle could improve the maximum pull capacity of joints. Considering pipe angular deflection, a new pullback load estimation model was established and its accuracy was verified by a HDD river crossing project.
Scenario-Based Seismic Risk Assessment for Buried Transmission Gas Pipelines at Regional Scale
Raffaele De Risi Flavia De Luca Oh-Sung Kwon Anastasios Sextos
Abstracts:Buried gas pipelines in seismic-prone regions may suffer leaks or breaks as a consequence of an earthquake, especially if the pipeline is subjected to large differential displacements due to geotechnical failures (e.g., landslide or liquefaction). This paper presents a methodology to assess the risk of a gas pipeline infrastructure at a regional level in the aftermath of a seismic event. Once earthquake characteristics, such as magnitude and epicenter, are known, seismic intensity measures (IMs), such as peak ground acceleration (PGA) and peak ground velocity (PGV), are estimated at the location of each pipe through a simulation-based procedure. The potential updating from real-time data coming from accelerometric stations is considered. These IMs are then used to study the cascading landslide and liquefaction hazards, providing a hybrid empirical-mechanical-based estimation of permanent ground displacements (PGD). With the aid of damage and fragility functions from the literature, loss figures and damage maps are derived as decision-support tools for network managers and stakeholders. Losses provide a preliminary estimation of repair costs, whereas damage maps support the prioritization of inspections in the aftermath of the event. The risk methodology is a novel combination of cutting-edge and consolidated approaches. Firstly, different cross-correlation models between PGA and PGV are included. Secondly, a new three-phase back-to-back geotechnical approach is provided for both landslide and liquefaction, representing (1) the susceptibility, (2) the triggering, and (3) the PGD estimation phases. The 1976 Friuli earthquake and the high-pressure gas network of northeast Italy are used as a test-bed scenario for the risk methodology aimed at emphasizing pros and cons of the different alternative options investigated.
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