Journal of Pipeline Systems Engineering and Practice

With growing concerns about global warming and greenhouse gases (GHG), there is an urgent need to quantify and reduce the environmental impact (EI) of pipeline installation (PI). The most common and popular criterion used to describe sustainability efforts from the environmental perspective is the concept of carbon footprint (CF). A CF is the total set of GHG emissions caused by an organization, event, or product. It is expressed in terms of the amount of carbon dioxide (${\mathrm{CO}}_2$), or its equivalent of other emitted GHGs. The open-cut pipeline installation (OCPI) method involves digging a trench along the length of the proposed pipeline, placing the pipe in the trench on suitable bedding materials and then embedding and backfilling. The trenchless method (TM) involves methods, materials, and equipment capable of the installation of new, replacing old, or renewing existing pipelines with minimal disruption to surface traffic, business, and subsurface. Choosing an appropriate low-carbon emission method to install or renew pipelines is an important task and may consider environmental concerns due to several energy-consuming activities, including material manufacturing, transportation, and installation. Because essentially, every PI and renewal project impacts the environment, it is of utmost importance for the pipeline project owner and the design engineer to evaluate this impact and take necessary actions to minimize any negative consequence. The objective of this paper is to present a literature review on progress acquired over the years in understanding GHG emissions from OCPI and TMs and to discuss a framework for CF estimation. Published papers were identified that reported GHG emissions and CF of the open-cut (OC) method and TM over a period from 1989 through 2019. This literature review suggests that for most of these PI and renewal projects, the material production phase consumes a large amount of energy and is a major contributor of GHG emissions. Higher GHG emissions in the OCPI method is a result of longer project durations and more equipment requirements compared with TMs where a smaller footprint or excavation area is used. Early phases of project planning should include appropriate ecological decisions consistent with the life cycle cost (LCC) and CF considerations. Pipe material and outside diameter should be considered during the installation phase by OC and TM to allow a detailed evaluation and comparison of their sustainability impacts. Incorporation of additional factors, such as cost and duration of the project, into the environmental analysis is recommended for the development of a comprehensive decision-making model to select the most environment-friendly PI method.

Proper estimation of the critical flow velocity of slurries ($V_c$) is one of the most important parameters to design slurry transport in pipeline systems. In this study, three standard soft computing data-driven models including artificial neural network (ANN), group method of data handling (GMDH), and neuro-fuzzy inference system (ANFIS) as well as their hybrid versions combined with the teaching–learning-based optimization (TLBO) meta-heuristic algorithm are developed to estimate the $V_c$ through pipeline. The proposed models are built and tested for accuracy by evaluating the results of the models and the collected experimental data from the literature. The results are also compared with eight suggested empirical equations as well as the soft computing method of the gene-expression programming (GEP) model. The evaluation of the results indicates that the ANFIS-TLBO model surpasses the other models and suggested equations to determine the critical velocity of slurries. According to the finding of this study, using the TLBO algorithm improves the performance of ANN, GMDH, and ANFIS by over 15%, 21%, and 4% in terms of root mean squared error, respectively.

Significant investment is required to upgrade deteriorating underground sewer networks. Sewer failure and the subsequent rehabilitation process can have economic, social, and environmental impacts. It can disrupt critical urban function and adjacent utilities, such as telecom, electric, gas, and water supply lines. This paper identifies 48 indicators to assess the renewal complexity and the failure consequence of buried sewer pipes. A Bayesian belief network (BBN) model is used to capture dependencies among indicators, quantify uncertainty, and update belief when new information becomes available. Geographic information system (GIS) applications are used to collect and process model input data as well as visualize analysis results. The framework can identify locations where trenchless rehabilitation may be cost effective. Finally, the proposed method is demonstrated on a storm sewer network in the city of Vernon, Canada.

The aging water distribution networks in the US are approaching the end of their useful life, and more than 240,000 pipeline breaks are estimated to occur every year, which corresponds to an average of 25 breaks (or 100 mi) per year. Due to financial restrictions to maintain and rehabilitate their water distribution networks, many municipalities need to assess the reliability of their network and properly plan for their maintenance. Previous studies have mainly focused on the reliability assessment of individual network components such as pipes. Moreover, very limited network reliability models addressed the importance of network segments with customer accessibility to drinking water. Therefore, a model is developed in this study to evaluate the reliability of water distribution networks taking into consideration the weight of the importance of their segments. A modified Preference Ranking Organization METhod for Enrichment Evaluations (PROMETHEE) technique was applied to obtain the weight of the importance of segments using expert opinions. The working and failing states of pipes and segments were determined by developing the network’s failure tree, and their impacts on the network reliability were estimated. The evidential reasoning was applied to aggregate the effects of failure and working states of each component on the whole network and its segments. The failure rate and reliability of each component were determined based on what is available in the literature. Results obtained from PROMETHEE application showed that network segments of health care facilities are first in rank of the highest importance. Hence, maintenance and rehabilitation of these segments shall receive the top priority. A network in a Canadian city, which was evaluated using the proposed model, was found to have a reliability index of 0.93.

This paper proposes a new approach to determine the depth and location of buried pipelines using the remote magnetic field measured by aboveground magnetometer surveys. Calculation is presented and verified by the experimental results on 152-mm (6-in.). steel vessels. Performance of the technique is also evaluated through field trials against industrial pipe locators. The depth calculated from the measured magnetic field using this proposed technique agreed within the tolerance interval representing the confidence level of 99.7% of the depth determined by the industrial devices and was able to trend changes of the buried depth. In addition, it was possible to map the target pipeline using the survey route coordinates by calculating the lateral position of the survey route relative to the pipeline centerline from the measured magnetic field. So far, the depth measured by this proposed technique has shown a potential error of 8%. By producing a three-dimensional profile of buried pipelines through quick aboveground surveys, the proposed technique can be considered as a screening technique for asset and integrity management such as monitoring geohazard conditions.

Sedimentation in sewer networks is a major problem in urban hydrology. In comparison to the well-known classic sediment transport models, this study investigates the capabilities of soft computing methods, including multigene genetic programming (MGGP), gene expression programming, and multilayer perceptron to derive accurate sewer design models. A wide range of experimental data sets comprising fluid, flow, sediment, and pipe features was used to develop new models under the nondeposition with a deposited bed self-cleansing condition. The results showed better performances of the new models compared to the conventional ones in terms of statistical performance indices. The proposed MGGP model was found superior to its counterparts. It is an explicit model motivated to be used for self-cleansing sewer pipes design in practice.

Inserting a corrugated steel pipe (CSP) into an existing reinforced concrete pipe (RCP) is a common culvert rehabilitation technique in China. However, few studies have focused on the influence of grout strength and residual deformation on rehabilitated RCPs. Against this background, six specimens were used in experiments to investigate the mechanical behavior of RCPs rehabilitated with grouted CSPs and the influences of grout strength and residual deformation. The rehabilitated RCP had much higher test loading capacity and stiffness than the pre-rehabilitated (pre-rehab) RCP. The test loading capacity of the RCP with large residual deformation and rehabilitated with the grouted CSP was lower than that of the RCP without residual deformation and rehabilitated with grouted CSP, whereas the test loading capacities of the RCP without residual deformation and the RCP with small residual deformation and rehabilitated with grouted CSP were nearly the same. The specimens with high-strength grouts exhibited significant increases in test loading capacity and stiffness; the greater the grout strength, the higher the test loading capacity of the post-rehab RCP. A method for calculating test loading capacity based on a “pipe-in-pipe” system is proposed, and the estimated value of the test loading capacity of post-rehab RCPs is provided within 30%. If a pre-rehab RCP fails to reach its ultimate test loading capacity or reaches its ultimate test loading capacity without large residual deformation, its ultimate test loading capacity can be used to calculate the ultimate test loading capacity of the post-rehab RCP.

One of the critical issues that engineers, contractors, and owners encounter during horizontal directional drilling (HDD) is inadvertent return of drilling fluid (frac-out or hydraulic fracture) to the ground surface when the annular pressure in the borehole exceeds the yield shear or tensile strength of the soil. In this study, numerical modeling using ABAQUS software (version 6.13) was employed to estimate the failure pressure in several case studies following the limit pressure solution. In the next step, a large-strain cavity expansion solution was used to estimate the failure pressure, which was then compared to the estimations based on numerical modeling following the limit pressure solution. A parametric study using numerical modeling was conducted to examine the influence of the geotechnical parameters of the soil medium on the limit pressure. The parametric study showed that overburden depth, friction angle, and elastic modulus of the soil have a significant impact on the limit pressure. The ratio of limit pressure according to analytical and numerical solution resulted in coefficients of limit pressure in different geotechnical conditions and can be used to estimate the failure pressure in noncohesive soils using the large-strain cavity expansion solution.

Most of the pipelines in the US are rapidly reaching the end of their useful service life. Now they need replacing or rehabilitating. In general, selection of a pipeline installation method is solved by selecting the lowest cost method; however, with an increase in public concerns about reducing emissions to the environment generated by human activities, other factors should be considered while choosing the pipe material and the installation method for a new pipeline: direct cost, social cost, and environmental impact. This study focuses on the environmental impact during installation, operation, and disposal phases of the pipeline life cycle. The life cycle of a pipeline can be categorized into four phases: fabrication, installation, operation, and disposal. The fabrication stage, which is the first phase of the pipeline life cycle, was examined in a previous study, and the results showed that prestressed concrete cylinder pipes (PCCPs) are the most environmentally friendly compared with polyvinylchloride (PVC), high-density polyethylene (HDPE) pipes, and cured-in-place pipes (CIPPs). This study includes the pipeline installation phase, operation phase, and disposal phase. The major construction activities in the installation stage are transporting pipes and equipment to the job site, excavation, loading, backfilling, compaction, and repaving. The energy consumed in the operation phase includes pumping energy and pipe cleaning. For the disposal phase, the study will consist of the energy consumed for disposal of the material of the pipes, which cannot be recycled. The objective of this study is to quantify the carbon footprint and to analyze the environmental sustainability of 30 m (100 ft) of pipeline during the installation, operation, and disposal phases. For the study, a pipeline installation analysis and consideration of ${\mathrm{CO}}_2$ emissions was conducted for three different installation methods: open cut, pipe bursting, and CIPP. The study focuses on a large-diameter 90 cm (36-in.) sewer pressure pipe operating at 690 kPa (100 psi) internal pressure for 100 years of operation. The pipeline materials included in this study are PCCP, PVC, HDPE, and CIPP. The results show that PVC pipe has a lower environmental impact than PCCP, HDPE, or CIPP.

Economic and efficient transient control measures are always required to ensure safe and performant operation of water distribution networks (WDNs). This study presents extensive numerical investigations of some cost-effective water hammer control strategies in pumping stations. To this end, an abrupt stoppage of pumps was considered for the numerical investigations because this event is likely to generate high transient flow disturbances in WDNs. The transient analysis was conducted using a MATLAB code based on the method of characteristics with linear integration, which is used to discretize the governing momentum and continuity equations. The considered cost-effective water hammer strategies were based on the single and combined usage of flywheels, check valves, and inline valves. Through a detailed numerical study, it was demonstrated that the performance of larger flywheels is relatively limited considering that pumps with higher moments of inertia engender extra costs in terms of space and starting energy. Alternatively, additional water hammer devices should be introduced in the pump station. It was evinced that single usage of check valves guarantees full protection of the pumps; however, it generates an additional severe water hammer effect on the pipeline integrity following the closure. On the contrary, joint use of check valves and an inline valve with an optimized closure rate resulted in a remarkable transient pressure attenuation. Results of this study prove that in some cases, a convenient combination of simple water hammer control devices can alleviate remarkably the transient pressure disturbances in WDNs without the need for more expensive and sophisticated anti-ram devices.

The operation of multistage pumps transporting water from the source to the delivery point requires balancing of the pressure at the junction of the pump and pipeline according to their characteristics. In this paper, nonlinear optimization models are developed to minimize the total annual cost for selecting the sizes of the pipelines in series and parallel connections of pumps taking water from one or more sources. The models are based on life cycle cost analysis, including replacement cost and escalating energy cost factors. The combined characteristic equations of the pumps in series and parallel connections are obtained using the characteristic equation of a single-stage pump. The constraints are imposed for the pressures at the junctions of the pipeline, with the pumps having different characteristics especially drawing water from different sources. The discharges of the pumps are regulated automatically according to the pressures adjusted at the junctions due to the resistance developed by the optimally designed pipe sizes. The requirements of the desired efficiency also are considered constraints in the models. The applicability of the developed models is illustrated through design examples to obtain optimal discharge and pipe sizes from a single water source for series and parallel connections. Also, the examples are solved to obtain the optimal pipe sizes and discharges from different pumps with the same and different characteristics and drawing water from multiple sources.

The vertical and lateral pullout capacity of a long pipeline buried in a cohesionless soil nearby sloping ground has been investigated by using lower-bound limit analysis in combination with finite elements and linear optimization. The ultimate uplift and lateral resistances offered by the pipeline in cohesionless soil have been computed for different combinations of embedment ratio, slope angle, distance between slope crest and center line of the pipe, and soil friction angle. The results obtained for a pipeline buried in cohesionless soil with a horizontal ground surface compared well with the existing theoretical and experimental data. The present work illustrates that being near sloping ground can cause a significant reduction in the pullout resistance of a buried pipeline as long as it is located within the optimum crest distance. The effect of being near sloping ground has been found to be greater for a larger slope angle. The normalized optimum crest distance depends on the embedment ratio, slope angle, and soil friction angle of the ground soil. For a pipe subjected to lateral pulling, the values of optimum normalized crest distance are found to be higher than the pipe subjected to uplift. The proximity of the stress state to yield for different crest distances is presented to illustrate the failure mechanism.

The cohesive zone model (CZM) is one of the most widely used damage models to describe the fracture processes of brittle and ductile materials, and has been usually combined with the conventional finite-element method (FEM). CZM in the context of the more effective extended finite-element method (XFEM) has recently been implemented in many applications, but it has not been widely used for crack propagation of pipelines. This paper aims to investigate the capability of the XFEM-based cohesive segment approach implemented in Abaqus to predict crack propagation of pipelines by calibrating a linearly decreasing traction–separation law with two damage parameters, the maximum principal stress and the fracture energy. The damage parameters for vintage pipeline steel (API 5L Grade X52) were systematically calibrated and verified by comparing the numerical results with eight full-scale experiments of pressurized and circumferentially surface-cracked pipe specimens. A correlation between the damage parameters and material yield strength and fracture toughness is discussed and an investigation of mesh size sensitivity included.

The structural integrity of buried pipe is always threatened by explosive loads. To investigate the mechanical response of a buried steel pipe under multiple explosions, pipe–soil interaction models in soil and rock layers under two-point explosive loads were created. The effects of explosion point, interval time, trinitrotoluene (TNT) magnitude, pipe pressure, and the diameter-thickness ratio on the mechanical behavior of a steel pipe were investigated. Those results show that plastic deformation occurs and a dent appears on the right and upside wall of the steel pipe. The difference between pipes in soil and rock layers is small. When two points explode simultaneously, the maximum plastic deformation and total energy are larger than in a one-point explosion. With increasing interval time between two-point explosions, a pipe’s deformation and total energy decrease gradually. The deformation, total energy, and plastic strain of the buried pipe increase gradually in a soil stratum as the TNT magnitude ratio and the pipe’s diameter-thickness ratio increase. For a nonpressure pipe, plastic strain, deformation, and total energy are greater than in pressure pipes.

The temperature variation of the district heating (DH) pipelines during the operation is the most severe threat to the lifetime of the systems. The number of cycles used in the fatigue analysis in the European standard were based on the lEA projects, and there were no sufficient studies conducted in China. This paper aims to make reasonable estimations of the maximum number of temperature load cycles for DH pipelines in China. Based on the data, the rain flow cycle-counting algorithms were applied to calculate the number of full temperature cycles. The regression models of design lines between full temperature cycles and temperature variations were established. The maximum values for supply pipelines and return pipelines were obtained by using the design lines. The equivalent full action cycles ($b=4$ and $\mathrm{\Delta }{T}_{\mathrm{ref}}=110°\mathrm{C}$) are about 200 cycles for supply pipelines and 136 cycles for return pipelines which are both less than 250 cycles recommended in the European standard. Using 200 for the supply pipelines and 136 for the return pipelines, the stress limits could increase from 707 to 750 MPa and from 707 to 823 MPa respectively.

High strength steel pipes internally clad with nickel (Ni) superalloys are components widely used in the oil and gas industry in the production of rigid risers. The joining of clad pipes is carried out through a girth welding in which the joint is totally filled with a material similar to the internal clad. However, depending on a substrate’s mechanical strength, an undermatching condition is created. This work aims to develop and parameterize a double-sided welding as an alternative method of joining steel clad pipes, enabling the application of steel wire as filler metal. An American Petroleum Institute (API) X-65 pipe cladded with Inconel 625 was used as a sample. In order to reduce the girth welding difficulties, modern welding techniques, such as gas metal arc welding with controlled metallic transfer (GMAW CCC), and gas tungsten arc welding with dynamic wire feeding (GTAW-DF), were applied along with internal pipe inspection by videoscopy. Developments showcased welding beads without macroscopic defects and good appearance in the entire circumference. Chemical composition tests indicated low iron dilutions, around 2.8% in weight, on the internal Inconel 625 weld.

Brittle failure of a buried pressurized water pipe can result in rapid crater formation, causing debris to be thrown out over large distances as well as longer-term flooding and scour effects. Due to the potential for injury and property damage in a failure event, it is desirable to develop policies to enforce safe stand-off distances around high-risk pipes. Little published data are available on the formation of craters during the initial pressure release from a pipe burst, but an analogy can be made with buried explosives events, for which a large body of data exists. This paper uses finite-element modeling of buried pipe failures to assess the parameters affecting crater diameter, where pipe diameter, pressure, air content, and burial depth are shown to be significant. An explosive cratering tool is modified for use with water pipes by converting the energy release from a failing pipe to an equivalent mass of explosive. The modified tool reliably replicates the crater size from the modeling results, and accurately predicts the modeled crater size in new failure scenarios ($r^2=0.95$), indicating the potential of the tool for use in developing policy on safe stand-off distances.

Alleviating the pressure due to increasing freight transportation traffic by using low-emission and innovative transportation methods can reduce a number of problems, such as transportation network capacity limits and environmental pollution, and contribute to the development of resource-efficient and sustainable cities in the future. An underground logistics system (ULS) can improve the service quality and transportation efficiency of urban logistics and alleviate traffic congestion and associated problems, such as energy consumption and air pollution. Previous studies on urban ULS have primarily focused on technical feasibility and policy requirements, whereas analyses of the effects of introducing ULS on the existing transportation network are scarce. The main goal of the present research is to develop a method of freight transit assignment for an integrated transportation network of aboveground roads and the main line and branch lines of the ULS. A formulation for an integrated transportation problem of freight for roads and ULS was established along with a process that considers the loading, unloading, and transfer of freight among each mode. Based on the random utility theory method, a stochastic assignment model was used to divert freight from the road to the ULS using a network that possesses critical transport features, including multiple freight demands and alternative transit routes. The influence of several factors, such as travel speed, departure frequency, and the capacity limitations of lines and nodes, was analyzed, and the results showed that the ULS was the preferred mode of freight transportation. Freight transportation via ULS is more efficient than road transportation, which provides a foundation for further investigation into the integration of ULS in road transportation networks in aboveground and underground spaces.

The integrity management activities should aim to ensure that all safety requirements are maintained within acceptable levels. A fully comprehensive inspection of all equipment in a unit/facility is not a cost-effective method. Therefore, in recent approaches, the budget and resources are assigned in a way to only fully cover the equipment with a medium-high or high-risk level, while preserving a sufficient effort on lower risk components. In this regard the risk assessment procedure of the underground polyethylene (PE) natural gas piping networks has not been developed yet. Hence, the current study was conducted to (1) identify the credible failure mechanisms in urban natural gas PE piping systems and (2) evaluate the probability of failures and consequences of failures for various failure scenarios. The ultimate goal was to find the critical piping segments. It proposed a methodology to prioritize technical inspection activities for different segments in the urban natural gas piping systems based on their risk levels. The procedure was applied in the piping network of a small city (Ardabil, Iran) to identify the critical segments. Relevant recommendations were made after successfully detecting these segments.