Journal of Pipeline Systems Engineering and Practice

It is of fundamental importance in engineering design practice to accurately evaluate the structural response of buried pipelines subjected to seismic hazards, like landslides, lateral spreading due to liquefaction, and faulting, because these seriously threaten pipeline safety. The present paper investigates the seismic performance of a buried operating steel pipeline subjected to strike-slip faulting using the continuum finite element modeling approach and considering appropriate equivalent boundaries representing the interaction with the rest of the soil–pipeline system. The latter are derived analytically in terms of an axial spring expressed in function of the soil–pipeline nonlinearities, service loads like the internal pressure and temperature variation, pipeline unanchored length, cross-section area, and the different loading paths either in tension or compression. The obtained analytical and numerical results give a better insight into the mechanical behavior of the soil–pipeline system subjected to strike-slip faulting that induces overall tension in the pipeline under different levels of operating loads. The methodology described in this paper, including the formulation of the equivalent boundaries, can be applied to accurately and efficiently assess the seismic performance of operating buried pipelines subjected to strike-slip fault movement and similar permanent ground deformations (PGDs).

This paper presents comprehensive results on the mechanical behavior of submarine steel pipelines subjected to various strike-slip fault displacement loads. The investigation uses strain-based criteria to estimate pipeline performance based on rigorous numerical modeling and simulation of a soil–pipe system, accounting for nonlinear material behavior and large strain of both pipeline and surrounding seabed soil. Equivalent boundary conditions are derived and applied at both ends of the pipeline to take the effect of pipeline segments far away from the fault into account. Parameters affecting the response of submarine pipelines subjected to active faults (including pipe diameter, diameter-to-thickness ratio, burial depth, soil stiffness, and intersection angles) are studied. A uniform design experiment is also carried out to predict the critical fault displacement. The results show that the segments of the pipe embedded in both blocks near the fault plane are critical locations where buckling or rupture is more likely to occur. The ability of the pipeline to withstand more fault displacements can be enhanced by increasing the diameter and wall thickness. In addition, the choice of proper burial depth and differential pressure can lead to an increase in flexural stiffness and weaker soil–pipeline interaction. Pipe diameter, crossing angles, and burial depth determine the pipeline’s failure modes. An accurate regression derived from finite uniform design experiments is proposed for the performance-based design of future submarine pipelines.

In recent years, HDPE plastic pipe producers have begun to recycle waste generated from their own production. However, there are some concerns with regard to the effects of using postmanufacturer recyclable HDPE compounds (RCs) on the long-term performance of pressure pipes. Because the failure phenomena of landfill leachate collection pipes are fundamentally different from those affecting pressure pipes, it is possible that these RC materials can instead be used in the production of landfill leachate collection pipes. In order to develop a better understanding of the effects produced by using RCs on the performance of leachate collection pipes, a series of different laboratory experiments is performed. The pipe deflection ratio (DR) and settlement of the soil surface (SSS) are used to define the consequences. According to these results, although the maximum DR and SSS of the pipe samples slightly increase with the addition of RCs, the results are almost the same. Hence, the addition of RCs has no significant effect on the behavior of these gravity pipes. In addition, this research investigates the effects produced by perforations, magnitude of construction loads, and buried embedded depth of pipes ($\mathit{H}/\mathit{D}$).

With the nation currently experiencing record droughts and water shortages in the western and southwestern states, the importation of water via large-diameter pipe transmission systems from distant more reliable sources is becoming a viable option. As drought conditions worsen, engineers and water planners will need efficient cost models to plan and design these large water transmission systems. To address these challenges, a Water pipe installation COnstruction CoST Estimation model (WaterCOSTE) has been developed to estimate the installed pricing for various pipe materials and diameters under a wide range of bury and embedment conditions. The WaterCOSTE model uses a bottom-up pricing approach commonly used by contractors to estimate installed pricing for high-density polyethylene (HDPE), PVC, ductile iron, and steel water pipe. WaterCOSTE is used to estimate installed pricing for a potential large-scale real-world water transmission project in northeastern Arizona. Pipe material cost and pressure class are found to be significant cost factors, followed by embedment type, soil type, and bury depth. A cost comparison based on pressure class was performed for the candidate materials.

This paper presents a method for prioritizing water mains for inspection and maintenance with consideration of municipalities with a lack of data for failure probability assessment. The method employs reliability and risk of a pipeline system to determine the maintenance schedule for each pipe component in the system. A simple Weibull function–based failure prediction model is developed for the pipe components based on a stochastic analysis using Monte Carlo simulation. The failure consequence of the component and the system is determined using an impact factor approach. The system failure of the pipeline network is modeled using fault-tree analysis. The method is demonstrated through application to a simple idealized pipeline network. The study reveals that the choice of thresholds plays an important role in the decision making using this method. A relationship between the risk and the reliability for the system is developed to assist in the experts’ judgment for the selection of the thresholds in a rational manner.

It was reported that the leak-before-break (LBB) concept has potential merit for use as a tool for large-diameter pipe failure prevention in the water industry. For this purpose, a detailed understanding of pipe failure mechanisms and the LBB time window between leak initiation and failure is essential. Controlled laboratory experiments can provide valuable information to address this research question. Therefore, this paper presents a new fully automated laboratory test facility that was developed to investigate the time window between leak initiation and final burst (during fatigue crack growth with variable internal loading including pressure transients) in large-diameter cast iron water pipe. The new setup will be used to validate the application of LBB and to quantify the LBB time window for proactive pipe monitoring for failure prevention. A full-scale pipe test conducted using the new test facility is presented to demonstrate the capability of the new test facility.

Water loss through leaky pipes is a worldwide issue leading to economic loss, environmental damage, and dangers to public health. Leak detection via leak noise correlation using vibroacoustic emission techniques is a common method for reducing water loss in water distribution systems (WDSs). This has been reported to be highly successful in detecting leaks in metallic pipes, but reports of its efficacy in plastic pipes is varied, highlighting a strong influence of pipe material on the performance of leak noise correlators. However, this has never been experimentally quantified in the context of other pipe materials with a good experimental methodology whereby other factors (such as leak flow rate) are standardized. Moreover, the majority of leak detection research using leak noise correlators is conducted on pipe rigs or buried test facilities, which bear little resemblance to the complexities of a real WDS. The overall aim of this research is to study the impact of pipe material on the transmission of the leak signal, investigating different pipe materials in a real, complex WDS. This article presents a rigorous, novel methodology whereby artificial leaks are created using standpipes on different pipe materials and the transmission of the leak noise studied. The results demonstrate a strong influence of pipe material on the transmission of the leak noise, influencing the frequency and amplitude of the leak signal, which varies with distance and leak flow rate. It was found that cross-correlation was a good method for identifying a leak’s location for cast iron and asbestos cement pipe materials, but had low efficacy on polyethylene pipe due to the high attenuative properties of the polyethylene material. This is shown to impact the cross-correlation of leak signals and therefore how effective leak noise correlators are at identifying leaks in plastic pipe.

Lifecycle cost analysis is a critical step in feasibility studies of future infrastructure projects. Lifecycle cost analysis of innovative infrastructure systems, such as a proposed underground freight transportation (UFT) is often challenging since there is not adequate historical cost information that is typically required for lifecycle cost analysis of these systems. The UFT system is a class of automated transportation systems in which vehicles carry freight through tunnels or pipelines under existing highways and roads between intermodal terminals. The objective of this paper is to assess the lifecycle cost of five UFT system alternatives in Texas. A stakeholder committee in conjunction with the Texas Department of Transportation (TxDOT) selected five alternatives: transporting shipping containers for 402.33 km (250 mi), 24.14 km (15 mi), and 6.43 km (4 mi); crate size cargoes for 24.14 km (15 mi); and pallet size cargoes for 24.14 km (15 mi). This analysis includes the capital and annual costs of a proposed UFT system in Texas over a lifecycle time of 100 years. The UFT system has major capital cost components including costs of tunnel construction, linear induction motors (LIMs), and vehicles. The annual cost components of the UFT system are the costs of maintenance, energy consumption, and administration. Historical tunneling costs are used to create a regression model to estimate costs of tunnels with various sizes. Quotes from the industry and RSMeans cost data are used to estimate the costs of vehicles, LIMs, UFT maintenance, energy consumption, and administration. The results of this paper inform transportation planners about lifecycle costs of the UFT system. Lifecycle costs of the UFT system include construction, maintenance, and operation costs. Unlike the capital costs of the system that increase as the cargo size increases, administrative costs decrease as the cargo size increases. This increase in the administrative costs for crate and pallet size UFTs is due to the need for more loading and offloading stations at terminals. This paper shows how the lifecycle cost of a proposed underground transportation system can be estimated using limited historical cost information.

Pipelines are regarded as the most practical and cost-effective mode of transporting oil and gas (O&G) and also have been the most reliable part of global energy infrastructure. In North America, the O&G pipelines provide basic infrastructure to transport petroleum products both for upstream and downstream sectors. Pipelines’ safe maintenance and operation are necessary to ensure de-minimums risk to the public and the environment. Regulatory authorities require operators to develop and implement pipeline integrity management programs (IMP) in accordance with applicable industry standards. Integrity assessments are common tools to ensure compliance with specific regulatory requirements. The traditional IMP assessment is the most practiced process which ascertains compliance but does not necessarily provide information about program effectiveness. Effective program is proactively responsive to the emergency conditions. In this research, a risk assessment framework for IMP is proposed and developed. The main objective of this research is to assess the effectiveness of the IMP for O&G pipelines. The proposed framework, integrity management program assessment and knowledge tool (IMPAKT), is not only useful for IMP assessment but also lays a foundation for developing a competitive and compliance benchmarking process for regulators.