Pipelines 2018: Condition Assessment, Construction, and Rehabilitation

In presence of financial constraints and dire need for inspecting deteriorated sewer pipelines, inspection prioritization tools are required. This paper presents a defect based risk assessment model for prioritizing inspection of sewer pipelines. Different defects that could be present in sewer pipelines are used to build a deterioration model that employs dynamic Bayesian belief network from which the probability of a pipeline to be in a certain condition state with respect to age can be determined. The consequence of failure for sewer pipelines are studied from a cost benefit analysis point of view, where the costs resulting from sewer pipelines failure are studied, and the benefits from avoiding such failures are analyzed. Sugeno-fuzzy inference system is used to integrate both the probability and consequence of failure. It is expected that the resulting risk map would help key personnel in municipalities to identify sewer pipelines that require immediate interventions and would assist in better planning for inspection programs especially in cases of limited funds.

On March 2, 2010, Miami-Dade Water and Sewer Department (WASD) suffered a catastrophic rupture of a 54-inch prestressed concrete cylinder pipe (PCCP) water transmission main. This failure prompted WASD to conduct an electromagnetic survey of the shutdown portion of the pipeline (approximately 1-mile of pipe). The results of the survey indicated that over 17% of the pipeline contained distress and that 24 individual, 20-feet long, sections of pipe were in immediate need of repair/replacement. A subsequent survey of the entire 4.75-mile long pipeline determined that over 9% of the pipeline contained distress and that another 47 individual, 20-feet long, sections of pipe were in need of repair or replacement. Due to the alarming state of this water main, WASD undertook a program to survey most if not all of the PCCP in their large diameter (≥36-inch) water transmission system. Survey priority was given to lines that experienced ruptures. Therefore, a significant amount of critical data is available on the state of each of WASD’s PCCP transmission mains. Additionally, the three pipelines found to be in the worst condition were retrofitted with acoustical fiber optics to record real time prestressing wire breaks. Lockwood, Andrews, and Newnam, Inc. (LAN) was contracted by WASD to perform a prioritization of their large diameter (≥36-inch) water (both treated and raw) system. Their system is comprised of PCCP, ductile iron pipe (DIP), and cast iron pipe (CIP). Because of the very limited data available on the DIP/CIP, and the mode of failure of each, the prioritization effort was separated between the two vastly different pipe materials (iron and concrete) with the PCCP prioritized first. This paper will discuss the prioritization effort of the PCCP. Classic and previous utilized methods, such as the often utilized “consequence of failure” times the “probability of failure” did not fit this WASD prioritization effort. Therefore, a new, unique to the WASD system, prioritization was developed. The WASD prioritization utilizes known technical factors about the pipe design, date of manufacture, PCCP manufacturer, line redundancy, known problems, and presence of wholesale customers. This technical determination is then combined with social and economic impact factors to develop the prioritization listing.

The primary purpose of this paper is to highlight the data driven approach used to forecast asset performance for a water utility (Des Moines Water Works). This approach was used to develop multiple scenarios with forecasted service levels with the end goal of sustainability sizing and resourcing a water main replacement program. Statistical analysis of main breaks combined with pipe asset information can be a valuable tool for planning the rehabilitation and replacement program of a water distribution system. The purpose of this analysis was to leverage readily available data to determine which factors impact deterioration in each of the systems and quantify the relative strength of each factor. The intent was to advance our understanding of primary drivers of deterioration in each system. This information was then used to identify the useful life of each system, size sustainable renewal budgets, and prioritize condition assessment and renewal resources.

The city of Calgary carries out an annual asset management program of concrete water feedermain inspection to ensure the safety and reliability of its water network. The program began in 2004, when a 48 in wire wrapped C-301-L feedermain burst apart in Calgary's northeast, flooding the roadway, and releasing over 20 ML of water. Investigations of the failure pointed towards sulphate attack; the sulphate resistant concrete coating was not resistant enough to handle the local conditions of 5,000 PPM. Over time the coating had degraded, letting water seep in and corrode the steel wires that provide most of the strength of this material. The initial inspection program focused on feedermains that were in the same soil type and vintage as the original break. In 2011 our focus expanded, as a 24 in bar wrapped C303 main burst, damaging a nearby garage and flooding alleyways.

Sediment deposition in pipelines is an often-overlooked future maintenance headache, which can cause increased headloss and decreased efficiency of water transmission systems. Pipeline designers can better understand the potential for sediment deposition and mitigate the future problems by investigating water quality and developing procedures for maintaining pipelines. Collecting water samples can provide sediment type, size, and quantity within a water source. That data can then be used to calculate the deposition and settling velocities of the anticipated sediment and provide the designer with design criteria for the pipeline. The methods for removing sediment can vary in cost especially if not included in the initial pipeline construction. In the end, determining the anticipated cost of sediment management provides owners with valuable information for operating their transmission systems to the performance they were designed for and saves money in the process.

Models and tools help asset managers for advanced asset management by helping answer crucial questions such as; where, when, and why the resources should be used to keep the infrastructure at the desired performance levels. This research provides infrastructure asset managers a suite of models and tools for long-term advanced decision support for gravity and force main pipes called the remaining economic life analysis (RELAY) tool. This tool consists of data standards for the pertinent data related to pipe performance. These data standards are used to assess the performance of the pipes at a ten-grade scale to predict the likelihood of failure at the time of inspection. The performance index grades are then used for state and time-dependent prediction models to determine the future deterioration of the pipes for proactive asset management decision support. Currently, thirty-five utilities nationwide have been participating this research. The piloting efforts have been conducted for the suite of models and tools with the help of these utilities. The RELAY tool is integrated with the National Infrastructure Database called PIPEiD for long-term data collection and dissemination. This integration forms the methodology and proof of concept for the aforementioned national database.

Factors affecting the performance of infrastructure systems vary depending on the geographical, operation, maintenance, and socioeconomic factors. The key to an efficient infrastructure program is to understand these factors and identify proper inspection, condition assessment, and risk assessment strategies to provide effective decision support for infrastructure asset management. AECOM’s San Antonio Asset Management Team had been tasked to provide asset management services for a Department of Defense (DoD) installation in Northern Alaska. The assessed system is a closed loop system where the gravity and force main pipes are located inside the utility tunnels to protect utilities from harsh environmental conditions. The presence of the utility lines in the utilidors creates insufficient internal access to the wastewater pipes for inspections. The team conducted 96,000 linear feet of utility tunnel assessments and 49,000 linear feet of pipe inspections. This inspection data was used with the combination of other structural, environmental, and operational factors with the help of deterministic logical decision tree algorithms to assess the condition of utility tunnels and wastewater pipes. Statistical prediction models were then used to determine the remaining life of the assets inspected.

Managing critical water mains requires a good condition assessment program. The program will assist in a long-term asset management program by establishing a baseline for these critical assets. This program is in place to assess the 176 km (110 miles) of critical water mains. In 2006 the city started to address critical water mains. Managing these mains presents some challenges in obtaining condition ratings. Since these pipes are critical in nature and as such we have a zero tolerance for failure, it is necessary to undertake a multistaged approach to the assessment of these critical watermains. Data collected helps in identifying any preliminary deterioration factors, detailed deterioration factors, preliminary distress indicators, and detailed distress indicators. This paper will discuss the city of Hamilton’s approach to the management of critical watermain infrastructure. The city has been working to determine the condition of the critical water mains by a variety of methods. Planned operations include field corrosion evaluations such as soil corrosion studies, ultrasonic inspection, corrosion pitting analyses, and corrosion rate testing of pipe coupons extracted from select locations. Other nondestructive methods include the deployment of remote field eddy current (RFEC) and/or acoustic leak detection (ALD) inspection technologies to determine pipe wall thickness or to detect the presence of active leaks and air pockets of potentially corrosive gases. This paper will describe the development of the city’s approach to developing a critical water main condition assessment program; the development of a risk model, opportunistic sample procedure, leak detection, and implementing inspection technologies.

Sewer networks are comprised of a huge maze of underground pipelines. They are designed and laid to transfer sewage medium to treatment plants or disposal areas. However, their conditions are subject to deterioration owing to ageing. The American Society of Civil Engineers claimed that the sewer infrastructure grade is D+. Inspection, assessment, and effective decisions are required to enhance their performance through their service life. There are several inspection methods and assessment models that can evaluate the condition of the pipelines. When evaluating the global network, the city or municipality will end up having thousands of pipeline conditions. Therefore, they confront obstacles in deciding which pipelines to tackle first. The objective of this study is to design a criticality model that is based on multiple factors that could affect the criticality of one pipeline to another. The study evaluates the weights for the environmental, economic, and public factors as well as their subfactors by using the analytic network process (ANP). The results concluded that the most important factor is the economic factor. The criticality model is implemented on an actual case study brought from the city of Edmonton, Canada. Based on the results, 20% of the pipelines are of low criticality; 70% are of medium criticality; and 10% are of high criticality. This study is expected to enhance the prioritization of the pipelines in the network for efficient future decisions.

In most Canadian municipalities, wastewater collection (WWC) and wastewater treatment plants (WWTPs) are owned and managed by separate municipal governments. Linear sewer pipe networks are owned and managed by utilities at the lower tier of municipal government, and vertical treatment plant assets are owned and managed by regional governments at the higher level. Under this arrangement, regions charge utilities for treating their collected wastewater. The linkage between the WWC and WWTP systems are presented and modeled by taking the system dynamic approach. Three asset management scenarios are developed and evaluated for a joint WWC and WWTP system. Based on the simulation results, the main goal of financial self-sustainability is achieved when the maximum annual rehabilitation rate is 0.88% of the total WWC network length. However, adapting the higher rehabilitation rate of 1.1% is more desirable because of avoiding the downstream capital costs for building new WWTP capacities. This study demonstrates that the applying such integrated models will help decision makers to evaluate the behavior of interrelated wastewater collection and treatment systems, and find synergistic cost-saving opportunities while taking decisions on when, where, and how to invest in infrastructure upgrading and rehabilitation.

The deterioration and subsequent failure of sewer pipes impacts the community, the environment, and has significant economic consequences for utility owners. As a result, it is vital that sewer utilities have a robust methodology that accurately assesses the consequences of sewer pipe failure. The aim of this paper is to present a consequence of failure of sewers (COFS) model that uses a weighted sum multicriteria decision making method based on sewer expert opinion to assess the economic, social, and environmental consequences of sewer pipe failure. The first part of this paper briefly reviews methods used in practice to assess the consequence of failure (CoF) of sewer pipes. The proposed methodology is presented next, where the analytical hierarchy process (AHP) is used to develop the COFS model by incorporating a series of internal and external pipe factors. When incorporated with probability of sewer pipe failures, the COFS model is useful in determining the risk of sewer pipe failures to budget and prioritize maintenance actions more efficiently. The final part of the paper presents a short example where the model was applied to a 54-inch diameter reinforced concrete sewer pipe segment.

Toronto Water (TW) manages an inventory of over 6,600 km (3,800 miles) of watermains that directly service a population of 2.81 million. The greater metropolitan area is over 5.5 million and it is the largest urban and metro area in Canada. While the age of the inventory dates back to the 1870s, the system experienced significant growth post-second World War. TW has maintained a comprehensive database of watermain failures (>78,500) and intervention techniques dating back to 1928 as well as a comprehensive failure watermain coupon dataset with detailed information on failure mode, material type, condition state, soil chemistry, and electrochemistry. Approximately 79% of the inventory is comprised of ferrous metals (largely cast iron with ductile iron and steel) which account for 98% of the historical failures. In 2016, TW desired to develop a comprehensive model to relate watermain replacement/rehabilitation funding and techniques to resulting service levels in the system to facilitate communication with policy makers the ramification of different funding levels and to optimize investment with respect to achieving stated service goals in the most cost effective manner possible. Using a balance of both probabilistic and deterministic modeling techniques the work has enabled the development of not only a global view of funding versus service level, but a very discrete “stick-by-stick” view of failure risk such that implementation of the watermain replacement/rehabilitation program can utilize risk-based decision logic to preferentially replace/rehabilitate higher risk mains. The review of failures in the program has provided unique insight into the “vulnerability of era” in the ferrous metal inventory as 150 mm centrifugally cast iron manufactured and installed from 1953 to 1975 is only 25% of the total pipe length but accounts for over 50% of the failures. This insight into era and exposure condition vulnerability allows the development of programs that preferentially target portions of the system that will produce the greater reduction in failures. The optimization work has utilized genetic algorithms to analyze literally thousands of alternatives with subtly different objective ranging from pure least total cost over time at different service level objectives, stabilized funding over time, stabilized failure reduction or service level rates (by adjusting funding to eliminate variability due to vulnerable era demographics), and variable time frames to reach service level objective goals.

The Region of Peel makes “set-and-forget” a thing of the past when managing its most critical buried water pipeline. The Regional Municipality of Peel is a regional municipality in Southern Ontario, Canada. It consists of three municipalities to the west and northwest of Toronto: the cities of Brampton and Mississauga, and the town of Caledon. The region is home to approximately 1.3 million people. Potable water is sourced from Lake Ontario and treated at the Lakeview and Lorne Park Water Treatment Plants. Since 2003, the Lakeview Water Treatment Plant has been undergoing significant upgrades to increase capacity and improve treatment processes. With the completion of the latest expansion in Fall 2014, it is now capable of producing 1150 million litres of water per day, making it one of the world’s largest membrane treatment facilities.

With the pressure to provide excellent services under constrained budgets, utilities are adopting asset management as the synergistic framework combining strategic and financial planning, levels of service, and risk-based analysis to determine investments. GIS (geographic information system) helps to empower a utility with the tools to drive a robust and strategic, decision making process. When a CMMS (computerized maintenance management system) has asset management functionality, the capabilities of service requests, inspections and work orders, capturing costs, and work history can be leveraged into asset condition and risk-based spatial analysis by determining what, when, why, and where the next round of investment should occur. A critical step in the process includes analyzing the data and location to potential take actions to reduce the risks. In alignment with ISO (International Standards Organization) 55000, risk is defined as the probability of failure (PoF) multiplied by the consequence of failure (CoF) which produces the business risk exposure (BRE). While calculating risk is important, the risk-based data can be used to build business cases and determine future projects. GIS can help users gain an understanding of what assets are high risk, where they are located and what factor can influence the risk. Risk-based analysis provides the reasoning for potential solutions and action. This paper defines and explores the use of GIS-centric analysis tools to enhance the asset management decision making process.

Polyurethane coatings are selected as an external coating on welded steel pipelines for its properties as an excellent means to control corrosion, minimize cathodic protection requirements, and, in this case, help the pipe achieve a trouble-free, 100-year design life in the underground environment. For this cross country water transmission pipeline project, typical pipeline segment lengths approach 20 miles (32.2 km) and pipeline diameters range from 84 (213.4-cm) to 108 inches (274.3-cm). It is anticipated that pipe manufacturing and coating production will outpace the contractor’s field installation and subsequently lead to variable storage times of pipe strung along the alignment. During this time, the stored pipe will experience extended time above ground in extreme temperature and in the presence of solar light, including ultraviolet (UV) radiation. Construction and delays can result in pipe section exposure beyond the specified period of 180 days. Therefore, it is important to understand the expected magnitude of exposure deterioration beyond that limit. A previous study was conducted, and the results were presented at American Society of Civil Engineers (ASCE) Pipelines Conference 2014. Sample pieces of large diameter polyurethane coated steel pipe, exposed to elements for up to 2 years, were monitored for surface temperatures during the peak of summer. Darker-colored pipe surface temperatures exceeded 150 degrees F (65.6 degrees C). That presentation was a snap shot of the postexposure effects due to temperature and solar. This will illustrate and describe the periodic exposure results every 3 months, leading up to a total of 21 months of exposure. It will include discussion of the test set-up and procedures, laboratory measurement results, and polyurethane coatings response following each period’s weathering exposure.

During large pipeline projects, pipe sections can be kept above ground for many months before burial. Thus, their corrosion protective polymer coating, commonly an aromatic polyurethane, may be exposed to ultraviolet solar radiation and high temperatures that were not anticipated for its ultimate service, in the ground. The gloss of such coatings deteriorates very rapidly and the color of the coating changes a great deal quickly which can lead to concerns about their remaining corrosion protective ability. Previous evaluation at 6-month intervals of field exposure in Texas and Florida showed that these changes in appearance occurred during the first 6 months. An expanded study wherein the coatings were evaluated at much shorter intervals, in Texas, shows that color changes rather faster than the gloss, within one month approximately, whereas the gloss diminishes over 3 months. Interestingly, both the color and gloss properties change in a pattern described very well by an exponential trend. This pattern of deterioration can be derived easily using a very simple assumption that ultraviolet light, water molecules, etc. from the environment cause their damage at random times and locations. This approach shows there may be links between properties such as weight loss and gloss loss and, in this case, that corrosion protection would diminish very little in these very thick polyurethane films. In fact, the most recent results from extended field test exposure sites in Florida and Texas show that the corrosion protection of these coatings remains intact.

Between 2015 and 2016, as part of a study assessing the Ohio Department of Transportation's conduit service life prediction methodology, a team of researchers from Ohio University evaluated the resistance to abrasion of different coating materials, used to extend the service life of corrugated steel pipes (CSP). Specimens of polymeric coated, bituminous coated, aluminized, and galvanized steel plates were subjected to an accelerated degradation test. The test was performed based on the ASTM A926-03(2014) standard, using a variation proposed to overcome its limited industry use due to limited availability of the required equipment. The variation consisted on using a modified Los Angeles abrasion machine instead of the unavailable machine required by the standard. Although the mentioned limitation led to the standard being withdrawn from the ASTM later in 2016; the modified equipment used in this study produced results that suggests it could be an alternative method for any research group in the industry wanting to evaluate the resistance of protective coatings used on CSP. In this test, the polymeric coating proved to be the most durable treatment, followed in order by bituminous coating, aluminized coating, and galvanized coating.

The San Diego County Water Authority’s asset management activities commenced over 25 years ago and initially focused on the highest risk pipelines consisting of prestressed concrete cylinder pipe (PCCP). With active acoustic monitoring and rehabilitation of the PCCP ongoing, and scanning of the oldest portions of welded steel pipe complete, the next focus was concrete bar-wrapped cylinder pipe. This paper will discuss a 5-mile comprehensive condition assessment of concrete bar-wrapped cylinder pipe constructed in 1948, including the basis for the selection of the technology used, the results of the assessment, and the actions taken by the San Diego County Water Authority to verify the findings.

Seventeen years ago, Howard County piloted one of the first acoustic systems for monitoring the changing condition of prestressed concrete cylinder pipelines in the country. Over the years they have invested and benefited as an early adopter to various condition assessment technologies and techniques for the proactive management of their water and wastewater systems. The Howard County Department of Public Works Bureau of Engineering provides water and wastewater services to more than 260,000 people with an average demand of more than 26 million gallons of water each day. The water system is comprised of more than 1,000 miles of pipelines, approximately 90% of which are metallic. Understanding the condition of critical large-diameter mains helps Howard County proactively reduce water main breaks while more efficiently planning capital replacement programs. Traditionally, Howard County has employed physical entry methods or tethered robotics techniques for inspections which can be logistically demanding and may require dewatering of the pipeline. In January 2018, Howard County began planning to pilot a free-swimming condition assessment technology on a 2-mile section of a 24-inch ductile iron and cast iron water main. The tool is designed to inspect the line while in-service, therefore reducing disruption of service, logistics, and the need for dewatering. This paper will summarize the planning phase of the pilot inspection, providing an overview of the issues needing to be addressed prior to performing an internal inspection of an in-service transmission main using a free-swimming technology platform.

Pipe penetrating radar (PPR) is the in-pipe application of ground penetrating radar (GPR), a nondestructive testing method that can detect defects and cavities inside and outside nonferrous pipes. The advantage of PPR is the ability to map pipe wall thickness and deterioration, including voids outside the pipe, enabling accurate predictability of needed rehabilitation. This paper presents recent advancement of PPR technology together with selected case studies. A new, small diameter robotic system was developed for the condition assessment of asbestos cement (AC) sewer pipes, as well as other nonferrous pipe materials. The asbestos cement pipe scanner (ACPS) was deployed in a 250 mm (10 inch) diameter sewer main in Surrey, British Columbia. Analysis of the data revealed localized wall thinning and provided engineers with critical information to proceed with their rehabilitation plan. The 4th generation surveyor was deployed on a condition assessment project in Melbourne, Australia. This involved surveying 600 mm (24 inch), 750 mm (30 inch), and 950 mm (37.5 inch) reinforced concrete pipe (RCP), as well as 1050 mm (42 inch) brick-lined pipe, totaling 3521 m in inspection length. PPR allows utility owners to accurately estimate the remaining lifetime of pipelines, and refine the timing of repairs.

The application of acoustic wall thickness technology to assess pipeline condition holds significant potential benefits as it does not require the insertion of internal sensors or equipment or the exposure of the external surface of the pipeline. This technology was introduced over 10 years ago and this paper describes a meta-analysis that endeavors to examine how well this technology works and whether the data obtained from the application of this technology can be used effectively. This paper describes and summarizes the underlying theory of the acoustic wall thickness test method. Subsequently, the relevant published literature (including journal papers, conference proceedings, case studies, and project reports) with focus on the application of the acoustic wall thickness technology is briefly reviewed. Results are presented of statistical analyses conducted on over 100 destructive test coupons with the aim to quantify the accuracy of the acoustic technology to estimate effective pipe wall thickness. This paper also briefly reviews how two water utilities effectively use acoustic wall thickness data to improve their operational and long-term management strategies.

The complexity of piping at a typical wastewater treatment plant (WWTP) should never be underestimated. Owners must employ strategic decision-making skills to allocate a portion of their limited resources to determining the condition of piping. Factors such as temperature, pressure, material being conveyed, flow velocity, and solids content play a much larger role in the overall condition of the piping in a WWTP than age of the piping itself. The consequence of failure for each pipe may vary regarding impacts on the overall operation of a WWTP. This must be considered when prioritization is used to systematically evaluate piping systems plant-wide. This paper will present and discuss several approaches to formulating a strategic asset management strategy while considering and prioritizing data around risk analysis and condition assessment.

As the need for making better use of resources becomes more acute, hot tapping can facilitate access to pipelines for the introduction of devices to perform condition assessments without interruption of operation and services. Sets of assessment data can serve as a basis for more effective and sustainable solutions for pipeline maintenance or repair programs when a first set of data is used as baseline reference against data of later assessments to estimate the rate of deterioration occurring in the installation. The rate of deterioration can be used to establish a rational and more sustainable risk-based approach for maintenance and repairs, focused on distress locations, rather than a complete replacement of a pipeline approach based on an expected service life projection. The purpose of the paper will be to provide an illustrative case study of the organization, execution, and summary of the results of an initial in line condition assessment of several miles of 36-inch prestressed concrete cylinder pipe (PCCP), located in a congested urban area, which was accomplished with a free-floating device, facilitated by hot taps at the points of entry and retrieval. Projects using this type of procedure can provide the assessment data needed to define the first phases of a pipeline maintenance program.

The city of Ottawa is regularly confronted with challenges assessing the condition of large diameter water transmission mains. Planned construction as well as ongoing maintenance activities must be coordinated to ensure service level requirements are maintained and are a few of the many obstacles the city must manage when performing condition assessments. When encountered with such challenges, the city of Ottawa must mitigate and manage risks associated with condition assessment inspections. To develop a risk mitigation strategy, the city of Ottawa along with its consultants work to develop risk management plans to address foreseeable challenges associated with the pipeline condition assessment. The paper will present the city of Ottawa’s approach to minimizing risk in the condition assessment program. Addressing risk through contingency plans, managing risks external to the condition assessment inspection, and adapting the overall project plan when unforeseeable risks arise will all be discussed. The paper will present how staff manage risk through a case study with the total cost of the inspections as well as risk mitigation measures included.

The North Fork Siphon is an essential element of the Central Utah Project, a vast network of water facilities operated by the Central Utah Water Conservancy District (CUWCD) to deliver clean water to customers in northeastern and central Utah. The 72-inch diameter siphon was completed in 1987, and was constructed using primarily prestressed concrete cylinder pipe (PCCP). The siphon has a lay length of 4,750 feet, a vertical elevation difference of 716 feet, and an inclination in places up to 70%. CUWCD commissioned two visual/sounding and electromagnetic (EM) inspections of the siphon in 2009 and in 2014. Of 233 PCCP segments inspected in 2009, eight pipes were identified as having significant structural damage (wire breaks). In 2014, only one of these 8 pipes was reported as having significant structural damage. This discrepancy in EM results led CUWCD to commission an independent inspection of the siphon in November 2016. The number of defects detected during the new inspection was much greater than anticipated: 196 pipes exhibited serious defects, with 24 having structural defects indicative of incipient failure. This paper provides an overview of the inspection and its findings, the condition assessment and pipe rating system devised for the siphon, and the options presented for managing the siphon.

A comprehensive pipeline condition assessment allows utilities to make informed financial decisions, helping prioritize or defer maintenance, and capital spending. When you consider that the pipeline is a force main that services over 45,000 people and incudes a five-kilometer portion installed along the foreshore (intertidal zone) of the Pacific Ocean, a comprehensive pipeline condition assessment can also significantly reduce the risk of a failure with devastating consequences to the surrounding environment. The 750/820-millimeter force main was installed in the early 1980s and is nearly nine-kilometers long, servicing the communities of Courtenay and Comox, British Columbia. A recent risk assessment of a three-kilometer section along highly exposed coastline concluded that it was at high risk of failure, but a condition assessment was required to gain a better understanding on the condition. A rapid inspection plan collecting quantitative data on each pipe section with minimal operational downtime was essential. The resulting information could be used in a risk of failure analysis of the pipeline. The final deliverable from the project discusses the risk analysis of distressed pipes and their repair priorities. The information collected is assisting the CVRD with significant capital decisions and provides an enhanced safeguard against an environmental disaster.

The North Transmission Main is generally located along Lake Michigan Drive (M-45) starting at the City of Grand Rapids Lake Michigan Filtration Plant (LMFP) near Grand Haven and ends at the Monroe Avenue storage tank, in Grand Rapids. When constructed, the initial use of the pipeline was to pump raw water from Lake Michigan to the original filtration plant located on Monroe Avenue for treatment. In 1963, when the new Lake Michigan Filtration Plant was constructed on the lakeshore, water from Lake Michigan was treated and pumped into Grand Rapids. The pipeline has several major crossings: the Grand River in two locations, Sand, Buck, and Indian Mill Creeks, two major highways (US-31 and US-131), and CSX railroad tracks as well as many heavy traffic, backcountry, residential, and urban area installations. The first step in the condition assessment process is data collection. The data collection effort began by reviewing existing reports and drawings, and performing field reconnaissance. Many historical documents and record drawings were obtained in the data collection phase. A data request was submitted to the city of Grand Rapids that included items such as the as-built drawings from the transmission main installation, maintenance and leak repair history, specifications or shop drawings, any soil testing, ground water depths, SCADA data, and any connections to the pipeline for other municipality feeds. Some of this information was able to be obtained (as-built drawings of the pipeline and SCADA data) but much of this information did not exist. The city was also able to provide a video of the pipe installation from 1939, a lay schedule, a copy of the chamber and equipment listing book (from both 1989 and 1994), as well as other various project reports. GIS shape files were obtained from the city as well which helped to create the base drawings for this project. Once the base drawings were set up, private utility companies were contacted in order to obtain location and utility maps. Surrounding municipalities were also contacted to locate their main water supply feeds. This information was incorporated into the drawings set. Since this is a “one-of-a-kind” pipeline and very little information was available, the original manufacturer of the pipe was contacted to attempt to gain as much information about it as possible. Price Brothers Company was not only the manufacturer of the pipe but also acted as the contractor for the installation in 1939. The local representative from the new owner of Price Brothers, U.S. Pipe, was contacted and they mentioned that they had no information on the pipeline at all but knew the pipeline well as they use this as an example pipeline all over the world. U.S. Pipe also recommended to reach out to Wright State University near Dayton, Ohio. The university holds all of the past records of the projects under the name Price Brothers. The university mentioned again they did not have much information but did have a short brochure of the pipeline.

Acoustic wave propagation has been widely applied for detection of corrosion and cracking defects in buried pipelines. Damage and defects in a pipe reduce the stiffness of the pipe, and investigating the attenuation of the guided wave is a reputable approach to detect this damage. Acoustic wave propagation based structural health monitoring (SHM), which aims to perform a nondestructive evaluation through integrated actuators and sensors, has been used extensively for condition assessment of different types of pipe in the past decade. A validated physics-based model for wave propagation, combined with field verification, is required for complete characterization (presence, location, and severity) of damages. To identify damage, the acoustic wave propagation of undamaged and damaged pipe is compared. This study illustrates the effects of damage or defects on acoustic wave response of a buried pipe. Based on the obtained results, limitations, and deficiency of acoustic wave propagation are presented and discussed.

Increasing regulatory pressure to prevent inadvertent spills of both chlorinated water and wastewater to the environment has resulted in a drive by municipalities across North America to inspect and quantify the condition of their river crossing inventory. Estimating remaining service life requires the use of both structural assessments and deployment of advanced condition assessment technologies, including sonar, closed circuit television (CCTV), and advanced electromagnetics tools. River crossings pose a unique challenge for condition assessment programs as they are highly critical assets subject to unique operating conditions and are often difficult to access for both inspection and repair. Deploying inline inspection tools can require extensive system modifications and are often located in environmentally, geotechnical, and socially sensitive areas such as river banks and mature neighborhoods. As a result, developing a river crossing inspection program requires extensive planning, assessments of system hydraulics, pipelines access, geotechnical conditions, and contingency planning. Lack of system redundancy often makes removal from service difficult, if not impossible and planning system modifications and inspections requires reviewing system operations as a whole in addition to localized flow control requirements. Inspection of both gravity and pressure pipelines requires review of a myriad of potential operations to permit both system modifications and the inspection work itself. These include: upstream system storage, lift station shutdowns, pressure drops, and flow reversals in looped water systems, etc. As a result, extensive hydraulic modeling and coordination with system operators is required to develop flow control plans permitting necessary system modifications and tool deployment. This paper outlines the authors approach to developing advanced river crossing inspection programs addressing pressure and gravity system hydraulics, system modifications, tool deployment, and procurement of inspection and support contractors.

St. Paul Regional Water Services (SPRWS) supplies drinking water to nearly 415,000 customers in the city of St. Paul and neighboring communities. The primary source for this water is the Mississippi River at Fridley, where an intake pumping station with a capacity of 340 MLD (90 MGD) pumps water into the raw water system. The raw water system is comprised of 41 km (25.5 miles) of various pipe types and vintages including cast-in-place concrete (1924 and 1936), riveted steel (1924), welded steel (1958 (1960), reinforced concrete pipe (1958), and prestressed concrete pressure pipe (1989/1990). The diameters range from 1500 mm to 2250 mm (60” to 90”). The current day replacement value of the raw water conduit system is $1.2 billion. Given that 88% of the concrete pipe was over 90 years old and 99% of the steel was approaching 60 years and older, the condition of the pipes needed to be understood with greater certainty. In 2016/2017, SPRWS initiated a large scale condition assessment program to determine the condition of all 41 km (25.5 miles) of pipe. Using a vast array of condition assessment techniques over 98% of the system was inspected and assessed. Using risk-based programing techniques a very innovative $24 million rehabilitation program was developed; phased in over a 15 year period to extend the projected service life of the raw water system for another 100 years or more.

Since the presence of air can change the transient responses of pressurized pipe systems, the inverse transient analysis (ITA) may be a feasible approach for detecting entrapped air pockets. In this study, the ITA method was utilized to determine the size of the air pockets at key high points of the system. This was achieved through an optimization process in which the discrepancy between the measured and calculated transient responses (primarily pressure head and/or flow rate) are minimized. Genetic algorithm (GA) was used as the optimization engine. This paper intends to provide preliminary insight with regard to the performance of the ITA in determining entrapped air pocket sizes. The numerical results show that the ITA can capture the size of the air pockets fairly well providing that the number of population used in GA is sufficiently large. Since the number of population increases with increasing number of high points in the system, its application for real pipelines can be encumbered by the impractically long computational time. In such cases the solution is to use a more efficient optimization method and/or to perform parallel computing.

Air, fire, water, and earth are all necessary for the survival of mankind. However, these same necessities can also prove to be sources of great destruction when out of our control. The same principle holds true for the most ubiquitous creature on earth; the microorganism. Both harmful and beneficial microorganisms exist everywhere that water and the appropriate nutrients are available for their growth and survival. Sewer systems are perfect examples of how this process known as MIC “microbiologically induced corrosion” produces sulfuric acid which has destroyed millions of concrete structures such as manholes, pumping stations, and sewer pipe. Over the years, scientists’ have developed chemical agents, known as antimicrobial agents, biocides, or preservatives, to combat the growth and proliferation of harmful microorganisms in various industrial applications. Since 1996, an effective anti-microbial admixture has successfully protected concrete from this type of corrosion. This paper shares specific examples of tests and proof of long term protection against MIC.

Biogenic corrosion of concrete has challenged wastewater infrastructure since concrete was introduced as a sewage collection and conveyance system material. The combination of anaerobic and aerobic biological processes within wastewater collection systems results in the generation of sulfuric acid (H₂SO₄) which weakens concrete infrastructure and leads to potential failure. Biogenic corrosion mitigation alternatives (BCMAs) can be installed to mitigate biogenic corrosion by proactively addressing the need for costly, complex repairs (and/or replacement) to underground infrastructure with inherently restricted access. BCMAs were categorized as concrete permeability reducers, physical barriers, or reactive coatings. A total of fourteen (14) different BCMA products were evaluated by examining corrosion mitigation performance, proven history of applications, constructability, local availability, and associated construction costs. Top performing BCMAs were selected for pilot installation within a trunk sanitary sewer section and will be subject to a comprehensive testing program to evaluate in situ biogenic corrosion mitigation performance.

During a large diameter pipeline shutdown, that permitted no more than 72-hours total shutdown to replace approximately 24-meters (78-feet) of 1,067-millimeter diameter (42-inch) pipe, a significant hurdle was identified in the field. The installing contractor supplied new steel pipe to connect to the existing prestressed concrete cylinder pipe (PCCP) but did not successfully match the steel pipe diameter with that of the PCCP bell and spigot. This paper reviews the solution developed in the field, within 4-hours of notification to the design engineer, and successfully installed by the contractor less than 36-hours later. The design included a built up concentric reducer to connect the new steel pipeline with the existing PCCP installation. In order to ensure timely completion, the design was prepared with careful consideration of the contractor's available materials, equipment, and staff. To date, the affectionately nicknamed Frankenstein reducers have proven to be effective solutions and are a dependable asset in the owner’s water transmission system.

Large diameter gravity storm and sanitary sewer pipes are widely used all around the world. Failure of these system is costly both directly due to emergency repairs or replacement of the failed system and indirectly due to its impacts on general public and social life. Therefore, they routinely require inspection, maintenance, and eventual renewal or replacement. The structural rehabilitation or renewal process can be performed using trenchless structural methods such as sliplining with precast fiberglass pipe materials. Conversely to circular liners, for which in the U.S. the ASTM F-1216-16 standard design methods are available; in Europe, specifically U.K., Germany, and France there are structural design guidelines for non-circular shapes. The objective of this paper is to evaluate and compare design methodologies for large diameter pipeline renewal.

An aerial portion of the 72-inch arched concrete Blue River interceptor crossing Brush Creek collapsed in July 2016. On call emergency responders were mobilized immediately and established a bypass pumping system to divert the wastewater from flowing into the creek. The Kansas City, Missouri, Water Services Department (WSD) began work on a conceptual design for the repair and ultimately chose the design build delivery method to facilitate a timely repair. Given the emergency situation, potential design build teams were given one week to prepare a preliminary design and a guaranteed maximum price proposal to meet a 90-day design and construction timeline. WSD reviewed the qualification and price proposals. A team was selected and a notice to proceed (NTP) was given within three days. WSD contracted with the design build team of Leath & Sons/Burns & McDonnell to design and construct the repairs. The repairs included replacement of the entire aerial portion of the interceptor (approximately 375 linear feet) with a 72-inch steel pipe mounted on piers supported on drilled shafts. The replacement pipe joined the existing arched sewer at junction structures constructed on each end of the crossing.

The Southwest Arkansas Water District (SWAWD) delivers up to 70 million gallons per day (mgd) to the Domtar Paper Mill (Domtar) in Ashdown, Arkansas, via a raw water canal. The canal traverses a small stream near the paper mill by two parallel inverted siphons: a 60-inch reinforced concrete pipe (RCP) and a 66-inch corrugated metal pipe (CMP). In 2016, SWAWD observed an apparent leakage of water from the pipelines into the stream. The age of the pipes (40–50 years) suggested that the wall integrity of the CMP and the joint integrity of the RCP were compromised and were the sources of the leak. Because the canal is the sole source of process water for the paper mill, maintaining uninterrupted flow to the mill and ensuring the long-term integrity of the canal walls was paramount. While evaluating repair options, a sinkhole near the leak (approximately 500 gallons per minute) developed, suggesting the leak was worsening and risking the integrity of the canal walls; thus, an emergency design/build approach was taken. Available options included pipeline repair, pipeline removal and replacement, and construction of a new pipeline(s) with abandonment in-place of the old pipelines. A synopsis is provided on the emergency construction techniques used in implementing the chosen alternative: lining the pipes with cured-in-place pipe (CIPP) and constructing headwalls on the both sides of the pipes. Installation of a 70 mgd bypass system consisting of eight 18-inch pumps, earth/rock cofferdams, and dewatering pumps allowed site access while maintaining the provision of raw water supply downstream.

The North Texas Municipal Water District (NTMWD) and the city of Irving (Irving) jointly operate and maintain an 84-inch raw water pipeline that transfers water from Lake Chapman to Lake Lavon and Lake Lewisville for NTMWD and Irving, respectively. In June of 2015, Irving performed an aerial survey of the pre-stressed concrete cylinder pipe to observe portions of the line difficult to access by land. The aerial survey revealed a portion of the pipeline exposed at its crossing of the South Sulphur River, near Greenville, Texas. Further investigation established that the river bottom and embankments had eroded substantially, undermining the pipeline as much as eight feet in some locations. NTMWD and Irving declared the stabilization and repair of the crossing to be an emergency, expediting design, and construction services. Competitive sealed proposals were obtained from three trusted contractors. The selection process included interviews with two finalists, with Garney Construction selected to perform the project. The project key objective was to first stabilize the at-risk 84-inch water main servicing NTMWD and Irving with concrete cradling up to the spring line of the pipe. The concrete was placed by a tremie installation after the flow of the river was controlled with cubic yard sand bags. Once the pipe was determined to be successfully stabilized, the second phase of the project was to armor the steadily eroding riverbanks that had already lost more than 30 feet of shoreline since the original investigation that qualified the project to be an emergency. The banks were armored, crest to toe, with filter fabric and 36-inch rock rip rap up and downstream of the pipeline crossing. Sequentially, the permanent easement through the river was bordered with sheet piling in which a flex base backfill encased the supported pipe. Lastly, a one-foot thick, reinforced, concrete slab capped the flex base fill protecting the endangered pipe across the span of the river. Engineering design, environmental permitting, and innovative construction methods brought this project to a successful completion in March of 2017.

The Green Bay Water Utility (GBWU) conducted an electromagnetic inspection in 2010 of three 36 inch diameter water transmission mains (about 25 miles total length) that deliver water between the water treatment plant and the distribution system. The pipelines were installed in 1953, 1965, 1969, and 1974 and were, therefore, manufactured according to different American Water Works Association (AWWA) standards. The results of the electromagnetic inspection in 2010 identified 20 pipe segments that displayed evidence of 5 to 15 broken wires. In December 2012, a pipe failure occurred on the 1974 pipeline at one of the locations identified in the electromagnetic inspection as having broken wires. The GBWU recognized the need to identify the cause of failure and evaluate the potential for additional failures by conducting a forensic evaluation. The first phase of the investigation included inspection of the failed pipe, petrographic analysis and testing of mortar coating, testing of prestressing wires and steel cylinder, soil corrosivity testing, structural and failure risk analysis for pipes with broken wires. In addition, to assess the risk of failure of other pipes, external inspection and half-cell potential testing were conducted on five additional pipes in place and the alignment was evaluated for potential stray currents, soil, and groundwater corrosivity. Interconnects between the two pipelines were identified as the first priority for managing the pipelines, and the construction of new valves and interconnects was completed in 2016. This allowed segments of the pipe to be taken out of service to replace those pipe sections with broken wires and provided flexibility in operations in case of a future failure. Removal of the additional pipe segments with broken wires was completed in February 2017, and these segments were evaluated by removing the mortar coating and inspecting the prestressing wires and cylinder. This investigation identified one pipe segment that was at the stage of imminent failure, other segments with no broken wires, evidence of corrosion on adjacent pipe segments, and wires broken from corrosion and from embrittlement. This paper presents the forensic analysis results that identified the likely causes of failure, an evaluation of pipe segments removed, and the options for effectively managing the pipeline in the future.

A 16-inch PVC pipe (DR 25) failed catastrophically when a contractor was performing a service one-inch tap. A fracture initiated at the tapping hole and it immediately propagated several feet forming a V-shape hole in the new pipe. American Water thoroughly investigated the event to understand the root cause of the failure and avid future failures. The failure was unexpected. The pipe operated within normal working pressures (approximately 70 psi) and the crew made the two taps successfully just prior to this failure. This paper presents the approach and methodology that American Water took in conducting the forensic study of this pipe failure. The project team began this effort with a comprehensive literature and practice review to understand the failure modes and failure factors of PVC pipes water mains. The team then built a three-dimensional (3D) finite element (FE) model to simulate the process of making the three taps on the pipe, following the location of the taps on the pipe. This numerical simulation helped to know the actual stress level in the pipe with three tapping holes placed at differing points along the pipe length and tapping orientation. A series of lab tests were conducted to confirm the mechanical properties of the pipe to confirm the material was not defective. The numerical simulation results were further compared with the site observations to identify the likely factors contributing to the tapping failure. This research outlines a systematic approach for conducting forensic study of PVC pipe failures. With appropriate modifications, the approach can be used for failure investigation of other pipe materials.

The 2015–2016 holiday season brought unwelcome surprises to the Canadian River Municipal Water Authority (CRMWA). Without warning the day before New Year’s Eve, their 50-year-old aqueduct that supplies water to their 11 member cities had its first failure. CRMWA crews quickly mobilized, located the failure, and repaired it with a clamp. CRWMA was able to re-fill the aqueduct a week after the failure but, when doing so, they noticed a new failure near the original—failure number two. One week later, they experienced a third failure. Fearing more failures, CRMWA expedited a condition assessment of 47 miles of their aqueduct. Where the condition assessment identified concentrated areas of vulnerability, CRWMA decided to proactively and strategically install emergency bypasses. This paper is a case study of CRMWA’s response.

Over the past 20 years, advances in large diameter pipeline condition assessment and inspection tools have made pipeline asset management programs more exciting and effective, yet water distribution systems are still plagued with chronic valve problems. Unfortunately, the valve problems are often realized prior to planned pipeline inspections and during unplanned and reactive maintenance events. Whether performing planned and routine maintenance, or responding to reactive maintenance and catastrophic failure, the success of any pipeline project of any pipeline size, is largely dependent on the health and reliability of control valves. Unreliable valves are the leading factor in change orders, cost over-runs, extensive collateral damage, or even cancelation of important pipeline condition assessment projects. All of these problems and symptoms can be avoided by prioritizing the role of control valves and ensuring specific maintenance tasks occur before, during, and after pipeline shutdowns and inspections occur.

Leakage rate has long been known to be related to the internal pressure of the pipe at leak locations. Reducing leakage and excess pressures are two main goals in pressure management activities. Computer model-based leak detection methods that detect leaks by analyzing the pipeline hydraulic state have been widely employed in the industry, but their effectiveness in practical applications is often challenged by real-world uncertainties. This study quantitatively assessed the effects of uncertainties in leakage rates, consumer water demands, and pipes roughness on the delivery pressures in water distribution systems. Variations in leakage rates due to changes in pressure and discharge coefficient are shown. And, the most sensitive uncertain parameters contributing to uncertainty in leakage rates are determined. For this purpose, the mean-centered first-order method is used to estimate the first and second moments (i.e., mean and variance) of leaks. Then, changes in delivery pressures caused by uncertainties in leakage rates, consumer water demands, and pipes roughness are quantified using Monte Carlo simulations. This study provides valuable quantitative results contributing toward a better understanding of how real-world uncertainties affect pressure distributions in water distribution systems and can be helpful in pressure management studies.

The water industry has seen many types of academic surveys and studies on water main replacement programs and the benefits of asset management and prioritization. However, many utilities have not historically tracked all of the elements of water main break data. One factor used to quantify the occurrences of failing underground pipe networks is water main break rates. Water main break rates are calculated for all pipe materials used in water delivery to create a measurement to judge pipe performance and durability. Water main break rates can vary year to year and by utility. However, in aggregate, break rates produce a compelling story which can aid our prudent decision making as it relates to repairing and replacing our underground pipes. In April 2012, Utah State University published an initial comprehensive survey of water utilities. This was a survey of water main breaks and operating characteristics at utilities located in U.S. and Canada. Six years later in 2018, a new water main break study was released reviewing the national metric for citizens served per one mile of pipe, aggregate data on pipe material break rates, the analysis of age and corrosion in failure modes, and related observations on pressure, delivery volumes, effects of soil corrosivity, and trenchless technology practices. This paper reviews the newest water main break study metrics and findings and outlines various trends and projections of water main breaks in the U.S. and Canada which can be used to benchmark an organization's water main breaks and use this critical data in asset management plans.

Major advancements have been made utilizing spray in place pipe (SIPP) renewal technologies for both pressure and non-pressure pipe applications. For pressure pipe, current systems have been developed for non-structural, and semi-structural linings only. This paper will describe the development of a fully structural SIPP technology for pressure pipe applications including but not limited to potable water systems capable of meeting NSF 61 requirements. SIPP technology has several benefits such as same-day return to service, effortless service reinstatement, reduced environmental footprint, economy, market versatility, and minimized community impact. Conversely, the mechanical and control deficiencies of SIPP lining systems preclude current processes from yielding structurally independent linings in pressure pipe systems: Traditional SIPP lining materials have low creep resistance; adhesion between host pipe and lining can cause fracture of the lining during pipe failure events; both radial and longitudinal shrinkage of thermosetting materials will create an annular space between the lining and pipe. This annulus will result in hydraulic failures when fluid infiltrates behind the liner system at discontinuities. This study will explain in detail how the robotic and concurrent application of a closed cell porous elastomer, helically wound carbon fiber filament, and high-tensile strength rigid polymer will result in a composite system to create structurally independent linings. This paper will explain how this lining system can meet the requirements to be able to span perforations, cracks, and other discontinuities in host pipe to provide hoop strength and resistance to buckling forces.

Twenty-one large diameter water line above grade crossings, ranging in diameter from 24-inch to 60-inch, were identified for rehabilitation or replacement in the city of Houston. Lockwood, Andrews & Newnam, Inc. (LAN) performed field investigations to catalog deficiencies and explore options for repair or rehabilitation. Fifteen of the 21 crossings were identified as in need of re-coating and were re-coated as part of Rehabilitation of above Grade Crossings—Package 1. Challenges included accessibility, surface preparation, and presence of contaminants including lead, asbestos, and cadmium. Construction notice to proceed was issued in December 2016, and substantial completion was received in January 2018. This paper will follow the construction process for the coating rehabilitation at each crossing, highlight the challenges faced, and report the outcomes for the 15 locations selected for re-coating.

Polymeric coatings consisting of epoxies, polyurethanes, and polyureas have been utilized in the municipal industry for years to rehabilitate manhole structures, typically with the intent of arresting infiltration and maintaining the structural stability of the manhole/soil structure. While spray applied products are an effective means of controlling infiltration and arresting deterioration, their use as fully structural solution is sometimes limited by practical installation and product limitations. As a result, the use of spray applied polymeric coatings as a fully structural rehabilitation system and specifically their use in non-circular applications can result in liner thicknesses exceeding the practical limits for application resulting in both installation issues and increasing costs. Recent experiences in the North American manhole rehabilitation market has highlighted a trend of adopting the North American sewer rehabilitation terminology of full and partial deterioration for describing host manhole conditions and liner structural requirements. Since candidates for spray applied manhole rehabilitation systems are typically not in a state of incipient failure and receive considerable stabilization and repair efforts as part of the rehabilitation process, the use of fully deteriorated load models requiring the liner to support all applied overburden loads is often unnecessary and can render liners unbuildable. Due to their vertical orientation within the soil strata manhole structures and liners behave differently and are exposed to different applied load models than gravity pipelines making the use of North American pipeline rehabilitation design methods problematic. Further, when moving from circular to non-circular structures, specifically those with flat walls there is a need to address both applied bending stresses and liner deflection. The lack of formal guidance on both circular and non-circular manhole liner design has resulted in the authors of this paper to develop design procedures based on first principles, considering applied bending forces, end support conditions, and serviceability criteria. This paper strives to define a rational approach to developing design criteria for spray applied polymeric coatings as well defining appropriate applied load models for use in both circular and non-circular applications. Properly, matching existing structure condition with the appropriate load models and structural requirements is critical for ensuring both a successful and cost effective rehabilitation program.

Cured in place pipe (CIPP) pressure liner can be designed as fully structural or AWWA type IV liners. This means the liners must carry all soil and live loads, as well as, all internal pressures that act on the pipe over its design life (50 to 100 years). For water pipelines, internal pressures that a liner needs to be designed for are the working pressure and recurring, and occasional surge pressures. These surge pressures can be two to three times greater than the working pressure and as high as 2000 to 2800 kPa (300 to 400 psi). The design of CIPP also has safety factors. This paper reviews typical pressures that occur in water distribution pipelines that need to be considered in CIPP liner designed. It also presents CIPP liner short-term pressure burst pressures for two commonly used CIPP liner systems. It then compares CIPP liner burst pressures with typical design pressures to investigate the design factors and compares these to current practice factors. It also discusses the construction of new liner pressure test facility at the University of Waterloo to advance CIPP pressure liners design, and to better understand CIPP liners’ response to surge and cyclic pressures.

Cured-in-place pipe (CIPP) was initially created to repair aging gravity sewer systems. The addition of glass reinforcing layers to the felt tube in the 1990s provided CIPP with the structural integrity necessary to be used in the rehabilitation of pressurized pipeline applications. The use of CIPP for pressure applications requires reconnecting and sealing existing service lateral connections. Improperly sealed service connections can result in leakage or migration of water into the annulus between the CIPP and the existing pipe that has been rehabilitated. This leakage is not often apparent during the initial quality and proof testing of the CIPP liner. Minor leaks in the annular space between the liner and host pipe can worsen over time, creating a pipeline that not only lacks the integrity necessary to comply with standard industry guidelines, but one that may also suffer from reduced operational functionality. This paper will review two of the most commonly accepted internal service reconnection methods, both mechanical and adhesive, as well as testing data that was generated during a 12-month research and development project into these two methods. This data will be reviewed and conclusions drawn in regards to the critical aspects required of these methods to ensure long-term, water-tight connections in pressure CIPP systems.

This paper outlines water distribution system research, planning, modeling, testing, and operations required by the city of Toronto to help facilitate transit expansion. The city of Toronto is experiencing public transit expansion not seen in a generation. This expansion is happening in a dense urban environment with water infrastructure that developed and evolved for over a hundred years. As transit is designed and constructed, water infrastructure often needs to be relocated or isolated while work occurs around it. These relocations and isolations mean shutting down watermains. No matter how big or small, shutting down a watermain has an impact on the system. Sometimes the magnitude of impact can be hard to predict. Most watermain networks have built-in redundancy. During ongoing transit construction, the sheer number of shutdowns required can stretch the limits of that redundancy. In some cases, critical pipes pose a significant challenge just to turn them off, let alone for much duration. In the case of large diameter transmission watermains, isolating them can take months of planning, and in some cases, new supplies need to be constructed before the pipe can be deactivated. To ensure uninterrupted supply to residents and businesses, an intimate understanding of the system is needed. To assist the transit authority requires a close working relationship and early planning.

The 12.3-mile long 132-inch diameter and 5.5-mile long 96-inch diameter tunnel liners for the East Central Interceptor Sewer (ECIS) and the North East Interceptor Sewer (NEIS), respectively, consisted of an initial liner and a prestressed concrete cylinder pipe (PCCP) primary liner. The primary liner for ECIS was stiffened steel at the future 13 lateral locations; the lateral connections to the 132 inch stiffened steel tunnel liners varied from 48 inch up to 96 inches in diameter. The 132-inch diameter PCCP primary liner, had a deep single gasketed joint and the 96-inch diameter liner had a double-gasketed testable joint since it runs parallel to the Los Angeles River and is subjected to 100 ft. external water head. Qualification testing prior to pipe manufacture included testing the joint to 120 ft. of external head. The tunnel design loading and handling conditions and design procedures utilized for the PCCP and stiffened steel tunnel liners will be presented in this paper. The liners were installed, with a specially designed laying machine with wheels and lifting hydraulics in 24 ft. long lengths, except at one seismically sensitive area in 4 ft. long lengths. Both tunnel liners were installed with a PVC liner in the concrete lining for corrosion protection.

Sacramento Regional County Sanitation District (Regional San) completed Phase 1A of the Sacramento Power Authority Cogeneration Recycled Water Pipeline Project (SPA Project) in July 2016. Construction of the second phase, 1B, is estimated to be completed in March 2018. The purpose of the project is the conveyance of approximately 1,000 acre-feet per year (AFY) of tertiary filtered and disinfected recycled water to the Sacramento Power Authority Cogeneration Plant for use as cooling water, and an additional 1,700 AFY for irrigation at landscaped areas, parks, school playing fields, and golf courses adjacent to the 1B pipeline alignment. Phase 1A of the SPA Project included the trenchless installation of 3,220 lineal feet of dual fusible PVC (fPVC) pipelines (18-inch reclaimed water, and 10-inch side stream effluent) via horizontal directional drilling (HDD). This paper will discuss the benefits of trenchless installation as it relates to this project, the design criteria used to develop a horizontal directional drilling plan, the challenges encountered during construction, and the overall risk mitigation strategy that resulted in a successful trenchless HDD installation of parallel dual pipelines.

The city of Covington, Washington, has seen continual growth over the past decade. To accommodate the growth, Soos Creek Water and Sewer District embarked on the design and construction of a complex regional sewer project. The overall project included the installation of 6,200 feet of 18-inch diameter gravity sewer using conventional open-cut and trenchless construction methods and the construction of a new regional sewer lift station. Delivering this project required substantial effort that involved designing and constructing eight trenchless crossings from 122 to 288 feet long under state highways, environmentally sensitive areas, streams, and hills. This paper looks at the initial design and construction of the crossings using pipe ramming technology and why that method was chosen. The paper covers the challenges encountered during the pipe ramming portion of the project and how the project owner, engineer, and contractor partnered to identify the best approach for successfully completing the sewer installation when it was determined that pipe ramming could not meet the line and grade requirements for the gravity sewer. The process used to determine why the project would be completed using microtunneling technology will be examined and how the change order language was developed, protecting both the owner and the contractor.

The regional transportation authority, Sound Transit, is in the process of constructing light rail transit expansion to its Tacoma Link service. The existing 2.5 kilometer light rail line serves six stations and over a million riders; the expansion will add four kilometers of light rail line and six new stations. The proposed project is within the city of Tacoma's existing urban corridor, which consists of high-density urban development, and high-traffic-volume streets. Construction is anticipated to start in 2018, with commissioning of the new rail service in 2022. As part of the project, approximately three kilometers of 6 to 12-inch water main servicing 160 customers including two large regional hospitals will be relocated. This paper will go over the techniques and design approach used to relocate the water main and will provide details on water main criteria to mitigate light rail stray currents and space constraints, utility conflict resolution through cross-disciplinary design reviews, and methods for maintaining water service during construction.

The city of Marietta, Ohio, was facing significant challenges to replace an aging 10-inch diameter cast iron sanitary sewer force main that was installed under the Muskingum River in the 1950s. The existing force main was in poor condition and significantly undersized and at least partially responsible for causing sanitary sewer overflows along Gilman Avenue on the west side of Marietta during relatively minor wet weather flows. City officials authorized a sanitary sewer study and modeling and final report which recommended the replacement of the aged, undersized 10-inch cast iron force main. During construction, 1,960 lineal feet of a larger 16-inch diameter fusible polyvinyl chloride pipe (FPVCP) DR-21 force main was installed adjacent to the Harmar Lift Station and very near the confluence of the Ohio River. This horizontal directionally drilled (HDD) river crossing project was very complex and had many scheduling and site constraints and challenges; however, it was completed on time and under budget. This was accomplished by having the city select and obtain the right team of professionals including AECOM as Engineer of Record, DRS Enterprises, Inc. as HDD contractor, Inrock Guidance Systems, Inc. as specialty subcontractor responsible for steering, guidance, and tracking services, Underground Solutions, Inc. as supplier and specialty subcontractor responsible for staging, assembly, and installation of the 16” diameter FPVCP force main, and Pickering Associates as the consultant to provide construction management and inspection services. This paper will summarize the key concepts that were critical to the success of this extremely challenging HDD project under the Muskingum River and its location at the river’s confluence with the Ohio River. This project also required the FPVCP to be assembled and staged along the very popular Multi-Use River Trail in the heart of the historic downtown district during peak tourism season for the city of Marietta.

The city of Frisco, located just north of Dallas, Texas, has experienced a drastic population increase over the past 15 years. The rapid population growth coupled with recent drought conditions and limited overall water resource options posed an increased focus on water conservation efforts. This conservation effort, combined with an overall need for additional infrastructure to support a growing population, has resulted in two projects with major trenchless components to lessen the impact of construction on a fully developed commercial area along on of the city’s major thoroughfares. The first project was for a new reuse pipeline to convey treated wastewater from Stewart Creek West Wastewater Treatment Plant (SCWWWTP). The design included a total of 10,000 feet of 12-inch reuse pipeline and a booster pump station. While most of the pipeline was installed by open trenching within the roadway median, one section of the alignment employed horizontal directional drilling (HDD) methods to bore 2,500 feet of the reuse pipeline under a busy intersection that could not be open cut. Based on the reuse project’s success, the city decided to install approximately 4,000 feet of 18-inch and 10,000 feet of 20-inch sanitary sewer force main along a similar alignment to convey raw sewage to the SCWWWTP. The second project required installation of a 2,680-foot portion of the 20-inch force main via HDD. This paper will discuss the benefit that HDD provided and the challenges faced in drilling a compound curvilinear alignment with the encounter of hard rock formations.

The City of San Diego Pure Water Program will treat 34 mgd of raw sewage and convey the water to the Miramar Reservoir for blending with surface water for direct potable reuse. The sewage is treated in secondary and advanced processes and conveyed 7.5 miles in 48-inch ID cement lined welded steel pipe to the reservoir. The last portion of the conveyance system is a HDPE subaqueous pipe laid on the bottom of the reservoir with depths ranging from 50 to 110 feet. The subaqueous conveyance systems consist of 0.63 miles of a 54-inch mainline with step down sizes of 48, 42, 36, and 30 inches. Eleven branches totaling 0.4 miles with pipe sizes ranging from 8 to 24 inches with duckbill type diffusers to distribute the PW within the reservoir. The reservoir contains invasive quagga mussels creating significant potential for plugging the diffusers and pipes. The last portion of the landside pipe is tunneled into the reservoir and must be protected from the intrusion of reservoir water. This paper discusses the reservoir modeling effort to ensure adequate dilution is achieved and focuses on the design aspect of the subaqueous pipeline to facilitate uniform flow and mixing. Construction sequence and procedures for connecting the land and subaqueous segments was elaborated as it a crucial part of this work.

The Los Angeles Department of Water and Power’s City Trunk Line Sequential Excavation Method (SEM) Tunnel Project consisted of the planning, design, and construction of a 252 foot-long, 10-foot diameter tunnel that needed to navigate through and around bridge abutment piles 60 feet below the ground surface that supports the major intersection and Tujunga Wash above. SEM tunneling was selected to provide the engineers with more control during the construction process, to allow for modifications to be made based on actual tunneling conditions, and to utilize the strength of the surrounding ground to provide optimized support for the tunnel. The tunnel excavation was carried out in short increments, where fiber reinforced shotcrete was sprayed onto the exposed soil immediately following excavation. A 60 inch trunkline was installed in the tunnel after completion, as part of the larger City Trunk Line Project, which involves replacing over 9 miles of riveted steel pipe that was installed in 1914.

Citizens Energy Group (Citizens) is implementing a long term control plan to address combined sewer overflows (CSOs) in Indianapolis, Indiana. Included are provisions for a series of CSO diversion structures, consolidation sewers, drop shafts, and a tunnel for storage and conveyance. There are multiple tunnel segments as well as multiple near surface projects planned over a span of 10 years. The design and construction of the Fall Creek Collection Consolidation Sewer Phase IA project faced challenges of construction in an urban environment around numerous utilities including existing water, sanitary, gas, and overhead electric utilities. Coordination with other municipal projects that were being planned, designed, and constructed concurrently was also a challenging aspect of the project during design. Additionally, coordination with multiple stakeholders and community neighborhoods, and managing project risks and schedule assisted with completing a successfully managed and executed project.

The San Antonio metropolitan area has experienced sustained growth for decades, putting increased pressure on existing wastewater infrastructure. In June 2013, the San Antonio Water System (SAWS) approved a settlement agreement with the U.S. Environmental Protection Agency (EPA) that requires significant improvements to the SAWS wastewater system over a 10-year period to reduce sanitary sewer overflows (SSOs). This work includes the targeted replacement and rehabilitation of an aging infrastructure system that consists of over 5,200 miles of sewer pipe. One such pipeline is an existing 48-inch concrete trunk sewer which currently operates at capacity during dry periods and during periods of minimal rain, routinely experiences SSOs of 50,000 to 100,000 gallons or more. SAWS has identified the replacement of this critical sewer as one of its highest priorities, initiating design of a six-mile segment of 60- to 78-inch sewer to increase the current capacity. As a key component of the EPA consent order, this project was time-critical. Numerous challenges existed along this six-mile alignment, each of which had significant potential schedule impacts: narrow corridor through U.S. Military installation for over a mile; pipeline depths between 30 and 40 feet; construction under two Department of Transportation roadways and a municipal overpass; and alignment adjacent to a major waterway (Salado Creek) where historic artifacts, flood plain, and tree coverage were likely to require mitigation. In one example, a 4,000-foot tunnel was designed, over 30-feet deep, in a 25-foot easement, that was installed between transmission and distribution power lines, on a U.S. Military installation. This 94 ½-inch tunnel was installed via micro-tunneling, for a 78-inch fiberglass reinforced pipe (FRP) sewer carrier pipe. This paper will focus on four tunnels such as the tunnel mentioned above, each of which was designed and installed in locations that would eliminate the need for mitigation. In each location, special considerations were incorporated into the tunnel design related to depths, soil strata, reduction of time limiting impacts, and reduction of SSOs.

The Limestone County Water and Sewer Authority (LCWSA) is a water and sewer utility that serves more than 21,000 customers in Limestone County, AL, and surrounding areas in north central Alabama. On average, they provide 8 million gallons of water per day (MGD) to their customers. However, in order to meet the current and future demands for water in their rapidly developing service area, the LCWSA knew that a large-scale construction project was inevitable. After years of planning, budgeting, and coordinating with local, state, and federal authorities, the decision was made to install a large diameter water transmission line that would allow Limestone County to purchase water from nearby Decatur, AL, which happens to be on the other side of the Tennessee River. Upon completion, the new line will allow the LCWSA to purchase an additional 15–20 MGD from Decatur Utilities. The project came to be known as the Decatur to Limestone County Water Transmission Line, and was awarded to Garney Companies, Inc. in April of 2016.

To allow for future development, the city of Calgary (The City) retained associated engineering (AE) to investigate increasing capacity of a sanitary trunk installed in the 1970s. The design solution was to twin an existing 600 mm diameter trunk crossing Deerfoot Trail with a 750 mm diameter pipe. With an annual average daily traffic (AADT) count of 169,000 vehicles per day, the portion of Deerfoot Trail to be crossed required a trenchless method and micro tunnel boring machine (MTBM) was recommended. The trenchless method selection was considered for existing site constraints including: an 8-lane freeway, a pedestrian bridge, a golf course, a regional pathway, and existing utilities. The selected option was 210 m of 1200 mm diameter casing (750 mm diameter carrier) which passed beneath Deerfoot Trail and the golf course. From design through tender and construction, there were deviations from the original design to achieve the project outcome. This paper focuses on these changes, the construction process, and the final successful outcome.

This paper presents a case history from the engineers perspective of the use of a patented ArrowBore technology for installation of three parallel water lines. Additionally, this paper researches other installations of gravity pipelines by the ArrowBore technology and evaluates suitability for future projects. The ArrowBore technology (also known as close tolerance HDD) is a modification of standard HDD process where vertical sight holes are drilled about every 15 to 50 feet over the alignment to facilitate sighting the pilot bore and to relieve the drilling mud pressure. As the product pipe is pulled into the reamed hole, the drilling mud is displaced up the sight holes and is vactored out of the holes. As the product pipe passes the first sight hole, the path of the drilling mud is effectively shifted to the next sight hole. The case study is for the three water lines installed as temporary pipelines for bypass flow to allow CIPP lining of the larger diameter water transmission lines. The design engineer specified HDD for installation of the three temporary water pipelines. During the submittal review phase, the contractor proposed using the ArrowBore technology. The owner agreed to this innovative technology as a “pilot project”. This paper discusses the ArrowBore process, how concerns raised by the design team during the submittal review were addressed, and how construction using the ArrowBore process progressed. Additional information about other installations will be summarized and we will present our conclusions regarding the benefits and risks of this technology and the applicability of the CTHDD process to other projects.

To facilitate condition assessment in sewer pipeline networks current practice is using the available technologies to visually inspect the internal condition of pipelines. Closed circuit television (CCTV) has been one of the most used methods in North American municipalities in last decades. However, this method requires hours of videos to be inspected by certified inspectors which is time consuming, labor intensive, and error prone. The main objective of this research is to propose an automated approach for inspection and condition assessment of sewer pipelines using computer vision techniques. This research includes two main part: identifying region of interest (ROI) in sewer inspection videos which are most likely to contain sewer defects, and defect detection and classification among the identified anomalous frames. The ROI detection model employs proportional data modeling using hidden Markov models (HMM) to extract abnormal frames from sewer CCTV videos. In the next step, a deep learning approach using convolutional neural networks (CNN) is proposed to detect the defects and classify them. The presented algorithm has been developed and tested using the data sets from CCTV inspection reports.

Cleaning and lining of older cast iron mains is a cost-effective method of extending their useful life. New Jersey American Water has employed this practice for several years as a means of extracting maximum value out of its buried infrastructure assets. Different rehabilitation methods are available, each of which comes with a different cost and a different level of reliance on the pipe wall for structural strength. Selection of the most cost-effective rehabilitation method is crucial to an efficient program. Obtaining pipeline inspection data prior to implementing a rehabilitation program has an impact on the efficiency of this program. This data makes it possible to select the most cost-effective rehabilitation option based on the actual condition of each main, thereby saving money. Gathering the data comes with a cost as well, which needs to be weighed against the value of the information provided. This tradeoff between the cost of information and the savings achieved is captured with the economic assessment level model. This paper reviews New Jersey American Water’s approach to collecting pipeline inspection data and using it to make rehabilitation decisions. The use of acoustic propagation velocity testing is described, and an analysis is provided of the savings achieved through better selection of rehabilitation methods. The financial impact achieved by this program is also compared to the expected savings predicted by the economic assessment level model.

Construction of large diameter (48-inches and larger) pipelines is a large investment for any water utility. Quality construction is critical to the overall performance, reliability, and service life of any water transmission system. Construction inspection is a critical for quality. Large diameter pipelines offer many challenges to the owner’s team. Large diameter pipelines typically use more complex pipe materials, bedding and backfill materials, appurtenances, corrosion protection requirements, and construction methods than do smaller diameter pipelines. This paper is an update of “A Guide for the Construction Inspection of Large Diameter Pipelines,” from ASCE Pipelines 2009. This paper discusses critical components of large diameter pipeline inspection in the field and at the manufacturer, and includes a convenient checklist for the field inspectors. The paper focuses on the use of large diameter steel and concrete cylinder pipelines for water transmission service. The checklist covers important inspection and testing procedures: right-of-way clearing and restoration; pipe material inspection at the manufacturing plant; pipe handling; pipe material inspection before installation; trenching; pipe-laying; bedding and embedment around the pipe; backfill over the pipeline; external and internal field joints; field welding (weld after backfill, butt straps, and double welds); internal pipe inspection after installation; inspection of appurtenances; patching of coating and lining; installation through tunnels; and hydrostatic, compaction, and non-destructive testing of pipelines.

Pipeline inspections are recommended and may be required by law in many jurisdictions depending on the pipeline type. Areas where the pipelines cross waterways or travel for some distance along the seabed have a higher risk due to the probably of deterioration/damage and the consequences of failure. These important asset locations are often challenging to monitor and manage due to limited access and varying underwater conditions. In order to promote the long-term serviceability of these pipelines, as well as to ensure safety, this paper recommends methods for the efficient and effective underwater inspection of pipelines. Assessment methods will cover the use of commercial divers, remotely operated vehicles (ROVs), autonomous underwater vehicles (AUVs), unmanned aerial systems, and a variety of underwater technologies with special emphasis on acoustic imaging. High resolution images with detailed measurements of a pipeline can be obtained even in zero visibility conditions. Some regulations and guidelines related to pipelines are mentioned herein.

The low service area of the District of Columbia Water and Sewer Authority’s (DC Water) water distribution system provides water to the downtown area of the city (including federal buildings and the White House) and is the source for pumped water to three higher pressure zones. As part of DC Water’s asset management program, one particular element of the low service transmission system was identified as needing attention. This is an 8,000 foot (2,450 m) section of large diameter 66-inch (168 cm) welded steel water transmission main in the northeast section of Washington, DC. The pipe was constructed in the 1960s with an internal and external coal-tar enamel coating, and a portion was equipped with a sacrificial buried anode cathodic protection system. However, the pipeline has never been taken out of service and dewatered for inspection. The purpose of the project is to perform a manned entry of the pipeline for internal inspection of the joints and walls by visual, physical and electronic testing.

Polymeric liners offer very competitive lining options for aging, buried water infrastructure. This paper presents the technical background and a case study for the deployment of polymeric linings inside water pipes using a tethered aerodynamic shape in a flowing airstream. Polymeric linings are conventionally applied inside of water pipes using computerized spray rigs. A new, simplified application method offers advantages for the rapid, economic application of a polymeric barrier lining inside of a water pipe. The authors were involved in the development, testing, and field deployment of this new method. This paper explores the details of development, testing, and validation for airborne polymeric lining. A case study is also included in support of the commercial deployment of this method for users needing AWWA Class I barrier linings for aging pipes.

Years of salt exposure from the Atlantic Ocean has taken its toll on two aged water and sewer pipes mounted under the Matanzas Inlet Bridge in St. Johns County, Florida. The inlet, named after the 1565 massacre of 245 French Huguenots by Spanish Conquistadors, is home to a National Monument, four different endangered species, and was hit by hurricanes during both the design and construction of this project. Replacing these pipes over the Matanzas Inlet combined unique technical, environmental, permitting, and construction challenges. The Matanzas Inlet is known for its swift currents and shifting sand bars. This limited construction options for replacing the pipes. The location of the water and sewer pipes was very difficult to access under the bridge—given safety and constructability concerns, the design team developed three different construction approach options for contractors to consider. Additionally, with these pipes being on the coast of Florida, the support structure had to be designed to withstand hurricane force winds and significant thermal variation. The beautiful coastal habitat of the National Monument is home to protected nesting sea turtles, gopher tortoises, the Anastasia Beach Mouse, and the Least Tern (a small ground nesting bird). With multiple endangered species present, the team coordinated closely with the National Park Service throughout the design and construction of the project. Additionally, the team included an environmental consultant that provided monitoring, protection, and educational presentations for the construction workers during the project. These environmental constraints created strict seasonal and daily construction constraints for the contractor. Besides the known environmental challenges of this project, Mother Nature provided two additional surprises. As the project was nearing bidding, the inlet was hit by Hurricane Matthew which impacted the base design information and further deteriorated the condition of the pipes—accelerating the need for the project. Then, during construction the site was hit by Hurricane Irma which required demobilization and stabilization of the site before the hurricane’s impact. This presentation explores the unique aspects of this project, the technical solutions the team developed, and the close collaboration with various stakeholders.

This project extends the life of one of Louisville Water Company's oldest water mains. Installed between 1923 and 1930, this 48-inch cast iron transmission main carries water from the Crescent Hill Treatment Plant on Frankfort Avenue to downtown and the Cardinal Hill Reservoir. It transports 15 to 20 million gallons of drinking water daily to Crescent Hill, the Highlands, downtown, Old Louisville, and South Louisville. The pipe runs along historic Olmstead Parkway, a major east/west arterial with an average traffic volume of 20,000 vehicles per day, bordered by established neighborhoods, businesses, and popular recreation areas. Being the largest water main repair project in Louisville Water's 156-year history along a heavily traveled historic parkway, the project presented many challenges. A partnership by the owner, consultant, stakeholders, contractor, and pipe manufacturer set the foundation for successful design and construction for Phase I, renewal of more than 11,000 feet of pipe during a restricted off-peak winter demand period, and providing continued service to all existing customers. This paper discusses aspects of the preliminary engineering evaluation, stakeholder involvement and communications, final design solutions, and effective construction modifications that resulted in a successful project that exceeded expectations.

The city of Taylor, located in Wayne County, Michigan, serves a population north of 60,000 residents and, like many municipalities in the U.S. with aging and undersized infrastructure, they are experiencing systemic water system failures that require major system updates. For the city of Taylor, most of these recurring failures are happening in their residential neighborhood distribution piping, which consist of 60-year-old 6-inch cast iron water mains. The city with the help of their consultant, Wade Trim Engineering, decided that since the pipe issues were systemic and replacement of those water mains would require a larger diameter pipe, the preferred method of rehabilitation would be pre-chlorinated pipe bursting with the installation of an upsized 8-inch DR 18 fusible polyvinyl chloride pipe (FPVCP). This method meant less disruption to the homeowners’ property, provided a discrete water shut-off and disruption schedule for homeowners, and kept the installation of the new main within road rights-of-way and existing easements. Since the start of the project in September 2016, Bidigare Contractors have installed over 35,000 feet of 8-inch DR 18 FPVCP and 1,000 feet of 12-inch DR 18 FPVCP. This paper will review the basic steps and process for the pre-chlorinated pipe bursting method being used in Taylor. It will also review the results of the project construction and the program in general.

This paper focuses on the rehabilitation design for old brick sewers based on an ongoing project in Columbus, Ohio. These brick sewers date back to 1800s and some of them sustained severe deformation (ovalization) as well as buckling over time. As a first step, a stress-strain approximation was performed for select sewers (with a diameter range from 48 to 136-inch) for single, double, and triple ring configuration, and the results suggest remarkably high stress concentrations in areas where bricks are missing or pipe was not originally built to the plans. The overall rehabilitation design approach as well as the computation methods used for trenchless rehabilitation of large brick conduits are discussed.

The Miami-Dade County Water and Sewer Department (WASD) has a significant amount of large diameter wastewater prestressed concrete cylinder pipe (PCCP). WASD decided to rehabilitate some of these large diameter pipelines instead of performing pipe replacement in order to reduce operational, cost, and construction impacts. This paper discusses the benefits of pipeline rehabilitation using performance based criteria. Historically high costs, complexity of construction coordination, and traffic related impacts to the public necessitated a revised approach to addressing rehabilitation methodology. There was also a need to identify an approach that required less administration and engineering to reduce the completion schedule without increasing the existing staff. Various methods and materials construction were considered in order to address engineering and operation challenges. Resources were explored and a level of service identified by performance specification for pipe rehabilitation was developed based on flow characteristics, maximum allowable hydraulic losses, operating pressures, test pressures, and allowable reduction of inside diameter. The contractor had the final responsibility for determination of the materials, design and calculations, and permitting which was evaluated during the bid process. As a result of providing performance specifications with options for materials and construction approach, WASD has mitigated construction effects and lowered construction costs.

What does it take to rehabilitate up to 60 km of watermain per year? What are the challenges? How much does it cost? What are the savings? Why structural lining vs. full replacement? The city of Toronto has been facing these questions for several years. Growing in size each year, the city’s rehabilitation program plans to renew 37 km of distribution watermain by cured-in-place pipe (CIPP) structural lining in 2018. This paper discusses how the city manages a program of this scale, including: considerations for identifying priority assets in need of renewal, selecting rehabilitation vs. full replacement, public communications management, data management, design and planning requirements, identifying staff resources for owner and consultant, qualifications for contractors, specifications for liners, quality control of liner installations, life cycle costs, and construction scheduling. CIPP for pressure pipe offers a number of benefits to the owner when compared with typical open cut replacement, but also presents a number of additional challenges that with appropriate planning and resources can be managed efficiently.

The Burrungubugge Intake Shaft is a critical structure in the Snowy Mountains Scheme. The Burrungubugge Intake Shaft was constructed by drill and blast through granite in order to siphon water from the Gungarlin and Burrungubugge Rivers into the Eucumbene-Snowy Tunnel, a 23.5-mile water diversion tunnel for the scheme. The 6-foot diameter, 433-foot deep, vertical shaft had deteriorated over the years in the form of stress cracking, corrosion, and tears in the steel liner. Continued deterioration of the steel liner introduces a danger of collapse and a loss of the intake shaft. The distress to the liner was caused by complex hydraulic forces and was not fully understood until engineers completed a detailed analysis including hydrodynamic finite element modeling. Based on the analysis, a repair methodology was developed that required a coordinated effort between various specialty contractors and the owner. This paper will review the project in detail, including the analysis, the repair methodology, the field quality control, and advanced construction procedures required to implement the repairs.

The Baltimore Siphon project for the city of Baltimore required the assessment of the Horner’s Lane Siphon, a 3-barrel concrete encased siphon (1–24 inch and 2–36 inch) built in 1931. Sewage was reported leaking from a crack in one of the pipes and discharging into the stream. The city’s goals for the project were threefold: (1) immediate repair: seal the crack on the 24-inch siphon pipe to stop the sewage leak, (2) short-term repair: re-support the siphon pipes, as the stream had incised so much that the pipes were exposed, with no soil supporting them, and (3) long-term repair: develop a long-term solution to repair/rehabilitate the exposed siphon pipes and restore the stream. This paper describes the process used to develop the immediate, short-term, and long-term repair solutions, and it also discusses how to deal with a new emergency situation when trying to correct an existing emergency.

Transmission watermains in the city of Toronto use predominantly the following two material types: cast iron with cement mortar lining (“CML”) and CML steel with concrete encasement. The focus of this paper is to discuss the history, current condition, the city’s cast iron watermain rehabilitation plan, and a few recent highlight projects related to cast iron trunk watermain replacement. Record drawings show that cast iron pipes in Toronto’s transmission water system were used from 1900s to early 1950s. After 1950s, cement mortar lined steel pipes with concrete encasement were the predominant standard for new trunkmains. Currently, there are about 100 km of cast iron trunk watermain ranging from 600mm to 900mm in diameter still in service today. Most of them in the older parts of Toronto such as downtown core and west end of downtown Toronto. Currently, the city has planned $153 million (Canadian Dollars—“CAD”) over the next 10 years to replace and rehabilitate cast iron trunkmains to restore the useful life of our trunkmain linear infrastructure.

The North Charleston Sewer District (NCSD) System includes 60 pump stations and approximately 500 miles of gravity and force main piping. The infrastructure serves approximately 31,000 customers and a total population over 100,000. The Felix C Davis Wastewater Treatment Plant (WWTP) is permitted to treat 32 million gallons per day (MGD) and is the only plant utilized by NCSD. Currently, the plant averages approximately 18 MGD from the 59-square-mile service area.

When an 85 year old large-diameter valve needs replacement, no one expects it to be a simple task. Typical underground valve vaults of the 1920s seldom afford easy access for replacement, and can provide their share of surprises. When the valve is one of five large diameter valves housed inside the same 1,100 square foot vault that was constructed in three distinct phases and subsequently modified over its lifetime, however, the challenges and opportunities are certain to extend beyond replacement of the broken valve alone. The city of Minneapolis, along with engineer CDM Smith and contractor PCI Roads, recently completed a project that included redesign and renovation of the entire reinforced concrete and brick valve vault. The project included structural repair and replacement (including replacement of the cast-in-place roof with sectional precast slabs that can be removed for future work), replacement of the broken valve and associated piping, and extensive rehabilitation of four other large-diameter valves inside the vault, which offered a less expensive alternative to replacement of those valves. The project is an example of utilizing the need to replace a specific component as an opportunity to think holistically and make other cost-effective improvements for the long term.

The Metropolitan Water District of Southern California (MWD) owns and operates the Orange County Feeder. The Orange County Feeder is a 36-inch-diameter steel pipe with coal tar enamel lining. A nine and half mile-long stretch of the pipeline was originally installed in the 1940s using refurbished steel pipe with coal tar enamel lining and coating. The lining in this stretch of the pipeline has reached the end of its useful life. This project involves removing the coal tar enamel lining, installing internal butt straps at every joint, and lining the pipe with mortar. The biggest challenge associated with removing the coal tar enamel is that coal tar can’t be removed with a traditional abrasive blast because it tends to melt. The only practical way to remove the lining is with a high-pressure water blast. The project also replaced old boiler type manholes (which were difficult to maintain) and valves that had reached the end of their useful life. MWD took a comprehensive approach to the rehabilitation so that all components in need of refurbishment were rehabilitated at the same time as the lining was replaced. To perform construction the pipeline had to be accessed every 1500 feet along the length of the pipeline to install the construction equipment. These access locations had to be installed in some of the busiest streets in the city of Santa Ana. The design team developed construction and traffic plans so that the pipeline could be accessed while minimizing impacts to businesses and the public. The construction of the pilot project was recently completed which was about 2 miles long. The construction was successful in removing the lining, installing the buttstraps, installing a new mortar lining, installing new manholes, and valves.

This paper presents the background, alternatives analysis, and design approach for the trenchless rehabilitation of a 1.5 mile, 30-inch culinary water pipeline, with an emphasis on the resources and calculations used to design the liner for a “partially deteriorated” host pipe. The benefits in terms of constructability and cost are compared for the “partially deteriorated” versus “fully deteriorated” design requirements. The subject matter is germane for pipeline designers and city asset managers faced with the challenge of rehabilitating deteriorating infrastructure.

Helix is a unique water district with history dating back to 1885 serving a nearly 50 square mile service area that includes the cities of La Mesa, Lemon Grove, and El Cajon, the communities of Spring Valley and Lakeside, and other areas of unincorporated San Diego County. The district operates a 5.8-mile-long 36-inch pipeline that is part of an aqueduct transporting raw water from the regional water wholesaler, San Diego County Water Authority’s raw water system, to downstream treatment facilities. The 36-inch concrete-lined cylinder pipe line was inspected in early 2017, and the inspection flagged a number of localized areas with distress. Since most of the distress appeared to be externally induced, there were no internal visual indicators available to help facilitate subsequent repairs. As such, the repair efforts required a multi-stage approach where initial verifications efforts drove future verification and repair decisions. Initially, pipe tally listings and heat-color map representations of the pipes were used to locate areas of distress. While this allowed verification and rehab efforts for distressed areas nearby manholes, areas further away required a different approach. This paper discusses the challenges involved with location and verification of the distressed areas, the unique techniques implemented to resolve the challenges, and the drivers for selecting the optimal rehabilitation type. Factors that were considered were accessibility of the above ground terrain, nearness of infrastructure such as overhead busy roads, and the severity of the identified distress. The paper concludes with a cost comparison and overview of lessons learned which the authors believe will benefit other aqueduct operators.

The Middlesex Water Company (MWC), discovered a large leak near a 30-inch prestressed concrete cylinder pipe (PCCP) transmission main in November 2016. After confirming the location of the leak, MWC went through a deliberative repair evaluation process to determine the most suitable repair. During the repair method evaluation, several options were considered including conventional open cut replacement, slip lining, construction of a new crossing, and internal carbon fiber reinforced polymer repair (CFRP). After an extensive evaluation, MWC chose to proceed with a stand-alone internal CFRP rehabilitation. Several construction challenges were overcome during the repair, including significant water intrusion due to heavy rainfall.

The city of Enid, Oklahoma, operates a two-stage active sludge system treatment plant which treats 2.3 billion gallons of wastewater annually with a primary goal of compliance with National Pollutant Discharge Elimination System (NPDES) permit. Following a recent inspection, sections of a 30-inch bar-wrapped pipe were identified as being close to imminent failure. Without this critical line, the city’s treatment plant could not operate and planning for repair needed to begin immediately following identification of the distressed area. A challenge identified early in the process was that the line could not be shut down to perform the repair. In addition, the distressed area of the 30-inch pipe was located on the interior of a subsurface vault, in a highly congested area. These factors, along with others, limited the number of repair options which would be viable. After consideration of all, carbon fiber applied externally to the distressed segment of pipe was the most feasible option to provide a fully structural repair. This paper will provide a detailed view of this challenge faced by the city of Enid and their process from inspection through repair of the critical pipeline within the vault structure. Technical details on the use of externally applied CFRP for fully structural repairs of pipelines is discussed.

Microbially induced corrosion (MIC) of concrete is a major cause of deterioration in sanitary sewer systems and requires considerable amount of rehabilitation investment every year. MIC is caused by the production of hydrogen sulfide by sulfur oxidizing microorganisms present inside the sanitary sewers. The objective of this paper is to investigate solutions for reduction and/or elimination of MIC in the concrete sanitary sewers. This study reviews the cement chemistry, basic science behind concrete deterioration, and MIC production that takes place due to various biological processes which lead to the production of dilute sulfuric acid. Historical attempts to fortify concrete along with methods to reduce odors and corrosion by treatment of raw sewage are discussed. Experimental testing as per ASTM D4783 standard shows resistance of concrete samples to microbial attack with the use of antimicrobial additives.

This study summarizes the results of full-scale three-edge bearing tests performed on 72 in. diameter prestressed concrete cylinder pipes (PCCPs) removed from the line after many years of service. The data collected from the experiments is used to develop analytical models, based on the finite element method, and to validate the capability of the modeling scheme in capturing the response and failure of the tested specimens. The concrete and mortar materials are modeled using a recently developed triaxial constitutive model that accounts for strength degradation due to compressive induced crushing and tensile cracking, as well as increased in strength and ductility due to confinement. The study is supplemented with a set of parametric studies to investigate the effects of interface formulation, interface strength (radial tension and shear sliding), concrete strength, prestressing loss, and biological and chemical degradation of concrete inner core.