Pipelines 2022: Construction and Rehabilitation

Municipal wastewater collection systems deteriorate over time demanding utility owners to involve in continuous revisions and development of asset management frameworks. Inspection and condition assessment of pipelines play a vital role in the successful operation and maintenance of systems. In the United States, closed-circuit television (CCTV) is the commonly used device for inspecting the inner environment of sanitary sewer pipes. Inspection of every individual sanitary sewer pipe segment is not feasible for any municipality owing to their large inventory of pipes and incurred cost. However, sanitary sewer pipe segments in need of repair or maintenance activity can be prioritized in advance for inspection based on their historical performance. Therefore, a condition prediction model based on various machine learning techniques, such as logistic regression (LR), k-nearest neighbors (k-NN), and random forests (RF), is developed. The developed model could forecast the condition of uninspected sanitary sewer pipe. With an area under the curve (AUC) value of 0.86, the random forests model performed better than both LR and k-NN models. The developed models can be utilized by utility owners and municipal asset managers to make more informed decisions on future inspections of sewer pipelines.

Sanitary sewer pipes’ infrastructure system in good condition is essential in providing safe conveyance of the wastewater from homes, businesses, and industries to the wastewater treatment plants. Most of the water utilities have aged sanitary sewer pipes. Water utilities inspect sewer pipes to decide which segments of the sanitary sewer pipes need rehabilitation or replacement. This condition assessment process is costly and necessitates developing a model that predicts the condition rating of sanitary sewer pipes. The main objective of this study was to develop a model to predict sanitary sewer pipes’ condition rating using inspection and condition assessment data. Sanitary sewer pipes were categorized based on various factors: physical, environmental, and operational. Physical factors included pipe material, diameter, age, slope, and depth. While the surface condition, soil type, corrosivity concrete, corrosivity steel, and pH were categorized under environmental factors, sanitary sewer pipe flow was deemed an operational factor. The environmental factors were used as independent variables and the condition rating score of the sanitary sewer pipes as a dependent variable in the model development using the city of Dallas’ data. The logistic model was built using 80% of randomly selected data and validated using the remaining 20% of data. The NNs model was trained, validated, and tested, and performed better than the logistic regression model. This study helps to predict sanitary sewer pipes’ condition rating that enables policymakers and sanitary sewer utility managers to prioritize the sanitary sewer pipes to be rehabilitated and/or replaced.

Pipeline condition assessment needs routinely challenge water utilities in the US. Our buried water pipeline infrastructure is old and deteriorated, resulting in significant leakage and an increasing number of main breaks. The consequences of these failures are serious, thereby warranting proactive approaches to prevent them. While many technologies currently exist to support water pipeline condition assessment, they are either expensive to cover larger sections of the distribution network or intrusive, limiting their suitability. Many existing technologies also only offer a snapshot assessment at the time of inspection. Continuous monitoring networks enabled by sensors that serve multiple purposes in distribution network monitoring can support primitive pipeline condition assessment. This paper proposes and demonstrates a model-based approach for primitive prediction of pipeline condition parameters such as leakage location and severity as well as pipeline roughness. The model-based approach uses the approximate hydraulic model of the distribution network to predict pipeline condition parameters that would result in pipe flows and pressure values matching the actual pipe flows and pressure values obtained through monitoring equipment. Machine learning approaches are leveraged to predict the pipeline condition parameters in this study. The whole approach is demonstrated on a benchmark water distribution network with promising results. This approach requires synchronized monitoring data comprising pressures, pipe flows, and water consumption from distribution networks. The paper offers value to water utilities that are embracing monitoring technologies such as the AMI to transform into smart water utilities.

Water pipe condition models have been important for water infrastructure management systems. Practitioners are in need of a robust and reliable condition rating system to help with the decision making related to water pipe infrastructure management. Over the past decades, researchers have developed a variety of condition models, among which fuzzy logic models are an essential category. Previous researchers have confirmed the advantages of fuzzy logic models over weighted factor models. However, there are still some shortcomings in the existing fuzzy logic models, such as the limited coverage of pipe types, limited piloting with utilities, use of rarely available variables, etc. The objective of this study is to develop a fuzzy logic software system for a variety of pipes, including metallic, cementitious, and plastic pipes, making use of structural, operational, and environmental variables. The fuzzy logic model together with a management plan will aid in the prioritization of future inspection and maintenance practices.

Sewer defect recognition and smart models have been in development for the past few decades. A number of algorithms were used under the artificial intelligence (AI) domain, including computer vision, machine learning, and expert systems to improve the traditional sewer assessment process. Despite the significant contributions in this field, few works have comprehensively demonstrated a systematic approach to validate the developed algorithms. Validation is integral to verify the applicability and test the reliability of the model to precisely and accurately classify and detect sewer defects. Besides, it assists researchers/engineers to pinpoint the limitations of any model developed for improvements so it can be applicable on a larger scale. Albeit this process may seem to be simple, the validation gets complicated while running multiple AI algorithms on videos rather than fewer frames or images. Therefore, it is important to shed light on the validation process to test AI algorithms in the detection and recognition of sewer defects. This paper will present the use of the Intersection over Union (IoU) in such application. The validation and testing process is implemented on SewerLogic’s detection and recognition modules. This paper contributes to the body of knowledge and the engineering profession by demonstrating a systematic and comprehensive validation process of any AI tool developed to detect and classify sewer defects.

A finance department is primarily composed of budget and accounting areas, with other functions such as investments, debt issuance, rate and fee setting, revenue, billing, and purchasing. Most finance directors come from an accounting background, especially for smaller to mid-sized organizations. Their training is not in quantifying risk, and in fact they are not rewarded for taking risks. However, the principles of life cycle asset management is to manage an asset at its lowest life cycle cost while still meeting a target service level. This directly ties into managing cash flow (current revenues used to pay for operations and maintenance), which in turn impacts various financial metrics such as operating cash on hand and the debt coverage ratio. Separate, but connected, is the capital plan, which can be a combination of both debt and an allocation of reserves. The justification of funding asset management practices involves benchmarking costs and demonstrating how and when assets deteriorate and the maintenance costs increase, the repair costs increase, and if the right investment intervention is not made, the asset could fail prematurely and catastrophically, thus costing a great deal more. This paper walks through the various financial/asset management concepts to convince finance to support asset management and condition assessment activities.

Underground infrastructure (UI) in the United States is facing many challenges, such as difficult construction conditions, severe aging, low productivity, workforce shortages, and underperformance in global competition. Close collaboration between industry and universities will greatly help to address these challenges. The Industry-University Cooperative Research Centers (IUCRC) program initiated by the National Science Foundation (NSF) is the most successful of the 28 linkage mechanisms. To date, none of NSF’s 75 IUCRC programs involve research in UI. This paper summarizes in detail the current challenges of UI and some components to address them. It describes the IUCRC and the benefits of the IUCRC to all parties. An introduction of Purdue University’s proposed IUCRC for development of underground space (DUSC) is also presented. Based on the function and uniqueness of DUSC, this IUCRC will be a critical component for addressing the UI challenges in the US.

Subsurface damages significantly impact national growth and citizens’ well-being. Alongside one call centers, private locating firms play a critical role in subsurface damage prevention through locating underground utilities before excavation starts. Therefore, there is a vital need to better understand the resources currently available to construction practitioners and designers to reduce third-party damages to underground utilities. This study investigates the market need for private locating firms in the USA. Among other findings, the study reveals that the need to locate private utilities is one of the most important reasons to utilize private locating firms. In addition, the study highlights the importance of investigating underground utilities during the design phase. It is anticipated that the findings will contribute to better damage prevention processes and a lower number of strikes to underground utilities.

According to a US DOT factsheet, about 12% of total pipeline accidents in the past 20 years are caused by internal pipeline corrosion. The internal corrosion in crude oil pipelines is caused by the contaminants and corrosives such as salt water, hydrogen sulfide, carbon dioxide, and bacteria. Film-forming corrosion inhibitors are commonly used in small quantities to mitigate internal corrosion in steel pipelines, which can be expensive, environmentally unfriendly, and partially effective under certain pipeline conditions. The present study aims at utilizing a novel bio-based corrosion inhibitor to mitigate internal corrosion in pipelines. Polyols are sugar alcohols primarily derived from corn starch, which are demonstrated in the past to inhibit chloride-induced corrosion in structural steels through physisorption. In this preliminary study, brine-in-corn oil emulsions containing polyol with weights ranging between 0% and 3% are prepared and dripped on uncoated ASTM A572 steel specimens to assess the corrosion inhibition efficiency of polyols. Significant corrosion protection is achieved by employing polyols in oil emulsions.

Polyethylene encasement (PE) film has been utilized to effectively control external corrosion of iron pipe for over 70 years. During those years, various associated technological advancements have been made in polymer science and corrosion control, including inhibitors and biological sciences as related to microbiologically influenced corrosion (MIC). This paper gives a brief history of PE film as a method of corrosion protection and describes how adoption of these advancements has led to the development of an enhanced PE film, designed to control MIC and initial corrosion reactions. Additional complimentary corrosion control measures, that are considered here, are metalized zinc external coatings and cathodic protection used in conjunction with PE encasement. Case histories and field-based corrosion testing, in what is described as a uniquely severe corrosive soil environment found in the United States, are summarized.

In 2021, the City of Ottawa (Ottawa) managed an urgent repair to their 1,200-mm Woodroffe Water Main, ensuring continued safe and reliable pipeline operation. They were alerted to an increased rate of deterioration via their acoustic fiber optic (AFO) system that has been installed since 2011 to monitor the pipeline for wire breaks in near real time. The Woodroffe Water Main is comprised of prestressed concrete cylinder pipe (PCCP), for which wire break is an indicator of deterioration. In February 2021, an increase in wire breaks was observed at two pipe sections. Ottawa has performance curves based on finite element analysis, for the Woodroffe Water Main, which provide a threshold number of wire breaks for rehabilitation recommendations. While the two pipes were still below the threshold, the breaks were occurring quickly and Ottawa had to consider the limited time options for taking the pipeline out of service for repair with respect to upcoming projects. The pipe sections were under a culvert, making excavation extremely difficult; therefore an internal repair method was required. Ultimately, Ottawa decided to move forward with rehabilitation using internal carbon fiber reinforced polymer. This paper presents the planning, challenges, and decision making that took place from the time of increased break activity to the completion of the repair. The results of this rehabilitation allowed Ottawa to continue confidently utilizing this water main.

The Middlesex Water Company (MWCo) owns and operates two parallel pipelines that convey up to 60 million gallons per day (MGD) of raw water between their raw water pumping station located in the city of New Brunswick, New Jersey (NJ), and their Carl J. Olsen Water Treatment Plant (CJO WTP) located in the township of Edison (Edison), NJ. One of these pipelines is a 5,200 linear foot (LF) 54-in. prestressed concrete cylinder pipe (PCCP) installed in 1969, and the other is a 6,250 LF, 60-in. ductile iron pipe (DIP) installed in 2005. Although there had been no known issues with the 54-in. raw water supply main throughout its 52 years of service life, MWCo recognized the importance of inspecting this critical pipeline to determine its current condition and ability to reliably convey raw water to its treatment plant. In order to assure its long-term integrity and viability to supply MWCo’s treatment plant serving approximately 450,000 residents in eastern Middlesex and northern Monmouth Counties, MWCo undertook a condition assessment of the 54-in. PCCP pipeline in early 2021. This condition assessment consisted of a manned internal inspection involving wall sounding, and visual and electromagnetic assessments. The electromagnetic inspection determined that a number of pipes had broken prestressing wires, which necessitated the need to perform a finite element analysis. This analysis determined the yield limit for failure of the PCCP pipe class used in the construction of the pipeline. The visual inspection found a number of pipes with circumferential/longitudinal cracking, hollow-sounding areas, and delamination of the inner core. Additionally, one (1) pipe was found to have a circumferential failure within the pipe barrel, which was allowing water to actively infiltrate into the pipe. As a result of this, MWCo undertook an emergency repair, which involved the installation of an internal carbon fiber reinforced polymer (CFRP) system. Additional intrusive investigations were performed on various pipes with observed and detected damage in order to determine the need for additional repair and to determine the reason for damage. MWCo also utilized this inspection as an opportunity to perform an inertial mapping survey of the pipeline in order to better understand how the actual horizontal and vertical alignment of this critical pipeline compared to the original design and construction documents. This paper will discuss the need for the inspection and planning efforts that were undertaken by MWCo as well as the types and results of the inspections performed as well as the emergency repair work.

This paper will discuss the investigate-design-build project from inception to implementation and allow attendees to learn about the approach to asset management of this critical pipeline, including a detailed overview of this type of pipe, the condition assessment technologies utilized, and the subsequent internal pipe upgrades that were performed. The investigation consisted of a two-phased internal condition assessment of the 3-mi (4.83 km) makeup water pipeline with contingency repair plans, which included the use of carbon fiber-reinforced polymer (CFRP) for upgrading distressed pipeline segments. As part of the project development, multiple condition assessment techniques applicable for C303 pipe were considered. The planning phase also included traffic control, pipe access, dewatering, and a variety of contingency design-build repair and rehabilitation scenarios.

The Southern Nevada Water Authority (SNWA) is a leader in water planning and management as it contends with 20 years of drought and climate change conditions to balance regional water supplies with the water demands of more than 2.2 million people and approximately 40 million annual visitors. As industry studies continue to highlight the issues surrounding aging water and sewer infrastructure, policymakers at the local, state, and national levels of government are beginning to recognize the growing problem by making infrastructure renewal programs a priority. The SNWA is regularly faced with many challenges when it comes to condition assessment of its large diameter water transmission mains. Impacts from ongoing construction on the water mains, service level requirements, and lack of system redundancy are some of the many obstacles that water agencies like the SNWA face each time a condition assessment inspection is performed. Faced with such challenges, the SNWA must regularly find ways to mitigate and manage any potential risks associated with condition assessment inspections. The paper will present the SNWA’s assessment of the Aqueduct A pipeline (the Aqueduct). The Aqueduct is a 96-in. PCCP transmission main and one of several that supply water to the Las Vegas Valley directly from Lake Mead. The paper will include justifying the need for condition assessment, selecting the appropriate condition assessment approach, and choosing the most appropriate tool for inspection to maximize actual condition data collected while reducing risk within established budgets. Having inspected the Aqueduct 16 years prior, the paper will also discuss changes in near field electromagnetic inspection of PCCP, including the tools, data analysis, and reporting. Finally, the paper will present the change in pipeline condition between the two inspections and how inspection data informed rehabilitation and pipeline management decisions.

The city of Saskatoon supplies water to approximately 320,000 residents within the province of Saskatchewan via 1,192 km of water main at an estimated replacement cost of over CAD$2.5 billion. The city continually evaluates these linear assets within a long-term asset management plan that has contributed to reduced water main breaks (198 in 2020 compared to a 239 10-year average) and a more targeted water main maintenance and replacement program that is having an overall positive impact on the reliability of the system and citizen satisfaction. As part of this program, the city inspected 7.8 km of large diameter (600–1,050 mm) steel water mains in 2020 to assess their in situ condition. Assessing large diameter metallic pipelines was an expansion to the city’s overall inspection program, which had primarily focused on high-risk C-301 PCCP water transmission mains. Expanding the program to include metallic water transmission mains was driven by newly developed high-resolution free swimming inspection technology that would provide the city with the data they needed to make more informed decisions on these critical assets. The 2020 water main inspection program utilized multiple technologies to measure wall thickness and ovality, assess coating, and provide leak detection, all while keeping the water mains in service. In addition, structural (FEA) and remaining useful life (RUL) analyses were conducted to assist in repair recommendations, re-inspection intervals, and overall estimated pipeline life expectancy. Inspection results identified higher risk pipe sections at a highway crossing with both wall loss and out of roundness. A unique finite element analysis (FEA) was completed on pipes in this area that accounted for all these conditions—defects, out of roundness, and above normal external loading (significant depth of cover, highway crossing).

Sewer pipes are a big part of the nation’s aging infrastructure and require frequent inspection for maintenance and condition assessment. Recent advancements in inspection technologies such as multi sensor inspections (MSI) allow for a full condition assessment of these buried sewer systems. In this paper, an automated framework for condition assessment of a sanitary reinforced concrete sewer pipe is developed using LiDAR inspection data. The procedure for filtering and alignment of the 3D point cloud of raw data and conversion to pipe inner geometry coordinates and applicable 2D rings is presented in detail. For each ring, the actual diameter is calculated using k-nearest neighbor algorithm, while the ovality is calculated using the ASTM F1216 standard. This automated approach could be an alternative for in field pipe diameter determination such as mandrel testing, which is one of the first and necessary steps for an effective life cycle management of wastewater conveyance network.

The City of Stillwater, Oklahoma, owns and operates a transmission pipeline over a 36-mi corridor from Kaw Reservoir to the city’s treatment plant. This pipeline is a 36-in. carbon steel pipe built in 1981 to an API 5L specification. Over the last two decades, the pipeline has shown signs of distress and required various leak repairs. Since this transmission pipeline is integral to the city’s water supply, there is an immediate need to determine the extent of the leakage problem. It was determined that by using airborne remote sensing techniques such as Jacobs’ wide area multispectral system technology, data can be gathered relatively quickly to analyze and provide an indication of potential leaks in the existing pipeline. In August 2021, several passes with an airplane were conducted along the length of the pipeline using Jacobs’ wide area multispectral system. Thermal imagery was captured via a long wave infrared (LWIR) sensor, which identifies thermal radiation emitted from the ground, giving a measure of ground temperature over a wide area. Vegetation has a very high near-infrared response, and as a result, a calculated quantity called the normalized difference vegetation index (NDVI) is used to detect the presence, density, and health of vegetation utilizing the blue, green, red, and near infrared bands (BGRN). A water index is generated applying the triangle method, originally presented by Water-Tightness Airborne Detection Implementation (WADI). When applied to the imagery, it can reveal areas of water or wetness that is created by a leak in the pipeline. The generated water index looks at a pixel’s NDVI and temperature and compares it to all other pixels with the same or similar NDVI. Both wet areas and vegetation have a similar temperature profile (usually cooler than the surroundings) but have a different NDVI, with vegetation scoring high and wet areas having NDVI of nearly zero. Water index calculations use NDVI to distinguish between the wet areas and vegetation, hence enabling identification of active leaks along the pipeline. This paper presents the findings and discussions provided as part of the investigation. These discussions assist the city with future improvements, including rehabilitation or replacement of existing transmission pipeline. It also provides the city with expedient information about existing pipeline integrity to perform immediate repairs, if indicated.

Reliability centered maintenance (RCM) is a process used to determine the most effective maintenance approach, the goal being to establish the required function of a component with the required reliability and availability at the lowest cost. The RCM philosophy considers preventive maintenance, predictive maintenance, condition based monitoring, reactive maintenance, and proactive maintenance techniques in an integrated manner to increase the probability an asset will perform its designed function throughout its design life with minimal maintenance. The principles underlying RCM are so diverse they can be applied to any asset. RCM has been used by aircraft manufacturers, nuclear power plants, submarines, surface ships, automobile manufacturers, HVAC systems, breweries, hospitals and medical equipment, railroads, electrical power facilities, oil and gas, and militaries across the globe. RCM principles can be widely applied to an entire asset or more narrowly applied to select pieces of equipment comprising the asset. In all applications, RCM requires maintenance decisions be based on maintenance requirements supported by sound technical and economic justification. However, one industry where principles of RCM are in its infancy is the water/wastewater industry. The American Water Works Association’s (AWWA) 2020 State of the Water Industry report states that the top issue facing the water industry since 2016 is aging infrastructure, with the second being financing for improvements. The industry needs to find novel ways of extending asset life and reducing maintenance expenditures. While there are many different assets that comprise the water/wastewater industry, pipelines are a major component and are often neglected because they are typically buried. This paper reviews several current models used in RCM analyses and proposes an approach for determining the most effective and efficient maintenance activities for large diameter water pipelines.

Evansville Water and Sewer Utility (EWSU) owns and operates a 36-in. water prestressed concrete cylinder pipe (PCCP) transmission main that is approximately 6,000 lineal feet in length. This water main was installed in 1954. This water main was installed in downtown Evansville along the Ohio River front. The sandy conditions along the river absorbed water leaks, and a parking garage had been built over a section of this pipeline. The integrity of this crucial pipeline was largely unknown. EWSU hired Pure Technologies, a Xylem brand (Pure Technologies), to perform a condition assessment of the water main to mitigate risk. Electromagnetic technology was used to identify broken wire wraps. This technology enabled inspections while the water main remained under pressure and in service. A forensic analysis was performed to determine root cause. The impacted pipe sections were removed and replaced. Paper outlines the steps taken to extend the remaining useful life of this critical asset.

The City of Tucson is a Sonoran Desert community in Southern Arizona with a population of nearly 750,000 people, and one million people when including the metropolitan areas. Tucson Water, a department of the City of Tucson, is a large, complex groundwater system receiving a Colorado River water allocation of approximately 148,000 acre-feet. The city recharges this groundwater system in a vast recharge and recovery system west of the community. In February of 1999, the city’s largest potable water transmission line, a 96-in. diameter (4,000 mm) prestressed concrete cylinder pipeline (PCCP), failed catastrophically, releasing a flood of water, mud, rock, and debris, crashing into a neighborhood, knocking down block walls, trapping people in homes, floating vehicles out of driveways, and causing extensive damage to private property and homes within the community. This one failure of a pipeline having been in service just 11 years cost the city approximately five million dollars in private property damage, collateral damage, and litigation, and forced the city to revert to pumping native groundwater for months until the transmission line was restored to service. The forthcoming white paper will demonstrate how one water utility recovered from the catastrophic failure of its most critical water transmission line, progressed to one of the most forward-thinking water utilities, and implemented one of the most advanced and longest running asset management programs for PCCP in North America. This “snapshot” presentation of Tucson’s asset management program, entitled “Pipeline Protection Program” (PPP), will give a brief overview of the various challenges Tucson faced and highlight the various strategies, tools, and technologies applied that have collectively prevented any additional pipeline bursts for more than 23 years and counting.

When New Jersey American Water (NJAW) experienced three failures on one of their major transmission mains, they faced the challenge of how to effectively and efficiently spend their budget to maximize the remaining life one of the backbones to their conveyance system. Recognizing that while the pipeline had previously failed, it may still have significant remaining useful life, NJAW embarked on a phased, incremental approach to assess the condition of the pipeline and ultimately make necessary improvements to the main, while maximizing the value of their investment. One of the most significant challenges was to determine if the pipe had a few isolated problem locations or if uniform deterioration existed, which caused the three failures. The flexible approach was structured to optimize the collection of pertinent data by using collection methods of increasing levels of resolution, such that once an adequate level of information had been collected, the process could be halted, and necessary repairs and improvements could be made. The intent was to develop a proven, repeatable process that could be used to assess all of their high-risk transmission mains. This paper will discuss the phased approach used by NJAW to confirm reliability of this pipeline for years to come.

Management of PCCP transmission mains has advanced rapidly in the past two decades. The Water Research Foundation (WRF) Project 5069 examined the practices used to proactively manage PCCP mains to determine if failure rates have actually declined due to these practices and what lessons have been learned on PCCP programs that could be applied to transmission mains constructed of other pipe materials. The paper reviews these practices and documents practical measures and management practices that contribute to improved pipeline performance. One of the primary findings of the research is that many of the technical challenges associated with assessment and management of PCCP have been addressed. The primary challenges remaining are managerial and operational.

Citizens Energy Group, a natural gas pipeline operator, piloted a GIS (geographic information system) based solution to collect barcode information, create barcode/QR codes, and capture high accuracy GPS locations of underground assets. This paper will provide details on the solution, share lessons learned, and present the next steps. Compliance with the natural gas federal rules has driven part of the solution. This paper will, at a high level, touch on those rules. Then, the paper will discuss the approach taken and how the solution meets those requirements for both distribution and transmission pipelines. Once there is a basic understanding of what approach was taken, this paper will then jump into some of the details of the solution. That includes the GIS based mobile solution, and hardware for the mobile solution to include tablet, GPS unit, barcode reader, and QR code creation. This paper will continue to follow the workflow and discuss field data collection and the approach to crew roll out and training. Now that the data has been collected, this paper will then move into the details of document storage, retrieval, and GIS editing. At the end of this paper, we will discuss lessons learned as it relates to the GIS solution development, hardware selection, data storage, and field crew feedback. The paper will then conclude with next steps for the solution.

In the past 10 years, about 1,200 fire accidents were reported in oil and gas pipelines with protective coatings. Metallic coatings are popular in oil and gas pipelines due to their excellent performance in corrosion prevention. This paper quantifies the changes in mechanical properties such as hardness and wear-resistance of thermally sprayed anti-corrosive coatings in steel oil and gas pipelines exposed to fire accidents. Specifically, two types of wire arc sprayed metallic coatings, including the Zn-15Al and Zn-Al pseudo alloy coatings, are investigated. These coatings are exposed to high temperatures ranging from 300°C to 700°C for an hour simulating fire accidents and are cooled down by air cooling, which is common after an accident in the field. Results indicated that the Zn-Al pseudo alloy failed at 600°C and the Zn-15Al survived until 700°C. The results of this study will help to evaluate the integrity and residual life of metallic coatings used in steel pipelines after being exposed to fire accidents.

Asbestos cement (AC) pipe was used as pipe material starting from 1930s. It was widely used during 1950s–1960s, and it phased out in the US in 1980s due to health concerns and the availability of PVC pipe. It was estimated that 600,000 mi AC pipe were installed in the United States and Canada. Several studies show that AC pipes are experiencing accelerated failure in recent years. To prioritize the AC main replacements, it is important to understand the performance of AC pipe in the water system. This paper analyzes the failures of AC pipe using the most recent 12-year main break data. AC pipes in coastal area and inland area were analyzed separately to understand their break rates. The results of this analysis could help utilities better understand the performance of AC pipe and prioritize AC pipe replacement.

When ductile iron pipe was introduced into the marketplace in the late 1950s, it was destined to supplant cast iron pipe as the pipe of preference for many utilities. However, there was a time when both pipes were available, which has resulted in some difficulty in identifying which pipe was which, today. While cast iron and ductile iron pipe are similar, there are significant differences in physical properties and failure modes that differentiate the two. For proper asset management, it is important that the iron pipe in a system be correctly identified. If performance data are incorrectly attributed to the wrong pipe material, it will result in inaccurate analyses leading to potentially flawed planning decisions. This paper provides information that will be useful in the effort to correctly identify cast and ductile iron pipes in service.

WSSC Water (WSSC) is among the largest water and wastewater utilities in the United States, serving approximately 1.8 million residents in Montgomery County and Prince George’s County, Maryland. The backbone of WSSC’s potable water transmission system is 145 mi of large diameter (36-in. and greater) prestressed concrete cylinder pipe (PCCP). For over ten years, WSSC implemented a condition assessment and asset management program to ensure the reliability of their PCCP transmission mains. WSSC Water employs a proactive approach to manage the condition of their PCCP transmission mains with a five year cycle multi-approach inspection followed by near-real-time pipeline acoustic fiber optic (AFO) monitoring. Inspection data and structural analysis together with AFO provide to WSSC up-to-date condition assessment information of each monitored PCCP to make informed proactive decisions. This paper will compare and discuss the results of four condition assessments performed in 2008, 2009, 2014, and 2020 on the same 48-in. PCCP Rockville Montgomery County High Zone transmission main. The 48-in. PCCP transmission main is comprised of approximately 31,895 ft of embedded cylinder PCCP (ECP) and approximately 517 ft of ductile iron pipe (DIP). The main connects the system from east to west providing redundancy between two WSSC’s water treatment plants. A failure occurred in June 2008 resulting in an interruption of the service affecting residences and businesses primarily north of Randolph Road in Montgomery County. As a result, WSSC contracted Pure Technologies (Pure) to conduct a condition assessment of the transmission main. After the first condition assessment was completed in 2008 and the subsequent AFO monitoring technology installed for ongoing monitoring, this PCCP transmission main has been reinspected in 2014 and 2020 utilizing Pure’s electromagnetic inspection technology. This paper will also evaluate the progression of deterioration, review the frequency of reinspection, analyze how repairs extended the service life of the 48-in. PCCP transmission main, share the lessons learned by WSSC’s engineers executing the condition assessment every five years, and discuss what changes are ahead to improve the continuous success of the WSSC’s PCCP program.

A risk-based asset management approach facilitates maintaining acceptable pipeline reliability at minimum cost. This paper presents tools to support a risk-based approach for pipeline management, so pipeline owners can make easier, informed decisions at a system level or pipeline level to prioritize maintenance activities and repairs. System-level tools evaluate the likelihood of failure, consequences of failure, and system constraints based on available data to determine an overall criticality ranking that allows an owner to prioritize inspections and select appropriate inspection technologies based on the pipeline criticality and pipe material. Pipeline-level tools evaluate pipe pieces to identify pipes with the highest risk of failure and prioritize repairs to maintain a target reliability. The tools can be GIS-based for integration with an owner’s existing system or non-GIS-based for those without existing GIS. GIS-based tools additionally provide visualizations that can assist in presenting easy-to-understand information to stakeholders for short-term and long-term asset management.

The City of Baltimore owns and operates the 108-in. Susquehanna Raw Water Main, which runs parallel to Interstate I-95 for much of its length. With construction of four new express toll lanes on the interstate beginning in 2019, Baltimore City Department of Public Works (DPW) needed to find a way to protect the prestressed concrete cylinder pipe (PCCP) water main and ensure that construction activities would not result in wire breaks. After developing new specifications for the transportation authority to ensure that their contractors would be engaged with the monitoring of the buried asset, the city partnered with Xylem Assessment Services to develop a custom-built solution that utilizes acoustic monitoring technology at five construction sites, with no wire breaks from construction activity yet detected. This paper reviews PCCP and its failure modes, the City of Baltimore and Xylem Assessment Services’ approach to managing the city’s PCCP, the specific concerns arising from the heavy construction conducted by others, and the development of the monitoring solution.

The purpose of this study was to evaluate the nonlinear response of the steel buried pipelines subjected to pipe crossing a strike-slip fault. When pipe crosses a strike-slip fault, the fault moves horizontally. A strike-slip fault can cause significant plastic deformation in the buried pipeline. This analysis is based on numerical simulation of the nonlinear response of the soil-pipeline system through finite element analysis using ABAQUS software. The structural response of a buried steel pipeline in different soil conditions subjected to strike-slip fault movement was evaluated. The parameters evaluated were the soil modulus of elasticity and frictional angle of soil-pipeline system. Stresses at different distances from the middle of the pipe were captured for three circumferential locations: crown, springline, and invert. The results of the FEA analysis were compared with the analytical solution. The present study results can be used to develop and improve steel pipe design methodologies for buried steel pipelines in earthquake hot spot areas.

Inline pipeline inspections provide actionable information for pipeline managers to ensure reliability of their water assets. Ideally, inline inspection tools provide 100% coverage of the inspected asset; however; in practice, environmental elements or tool limitations may prevent full inspection coverage of the subject asset, therefore resulting in incomplete condition data. This leads to decreased confidence in the actionability of those inspection results. To improve upon the confidence in insights gained from incomplete inline inspection coverage, this paper presents a statistical approach to maximize and leverage the inspection data to better understand and quantify potentially undetected defects. It then applies this approach to a 900-mm (36-in.) ductile iron pipeline. Leveraging the inspection data, a series of statistical methods have been used to provide insights and extend past the perceived limitations in that data, for a better understanding of potentially undetected defects. These insights can then be used to plan a more targeted approach to manage the asset, for example, by informing recommended next steps for data collection.

Pipeline systems are widely used for transportation of natural gas, crude oil, and petroleum products. Due to aging, loading, or third-party damages, the integrity of the system is susceptible to be destroyed by defects, like cracks, corrosion, or wielding defects. The non-destructive evaluation (NDE) technique, such as ultrasonic guided waves, is sensitive for damage detection without destructing pipelines. However, the signal processing is still challenging for ultrasonic guided waves. Deep learning method, convolutional neutral network (CNN), has the ability of high-dimensional and complex data analyzation, which is feasible for guided wave signal processing. In this study, different damage states related to damage size and severity were designed. In addition, noise interference and temperature change will be considered. CNN based learning framework was established, which extracted sensitive features and predicted damages. The results demonstrated that the deep learning method was effective for damage detection, as compared to conventional physics-based approaches. It also has the robustness for noise and structural uncertainty, which increase the damage diagnosis and prognosis.

Long-term capital planning of intervention programs for water distribution networks involves the selection of pipe for intervention by applying the appropriate strategies such as replacement, lining, or cathodic protection as examples. A proposed program consists of both the selection of pipe and the time at which the interventions are to be performed. The assessment of the costs and benefits of long-term programs necessarily require a prediction model to forecast water main break rates into the future. However, in proposing a rehabilitation scenario the use of predicted failure rates can be problematic in the immediate short-term. There is always some variation expected between predicted failure rates and observed failure rates. Failure history rather than predicted failure rates is the preferred method for selecting pipes for intervention in the short-term. Replacing a pipe that has not failed cannot be justified on the grounds that it is predicted to fail. Therefore, long-term planning models should transition from pipe selection based on past failure history for the immediate present to selection based on predicted failure rates in the distant future. This paper describes how Monte Carlo simulation can be used to shift from short-term, history-based modeling to long-term, prediction-based modeling in a single planning scenario. The method is demonstrated using examples from the City of Hamilton, Ontario.

SewerVUE introduces the ability to scan, map, and localize large-diameter underground pipelines with an unprecedented combination of speed and precision. Pipeline stakeholders often require detailed analyses of their assets’ geometries and internal surface conditions. Precise pipeline analysis presents unique challenges: Global positioning systems will not work in underground pipes, and wheel-based odometry is unreliable, precluding external sensor localization. This paper explains how the multi-sensor condition assessment technique has overcome these obstacles using light detection and ranging devices, and other sensors mounted to a remotely driven vehicle through the pipeline, along with novel reconstruction algorithms. This paper presents a case study wherein this workflow was used for digitizing, localizing, and mapping 16,860 linear feet with a 48-in. pipe that makes up the South Shore Force Main in Milwaukee, Wisconsin. Here we inspected the interior of this asset with 3D LiDAR and video analysis. Advanced data processing methods allowed for unprecedented accuracy in reconstructing a digital double of this asset. Despite efforts to ventilate the pipe, visual conditions were limited during the inspection. This paper discusses the difference between a visual-only inspection and the insights learned from LiDAR intensity mapping in low visibility conditions.

Pipe penetrating radar is a condition assessment technology that uses high-frequency ground-penetrating radar from inside non-ferrous pipes. It sees past the pipe’s inner surface, measures the pipe wall’s thickness, and detects voids. With millimeter accuracy, pipe-penetrating radar can detect voids while still small and well before they develop into sinkholes. This paper will look at how pipe penetrating radar is used as part of effective asset management plans through a case study on a recent project. Milwaukee Metropolitan Sewerage District chose SewerVUE Technology Corp. to determine the concrete thickness and map reinforcing rebar for some linear assets. A complex manned-entry pipe-penetrating radar survey was undertaken to assess the conditions of two sections of a reinforced concrete force main with different diameters running through the Jones Island Peninsula in Milwaukee, Wisconsin. More than 1,110 ft of line data was collected. The survey detected no significant variance in the inside and the outside surfaces of the pipe walls; however, a few sections were found to be delaminating. We completed the inspections in a single day and delivered the pipe penetrating radar data, reporting anomalies, wall thickness, and reinforcement positioning. Pipe penetrating radar is a valuable tool for effective asset management plans. By measuring wall thickness and detecting voids early, owners and managers can prioritize rehabilitation for pipes where it is needed most.

How does a major wastewater utility brace itself for certain future environmental, social, and economic disruption? On what foundation must the knowledge of its buried infrastructure be built? What tools and information must it be armed with to minimize impact and maximize relief? In a state that experiences extreme weather events, population surges, and budgetary spending stresses, these are questions Toho Water Authority (Toho) routinely asks itself. Implementing a risk-based approach to condition assessment of its force mains, Toho has maximized its resources and optimized its operational resilience through data driven decisions. Established in October 2003 by a special act of the Florida legislature, Toho is the largest provider of water, wastewater, and reclaimed water services in Osceola County. Toho currently serves over 100,000 customers in Kissimmee, Poinciana, and unincorporated areas of Osceola County. Toho owns and operates 13 water plants and 8 wastewater plants. With a 300+ person workforce, Toho treats and distributes approximately 37.5 million gallons of potable water and reclaims 27 million gallons of wastewater each day. Toho is governed by a five-member board of supervisors responsible for approving all its operating policies and its $124M operating budget. Toho was established for the sole purpose of providing regional stewardship over water resources in Osceola County. Wastewater is collected by the gravity sewer system consisting of 921 mi of mains and 23,166 manholes and is gravity fed to one of 423 lift stations owned and maintained by Toho. Wastewater is then conveyed through 323 mi of force mains to either a downstream lift station area or one of the eight (8) water reclamation facilities. Toho’s eight (8) water reclamation facilities operate independently in specific geographic areas. Historic assumptions associated with force mains are proving to be less reliable based on advancements in condition assessment. Historically, a desktop study would identify known high points, utility crossings, and soil conditions as a basis for pipeline management decisions. This paper presents a condition assessment and risk management case study of 15 critical ductile iron pipe (DIP) and cast iron pipe (CIP) force mains, ranging in diameter from eight (8) to 30 in., and totaling approximately 30 linear miles.

Proactive maintenance is an essential first step toward healthy infrastructure and sustainable capital spending. Condition assessment tools are utilized to collect data that helps asset owners to assess the structural capacity or detect leaks in water pipelines. While there are various condition assessment tools, in some jurisdictions, such proactive maintenance is not so popular due to funding constraints. Generally, asset owners mainly rely on age to estimate service life concepts in making capital investment decisions. Despite age being a major consideration, the accuracy level is considerably lower compared to advanced field inspections. Currently, the existing literature lacks detailed information on owner preferences on condition assessment programs. Therefore, the main objective of this paper is to collect data from public owners, to help understand the level of utilization of condition assessment tools and other data that assesses the maturity of any condition assessment program. The data is collected and analyzed through a structured survey sent to water pipeline owners. Once completed, the study will help understand the maturity level of condition assessment programs established in many jurisdictions and aid as a tool for future benchmarking activities while recommending continuous improvements.

Pipeline condition assessment continues to gain in popularity as many reliable tools and technologies have proven beneficial, yet even more technologies continue to be introduced to the pipeline industry. On a parallel path, although not as common, greater awareness and focus has been placed on the importance of valve reliability to ensure the safety and success of pipeline outages and pipeline inspections. Despite pipeline and valve assessments getting so much deserved, individual attention, the practice of proactively integrating the two inspections has not advanced as much as each individually. For example, performing Level I valve assessments to ensure valves are accessible and operable prior pipeline inspections is still too often overlooked. Furthermore, if a Level I assessment reveals that there is a problem with the gearing of the valve, whether it be a horizontal double disc gate valve, vertically oriented external geared gate valve, or a butterfly valve actuator, owners often fail to perform Level II assessment on the valve gearing or gear box to identify the problem and correct it in advance of the shutdown, complicating or compromising the pipeline inspection. Instead, and oftentimes, the size of the shutdown is expanded, and the problematic control valve just replaced, wasting tens of thousands and often hundreds of thousands of dollars. Lastly, while pipelines are shut down, it is the opportune time to perform Level III condition assessment and any corrective maintenance on the butterfly valve discs and seats, or gate valve gates and tracks during pipeline inspections. This level of integration saves the owner significant maintenance and capital improvement program dollars that can be allocated to additional asset management program work.

On November 8, 2019, Arlington County, VA, suffered a water main rupture at a critical location in their system near historic Chain Bridge. Arlington County Water, Sewer, Streets (WSS) staff were able to isolate the pipe quickly and limit the consequence of the main failure by accessing up-to-date location and operability data on the control valves in the vicinity of the break. Fortunately, Arlington County WSS had just completed a valve inspection and repair project conducted by Xylem Assessment Services prior to a pipeline condition assessment project on a parallel transmission main. One of the valves repaired during that assessment was utilized to limit the consequence of the main break. Having access to meaningful system control information enabled Arlington County WSS staff to disseminate information to the public rapidly and frequently, reduce the amount of water lost in the failure, expedite repairs, and limit the footprint of the break within their network.