Pipelines 2022: Planning and Design

Citizens Energy Group identified a strategic initiative to incorporate a risk-based capital programming approach for seven business units within the Citizens. The goal of the approach was to develop risk-based, sustainable, and affordable long-term infrastructure investment scenarios. The purpose of the report is to (1) analyze existing system data for each business unit (BU); (2) create a comprehensive, centralized location for all capital needs to address risks and levels of service; (3) generate a consistent approach for all BUs; (4) evaluate existing performance data compared to internal targets and industry peers (where available); (5) identify the desired future state and associated programmatic needs to shift the approach from financial-based planning to needs-based planning; (6) support future rate cases through data-driven analysis; and (7) establish the financial impacts each condition has on the current program into the future. To do so, a risk-based approach was taken to identify areas of need and quantify the capital investment required to meet the associated levels of service (LoS) and performance targets through data-driven analysis. Each business unit (BU) was involved with identification of the top three risks to their BU and development of levels of service, including categories, performance measures, and performance targets. The risks and levels of service were correlated to quantify performance improvement and the corresponding risk mitigation resulting from each mitigation measure identified. A 20-year long range plan was developed to show the needs-based results to mitigate the highest three risks for each business unit.

One of the top challenges of today’s pipeline industry is maintaining pipeline integrity with aging infrastructure and budgetary constraints. Effective planning is essential to optimize financial resources and maintain pipeline integrity. Citizens Energy Group provides natural gas, steam, chilled water, water, and wastewater services to about 800,000 people and thousands of businesses in the Indianapolis area. To achieve Citizens’ mission, it is critical to Citizens to provide safe, reliable services while maintaining the lowest possible rates by maintaining pipeline integrity. Historically, the capital planning processes for each business unit differed on their approaches to terminology, schedules, cost estimating, content, planning horizon, prioritization, and project selection. In addition, the planning methodology for each business unit used different terminology, formats, and strengths. In 2019, Citizens embarked on an initiative to consolidate the planning under one trust-wide approach and format. This resulted in a consolidated approach to resource management and equipped leaders with information to make future business decisions in a centralized location while optimizing financial resources. Benefits include more thorough documentation of short- and long-term capital needs, enhanced coordination and collaboration between groups, transparency and knowledge management, and project planning memos and metrics for cost and schedule adherence. The consolidated planning supported identification of best practices and opportunities for improvement. This presentation will describe the new consolidated planning process and how it supports maintaining pipeline integrity.

Condition assessment, risk analysis, project prioritization for pipes at risk, and long-term capital improvement planning for aging infrastructure are essential tools for water utility managers. Comprehensive long-term pipe renewal (repair, rehabilitation, and replacement) programs are often created to maintain full serviceability of the pipe network. These programs based on condition and risk assessments help utilities spend maintenance dollars judiciously and avoid costly repairs, the potential harmful effects of deferring maintenance, and negative social, economic, and environmental impacts. This paper focuses on using a GIS-based desktop computer modeling approach to collect condition assessment information for the water infrastructure. The modeling analysis then identifies and prioritizes where and when maintenance activities will be most effective. This approach can reduce maintenance inefficiencies, prevent costly system failures, minimize complaint calls, guide resource deployment, and help determine asset replacement and rehabilitation activities. A case study demonstrating the use of a desktop computing tool for condition assessment and development of long-term risk-based planning is presented to illustrate this modeling approach.

As momentum increases for the use of collaborative delivery methods in the execution of pipeline projects, there is need to pause and determine if all potential benefits are being achieved. This paper will highlight one area that is potentially underutilized in collaborative delivery projects. On a pipeline project, the pipe material can be as much as 50% of the overall project cost. Additionally, pipe material pipe supplier can have a significant impact on risk, schedule, and quality. Therefore, early pipeline material supplier involvement helps properly allocate risk, reduce costs, improves total project schedule, and enhances design and installation quality. This paper will address potential benefits of early supplier involvement in each major phase of project development, including design, procurement, construction, and commissioning/operations. In each phase, the benefits of pipe supplier involvement will be outlined in terms of cost, risk, schedule, and quality. Case studies will be incorporated into the paper to highlight tangible benefits from specific projects. Since the paper will not focus on any specific pipe product, recommendations will be made regarding the collaboration of the material supplier into the project. As the collaborative delivery method for pipeline projects grows, the need for harnessing benefits from this approach grows as well. Given that material is a significant portion of a pipeline project, enhancement of this integration in a collaborative delivery project is warranted.

The construction of a 72-in. (1.83-m) pipeline for UTRWD involved collaboration between the owner, engineer, and contractor to produce informed decisions throughout design and construction. The team’s diversity yielded practical solutions that minimized service interruptions (treatment plant and pump station). The presentation will outline some examples of the challenges encountered along with demonstrating that diversity and a strong team relationship always leads to success.

Trenchless specialty work carries inherent quality risks that can be managed through proper upfront vetting of contractor qualifications and field experience by requesting specific information to be submitted concurrent with standard bid documents. These submittals with bid may include, but are not limited to, testing describing the repair materials’ physical, mechanical, and environmental qualities, constructor and manufacturer qualifications, draft design approach, site specific safety documentation, etc. Owners, engineers, and consultants benefit from understanding the goals of these submittal requirements and how their requisite placement within the project timeline could affect key project parameters such as installation quality, design robustness, and total budget. In this technical paper, we aim to (1) provide a risk-based weighted approach to bid package evaluations and contractor selection (considering qualifications, price, and schedule); (2) define suggested qualifications to be submitted with bid, and the basis for inclusion within said bid; and (3) discuss an innovative approach for the procurement of high value specialty projects.

Modified cross-section trenchless lining methods include deformed and reformed, swagelining, and rolldown. A modified cross-section technology used in this study is to install a close fit HDPE lining in the existing host pipe. A flexible HDPE lining pipe material is extruded through a smaller diameter swage die to create its cross-sectional profile reduction temporarily. The deformed lining wall profile is restored after being installed in the existing host pipe. The principle of this trenchless technology was developed over 30 years ago by British Gas and United Utilities to address failing buried pipelines without excavation. This technology has been used for gas main, water main, and sewer force-main trenchless rehabilitation. The restoration rate and time are two significant performance factors to ensure constructability and quality control during the field application. However, technical information for the two factors is limited and not widely available for engineers, owners, and contractors. The focus of this paper is twofold: (1) description of a 50-m steel-framed pilot test bed for the restoration rate versus time test, and (2) verification of a hypothesis of HDPE pipe restoration by measuring cross-section profile and development of a prediction model for future field application. The project team selected 450 mm (approximately 18 in.) (DR 13.5) and 630 mm (approximately 24 in.) (DR 26) outside diameter HDPE pipes through different swage die sizes to verify the magnitude of the cross-section profile reduction between 6.7% and 17.14%. During the tests, the ambient temperature data were constantly monitored without artificial heating or steaming source to increase flexibility. A conventional static pipe bursting hydraulic rig rated 60 bars (21 metric tons) was used to pull HDPE pipe through the swage dies. This paper summarized the data collected from eight tests and a time-dependent deformation restoration prediction model. The authors anticipate that the test results and the prediction models in this paper provide a better understanding of the restoration behavior of the modified cross-section close fit trenchless rehabilitation technology to engineers, owners, and constructors.

This paper summarizes a recently completed investigation of corrugated steel structures. The project commenced with field testing of two corrugated steel arch culverts in the city of Kingston, Canada, using optical fibers to provide detailed measurements to permit assessment of thrust and moment distributions under static and dynamic truck loading. The detailed responses provided new understanding of the structural behavior, including the critical nature of the front axle of the truck, when normal practice would focus on the tandem axles at the rear of the truck. The study also permitted assessment of the impacts of vehicle speed and the asphalt pavement. Next, improved orthotropic properties were developed considering the arc and tangent geometries of four common corrugation plate sizes, revealing the shortcomings of traditional sinusoidal approximations. Finite element modeling was then used to undertake an extensive parametric investigation to develop new design equations providing improved moment and thrust estimates for single and tandem axle load patterns, at a range of burial depths and corrugation geometries. The paper provides a summary of this research as well as provides insights gained from the investigation.

Despite extensive efforts made by academic researchers and industries, the control of corrosion-induced damages in oil and gas pipelines is still facing challenges. Particularly for the internal surface, the exposure to harsh corrosive environment significantly accelerated the process of corrosion attacks. Nanocomposites have been attracting great attention for developing protection coatings as improved properties can be introduced by nanoparticle pigments. Our previous investigations revealed that nanofiller could enhance some properties; however, it may also have detrimental influences on others. Therefore, this study developed an epoxy-based coating reinforced by binary nanofillers with graphene nanoplatelets (GNP) and nano-silica (NS). The synergistic effects of GNP/NS on the mechanical, electrical, and tribological properties were comprehensively evaluated by experimental study. Results indicated the GNP/NS hybrid nanofiller system formed a more robust nanoparticle network with a higher dispersion, which provided a significant reinforcement on anti-corrosion performance and mechanical properties, compared to single nanofiller system. In addition, the simple fabrication method and easy application process showed its potential for large-scale commercial applications.

Pipeline infrastructure responsible for the transportation of natural gas plays a crucial role as the world diversifies its energy mix to meet the growing demand for power and other utilities. Expanding efficient oil and gas transportation is critical to the energy future and the overall economy of the US, and pipelines remain the energy lifelines that power nearly all Americans’ daily activities at home and work. Pipeline infrastructure projects are characterized as being capital intensive, with long economic life and a high level of economic risk. Front-end planning (FEP) plays a critical role in preparing projects for success. The FEP process can be used to develop sufficient strategic information with which project risks can be appraised and resource commitment can be calculated to maximize the chance for project success. This paper evaluates the potential applications of FEP for pipeline construction projects. The design considerations and constructability reviews for pipeline construction projects are examined using case study projects to elicit areas of probable application of FEP. Based on the findings of the study, recommendations for the implementation of FEP for pipeline construction projects are proposed. The outcomes of this study could be used to establish a baseline for the development of an evaluation tool for measuring the robustness and efficiency of FEP for pipeline projects.

The Trans Mountain Pipeline Expansion Project is the most largest technically challenging pipeline project ever constructed in Canada and possibly in North America. This project consists of 987 km (613 mi) of NPS 36 and NPS 42 pipeline, 11 pump stations, 3 berths, addition of 19 petroleum storage tanks, and elevation changes not normally designed for in liquid pipelines. The challenges are many and diverse. With similar challenging projects like Keystone XL being cancelled, Trans Mountain stands out in that this challenging project is under construction now with completion planned for late 2023. Challenges include environmental, regulatory, technical, geotechnical, geological, topographical, equipment, manpower, COVID-19, safety, schedule, public perception, design, and recent concerns in BC like fires, extreme temperatures, and overland flooding as well as others. Conceived by Kinder Morgan Corporation (KMC) as an expansion of its existing pipeline to expand offshore markets, ultimately the risk for the pipeline completion was such that KMC sold the pipeline to the Canadian government, essentially the people of Canada. It is very likely that once completed, Trans Mountain Corporation, the owners of the TMC system, will be sold to a major pipeline operator as the Canadian government is not in the pipeline operating business. This paper will outline where the project is now, how it got here, and how it managed all of the challenges faced.

In the water and wastewater industry, the importance of piping materials’ sustainability is often overlooked. This can be attributed to the fact that available information is based on qualitative statements made by manufacturers regarding the pipe materials’ manufacturing process. This makes it difficult to compare different pipes or assess the sustainability of a pipe project. This paper will show how a life cycle assessment (LCA) can quantify pipe sustainability and provide suggestions on how utilities can use this information. An example of a pipe industry performing an LCA will also be given.

In 1984, a month after the Reach 3 pipeline of Jordan Aqueduct was put into service, under the auspices of the Bureau of Reclamation, 66″ prestressed concrete cylinder pipe (PCCP) experienced a failure. In 1989, the 21-foot diameter concrete pressure pipe used for siphons on the Central Arizona Project began exhibiting evidence of corrosion, only 10 to 15 years after it was installed. Much has been written over the years on pipe failures due to materials and manufacturing processes used by the Interpace Corporation. Since then, the concrete pressure pipe industry has thoroughly revised the AWWA C301 Standard for the Manufacture of PCCP, with major revisions between 1984 and 1992 and the introduction of AWWA C304, the design standard for PCCP. The record shows that pipe manufactured today far outperforms the pipe manufactured in the 1970s and early 1980s. We would like to take this opportunity to discuss some well-known failures in the West, why they happened, and why PCCP made today would not suffer the same fate.

High density polyethylene (HDPE) pipe is increasing in popularity for installation in municipal water and wastewater systems. HDPE has been widely used for trenchless technology installations, such as horizontal directional drill (HDD), pipe bursting, and sliplining. Installation of HDPE through traditional open cut construction is increasing as municipal use of the material continues to grow. Pipe installation references provide typical design parameters as to which extensive design analysis is not required. Some installations fall outside of these parameters, and this paper will highlight areas of installation as to which the designer should perform the detailed analysis. This paper will provide detailed information on calculating important design installation equations. Project examples calculating wall buckling and compressive stress, pipe deflection, allowable external pressure for unconstrained pipe, allowable tensile stress during trenchless pull-ins, and more. Available references providing detailed information on calculations and installation procedures will be provided. Actual project examples will be provided in order to help the audience translate the analysis from equations to field installation conditions. While the focus on the paper is HDPE, the presentation of unique installation conditions requiring additional pipe installation calculations would be useful for any pipe material and engineering analysis.

The city of Fort Worth faced a potential environmental crisis. Erosion along the Trinity River had exposed a 90-in. RCCP pipeline. Emergency repairs were needed to stabilize the bank of a meandering river to keep the wastewater flow from polluting the river and to protect an adjacent 90-in. RCCP pipeline. Combined, this twin 90-in. wastewater system conveys 150 MGD of wastewater to the city’s wastewater reclamation facility. This size of project typically would take a year or more to design, permit, advertise, bid, and award, but commitment from all parties allowed for fast-tracking so the design-to-construction time took just three months. A multidisciplinary team of engineers, scientists, construction managers, and city staff overcame a cascade of challenges to produce a long-term solution with multiple community benefits (avoidance of a wastewater disaster; uninterrupted service; lower construction cost using sustainable, natural design techniques; and improving conditions along the river over the long term). By addressing this emergency using natural channel design flow deflection structures, a launchable rock toe, and a concrete terrace wall to secure the bank and protect the pipelines, this project showed engineering excellence in action. The design team introduced a new technique to the USACE’s Fort Worth District, opening the possibility to serve as an example for future river stabilization projects within the region.

Existing waterlines on Las Vegas Boulevard between I-215 and Sahara Avenue were constructed between 1955 and 1960 and are now in need of replacement. To address this issue, the Las Vegas Valley Water District has undertaken a multi-phase project that includes over three mi of 36-in. diameter steel waterline, and over 3.5 mi of 24-in. and smaller ductile iron pipe. The project is being constructed in one of the most heavily trafficked and utilized roadways in Nevada. The presence of many other utilities within the project alignment, as well as frontage by major businesses that are primary contributors to the Southern Nevada economy, creates unique challenges for designing and constructing a large-diameter waterline. This paper discusses challenges related to the design and installation of a large-diameter waterline in a highly visible, rapidly changing location that is densely developed by other utilities.

This paper focuses on awareness and understanding of “pipe performance curves.” What are they? How are they derived? How are they different? Why are they important? Meaningful predictions of pipe performance and life expectancy depend on accurate measurements of actual in-service pipe performance over significant time periods. The unpredictability and variability associated with factors that can affect life expectancy can be considerable. This is especially true for performance expectations on the order of 100 or more years. Recognition that different pipe materials/products deteriorate at different rates and for different reasons is a prerequisite to making product selections that optimize water infrastructure performance and longevity. Published performance curves for several pipe products commonly used for water transmission and distribution are reviewed. The various performance curve contours are categorized according to a pipe product’s inherent characteristics and limitations. Such information is key to selecting and engineering underground water pipelines that will perform, sustainably for 100 years, while failure to understand and recognize performance curve contour differences leads to inaccurate life expectancy forecasts.

Water meters are an essential function of any drinking water utility, and maintenance is critical. Meter accuracy is important to ensure that the customer is billed correctly and the utility does not experience lost revenue. An acceptable level of non-revenue water is inevitable but can be minimized with a control program designed to strategically target meters outside of their acceptable operating accuracy ranges. Citizens has over 340,000 active water meters serving 800,000 people in the Indianapolis area. In 2018, Citizens launched a continuous improvement initiative with Citizens Lean and Six Sigma (CLASS) to audit and document all water meter processes. In 2020, Citizens established a strategic replacement program to address aged and underperforming water meters by analyzing historical test data. This paper will describe the efforts made to date on creating a water meter program manual to effectively implement a strategic replacement program to address 40+ year old meters.

Critical large diameter pipelines around the world are often thought of as assets with a defined end-of-life. With the logistical and financial barriers that exist with a wholesale replacement of these assets, and the high consequence of failure associated with large diameter pipelines, inspection technologies have been increasingly deployed to avoid failures and better define the “remaining useful life” before replacement is planned. While these technologies have facilitated the avoidance of many catastrophic failures, it is worthwhile exploring whether these assets can be maintained indefinitely rather than planned for replacement. For example, a review of over 20 years of condition data collected on pre-stressed concrete cylinder pipe (PCCP) consistently demonstrates that over 90% of these assets are in near nominal condition, irrespective of age. Leveraging a significant library of condition and break data, the authors present an alternative to conventional wisdom: that with a data driven inspection and proactive management plan, these assets can be in service indefinitely.

Subsurface utility engineering (SUE) is a method to assign a quality level to locate designations of subsurface utilities. It was introduced by the American Society of Civil Engineers (ASCE) as a performance standard in 2002, and a new revision is currently up for public comment. The standard aims to address the lack of reliable standard procedures regarding the locations of underground utilities. SUE calls for utilizing new and existing technologies and engineering judgment to identify, characterize, and map accurately the underground utilities that goes beyond the current practice of one-call systems. Several Departments of Transportation (DOTs) have adopted SUE to reduce utility conflict, construction delays, design changes, claims, and injuries through better utility geolocation. Historically, DOTs have utilized a mix of utility owner records, the one-call system, and private locating firms to geolocate facilities in their designs. This study investigates the current SUE’s scope of work that is currently adopted by Michigan Department of Transportation (MDOT) and Colorado Department of Transportation (CDOT). Highlighting the similarities and differences between the two scopes of work would help DOTs utilize a robust scope of work that is compatible with the current SUE standard.

Renewal and replacement of aging sanitary sewers is one of the vital issues for the North American municipalities every day. Conventional replacement of these aging pipelines utilizes open-cut trenching methods that could be expensive both in rural and urban areas. In trenchless cured-in-place pipe (CIPP) pipeline renewal method, a liquid thermoset resin-saturated material is put inside the deteriorated pipe by hydrostatic, air inversion, or pulling inside mechanically and inflating. Then, the curing of the liner material used could be done in-place using three different ways such as hot water, steam-, or UV-cured to result in a final cured product. Trenchless methods are considered much more cost-effective; however, to make a comprehensive comparison, engineers and project owners want more data. The objective of this study is to review past studies dealing with CIPP renewal method and open-cut pipeline replacement, and to compare their construction costs for renewing the small, medium, and large diameter sanitary sewer pipelines with the help of statistical analysis. It was found that mean construction costs of CIPP renewal are 57%, 63%, and 18% less as compared to the open-cut pipeline replacement for small, medium, and large diameter sanitary sewer pipes, respectively. It can be concluded that using CIPP method, municipalities can save millions of dollars in the renewal of underground utility systems. A life cycle cost analysis to evaluate and compare the construction, environmental, and social costs between CIPP renewal method and open-cut pipeline replacement is recommended.

Over the past decade, cementitious spray applied mortar linings have gained increasing popularity due to their competitive cost structure for large diameter pipe rehabilitation as well as other installation considerations. However, the engineering community, and especially bodies such as ASCE, ASTM, and others, has yet to define a standard design methodology. This paper reviews the increasingly large number of scientific studies that have been conducted to reline existing pipe structures and determine a proper design method. The test data from five different engineering studies is analyzed. The experimental methods of each study are reviewed, and the limitations for each set of data are noted. Straightforward conservative design methodologies are presented and compared to the failure modes for each pipe type based on the material properties of the sprayed liner system and form a consensus on the design method. The results are also compared to a CANDE finite element model.

The paper presents the application of a new system, called “InfraShield,” which increases the performance level of steel water pipelines, which are connected to rigid structures and subjected to differential ground settlement. The application of the InfraShield system in the present problem consists of a pair of pipe wall projections located at appropriate locations along the pipeline that enable the pipeline to accommodate itself within the settled soil pattern in an optimum manner, minimizing its strain and deformation without the use of couplings or more complex systems. The problem is solved numerically using advanced finite elements, which simulate the steel pipe, the soil, and the soil-pipe interface in a rigorous manner. Extensive numerical results are obtained that verify the effectiveness of this system. It is also shown that pipeline response may not be very sensitive to the location of the projections, and this is a positive result on the applicability of the InfraShield system in pipeline design practice. Furthermore, the influence of pipe wall thickness and soil stiffness on settlement response are also examined.

Water pipelines are vulnerable for failure at locations where they cross active fault lines. Steel pipe for crossing faults (hereinafter SPF) was developed by the authors as a seismic countermeasure construction method for pipelines which cross faults and has an extensive record of use in Japan in key trunk pipelines in the waterworks field. Subsequently, using the SPF technology, “SPF large displacement type” was developed, which could deform by low reaction force. With this improved SPF, the range of the SPF application is being expanded to include large ground displacements other than fault offset, such as subsidence and liquefaction settlement. This paper introduces the outline of the SPF large displacement type to expand the range of SPF application and its application through a case study in Vancouver, Canada. In the study, the application of SPF large displacement type was verified, using a numerical analysis.

The American Society of Civil Engineers (ASCE) is currently developing a Manual of Practice (MOP) for the Seismic Design of Water and Wastewater Pipelines under the Pipeline Division of the Utility Engineering and Surveying Institute (UESI) in collaboration with ASCE’s Infrastructure Resilience Division (IRD). This MOP would include a prescriptive approach for seismic design of buried water and wastewater pipeline infrastructure that is potentially subjected to transient ground deformations (TGDs) and different types of permanent ground deformations (PGDs) such as those imposed by landslides, liquefaction-induced lateral spreads, and fault rupture. The work summarized in this paper pertains to an analysis framework being considered for the development of prescriptive design recommendations for PGDs from landslide hazards. These prescriptive design recommendations are presented in the form of design tables tabulated against primary seismic parameters such as site class and spectral acceleration for different pipeline criticality categories. A theoretical approach based on the simplified pseudo-static seismic slope stability evaluation approach has been adopted in developing the recommendations presented in these design tables. Data from either readily available landslide susceptibility maps, seismic slope stability hazard maps, and/or contour maps (i.e., steepness of the terrain) are being utilized to establish appropriate yield acceleration values in developing the design recommendations. This approach provides a mechanism to design commonly encountered water/wastewater pipelines against landslide hazards without undertaking significant and complex investigative, evaluative, and design efforts. However, critical pipelines located within high landslide hazard regions, especially those within very steep terrain and/or high seismic regions, will require site-specific analysis and design. Due to space limitations, this paper focuses on typical design tables and presents an example of how to use those design tables in a typical design.

This paper addresses the benefits of adding flexible, yet restrained, grooved pipe couplings (subsequently referred to as flexible couplings) to above- and below-ground piping interfaces of hydraulic structures to promote seismic resilience at the area where pipes enter and exit reinforced concrete walls. To assess the efficacy of this approach, a piping stress study was conducted using CAESAR II software’s beam-style FEA analysis. The moments on an assumed fixed end (structure wall) were calculated with and without pairs of flexible couplings to show the benefit and reduction in bending moments and shear forces on the structure wall. The results indicated that adding flexible couplings to piping interfaces of hydraulic structures can reduce shear forces and moments on hydraulic structures by approximately 89%. Example calculations, modeling, and data are provided throughout this paper to help assess shear force and moment reduction on hydraulic structures.

As technological advancements improve water distribution systems’ ability to accommodate significant ground deformations associated with earthquakes, fault rupture, landslides, liquefaction-induced lateral spreading, and other natural hazards, municipalities and pipeline designers need a systematic method to define and classify the seismic response and capacity of new and developing pipeline systems. This paper reports on a subset of full-scale tests, performed at the University of Colorado Boulder’s Center for Infrastructure, Energy, and Space Testing, that identify pipeline response to permanent ground displacements. The testing was performed on 6-in. diameter DR14 iPVC pipe with several different mechanically restrained joints. The results focus on categorizing the axial response of each tested iPVC pipeline system into seismic performance classes. Currently, ISO 16134 is the only design standard that includes a seismic performance classification for pipelines. However, ISO 16134 only considers the axial capacity or connection force capacity (CFC) of earthquake-resistant ductile iron pipe (ERDIP) and does not consider other commonly used pipeline materials. Recent work has expanded on ISO’s performance classification to include other common pipeline materials such as thermoplastics and polyethylene. This study expands on these efforts and defines seismic performance classes for several iPVC pipeline systems by relating the systems’ seismic response to ERDIP systems that have performed well during past seismic events. The results of this study are intended to provide a framework for how various systems can be assessed for seismic response, ultimately supporting ongoing development of ASCE’s Manual of Practice on seismic design of water and wastewater pipelines.

Design and installation of blowoff and drain line assemblies on transmission waterlines is commonplace. However, design of these accessories on large diameter transmission waterlines can be quite complex, especially in high pressure applications. A design and operation balance needs to be found between the need to drain the line in a planned or emergency shutdown versus the potential damage to the assembly and/or the environment. This paper discusses the different design considerations, including, but not limited to, required pipeline drain time, maximum flow rates, client preferences, environmental protection, operatory safety, durability, and ease of operation.

The Agua Vista Station, which is the cornerstone of the San Antonio Water System’s Vista Ridge Integration Project in San Antonio, Texas, includes one of the tallest 10 million gallon (MG) prestressed concrete ground storage tanks ever constructed. The tank was placed into service in early 2020 before the 45 million gallons per day (MGD) water supply project went online. The tank has a 60-in. diameter stainless steel inlet pipe that enters through the tank’s floor slab and extends vertically 82 ft to the high-water level. After construction, it was determined that if the inlet riser was empty while the tank was full, it would be subject to an external hydrostatic pressure of 36 psi that could result in a collapse of the pipe. The riser pipe will be retrofitted with stainless steel stiffener rings to increase its external pressure capacity to withstand the potential external pressure condition. Replacing the riser pipe with a new thicker pipe was not feasible. The 60-in. steel riser pipe has a 5/16-in. thick wall with only two flanged joints and is connected to the concrete tank wall by 3/16-in. × 4-in. wide stainless steel straps at 10 ft center to center spacing. The contractor is planning to perform the retrofit activities in-place since the window for the retrofit work is very short and must coincide with the annual maintenance window for the entire water supply project; the tank must be drained before retrofit work can start. In preparation for the retrofit, the contractor submitted the designs of the stiffener rings, including dimensions of the rings and required spacing, which had to be approved by the owner’s engineer. The contractor also submitted the installation and passivation after welding procedures. A total of nine, 1/2-in. thick × 4-in. high stainless steel stiffener rings are required. The retrofit work is scheduled to be performed by the end of 2022. The stiffener ring designs, installation, and passivation procedures will be presented and discussed.

Design methods for thrust restraint of PCCP using tied joints utilized by some pipeline designers prior to 2008 resulted in nonconservative designs resulting in failures the real root cause of which was not known and was often incorrectly related to pressure surges in the pipeline, corrosion, or other factors. The purpose of this paper is to present a comparison of historical and current thrust restraint methods of prestressed concrete cylinder pipe (PCCP) using tied joints, to identify methods to address deficient thrust restraint, and to identify future work to incorporate the effect of all loads that impact the thrust forces and bending moments in the pipe, such as temperature differentials, Poisson’s effect, and seismic strains in the design of pipelines against thrust near bends and fittings.

A method to estimate the maximum axial displacement at the free ends of unanchored buried pipe due to changes in temperature and pressure is necessary, among other things, to evaluate connections, develop slip or deformable couplers, and apply couplers in design. The problem is represented by a simple one-dimensional model in which thermoelastic pipe slips through embedment as it elongates or contracts axially due to temperature and pressure change. Axial movement is resisted only by stick-slip frictional resistance at the pipe-embedment interface. Dimensional analysis suggests that buried pipe maximum axial displacement for long pipe might be described using four dimensionless parameters. A relationship between the dimensionless products is discussed. The results advance understanding of buried pipe behavior and provide a basis for additional research. Experimentation needed to evaluate the hypothesized relationship is discussed.

The paper presents a discussion on the behavior of a pipeline near a bend with and without a thrust block when subjected to internal pressure, including the Poisson effect, and thermal loading resulting from the differences between the operation and construction environments. The paper presents load combinations that must be considered in analysis and design of thrust blocks and pipelines with tied joints near bends applicable to concrete, metallic, fiberglass, and plastic pipeline materials. The analysis of thrust effects is performed using FEA of pipe-soil interaction near the bends. The results show that the longitudinal strains resulting from the Poisson effect of internal pressure and thermal loads may result in significant differences in loads on thrust blocks and stresses in bends. The Poisson effect of pressure in the pipeline decreases the stresses in the pipe wall and the load on thrust blocks. Thermal loads may increase or decrease the loads on thrust blocks and stresses in the pipe wall. The case of a fiberglass pipe with restrained joints, which was analyzed, is discussed in detail.

Water line in primary tunnel liner or a similar note is much easier said than done. Ignoring the fact that the tunnel needs to be installed, that’s a topic for a much different paper, installing carrier pipe in said tunnel is no easy feat. The primary challenges are constructability, corrosion protection, and accessibility for repairs after construction, if needed. Freese and Nichols, Inc., has seen its fair share of pipe installed in tunnels and has developed innovative solutions for large diameter pipelines to mitigate challenges during construction and over the life of the tunnel. Polyurethane coated steel pipe with a mortar overcoat and mortar bands is one of the best solutions to install steel pipe in a tunnel since it can be pushed/pulled into place without damaging the pipe and does not require casing spacers that may get damaged or stuck. The steel pipe also allows the exterior heat shrink sleeve joints to be easily made up outside of the tunnel and tack welded before they are pushed into the tunnel and fully welded. This method also allows for minimizing the tunnel diameter. However, pipe axial loading may limit the length of pipe installed with this method. Corrosion protection and electrical isolation of the tunnel liner and carrier pipe is a challenge, and grouting the annular space is a great solution, since the liner can become sacrificial and the tunnel structure will still be secure. Grouting is recommended for large diameter steel pipe as it can be repaired from the inside but not for rigid concrete pipe, which is more likely to be replaced than repaired. Metallic pipe and tunnel liners may need cathodic protection to avoid corrosive effects from foreign metallic pipelines. They also may need to be isolated from each other to avoid corrosion of the carrier pipe. Fiberglass casing pipe is resistant to corrosion and can be great for isolating the carrier pipe from foreign pipelines outside of the tunnel. Installing the carrier pipe inside fiberglass casing can be done by lubricating the casing surface and pushing the pipe through while taking care to ensure the friction is low enough to not damage the casing. This can be a great option for jacked casing since it is one of the more cost-effective options. Improvements and innovations like this help better face the challenges of installing pipe in tunnels and deliver successful projects.

The North Harris County Regional Water Authority (NHCRWA) retained Arcadis in 2019 for the fast-paced design and construction oversight of a large diameter pipeline project. The project, titled 28G, is part of a larger pipeline project to supply portions of Harris County with surface water and take users off groundwater wells. 28G consists of 3,800 LF of 84-in. steel water pipe connecting a proposed regional booster pump station in the south to a proposed 84-in. pipeline in the north. A portion of the 28G pipeline is in close proximity to an existing detention basin to the west of the pump station. Several alternatives were considered and analyzed, with the route chosen to be the shortest distance but with many existing utilities, including three (3) outfalls to the detention basin. Preliminary design proposed tunneling the waterline under the existing culverts. Evident during design were several construction risks: tunnel depth, length, and cost due to potential scarcity of tunneling contractors, which drove analysis into alternative alignments. Survey data later determined the storm boxes to be several feet deeper than initially estimated. This allowed for a shallow pipe alternative, placing the pipes over the storm boxes in lieu of under. Alternatives analysis encompassed construction cost, constructability, O&M cost/feasibility, stakeholder impact, and discussions with the owner. The shallow pipe alternative provided its own set of hurdles, including pipe protection in shallow cover, impact to basin and existing storm culverts, and required appurtenances. This project provides a case study in the alternative of shallow pipe burial versus tunneling, benefits to client’s construction cost (savings of $1.3 million), and long-term maintenance while providing a safe, reliable water delivery system.

In less than one year, Citizens Energy Group (Citizens) and a team of consultants and contractors envisioned, studied, designed, and mined a sixth deep tunnel as part of Citizens’ DigIndy program. The Eagle Creek Deep Tunnel was a vast departure and enhancement from the originally conceived shallow interceptor system that comprised the Eagle Creek CSO Abatement Project included in Citizens’ Federal Consent Decree Long-Term Control Plan. This paper will address the rationale behind questioning an established design concept, the chronology of implementing a large project under a compressed schedule, a focus on the collaboration necessary to successfully implement a $37-million deep rock tunnel project in less than one year, unique contract terms that built on previous lessons learned and focused on risk sharing with the tunneling contractor, a look back at the deep tunnel construction, and a summary of the positive economic and third-party impacts resulting from the deep tunnel solution.

This paper describes the design and construction of a 155-ft long bored crossing of the Arlington Expressway in downtown Jacksonville, Florida. The crossing is for JEA’s Main Street Water Treatment Plant water transmission main project. This project assists JEA in meeting future water supply needs and increases system reliability. The crossing is part of a 36-in. water transmission main that will increase the amount of water that JEA can transfer between their North Water Grid and South Water Grid. The transfer of water between their major grids is a key component of JEA’s long term water supply plan. The Arlington Expressway crossing was constructed using pilot tube guided boring (PTGB) to install a 54-in. diameter steel casing pipe under the expressway. PTGB is a technique for installing casing accurately to design line and grade by first advancing a steerable steel pilot tube, followed by one or more boring passes centered on the tube to upsize the bore and install the casing. The Arlington Expressway crossing design required the boring contractor to use PTGB in conjunction with dewatering to overcome challenging ground conditions consisting of sand deposits below the water table. The designers selected the bore horizon to provide a minimum soil cover thickness of approximately 1.5 times the casing diameter, and to avoid an underlying layer of very loose sand, which presented a risk of difficulties maintaining soil stability at the face of the bore, and with steering. The designers specified PTGB considering the importance of preventing grade deviations and concerns for maintaining the required grade tolerance with conventional auger boring. Dewatering was required to stabilize the launch and exit pits, and to draw down the water table under the expressway to promote face stability. The casing was installed within 1.5 in. of design, and settlement along the alignment was negligible. The 36-in. carrier pipe was installed in the casing, and the annulus was backfilled with cellular concrete to complete construction of the crossing.

The Ayalon Sewage Transmission Project, known as the AY Line Project, was designed by Balasha-Jalon Infrastructure Systems Limited and built to enhance the sewage transmission system of the Dan Regional Association for Environmental Infrastructure (IGUDAN) and add redundancy. The project was designed to withstand future breakdowns and allow for major maintenance work without causing any sewer spills. This goal was achieved by creating two large transmission loops that interacted with each other, as with a water supply system. The project involved pipe jacking to install a 1,600 mm (64") diameter pipeline under one of the world’s most congested highways, using only the narrow shoulders and other small areas for work sites. The project also included a large pumping station with dry-installed submersible pumps and two rising mains. The AY Line Project was completed in 2021, and is fully operational, meeting or exceeding all of its design criteria. The successful completion of the AY Line Project demonstrated that large diameter sewage pipelines can be installed under major highways using microtunneling and other “no-dig” methods that work reliably, even under the most challenging conditions. It also demonstrated that water system design, using flow loops, can be applied to large sewage transmission system design, where sewage spills are unacceptable.