Journal of Pipeline Systems Engineering and Practice

This paper proposes an innovative buried wireless sensor network (B-WSN) system for detecting leakage from pipeline joints caused by large ground movements such as earthquakes. The key challenge to any such system is that electromagnetic (EM) signal strength becomes significantly attenuated over short distances when wireless devices are buried in certain materials—notably soil, this paper’s focus. After simulation results indicated that the EM radio frequency was a key factor influencing the depth through which a signal can propagate in soil, the B-WSN system was developed, which includes a high-performance sub-1-GHz transceiver that utilizes a low-power band frequency at 433 MHz. Field testing indicated that the BWSN can achieve a penetration depth of 2.13 m. The system configuration includes a radio link budget of 120 dB, transmit power of 26 dBm, receive sensitivity of $-125\mathrm{dBm}$, and omnidirectional antenna gain of 1.5 dBi. The system works on multihop topology, meaning that each sensing node also acts as a relay node to assist other nodes buried deeper in the ground with data communication. For purposes of this paper, four hops were used, and this made wireless communication possible at an overall burial depth of 8 m. As such, the proposed B-WSN system would be compatible with most buried utility pipelines. The conducted full-scale pipeline-rupture experiment results further verified that the system can, in close to real time, pinpoint locations and subsequent patterns of water leakage caused by severe ground deformation. The findings also exemplify how the B-WSN system could aid structural evaluation of pipelines that are likely to experience large ground deformation. The average packet-loss rate was less than 0.1% during the experiment, and in terms of average power consumption, each sensing node used less than 26.5 mA per 30 s data-reporting period. Thus, the sensing nodes can be expected to function continuously for 27 days if powered by four standard industrial D-cell batteries, or for more than 2 years if the data-reporting period is changed to 1 h.

Pipeline condition data collection and assessment is the first step for strategic infrastructure asset management and planning. However, since condition data collection and assessment is a highly expensive and time-consuming process, comprehensive asset management often fails even before it starts. Many municipalities perform periodic closed-circuit television (CCTV) inspections as a preventive maintenance and management strategy. However, due to limited budgets, not all the pipelines are inspected periodically as initially planned and only some parts that are believed to have some problems are chosen to be inspected. Municipalities often hesitate to use sampling inspection because of possible risks of not assessing the pipe assets correctly that may end up as liability issues. This paper shows the calculations of the possible risks of sampling and the techniques to control those risks. Acceptance sampling with the rectifying inspection method was used, which is a method widely used in quality control in the manufacturing industry. First, pipelines were categorized based on age, material, and any other characteristics that were believed to be reliable criteria for categorizing pipe assets in similar conditions. Then randomly selected pipelines in each category were inspected. The amount of the selection was determined by the municipality’s budget situation. The acceptance sampling with rectifying inspection method showed the improvement of average outgoing quality (AOQ). By repairing the defects in a sample inspection, not only was the quality level statistically measured, but the overall quality level also improved. By differing the sample sizes and the acceptance rates, optimization between inspection cost and quality can be achieved. The sampling strategy proposed in this paper presents the optimal CCTV inspection sampling strategy for an accurate condition estimation and provides the basis for the asset management plan.

The paper deals with an extension of a German advisory leaflet, which deals with static calculations for the rehabilitation of drains and sewers using lining and assembly procedures. Such procedures include, for example, pipe-lining technologies. For the structural analysis of new pipes, the advisory leaflet uses coefficients for the determination of internal forces and deformations. The coefficients were obtained based on certain assumptions and with the aid of nonlinear calculations. These assumptions place limitations on the practical design process in some cases. This especially concerns the use of different materials for new pipes, as well as geometrical imperfections in new and old pipes. Therefore, new coefficients were determined that are suitable for use in the practical design of new pipes made of polyethylene. Nonlinear analyses were performed using the finite-element method (FEM). In addition, a comparison of the German advisory leaflet and an American standard was performed.

Mine subsidence can pose a considerable threat to pipeline integrity. Three constituents quantitatively determine the distribution of strains along the pipeline: the function of ground displacements along the pipeline axis; the physical law of soil–pipe interaction due to their relative displacements; and the metal deformation response to axial stress in the pipe. All three are usually well understood, but there is still a small number of successful examples of prediction of stresses in such pipelines. In our opinion, the reasons are the following. First, the law of pipe–soil interaction with a large number of required pipeline elements is highly nonlinear; second, usually the history of ground displacement development is not taken into account even though it may be highly significant. Therefore, in this paper we develop an effective algorithm for axial strain and displacement calculation based on notions of basic and correction solutions. The basic solution is algebraically corrected after each iteration step for the correction solution, which is obtained by a numerically efficient transfer matrix method. The role of the basic solution is rather limited here: first, it determines the choice of the particular type of law of soil–pipe interaction; and second, the resulting solution is considered to be accurate when the basic and correction solutions coincide. The effectiveness of the algorithm is shown with a number of examples. The algorithm is updated to account for the effect of the history of ground displacements on the resulting stress-strain state. Two examples of significant influence of history are given: the first for two consecutive perpendicular mine seam developments; and the second for parallel mine seam development.

With the rapid rise in the development of urban districts, a ferocious demand for water-collecting urban sewer systems is inevitable. In fact, flexible sewer collection systems and drainage systems should be developed for controlling sewage and runoff, respectively. In the case of underground sewers, conducting water flow properly through high vertical distances needs reliable criteria design for dissipating flow energy. Vortex structure is taken into account as one of the economical infrastructures that can be used to eradicate destructive impacts of inflow over a drop with invert elevation. In the current investigation, a physical model, made of Plexiglas segments, was set up to study hydraulic performance of the vortex drop structure with tangential inlet in terms of flow energy dissipation efficiency (FEDE). A total of 144 experiments were conducted and analyzed by means of the full factorial method (FFM). Results of dimensional analysis demonstrated that Froude number ($F_r$), ratio of drop total height to shaft diameter ($L/D$), and ratio of sump depth to shaft diameter ($H_s/D$) were considered effective variables on FEDE. Furthermore, a regression-based equation in the form of a quadratic polynomial was proposed to estimate the FEDE variable. Experimental aims were to investigate the simultaneous effects of approach flow $F_r$, $L/D$, and $H_s/D$ on the FEDE. Results of experiments indicated that the FEDE variable had downward trends with an increase in the $F_r$ variable, and additionally FEDE has gone through upward trends with an increase of $L/D$ and $H_s/D$ ratios. Furthermore, an interaction effect of $F_r$ and $H_s/D$ on the FEDE variable remained meaningless. Ultimately, the sump depth at the base of the drop shaft for 1–1.6 times the diameter was recommended for getting efficient performance of the vortex structure.

Soil properties are stochastic in nature, and at a particular location, the soil properties will have an associated mean and probability distribution. However, in soil-pipeline interaction studies on oil and gas pipelines where the maximum response is associated with stronger pipe-soil spring properties, the soil properties used to determine the maximum soil resistance and soil spring stiffness are usually taken as deterministic, assuming no variation in soil properties. Alternatively, for soil-pipeline interaction scenarios where the maximum response is associated with weaker pipe-soil spring properties, the geotechnical engineer may assign deterministic lower-bound values in an attempt to apply conservatism. This paper examines the effect of variability of soil properties on the maximum soil resistances and soil stiffness values for both drained and undrained soil loading conditions. Then, the resulting probabilistic distributions are applied to two example soil-pipeline interaction problems common in pipeline design, a longitudinal landslide and a strike-slip earthquake fault displacement. The results show that the stresses and strains in the pipeline resulting from drained soil loading are relatively insensitive to the probabilistic distribution of soil properties, and for the most part, the use of average values may be adequate. However, for some soil-pipeline interaction scenarios and loading conditions, and given the large natural variation in undrained soil properties, the use of single deterministic average soil properties under undrained loading conditions may underestimate important pipeline strains or stresses. The use of probabilistic soil properties for some pipeline loading scenarios is recommended.

The accurate prediction of lateral buckling is crucial for offshore pipelines that are subjected to high temperature and internal pressure. As a challenging topic, modeling pipeline buckling involves geometric nonlinearity and complex pipe-soil interaction. This paper introduces a simple finite element modeling approach to simulate the pipeline lateral buckle behavior. After validation against established knowledge, a variety of parametric analyses were systematically performed to investigate the effects of out-of-straightness, seabed friction factor, elastic slip, internal pressure, and initial stress. This study aims to provide a practical numerical approach for pipeline buckling and conveys a better understanding of the key parameters that must be considered when modeling the pipeline buckling problem.

Concrete pipes are widely used in underground infrastructure and subject to different environmental conditions resulting in deterioration. Deteriorated pipes need to be rehabilitated to resume their normal service functions. One of the popular rehabilitation methods is spray-on cured-in-place lining, which has become increasingly popular due to its simplicity and cost efficiency. Rehabilitated concrete pipes form composite pipes and have different structural behaviors as compared to bare pipes. A good understanding of their behavior is essential to establish more efficient use and design of linings. In this study, third-point bending tests of concrete beams and concrete beam coated with epoxy were performed to determine their flexural strength. Three-edge bearing tests were performed on both unlined and lined concrete pipes. Results from the flexural beam tests are used to obtain tension softening curves for concrete with and without epoxy lining. FEM models of the third-point bending tests and three-edge bearing tests are created and validated with the experiment results. The validated FEM model of the three-edge bearing test is used to perform a parametric study on the effect of epoxy lining on the structural capacity of the lined pipes. The results indicate that by adding a 3-mm layer of epoxy lining inside the concrete pipe, the peak load increases only by 6% while 6- and 12-mm-thick liners result in 27% and 40% increases in the peak load, respectively.

A corroded corrugated steel pipe was buried with an erosion void simulated from the haunch to the shoulder on one side. Testing under simulated service loads revealed that the void appeared to compromise the stability of the structure at a load of 87% of the full service load. Changes in curvature under load in the springline adjacent to the simulated erosion void were about 3 times higher than those at the springline with soil support. Compressive wall thrusts were also substantially higher on the side adjacent to the erosion void. The culvert was then rehabilitated using a grouted slip liner. A steel-reinforced high-density polyethylene pipe was used together with low-density, low-strength grout. Stiffness after rehabilitation was enhanced considerably, with diameter changes at full service loads decreased by an order of magnitude. Strains in the corrugated steel pipe were also much lower. Strains measured on the corrugated steel pipe and on the steel ribs of the steel-reinforced polyethylene pipe suggest that below 300 kN, the grout had not fractured, and the steel pipe, grout, and liner within responded as a composite system. Above 300 kN, the grout appears to have fractured, and strains in the steel pipe and liner accelerated with applied load. The ultimate limit state appears to correspond to development of full plastic hinges in the steel ribs of the liner at the crown, the springlines, and the invert. The structural repair based on grouted slip lining was found to be more than adequate, because the force applied to the single axle at the ultimate limit state was well beyond the full factored load requirements for these structures.

A water distribution system is one of the lifeline systems of an urban area. Water distribution systems have been significantly damaged in past earthquakes. In this study, polynomial equations were developed to predict the postearthquake service ratio of water distribution systems. With these equations, the design of more robust water distribution systems will be possible. Parameters of the equations were service ratio of the system, repair rate of the pipes, and a graph index of water distribution system topology. The repair rate of pipes depends on the pipe, soil, and earthquake parameters, while the graph index is related to the topology of the system network. In this study, the medium articulation graph index was used. Two thousand Monte Carlo simulations were performed and mean service ratios were calculated for nine hypothetical water distribution systems with six different repair rates for each by means of GIRAFFE software. Thus, 54 mean service ratios were used in the regression analysis. Coefficients of three polynomial models were determined after regression analysis.

Acoustic wave propagation has been widely applied for the detection of anomalies in buried pipelines. Anomalies such as joints, damages, and defects in a pipe change the stiffness of the pipe, and investigating the interaction of the acoustic wave with these pipe features is a reputable approach to detect and locate them. Acoustic wave propagation–based nondestructive evaluation (NDE) through integrated actuators and sensors has been used extensively for condition assessment of different types of pipes in the last decade. This study illustrates the effects of the presence of joints on acoustic wave propagation inside the fluid bar in a buried pipe. Presence of the joint increases the local thickness and consequently the speed of the acoustic wave in the fluid bar. To identify joints, acoustic wave propagation was studied when a wave passes through a joint. Finite-element (FE) software was used to carry out simulations, and obtained results showed a good agreement with field data. A 93% increase in accuracy of localizing joints was achieved.

The Supervisory Control and Data Acquisition (SCADA) data are primarily used for pipeline-pressure monitoring and control. This investigation aims to develop improved methods of recording, storing, and filtering SCADA data for the purpose of predicting crack growth and remaining lifetime of both oil- and gas-pipeline steels experiencing stress corrosion cracking (SCC) and corrosion fatigue using a computational software. To ensure the modeling accuracy, the maximum time intervals for SCADA data collection were investigated, to reduce data storage and calculation time. SCADA data are to be recorded at appropriate sampling intervals to capture all pressure events that could affect crack growth, while the data should be minimized to reduce the time needed for crack-growth calculation without compromising the accuracy of prediction. In this work, it was proposed to record a set of data consisting of one maximum and one minimum point of pressure within a given sampling interval of 1 min (for oil pipelines) and 2 h (for gas pipelines). Screening models to determine and to remove unrealistic SCADA data because of either electronic noise or system errors have also been developed for both oil and gas SCADA data.

Given a vast inventory of culverts with different physical and environmental characteristics, the task of condition assessment can become difficult or impossible. Using a database of approximately 8,000 culverts in South Carolina with varying sizes, types, and configurations, a model was produced to predict the condition of these culverts. This model combined only the physical culvert information given in the database with mapped environmental characteristics including historical temperature, precipitation, pH, and estimated runoff coefficient. The resulting model used the combination of inputs that produced the model with the best performance measures, primarily the area under a receiver operating characteristic curve. A separate model was created for each of the 6 culvert types commonly found in South Carolina and the 10 condition categories given to each culvert in the database: cracking, separation, corrosion, alignment, scour, sedimentation, vegetation, erosion, blockage, and piping. Both a logistic regression model and an artificial neural network model were used to combine the input variables into a prediction of the desired output variables. The models produced were shown to have a coefficient of determination of between 0.25 for poorly correlated models and 0.80 for better correlated models when comparing the predicted culvert score with the actual culvert score. With the ability to predict culvert health without inspection or any idea of the age of the culvert, the culverts in need of assessment can be prioritized without comprehensive inspections or more detailed information about the culverts.

In responding to the need for improved technologies to accommodate permanent ground deformation imposed by earthquakes, landslides, and other sources, a new family of segmented pipelines has emerged employing joints that displace axially and deflect before locking up and restraining further movement. Other than employing finite-element modeling, there is no existing procedure allowing practicing engineers to efficiently evaluate displacements and strains that develop along segmented pipelines consistent with those of continuous pipelines at equivalent levels of potential ground movement. A methodology is presented that allows continuous and segmented pipelines of any defined material in the elastic range to be evaluated consistently using a single set of equations for block ground deformations moving parallel to the longitudinal pipe axis. The equations reduce to previously recognized solutions for continuous pipelines as the segmented pipe joints reach their allowable displacement. Results show how the hybrid-segmented pipelines have lower axial strains than continuous pipes for equivalent levels of block deformation. The proposed model provides a fundamental basis for engineering design selection of continuous and segmented pipelines in hazard-prone regions.

Sewers that constitute the main part of wastewater systems can be used as pretreatment units of wastewater treatment plants. The authors aim to increase the treatment efficiency of sewers by optimization. A hydraulic model is written and validated. A quality calculation section is added to the model according to the Wastewater Aerobic/Anaerobic Transformations in Sewers (WATS) method, and it is calibrated and verified using the data of a real wastewater transition line. An optimization engine is coupled to the proposed model. The new model can simulate the hydraulic and quality parameters of a sewer network and optimize it. Six objective functions and a general one with their decision variables were assessed. A predesigned wastewater collection network was used for the optimization of five scenarios. The results can be used to identify optimization priorities at the network design stage. Results showed that an increase in the removal of organic matter within the sewer can be achieved, but its other performance indices may worsen. Prioritization of objectives according to stakeholder views is required.

Despite the increases in freight transportation demand, options for increasing capacity of the overground freight transportation infrastructure system are limited. This paper investigated the design and operation of an underground freight transportation (UFT) system that uses space below highways. Underground freight transportation is a class of automated transportation system in which individual vehicles carry freight through tunnels and pipelines between intermodal terminals. This paper presents attributes for schematic designs and operations for two UFT scenarios: a long-haul system which transports standard shipping containers between the Port of Houston and a terminal near Dallas, and a short-haul system which carries pallet-size freight between the Port of Houston and a satellite terminal near Houston. The appropriate design details were determined by the size of the freight, the types of vehicles and tunnels, and the propulsion system. In addition, operational attributes such as operating speed, headway, line capacity, and associated fleet sizes were addressed. Design sketches and operational equations presented in this paper are generally independent of the freight sizes and route lengths and this case study can be used as guidance for the design and operation of other freight tunnels and pipelines.

Deepwater pipelines are commonly found to be suspended above, freely laid on, and buried underneath the seafloor due to complex seabed geomorphology and surrounding hydrodynamic conditions. Under different suspension height, the pipeline may undergo distinct impact forces arising from the vertical velocity profile of submarine debris flow. As such, suspension height becomes one of the most critical parameters when estimating pipeline movement subject to debris flow impact. In this paper, the coupling model of submarine debris flow with pipeline interaction was further improved. The formula incorporating the effect of suspension height was used to estimate debris flow impact force on pipeline. The improved model was then applied to two schematized cases representing continental shelves with a uniform slope and a sinuous canyon. In each case, the flow structures of submarine debris flow were investigated, including total thickness, thickness of shear layer, depth-averaged velocity, and vertical velocity profile of debris flow. The influence of suspension height on pipeline movement due to debris flow impact was also analyzed. Moreover, sensitivity analyses were performed to study the effects of yield stress and initial failure height of debris flow on pipeline movement under different suspension heights.