Pipeline Engineering and Construction: What's on the Horizon?

Pipeline infrastructure is decaying at an accelerating rate due to reduced funding, insufficient quality control resulting in poor installation, little or no inspection and maintenance, and a general lack of uniformity and improvement in design, construction and operation practices, among other things. New knowledge is needed to provide the intellectual support for pipeline infrastructure decisions necessary to sustain economic growth, environmental quality, and improved societal health. Developing an intelligent information and knowledge system can provide fast and reliable decision-making tools that are needed to handle the large volume of deteriorating buried pipeline infrastructure systems, particularly water and wastewater pipelines, that pose serious threats to environment if they fail. The dramatic growth in the development and use of sensors and information technology (IT) has had an untold impact upon the nature and performance of the fundamental civil infrastructure systems that support our economy and social environment. Sensors and IT has the potential to address many of the quality issues that infrastructure has faced, by providing detection capability for infrastructure condition, coordination of complex operations, and integration of multi-modal and multi-locational facilities to provide seamless services to consumers. A research project is underway at the newly created Pipeline Infrastructure Research Center (PIRC) at the Pennsylvania State University, to determine if a multi-sensory method can be used for structural health monitoring of buried pipeline infrastructure system. This paper presents our preliminary research efforts.

The term "Asset Management" is increasingly being heard around the offices of utility owners and managers. It is a term being used more frequently by planners, designers and regulators as well. Unfortunately, the term is developing the initial symptoms of becoming a buzzword. This tendency is dangerous in several respects. First, utility owners and managers may view it as something new, and therefore a potentially costly additional task they may be required to perform. Secondly, and perhaps more importantly, the concept loses cogency and impact as a buzzword. It becomes just another annoying fad that will hopefully go away. Neither could be further from the truth — Asset Management (AM) is neither something new nor, hopefully, a temporary fad. The goals of this paper are to discuss the terminology of Asset Management, and to reassure utility owners and managers that AM is not something new, and that there are tangible benefits to be realized in both the short and long term by the adoption of a coordinated AM program.

The Sewerage and Water Board of New Orleans (S&WB), with MWH, has developed a computerized data collection and decision making process that quickly and effectively converts CCTV video of thousands of feet of sanitary sewer into prioritized rehabilitation projects. Computer tools utilized include a database, a geographic information system (GIS), and decision making software. This paper describes the process and provides examples of how the S&WB has used this tool to provide a consistent and logical approach to sewer rehabilitation programs. It also describes how the process will reduce redundant efforts in the planning, design and construction phases, thereby saving time and money.

Operation, maintenance and rehabilitation of drain and sewer systems are among the most complex of communal assignments. On the one hand, depending on the size of the community, the systems are of great length and, on the other hand, because of their age structure, they mirror all the development stages so that, today, they consist of very heterogeneous networks, with numerous cross sections and dimensions, pipe materials, pipe joints, types of bedding, principles of construction, types of lines, drainage methods, etc.. To comprehend the interplay and linkages for the individual sewers and the whole network in order, to work out an economical optimized cost and investment strategy for cleaning, inspection and rehabilitation methods is one of the most demanding tasks of the network operator. In order to solve these tasks in a proper manner, conditions, substance acquisitions, assessments and forecasts must be balanced in order to formulate a sensible Whole Life Costing (WLC) concept. In the following, a concept of this type currently in a test phase in Germany is presented.

Valuation of infrastructure assets has been receiving greater attention by municipalities in the U.S. since the Governmental Accounting Standards Board Statement 34 (GASB 34) was issued in 1999. According to GASB 34, values of infrastructure assets should be estimated and included in the annual financial reports of governmental agencies. However, the two valuation methods recommended in GASB 34, i.e., the depreciation method and the modified approach, do not adequately reflect the deterioration of infrastructure assets in their values. To account for the condition changes in infrastructure asset values, a valuation method incorporating the changes in the asset condition due to deterioration is presented in this paper. The proposed valuation method estimates the asset values based on the Markov chain-based deterioration model that is developed using condition rating data of the City of San Diego. This paper includes comparisons of the values of wastewater infrastructure assets estimated by three valuation methods based on investment plans obtained from life cycle cost analysis. These valuation methods are: (a) the depreciation method, (b) the modified approach, and the (c) deterioration-based valuation method.

Many of the older potable water pipelines in the City of San Diego's system are made of cast iron or steel and have been in service for nearly 100 years. The Otay II Pipeline, consisting of approximately 16-miles of welded steel pipe and 3-miles of cast iron pipe, has been in service for 70 years and supplies water to the Otay service area. In spite of its age, a recent investigation by the City Engineering Staff shows that most of the pipeline is in good condition. However, some isolated sections are significantly corroded and require improvement or replacement. Planned pipelines maintenance and replacement is currently modeled by the CIP Planning Section determining the best and most efficient water transmission system to provide continued water service with minimal interruption during pipeline improvement or replacement projects. This paper presents how the CIP Planning and Engineering Sections worked cooperatively to devise the best management practice and plan for the Otay II Pipeline Improvements Project.

Numerous models have been proposed in the last two decades for the deterioration of buried pipes. The most prominent approach has been the Markovian deterioration processes (MDP), which requires that the condition of the deteriorating system be encoded as an ordinal condition state. This encoding is based on numerous distress indicators obtained possibly from direct and indirect observations, as well as from non-destructive tests. To date, few buried pipes have been inspected and their condition assessed. In addition, the encoding of distress indicators into condition states is inherently imprecise and involves subjective judgment. Furthermore, the consequences of failure for buried pipes are often difficult to quantify precisely due to lack of data. In this paper, a new approach is presented to model the deterioration of buried pipes using a fuzzy rule-based, non-homogeneous Markov process. This deterioration model yields possibility of failure at every point along the life of the pipe. The possibility of failure, expressed as a fuzzy number, is coupled with the failure consequence (also expressed as a fuzzy number) to obtain the failure risk as a function of the pipe age. The use of fuzzy sets and fuzzy techniques help to incorporate the inherent imprecision and subjectivity of the data, as well as to propagate these attributes throughout the model, yielding more realistic results. At the time of submission, adequate and sufficient data to validate the model were not available.

In undertaking an evaluation of an existing municipal sanitary sewer system, many agencies do not have the resources to commit to a detailed evaluation of every structure and every foot of sewer pipe. As a result, it is often necessary to prioritize evaluation efforts, to the end that those sewers most likely to be in poor condition may receive the earliest and most detailed evaluation scrutiny. A special application of the sulfide and corrosion model described in the American Society of Civil Engineers (ASCE) Manuals and Reports on Engineering Practice No. 69, Sulfide in Wastewater Collection and Treatment Systems, can be a useful element of sewer evaluation prioritization tools. Rehabilitative attention should generally be given to those sewer facilities likely to present the greatest risk of failure, prior to those facilities of lower risk. To that end, it is important that a thorough condition evaluation is done for those sewer facilities at greatest risk of failure. If limited evaluation resources are simply applied uniformly to all parts of the sewer system, rather than rigorously applied where conditions are likely to be the worst, the possibility of overlooking or inadequately assessing a high risk facility is greater, as is the potential of wasting scarce evaluation and rehabilitation resources on low- or no-risk facilities. In a recent case, over four million dollars was spent to rehabilitate a major interceptor sewer that had a remaining life expectancy in excess of 90 years. With scarce capital resources for sewer infrastructure maintenance, funding and effort must be appropriately allocated with thorough knowledge of sewer condition.

The Great Man Made River is a water supply project in the North African state of Libya. Water is conveyed from well fields deep in the Saharan desert to the population centers that are concentrated on the northern coastal strip. To-date almost 4,000 Kilometers (2,485 miles) of mainly four meter (158 inches) diameter Prestressed Concrete Cylinder Pipe (PCCP) has been laid. Because of the size of the pipes and the amount of water they convey over thousands of kilometers, the scheme became known as The Great Man Made River Project.

Interceptor sewer pipelines can be large in diameter or involve multiple lines such that construction excavations are deep and wide in open cut reaches. In environments near rivers and shorelines, such excavations and pipeline installations must be made below shallow groundwater levels and therefore require dewatering. Dewatering large excavations over long alignments requires careful assessment of many dewatering-related issues. This paper presents a checklist for design planning and evaluation on projects involving significant dewatering within both city and rural environments. The checklist was used as guidance for multiple design teams involved in the segmental design of the Lower Northwest Interceptor (LNWI) Program to be constructed in western Sacramento County and eastern Yolo County, California. The total length of the LNWI Program pipeline is approximately 31 kilometers (19 miles). Issues of potential concern are presented for this interceptor pipeline in relation to preliminary soil and groundwater conditions, physical features and improvements along the alignment, as well as for known environmental and regulatory issues. Alternative dewatering and construction methods are summarized to establish a common baseline of options to consider during planning and site evaluations. Finally, a plan of follow-on activities for the program manager and owner, to be concurrently undertaken during design development and review, is recommended for maintaining the Program's schedule and permitting needs.

To meet the growing demand on the congested Interstate Highway 10 (IH-10) in west Houston, the Texas Department of Transportation's (TxDOT) has begun the project of widening IH-10. To accomplish this project, TxDOT is acquiring additional right-of way (ROW), which includes the City of Houston's existing ROW known as Old Katy Road. Due to the presence of numerous utilities within the existing ROW, coordination was required between TxDOT and the City of Houston to relocate the utilities in an efficient manner within TxDOT's compressed schedule. This paper details how this project overcame numerous constraints and addressed critical issues. In addition, it demonstrates the importance of all the parties involved working together to provide aggressive solutions as issues arise, ensuring the successful completion of the City's water facility relocation.

Utility corridors traditionally have been engineered for the purpose of accommodating sewer, water, and other utility lines and providing access for their maintenance. Engineers employed by the Greater Vancouver Regional District were part of a cross-functional team that applied a common sense and innovative approach to the integration of utility corridors with greenway paths and trails. These combined corridors, termed "Integrated Utility Greenways" provide public recreation, habitat protection and vehicle free people movement concurrently with utility functions. This paper illustrates the subtle complexities introduced when a greenway is designed and constructed in conjunction with a utility project. The high visibility of this type of project heightens the public focus; consequently the key to success is securing support from the various stakeholder groups before hand. Understanding and acting on the concerns raised by these groups reduces potential design and approval difficulties. By balancing the sometimes divergent needs of all the stakeholders, one can successfully integrate the various functions cost effectively.

By 2020, U.S. public will enjoy benefits from an increase in gas use due to its affordable supply, reliable delivery, and environmental protection benefits. The Strategic Center for Natural Gas (SCNG) of the US Department of Energy oversees a wide range of research and development efforts that are producing innovative, affordable, safe, and environmentally-friendly natural gas technologies. SCNG is accomplishing its mission in partnership with the private sector, academia, and industry associations, to ensure that natural gas continues to be a viable component of a robust and diverse energy portfolio for America. The mission of SCNG is to be the focal point for an integrated gas program by spearheading annual DOE-wide gas research and development (R&D) planning and program assessment. This will provide science and technology advances through the Natural Gas & Oil, National Energy Technology Laboratory's (NETL's) on-site programs, shaping, fund, and manage extramural R&D, and conducting studies to support policy development. This paper presents a summary of SCNG's current research projects.

Sewage spills in year 2000 and 2001 along with the San Diego City Council's and City Mayor's goal to clean up beaches and bays initiated several major projects to update the City's sewer system. Metropolitan Wastewater Department (MWWD) took the initiative to rehabilitate 10 miles of sewer mains in calendar year 2002, 10 miles in 2003, 20 miles in 2004, and 20 miles each succeeding year to reduce sewer spills. Pipeline Rehabilitation in the Right-Of-Way (ROW) and Easements — Phase "A" project commenced in August 2002 to ensure that commitment for 2002 and 2003 was satisfied. Due to time constraints in meeting the spill reduction and rehab mileage goals, MWWD preceded with the advertising and starting of work prior to the Closed Circuit Television (CCTV) assessment of the sewer mains. The Contract was then developed based on Wastewater Collections maintenance logs and sewer spills reports. Sewer mains selected for rehabilitation were on a high maintenance schedule (six-month or less cleaning cycle) due to significant root intrusion. Contract quantities were based on the as-built drawings and Field Book data only.

The Calleguas Municipal Water District (Calleguas) is a water wholesaling agency that provides water to over 500,000 customers in Ventura County, California. As a large water purveyor, Calleguas owns and operates approximately 209 km (130 miles) of pipelines ranging from 0.61 meter (24 inches) to 1.98 meter (78 inches) in diameter. The pipe materials are mortar lined and coated welded steel pipe, concrete cylinder pipe, and pre-stressed concrete cylinder pipe. Many of Calleguas' pipelines were originally constructed through farmland and along two-lane roads. As Ventura County has grown, roadway and development projects have increasingly affected Calleguas' pipeline rights-of-way, often resulting in increases or reductions in earth cover and use of heavy construction equipment that are outside the pipeline's original design parameters. In addition, these projects often require additional utility crossings over and under the large-diameter Calleguas pipelines. This paper describes: (1) The development of minimum earth cover standards for large-diameter pipelines; (2) The development and enforcement of loading restrictions for large-diameter pipelines during grading and construction of improvements over the pipeline; (3) The techniques and methodologies that Calleguas has employed to prevent damage to its pipelines from insufficient or excess cover, including construction of concrete caps, alternative pavement sections, use of lightweight fill materials, and relocation; (4) Special considerations for protecting large-diameter Pre-Stressed Concrete Cylinder Pipe (PCCP); and (5) Protection and support of large-diameter pipelines during crossing of utilities over and under the pipeline by both conventional open-cut and trenchless construction methods.

The water infrastructure system is one of the eight key infrastructures that provide essential services to our society. The water distribution system typically consists of multiple subsystems in grid or network patterns. In addition, water network configurations vary based on geographical layout and water sources. Since water subsystems are interconnected, proper functioning of a particular component is highly dependent on other components. An intentional attack on a well-selected set of components can result in catastrophic disruption of water service. This paper discusses the development of a framework that can be used for the design, operation, and maintenance of robust water systems. The framework considers the vulnerabilities of the water network to intentional attacks and evaluates the consequences of such attacks. The paper also examines potential mitigation strategies to either eliminate the risk or to reduce the level of risk of the system in instances of intentional attack. Such an approach can help water infrastructure asset managers to plan and allocate their budgets when security is included as a significant factor in asset management.

A relatively short, 24-inch diameter, 415-foot waterline is a critical, high-risk piece of infrastructure when that pipeline threatens 9-1-1 service connections, and hospitals, and could possibly cause freeway fatalities. There are more, but few better reasons for relocating a waterline. Pacific Bell (SBC Communications) is in the process of upgrading their facilities throughout San Diego County. The expansion of their communications facility at Linda Vista Road was Pacific Bell's highest priority project in the County—they desperately needed more space for communication equipment.

Pipeline needs are increasing dramatically globally, both on shore and off shore. So too are the risks that are faced in attempting to meet project and stakeholder goals. Not meeting such goals has even greater consequences as a result. Project execution from potential identification of its need through execution and in-service use to decommissioning requires Project Management processes and tools at all stages of this timeline. The paper develops the types of risks for eight categories of risk factors being experienced, tools being used, application options and successes, and the contexts needed for success from the authors' global project management experience over the last 3 decades on six continents (on shore and off shore), including oil & gas, water, and wastewater.

In a hydroelectric power plant or in a pumping station in order to avoid sudden large increase of pressure due to instantaneous valve closure sometimes a surge tank can be installed. The height of surge tank is designed by the highest possible water level during the operation. The theoretical treatment of oscillation in a surge tank is difficult because of the non-linearity of friction term in the governing differential equation of the system. The present study attempts to find a general solution for the surge oscillation in a simple surge tank in terms of non-dimensional parameters. Equations for the highest and the lowest water level in the tank, i.e. very important in the design of a surge tank have been found. A special laboratory apparatus was devised to verify the obtained results. A very good agreement between the obtained equations and the experimental results was found. An adequate selection of involved parameters in the design can lead to very unsatisfactory design. Based on the Reliability theory the range within which the coefficient can be chosen also developed. Finally using these equations an optimal design of the system has been developed.

Quite often, steel buried pipelines exhibit local buckles due to imposed deformations, which may cause failure because of fatigue from repeated loading. When such buckles are detected in a steel pipeline, a decision must be taken whether or not to repair the buckled pipeline section. The present paper describes the experimental and numerical work conducted to assess the condition and to estimate the safety level of a buckled water pipeline crossing a river near Rotterdam, The Netherlands.

Current design guidelines for the design of thrust restraint system for the pipelines are primarily based on the geotechnical characteristics of the soil surrounding the pipeline and upon the ability of the soil to resist the unbalanced forces in the bends through a combination of frictional and passive resistances. The fact that the pipeline has to sufficiently deform in order to mobilize such resistance is often ignored in the design guidelines, including those published by AWWA. Consequently, most designers do not consider the additional axial and bending stresses induced on the pipeline from the Soil-Structure Interaction (SSI) effects near the bends, resulting in a potentially unsafe design. This paper presents finite element analysis models of a number of steel pipe bends that were analyzed, designed, and constructed in the field using thrust restraint joints. A typical project that was completed recently, consisting of horizontal and vertical bends, will illustrate the benefits of including soil-structure interaction effects in the thrust restraint system design for pipelines.

High-Density Polyethylene (HDPE) piping systems have been available since 1948. In 1955, the American Society for Testing and Materials (ASTM) established the Plastics Pipe Committee. In 1978, the American Water Works Association (AWWA) approved HDPE for water tubes that were up to 75 mm (3 inch) in diameter. In 1990, AWWA developed the first edition of the AWWA Standard for HDPE water distribution pipes that range in diameter between 100 mm (4 inch) and 1575 mm (63 inch). In 1992, the Indianapolis Water Company, now US Filter, adopted this technology and became one of the first municipalities in North America to install water mains using HDPE. In 2004, AWWA is expected to publish a new Manual (M55) to assist municipalities and consultants in the design and installation of PE pipes. This paper will present the properties of HDPE pipes and will compare their performance to other materials as related to environmental protection, seismic resistance, corrosion and chemical resistance, durability and reliability, and applicable Standards and Manuals. Relevant case studies will be presented to demonstrate the use of PE pipe for municipal and industrial clients.

In January 2004, the City of Corona, California started construction on the first phase of its recycled water system. Upon completion, annual average recycled water deliveries for landscape irrigation and groundwater recharge will roughly equal 7.1 million m³/yr. The first phase of improvements will entail approximately 44 km of PVC and ductile iron pipelines ranging from 152- to 610-mm diameter, largely within existing roads with limited space for new utilities. Because of the configuration of the system, operating pressures in some reaches will exceed 1380 kPa. Design of recycled water pipelines required significant effort to identify and locate existing utilities within the rights-of-way. The $32 Million improvement program also includes construction of modifications to the existing wastewater reclamation facility, two new pumping stations with surge control systems, three new pre-stressed concrete reservoirs (15,100, 7,600, and 3,800 m³ capacities), jack-and-bored crossings at railroads and major utilities, and two pressure reducing stations.

The Howard P. Curren Advanced Wastewater Treatment Plant (HFCAWTP) produces high quality water that historically has been largely discharged to Hillsborough Bay. In the past, the general demand for treated wastewater was low, as potable water sources were plentiful and relatively inexpensive. This paper summarizes the study of the feasibility of delivering reclaimed water to the Tampa regional area. The paper addresses supply and demand issues, infrastructure issues, and describes procedures used in selecting routes for over 37 kilometers (20 miles) of transmission pipelines up to 1200 mm (48 inches) in diameter. The paper also describes the regional partnerships that are being developed to provide viability to this project.

Shallowly buried pipelines may exhibit large deformation as a result of traffic loading, especially since the stress concentrates at the crown of the pipe. In this paper, numerical analysis was conducted using distinct element method to investigate the behavior of shallowly buried flexible pipe due to traffic load. The pipe examined was of diameter 2000 mm and backfilled with gravel. As a new technique for dispersing traffic loads under shallow cover depth, an installation method utilizing sandbags in the backfill materials was explored. The results indicated that the stress acting on the top of the pipe was distributed by the sandbags.

The Cutzamala aqueduct is one of the main works constructed to provide water to more than 6 million residents of Mexico City. The buried aqueduct comprises prestressed concrete pipes of 2.50m (99in) of diameter. The main components of these pipes are a steel cylinder embedded in two concentric rings of concrete; prestressed steel wires wrapped on the exterior concrete liner and an exterior coating of mortar. Failure of two buried prestressed pipes in the aqueduct occurred last year. An afterward inspection showed that some more pipes were showing important levels of corrosion, particularly that related to the prestressed wires. These facts prompted the development of technical studies oriented to evaluate the possible causes of failure, particularly those associated to the loss of prestress, due to corrosion of the prestressed wires. In this paper, the methodology used to predict failures of pipes when subjected to service loads under a progressive loss of prestress forces is described. The analysis used to evaluate the failure process of pipes when the prestressed wires loosestheir strength capabilities is presented, as well as 2D and 3D finite element models of the buried pipe, that were used to simulate different load conditions and distributions of prestress wires. Finally, a criterion for evaluation of failures of prestressed concrete pipes is proposed.

The Homestake Water Project is a pipeline jointly operated by the City of Aurora and Colorado Springs in the state of Colorado. In late 2003, Homestake identified the need to increase the pipeline's throughput from 382 million 1/d (101 mgd) to 447 million 1/d (118mgd) in order to satisfy increased end user demand. The consulting engineers, Black & Veatch, were charged with determining the stability of this pipeline and its ability to withstand increased pressures, as a result of the increased flow. In this case study we present and discuss how a combination of two condition assessment technologies, Remote Field Eddy Current / Transformer Coupling (RFEC/TC) and Acoustic Emission Testing (AET), were able to provide Homestake with high value information that established the risk of raising the pipeline's operating pressure. The two pronged condition assessment program involved establishing the baseline condition of the pipeline using RFEC/TC and continuously acoustically monitoring the line while changing its pressure to determine what effect, if any, the pressure tests had upon the structural integrity of the line.

The world's largest Prestressed Concrete Cylinder Pipe (PCCP) project is owned and operated by the Great Man Made River Authority (GMRA). Since it conception in 1984 the project has grown to include almost 4000 km (2,485 miles) of large-diameter prestressed concrete pipe. Eventually over 6.0 million m3 (5270 acre-feet) of water will be conveyed every day from aquifers in the desert to the coast in 4m (157 inch) diameter PCCP. The management of such a pipeline requires state of the art inspection tools coupled with a focused engineering strategy. This paper will describe the current condition assessment program and long-term management strategy developed by GMRA. Emphasis will be placed on the role of acoustic monitoring in condition and risk assessment of the pipes.

Concrete pipes are being effectively used to transport large quantities of fresh water and sewage over long distances. The deterioration of concrete in a pipe is a result of several degradation mechanisms that can lead to a shortened product life or loss of structural integrity. The integrity of these deteriorated pipes can be evaluated using non-destructive techniques such as the impact echo method. This paper presents the results of a study to evaluate the integrity of deteriorated thin walled concrete pipe with and without an epoxy coated liner. A methodology is developed to map the P-wave velocity throughout the pipe and to get qualitative information about surface opening cracks, honeycombing, and delaminations. The concrete to epoxy interface was also of interest. The pipes used in this study had a thickness varying from approximately 57 to 75 mm (2.24 to 2.95 in.). Impact echo tests were performed from both the outside and the inside of the pipe. The response obtained from impact echo tests on concrete pipes is more complex than for other concrete structures such as slabs because pipes are a bound structure. Therefore it is important to filter the strong low frequency peaks and optimize the frequency input from the impactor to detect the wall thickness, epoxy coating thickness and depth to any fault within the pipe wall. Research continues on various intact, damaged, epoxy coated and uncoated pipes. The experimental results to date are encouraging and the feasibility of evaluating the integrity of concrete pipe by scanning the pipe with impact echo is demonstrated.

During the failure investigation of a 2.59 meter (102 inch) diameter prestressed concrete cylinder pipe (PCCP) sewer force main, petrographic examination of mortar coating samples revealed that the protective qualities of the coating had been environmentally degraded by exposure to acidic soils. While the mechanisms of carbonation of PCCP from atmospheric carbon dioxide in the form of carbonic acid attack are well documented, relatively little information is available on the effects of acidic soils on PCCP mortar coating. Petrographic examinations of mortar coatings exposed to acidic soil is presented along with discussion of the mechanisms involved in the coating deterioration.

In March 2003, the Middlesex County Utilities Authority (MCUA) experienced a rupture of their 2.59-meter (102-inch) diameter prestressed concrete cylinder pipe (PCCP) Sayreville Relief Force Main. A previous failure of the pipeline in 1983 was due to hydraulic surges exceeding the design strength of the pipe caused by power loss to the pumping station. The 2003 burst was the first PCCP failure in the MCUA system attributable to environmental degradation of the pipeline. Subsequent to the pipeline burst, MCUA has pursued a proactive condition assessment and pipeline management program to mitigate the potential for future pipeline failures. Comprehensive failure investigation, condition assessment and monitoring programs are being implemented for the Sayreville Relief Force Main. Failure investigation of the March 2003 event concluded that the most probable root cause of the pipeline failure was environmental deterioration of the pipe caused by reactions with acidic soils in combination with failure of the hydrogen embrittlement sensitive wire. Environmental testing is being conducted to determine if the soils are aggressive to PCCP along the entire pipeline alignment. Internal inspections of the entire pipeline have been conducted utilizing visual and sounding methods in combination with P-Wave^TM non-destructive electromagnetic testing to detect and quantify existing wire breaks. A SoundPrint® acoustic emission monitoring system has been installed to allow continuous monitoring of wire break events in the pipeline. Structural analysis of the PCCP under actual field loading conditions is being performed using the electromagnetic testing results as baseline wire break data. The structural analyses will be routinely updated with the acoustic emission wire break event data. Results of the structural analysis will be used to set criteria for rehabilitation or replacement of individual distressed pipe sections.

The Elizabethtown Water Company (EWC) discovered a leak in their 1.52-meter (60-inch) diameter prestressed concrete cylinder pipe (PCCP) South Plainfield water transmission main in October 2002. Investigation of the leak determined that the root cause was corrosion of the steel cylinder where the concrete lining had been cut back to weld the joint and the lining had not been repaired. This design change was apparently made during construction as the original design called for external bell-bolted joint restraint for an adjacent 90-degree elbow. Based on the leak investigation findings, a decision was made to take advantage of the shut down to evaluate the condition and serviceability of 518 meters (1,700 feet) of the pipeline isolated for the leakage repairs. The investigations conducted and the subsequent pipeline rehabilitation techniques employed on the South Plainfield 1.52-meter (60-inch) PCCP are presented as well as current program efforts to monitor and assess the overall condition of PCCP pipelines in the EWC system.

Thames Water Utilities Limited is the largest water company in the United Kingdom, providing 2600 million litres of treated water for its 8 million clean water customers and treating 4200 million litres of sewage daily for its 13 million waste water customers, in London and across the Thames Valley. Factors such as the scale of removal of sewage from customers, the age of the underground assets and how the system has developed makes Thames Water's sewer network a highly complex system. This paper presents a literature review of information available on the mechanisms and its perceived main influences. In essence, it is understood that exfiltration could potentially lead to environmental pollution, whereas infiltration could result in operational problems both in the network and at treatment works. There is little published work on issues concerned with these mechanisms and accordingly, there are obvious benefits in investigating these topics further.

The City of San Diego has approximately 480 kilometers of sanitary sewers located in environmentally sensitive areas. Many of these areas are natural ravines or canyons that provide important habitat and aesthetic value. The City is implementing a program to review each of these sewers to see whether it would be feasible to relocate the sewers out of the canyon areas. This review includes hydraulic capacity analysis, sewer condition assessment, biological habitat assessment, and evaluation of maintenance access. The process also allows for input from community groups and local residents. Through this review process, the City intends to provide cost-effective wastewater collection services while protecting San Diego's canyon areas.

This study shows that sewer Electro-Scanning is able to pinpoint pipe defects that are large sources of collection system infiltration. These defects were not located using other investigation methods. The City of Redding has used flow monitoring, television inspection, joint air pressure testing and smoke testing for infiltration assessment and location for more than 20 years. Despite repairing all detected leaks, the collection system wet weather flows were consistently 300% greater than dry weather flows. A pilot study, Electro-Scanning 7.6 km (25,000 ft) of main line sewers was instigated to pinpoint the sources of the infiltration in a sub-basin that had particularly high peak wet weather flows of 1.7 megalitre (450,000 gallons) per day. This paper describes how the Electro-Scan data was used to select twelve locations for spot repair. Photographs of some of the defects found when the pipe was exposed are included. The locations were accurate and large defects were found and repaired. After the repairs the peak wet weather flow decreased to 0.9 megalitre (250,000 gallons) per day. This paper also discusses how the straightforward Electro-Scan testing was integrated into the regular jet cleaning maintenance operations.

The San Diego County Water Authority (Authority) is a water wholesaler in southern California. Delivery of imported water is through several large diameter pipelines; up to nine feet in diameter. In keeping with the Authority's mission statement to "provide a safe and reliable supply of water to San Diego County", an extensive (over 80 miles) multi-phase project has been initiated to mitigate deteriorating Prestressed Concrete Cylinder Pipe (PCCP). One method of mitigation is for the PCCP to be relined with steel. During construction, the steel liners are subject to collapsing (buckling inward) by external pressure during grouting of the annular space between the existing PCCP and the new welded steel liner. Several methods for the design of steel liners to resist external pressure are compared to model test results. A design example is provided at the conclusion of this paper.

A 1999 report from the American Society of Civil Engineers indicated at that time that the nation's 500,000 plus miles of sewer lines had an average age of 33 years. However, many cities today are maintaining and operating collection systems with sections that are nearly 100 years old. Significant proportions of these pipe segments have well exceeded their original design life and are failing at an alarming rate. To compound the problem, the line segments in question are not failing entirely from end to end, the failures and defects are occurring at specific points within the segment and with varying lengths. In the past, excavation or open-cut methods have been universally accepted as a means to address these problems. These traditional methods for rehabilitating or maintaining services have proven to be very costly, time consuming and disruptive. In addition, the true social costs and environmental impact of this type of repair method is not taken into full account and the effects are all too often realized during the construction and restoration phases of the project. This has resulted in an ever-increasing demand for proven methods of CIPP rehabilitation, which has the capability of restoring structural integrity for a particular "point" or "section" of varying lengths in a line segment without the need for traditional excavation or CIPP lining from manhole to manhole.

The authors' paper in the Proceedings of the ASCE Pipelines 2003 Conference described use of the Cambridge University geotechnical centrifuge to simulate the loading sequence and possible deterioration mechanisms of a sewer and its soil surround, both before and after renovation by lining with cured-in-place pipe (CIPP) or `close-fit' thermoplastics pipe. The preliminary results reported referred to tests using a sand surround placed at the same initial density, and a single model liner/host pipe assembly with consistent initial lack of fit, in which the main variable was the sequence of application of a series of extreme deterioration events in the soil (formation and collapse of large voids) and the host pipe (complete loss of both flexural and compressive ring stiffnesses). The effects of traffic loading on both deep and shallow buried lined pipes were also examined. This follow-up Paper describes the outcome of further centrifuge tests in which both the initial density of the soil surround and the initial annular gap between liner and host pipe were substantially reduced in order to simulate, in conjunction with the extreme soil and host pipe deterioration events previously applied, the worst practically conceivable case for transfer of soil and traffic loads to a close-fitting, flexible sewer liner. Some basic principles and the implications of the test results for liner design practice are also considered.

This paper will discuss the City's evaluation of horizontal directional drilling (HDD) high density polyethylene (HDPE) as compared to other pipe materials and construction methods. The discussion will include the City's recent experiences on the use of the product with HDD construction on two separate projects. One project is a 20-inch water main surrounding a major urban university campus with over 30,000 students and staff. The second is a 24/12-inch water line along a major thoroughfare in a prominent commercial area of Houston. Various issues that surfaced during the design and construction, as well as the outcome of the two projects will be presented.

Horizontal directional drilling (HDD) is a frequently used option for installing polyethylene (PE) pipes for subaqueous crossings, for wetlands crossings, and for municipal pipelines in crowded urban and suburban areas. While many consider horizontal directional drilling an "art," there are engineering principles that apply and if followed will result in reliable designs. This paper discusses the engineering design of polyethylene pipe for directional-drilled installations based on the engineering interpretation and methodologies given in the Plastic Pipe's Institute (PPI) Handbook on PE Pipe and ASTM F-1962, "Standard Guide for Use of Maxi-Horizontal Directional Drilling for Placement of Polyethylene Pipe or Conduit Under Obstacles, Including River Crossing." Strengths and limitations of these methodologies are discussed in light of recent field experiences.

The goal of this review is to provide design engineers with a complete information base on various Polyvinyl Chloride (PVC) pressure and gravity piping standards and products, for open-cut and trenchless construction and rehabilitation. The contents should contribute to the decision-making process for standard and product selection when PVC has been specified or is under consideration. Various trenchless pipe construction methods, such as horizontal directional drilling (HDD) and sliplining, are briefly discussed, followed by information on available PVC options. Different types of PVC pipe, as well as advantages and limitations of PVC, are given. Trade names of proprietary products are omitted and replaced with letter designations, to prevent commercialization.

Governmental Accounting Standards Board Statement 34 (GASB 34) sets new requirements for reporting operations and capital assets. It is requiring local government entities to create an inventory, and assess the condition, of all municipal assets. The documentation resulting from this undertaking will be utilized by lending agencies to determine asset management capabilities and the resulting financial rating of the entity. Future lending decisions will be based upon the complete itemization of the inventory appraisal. In addition to obvious assets such as roads, bridges, buildings, furniture, vehicles and equipment, unseen assets make up a significant portion of a municipality's asset base. Underground utilities are critical assets that must be assessed and recorded. Sanitary sewer pipelines, manholes, pump stations, storm sewer pipelines, catch basins, inlets and waterlines are among the utility assets a municipality owns, operates and maintains. This paper will present case studies where field inspections were utilized, in conjunction with condition ranking classifications, to create an inventory of sanitary and storm sewer system assets. Data obtained and summarized was utilized to develop a prioritization of defects for a phased replacement/rehabilitation plan of action.

A section of 1,448 mm (57 inch) semi elliptical sewer with a concrete base and brick arch was removed from the City of Los Angeles North Outfall Sewer. This paper describes the condition of the sewer with results of testing conducted on it. Additional testing was conducted on masonry removed from a special junction structure in the sewer. Future rehabilitation plans for portions of the North Outfall Sewer are presented.

The City of San Diego has embarked on a ten-year program to reduce sanitary sewer overflows (SSO's) in its 4,828 kilometer (3,000 mile) collection system by replacing, rehabilitating and repairing sewer pipes that are susceptible to overflows. An important component of this program is a plan for inspection and condition assessment of the City's sewer assets. The City has scheduled close-circuit television (CCTV) inspection for approximately 1,900 kilometers (1,200 miles) of pipe, as well as detailed inspections for approximately 26,000 manholes. As the inspection program nears completion, the City is able to report on the successes and challenges of its inspection program. This paper will discuss the factors that have made the assessment program run smoothly and point out some changes that were made to overcome obstacles.

The HubLine Pipeline project included the marine construction of approximately 46.7 km of 762 mm diameter pipeline in Massachusetts Bay from Beverly to Weymouth. At two critical segments, Horizontal Directional Drilling (HDD) was employed to avoid conventional construction in scenic Beverly Harbor and near historic Georges Island under a busy shipping channel. Past HDD projects have faced hard rock, large diameters, and long lengths. Several have been installed from barges into the seafloor. However, no two crossings have ever had such a challenging combination of these factors. The bores exceeded 1,280 m. Water depths were over 13.7 m with 3.7 m tidal fluctuations and exposure to the North Atlantic Ocean. The compressive strength of the rock ranged from 58,610 kPa (8,500 psi) to greater than 275,800 kPa (40,000 psi) These HDD installations have set a new standard for "state of the art" in a marine environment.

Pipeline crossings occur where an underground pipeline crosses over a waterway or other geologic depression instead of boring below the water or valley. One means of bridging the gap is by using cable-supported structures to carry the overhead pipeline from one side to the other. These structures typically are comprised of two tower frames, supported by concrete foundations, from which two main catenary cables are hung across the span with backstay cables anchored into the ground. Suspender cables hang vertically from the main cables, terminating at pipe hangers that directly support the pipeline. After many years of constant use, with only minor maintenance, these structures should be inspected to assess their current condition and determine their remaining useful life expectancy. Without this information, a potentially catastrophic scenario may unfold involving the full or partial collapse of the supporting structure and the potential for a breach in the pipeline. This paper illustrates the field inspection of cable-supported overhead pipeline crossings and the prioritizing of these structures for future maintenance program upgrading. Specialized inspection reports were developed for these structures, comprised of an inspection summary, digital photographs, completed field inspection forms (Microsoft Access database), structure inventory and appraisal data, sufficiency rating calculations, and maintenance recommendations. The overall results of this project will culminate in a manageable structure assessment plan.

This paper describes how and why a 3300-ft, 30-inch diameter, inverted siphon was constructed in a fast-track manner to convey sewage across the Ventura River. Construction included a combination of horizontal directional drilling and pipe ramming techniques. A particular challenge was getting through alluvial material in the riverbank areas, which are composed of loose sands, gravels, cobbles and boulders, to the more stable mudstone bedrock beneath. Regulations effectively prevented the drilling of exploratory holes within the river prior to construction. An innovative approach to gathering geotechnical data provided invaluable information to design engineers and bidders. Other design, contracting, and construction issues and hurdles are discussed.

The Dominguez Gap Seawater Barrier Project is part of a Los Angeles County Department of Public Works (LACDPW) project designed to limit the intrusion of seawater into the West Coast groundwater basin. The project involved the design and construction of approximately 2,130 m (7,000 ft) of parallel pipelines including steel water pipelines, stainless steel compressed air pipelines, electrical and telemetry conduits, and a PVC gravity drain pipeline. The pipelines connect to groundwater injection wells and provide water for injection, air for juttering and lifting of wastewater during periodic well redevelopment, and a gravity drain line for removing the wastewater from well redevelopment. Approximately 885 m (2,900 ft) of the pipelines were installed as abundle inside a 1370 mm (54 in) casing. The casing was installed using microtunneling and pipe jacking methods to avoid impacts to traffic along busy streets and an existing container facility. Approximately 460 m (1,500 ft) of the drain line was installed separately using pilot tube microtunneling methods in drive lengths over 80 m (270 ft). At each injection well, the pipelines were routed up the walls of an access manhole and connected to the well vaults that were constructed under a previous contract. Key design and construction challenges included installation of the pipeline bundle inside the casing; maintaining grade of the drain pipeline within the casing; corrosion protection of the steel pipelines, and vertical and lateral support of pipeline in the manholes.

Polyurethane based coatings are used to protect concrete facilities against corrosive environments. The performances of two commercially available polyurethane coatings were evaluated under sulfuric acid environment for over five years. Both a dry application (representing new construction) and a wet application (representing rehabilitation) concrete were used in this study. It was necessary to use a combination of full-scale, bonding and chemical resistance tests for evaluating coatings to protect concrete structures below ground water. Full-scale test facilities were used to evaluate the performance of coatings under hydrostatic pressure and to simulate underground concrete structures below ground water. Visual inspections and in-situ bonding tests were performed. Test results showed that bonding strength of one coating was affected by the moisture condition and hydrostatic water pressure in the full-scale test. Coated cement concrete specimens with pinholes were used to study the chemical resistance of the coated concrete under acidic environment to represent the worst sewer condition. Change in weight of coated concrete specimens was measured at regular intervals. Types of failures in coated concrete under acidic environment have been identified. Test results showed that the performance of the two coatings were noticeably different and one coating with pinholes extended the service life by 14 time while the other by 57 times. There was no direct correlation between bonding strength and chemical resistance of coated materials. Although both coatings were polyurethane based, their performances were different under the testing conditions adopted in the study.

The Manning Equation is an empirical formula commonly used for the design of sewer systems. This equation is also used to describe the performance of existing sewer systems by evaluating flow monitoring data using a variety of scattergraph methods. Scattergraph methods are classified as comparative or regressive methods, and each method applies a specific set of assumptions to the Manning Equation. An overview and comparison of one comparative method and two regressive methods are provided in this paper, including the Design Method, the Lanfear-Coll Method, and the Stevens-Schutzbach Method. The proper selection and application of these methods have a significant impact on the calculation of sewer capacity, the evaluation of sewer performance, and the allocation of critical resources for system planning, operation, and maintenance. Examples of each scattergraph method are provided from flow monitoring locations throughout the United States. Laboratory research by the authors is also provided to further explore the performance of these methods and provide guidelines for their proper application.

This paper presents an overview of the design-build of the New Mississippi Tunnel Outfall for the Transportation Expansion Project (T-REX). The Contractor was Southeast Corridor Constructors (SECC), a Kiewit-Parsons, Joint Venture. Parsons acted as JV partner as well as designer and provided a unique perspective in the design build setting. The Transportation Expansion Project's New Mississippi Outfall is a $30 million constructed value project. This is a small but important part of the 1.2 billion dollar highway widening and Light Rail Transit (LRT) expansion project of Denver's Interstate Highway I-25. The Outfall conveys highway and other urban drainage to the South Platte River as well as provides long needed relief from flooding problems in the southeastern portion of the Interstate 25 highway corridor. The Outfall tunnel conveys storm water under I-25 then under Mississippi Avenue to the river. The Outfall consists of a number of distinct elements with water flowing and connecting from east to west as follows: an Energy Dissipation Structure, 91 m of 213 cm diameter jacked pipe crossing under I-25, Junction Interceptor Structure, 554 m of 4 m ID tunnel excavated by earth pressure balance machine technology, a Transition Structure (connecting the circular section to a rectangular section and serving as the main tunnel driving shaft), 266 m of 5.5 m wide by 2.4 m high cut and cover box structure, and Outfall Structure at the South Platte River.

This paper presents the design concepts and a case study of the advantages of design-build construction for the Olivenhain Pump Station Surge Pipeline. The owner is the San Diego County Water Authority (Water Authority). The Contractor is Kiewit Pacific Co. (Kiewit) and the designer is Parsons Water and Infrastructure Group (Parsons). The Olivenhain Surge Pipeline is an important part of the Olivenhain Pump Station (OLVPS) project because it will allow for full design flow to be pumped to the Water Authority's Second Aqueduct. The following items are a few of the advantages of design-build construction for this project: (1) Negotiating a design-build contract significantly reduced the time (by six to eight months) to have the surge control facility operational. (2) The entire Olivenhain system (dam, pump station, and pipeline) will be fully operational, allowing full delivery of emergency water to member agencies, by summer 2004 rather than winter 2004/2005 (Schuler, 2003). (3) The contractor was familiar with the onsite requirements and the sensitivity of the community thus reducing impacts to the site and surrounding community.

This paper presents the design-build pipeline case history and lessons learned on the cooling water for the power plant expansion in Rosarito, Baja California Mexico. The Owner is Alston Power and Comision Federal de Electricidad (CFE). The Contractor is Meisener Marine and the designer is Parsons Corporation. The cooling water intake pipeline for the Rosarito Power Plant consists of 710 m (2,330 ft) of 2.9 m (9.5 ft) seafloor Prestressed Concrete Cylinder Pipe pipeline and five 2.4 m diameter intake heads as well as three maintenance access points. The intake is constructed in a seafloor trench with various armor rock sizes and tremie concrete armor. The main challenges included construction during high Pacific winter storms and the associated temporary cofferdam works. The main design challenge was configuring the intake to avoid sediment and air intrusion due to wave actions. This paper summarizes the design and construction challenges in the design-build setting.

This paper will discuss the current design practices for the primary water transmission products in the Central and Eastern USA: concrete pressure pipe, ductile iron pipe and steel pipe. It will detail a more efficient approach to the design of the pipe materials and the preparation of equal alternate specifications. Today, the concrete, ductile iron, and steel industries all utilize the Pressure Class Design approach. The differences in the design of the three products will be demonstrated using consistent performance criteria as established in the specifications. American Water Works Association (AWWA) design and installation manuals M-9, M-11, and M-41 cover concrete pressure pipe, steel pipe, and ductile iron pipe respectively. The products are also covered by AWWA manufacturing and quality assurance standards. Utilizing these standards in a project's design specifications capitalizes on the hours of work and knowledge already invested by industry peers. This paper will demonstrate the Pressure Class Design approach procedures and provide useful tools for engineers and owners in the design and specification of water and wastewater transmission lines.

This paper will review the design conditions of three flexible waterlines. All the projects were uniquely designed to economically supply the pipe using some form of modified soil backfill. The projects have all been built and the installed results of the design will be reported. The advantages were varied and resulted in cost savings for the owner. The pipelines represent two projects in Colorado and one in California. One project in Colorado was designed to use the native soil because disposal was a major cost. Another project in Colorado was designed for time constraints. The project in California was designed because of a limited right of way.

This paper discusses the causes, affects and remedies for excessive deflection of cement mortar lined and coated welded steel pipe during installation. A case study will examine the installation of 1,350 mm (54-inch) diameter cement mortar lined and coated welded steel pipe constructed on the Moreno Lakeside Pipeline project for the San Diego County Water Authority. Of primary concern is excessive cracking and delamination and the long-term integrity of the mortar lining. Contract specifications for installation will be analyzed paying particular attention to stulling procedures as well as backfill and compaction methods. The affects of in-situ and backfill soil characteristics will also be examined. When excessive deflection is experienced, field investigations are necessary to determine the extent of the damage. Once damaged areas are identified, repair methods need to be assessed. The Moreno Lakeside Pipeline is currently under construction and will be used to illustrate some of the pitfalls that may be encountered with excessive pipe deflection as well as the remedies considered to provide for the long term integrity of the pipeline. This paper will present case data that will assist in future design and installation of cement mortar lined and coated welded steel pipe.

The 7.24 km (4.5 mile) long Olmsted Flowline is a vital link in the Central Utah Project's (CUP) Municipal & Industrial (M&I) System. The Flowline originally served only as a hydroelectric penstock from 1912 through the 1980's. At that time its water began to be used for M&I demands. To protect the increasingly critical M&Ide liveries, the Flowline's O&M responsibilities were transferred to Central Utah Water Conservancy District (CUWCD). In the 1980's two additional M&I aqueduct pipes, the Alpine and Jordan Aqueducts were built to deliver M&I water from the Olmsted Flowline downstream to two recently constructed water treatment plants (WTP's) serving northern Utah and western Salt Lake Counties. In the late 1990's, the Flowlineand the downstream aqueducts began to approach their capacity. Concurrent needs to solve ongoing reliability problems of the 50-year old, 2,590 mm (102 inch) pipe, resulted in a study to evaluate how best to provide both the capacity and reliability for the Flowline downstream delivery system. This paper addresses unique capacity and system flexibility issues addressed in the planning and design of the Olmsted Flowline Replacement/Rehabilitation Project.

This paper will discuss the derivation and publication of the "Iowa Formula, Spangler" (1941), and it's later modification by Watkins. In use today by many publications, the modified Iowa Formula, was derived to predict ring deflection of flexible culverts, and is currently being misused as a design equation to determine wall thickness of pipe materials. The Iowa Formula demonstrates the importance of the soil on ring deflection. It over-predicts ring deflection because compression of sidefill soil is not uniaxial and elastic; but, rather, is a biaxial compression of particulate soil. The Iowa Formula for predicting ring deflection was not intended for the design of the pipe wall thickness. On the contrary, it shows that ring deflection is primarily a function of the soil embedment, not the ring stiffness of the pipe. Moreover, the properties of soil are imprecise. Published USBR values of an elastic soil modulus are based on back-calculations of the Iowa Formula from ring deflections of existing installations all of which disregard height of soil cover. This simplification proliferates the severe conservatism of the Iowa Formula for pipe wall thickness design. Because of the importance of wall thickness in the economic design of pipeline systems, proper analysis of embedment should be optimized for structural performance and costs. The intent of this paper is to analyze the variables in the Iowa Formula based on the original intent and to give guidance to its use for pipeline design. Alternate methods of analyses will also bepresented, based on fundamentals of engineering mechanics and correct properties of materials.

Alternative contract delivery methods continue to gain popularity as a method to reduce the overall cost of construction or reduce schedules. Many owners are now regularly selecting methods such as design-build, engineering procurement construction (EPC), construction management at risk instead of a conventional design bid build process. This paper will discuss through actual case studies the use of alternative design and construction methods as it has been applied to pipeline and trenchless projects. Insight on the appropriateness of each of the methods will be shared including past successes and lessons learned.

Water transmission pipelines and pump stations are critical to the success of any water utility. Typically, water transmission systems must be operational 24/7 to maintain service to large segments of the distribution system. Additionally, water transmission systems often make up the largest capital, operational, and maintenance costs of the utility. Therefore, getting the highest value for the design and construction of water transmission projects is critical to the overall success of any utility. This paper describes innovative value concepts used by the author on dozens of raw water and treated water transmission projects. This paper also compares projects that used the value concepts with other projects that did not. The comparison shows that the value concepts can save as much as 50 percent of the capital costs.

The conventional method of pipeline construction has been the traditional open-cut method. The advancement in technology over the recent years has led to trenchless pipe construction and renewals. However, the local government agencies, design and consulting engineers and municipalities are slow in recognizing the trenchless technology cost benefits compared to the traditional open-cut method. This is mainly due to initial construction costs of open-cut which might be lower, but a comparison of the life-cycle-costs between the open-cut and trenchless pipeline construction would reveal the real costs of both methods. This paper presents an investigation of cost-effectiveness of constructing underground pipelines with trenchless method in urban centers with cost of conventional open-cut method. The study includes a breakdown of the engineering and capital costs of the construction and the social costs for both methods. An analysis of factors for a decision making process are presented.

It has been widely reported that this country's infrastructure is in need of a serious overhaul; this includes drinking water systems, many of which are now considered to be approaching the end of their useful life. Complete replacement of such assets would be the preferred option but budget and construction constraints make this unrealistic. Water quality and hydraulic requirements will not reduce though, so the system owner is left with the balancing act of providing maximum benefit to customers at minimum cost. Rehabilitation of water mains can extend the operational life of the asset at a reduced cost but the Engineer needs to consider taking a rational approach to identify projects that are justifiable and beneficial. Development of a mains rehabilitation strategy will enable prioritization of the distribution network with an auditable expenditure profile. This enables the Engineer to cost-effectively target defined areas of long term need rather than operating an expensive reactive program which will only provide short term benefit. This paper describes how successful water mains rehabilitation strategies have been developed in particular referring to a project carried out with New Jersey American Water, and how it should become a key part of an asset management plan. It will outline the key elements of the strategy and how it can be flexible to suit the needs of any utility without compromising output.

Pipeline systems deteriorate over time. The deterioration can result from damage caused by adjacent construction activities, weather, ground movement, loss of ground support, degradation of materials, or vandalism. Regardless of the reason, the condition of the pipeline infrastructure must be managed so that a desired level of service can be maintained. This requires an appropriate amount of reinvestment at the right time. This paper discusses various aspects of reinvestment planning including system characterization, condition assessment, and application of life cycle models to assist utilities with their pipeline reinvestment planning.

Prestressed Concrete Cylinder Pipe, PCCP, (AWWA C301), is a rigid, pressure pipe, designed to take advantage of the compressive strength and corrosion-inhibiting properties of portland cement concrete and the tensile strength of steel. Principally used for the transmission and distribution of water in municipal systems, it was widely accepted and installed throughout the US beginning in 1942. Numerous catastrophic failures across the nation have halted the use of PCCP by numerous water agencies throughout the US. Due to the large diameters and critical nature of these pipelines, the San Diego County Water Authority embarked on a twenty-year plan to reline or replace nearly 112 km (70 miles) of large diameter PCCP. This paper describes the methods of manufacturing and installing the steel liner plates to reline existing PCCP. The project consists of relining sections of a 2438 mm (96in.) and 1753 mm (69in.) pipeline. This paper will describe the unique methods of collapsing the steel cans and the rapid installation requirements required by the owner. Cooperation between the agency, manufacturer, and contractor was essential for the completion of this project on slopes as great as 38 percent. The design and installation of this liner system allowed for a minimum reduction in hydraulic capacity.

This study experimentally and numerically investigates the load deformation characteristics of fiberglass pipes. Fiberglas pipes of 400 mm and 600 mm diameters were fully instrumented and loaded. Load cell, LVDT, strain gauges and data logger were used. Two sets of strain gauges, each consisting of five gauges, were attached inside and outside pipe circumferential line at 22.5° interval. Displacement controlled loading machine of 10-ton capacity was used to impose line load at rates of 1 to 10 mm/min. Results indicate that, rate of loading has no effects on the stiffness of fiberglass pipes. Nonlinear 3-D finite element analysis program (Z-Soil) was employed. Experimental results were simulated using Hoek-Brown model. It has been shown that, linear elastic prediction can capture pipe load-deformation response up to 5% vertical deflection. Advanced Hoek-Brown model further accurately predict deformation up to 10%. The calibrated numerical tool and the refined material parameters were used efficiently and realistically for further modeling and analysis of staged excavation and backfilling of buried fiberglass pipes. Beam and contact elements were utilized. Results show bending moments, contact stresses, deformations, stresses, and strains maps. Pipe deflection increases with burial depth, then arching effects predominant at large coverage. Acceptable small deformations were obtained under simulated common operational and environmental conditions.

This paper discusses the design aspects of fiberglass pipeline design which are either inadequately or not addressed in either AWWA Manual M45—Fiberglass Pipe Design, or AWWA Standard C950-01—Fiberglass Pipe. The experience from the design and construction of the Owens Dry Lake project, purportedly the largest application of fiberglass pipe in the world, is discussed, with specific recommendations for design for the water industry use filament wound.

Finite-element, soil-structure interaction analysis is used to calculate moments and thrusts in concrete pressure pipes installed in concrete cradles. The results show that the previously published results are incomplete for pressure pipe design and sensitive to assumptions that cannot be justified. The results of the finite-element soil-structure interaction analysis show that internal pressure produces significant bending in the wall of a pipe installed in a cradle. Although earth load on a pipe in concrete cradle can be much larger than that for the same pipe without cradle, especially for shallow cover depths, cradles can significantly reduce the bending moments in the pipe wall, and allow pipe installation in very deep covers.

Behavior of flexible PVC pipe with sand backfill material was investigated in a soil box, which represented the trench condition. Test was conducted using a pipe with a SDR of 55 to determine the load-deflection relationship during construction and service under incremental loads. During the test, pipe deflection, in-situ soil stresses, and strains on the pipe wall were measured. The sand used as backfill material had a maximum and minimum dry density of 17.6 kN/m³ (112 lb/ft³), and 15.4 kN/m³ (98 lb/ft³), respectively. Tests were performed at a relative density of 65% with a maximum surface vertical stress of 770 kPa (112 psi). Measurements were taken during backfilling and surface pressures were applied. Compressive strains developed in the pipe when surface loads were applied. Pipe material properties, soil box dimension, sidewall and soil-pipe interface friction angles were important parameters in predicting the pipe deflection and stresses in the trench using the finite element method.

HDPE pipes are being installed as buried conduits at an increasing rate. HDPE pipes are lightweight and resistant to corrosion and abrasion. Because HDPE pipes are flexible, the soil embedment is a major component of the conduit. To assure adequate pipe stiffness, corrugated and profile wall pipes are becoming available. Design is based on pipe-soil interaction using fundamental principles of pipe and soil mechanics. This paper examines performance, performance limits, and suggests design procedures for typical installations.

The City of Newark, New Jersey is experiencing significant development. Transportation infrastructure improvements include the reconstruction of State Route 21 by the New Jersey Department of Transportation (NJDOT). The project is located in a highly urbanized old section of the city with utilities installed continuously since the 1800s. Approximately 75,000 meters of existing utilities, including sewer, water, gas, electric, telephone and various communications systems, are located underground. Procedures presented in CI/ASCE 38-02, Standard Guideline for the Collection and Depiction of Existing Subsurface Utility Data were initiated early in the design process. This yielded an accurate horizontal and vertical location for existing utilities that allowed the design to identify and avoid most potential conflicts.

Plaguing the overwhelming number of projects dedicated to servicing and updating the nation's aging and increasingly congested infrastructure, the seemingly unavoidable delays due to utility complications continue to retard progress and emaciate already tight budgets. Subsurface utility engineering (SUE), the branch of engineering that specializes in utility identification, location, and advising, is quickly becoming the modus operandi for transportation departments nationwide. It is over twenty years old and yet no organizational system has been widely applied to harness the full potential of SUE. Conflict analysis is an organizational tool for SUE. Working with utility companies, designers, transportation departments, and contractors and employing a powerful new data management tool, the Conflict Matrix, conflict analysis provides a greater sense of coordination. The coalescence of SUE and conflict analysis, though a young concept, is beginning to reshape the industry. With this intimate connection, data transmission and management work in tandem, resulting in very little data loss and confusion. Higher data efficiency in turn propagates fewer missed conflicts. The potential of savings becomes obvious. By merging symbiotically to become one integrated entity, SUE and conflict analysis form the nexus of proactive utilities management that efficiently reduces needless utility relocations, minimizes utility complications, and diminishes overall cost.

ASCE/CI 38-02 applies to projects where existing utilities will be impacted and requires that the project approach used by engineers be modified in order to conform to the standard. The ASCE Standard 38-02 "Standard Guideline for the Collection and Depiction of Existing Subsurface Utility Data" provides much useful information. However, in order for the standard to realize its full potential, owners, designers and contractors must know how to best use the information provided. Intelligent use of the standard and appropriate incorporation of subsurface utility engineering (SUE) services will result in better designs and enhance damage prevention efforts. This paper/presentation will review the Standard Guideline and then proceed to discuss how to incorporate it and SUE services into an airport project. Also addressed will be maximizing the benefits of ASCE/CI 38-02 and Safety concerns.

Several factors may contribute to the structural failure of cast/ductile iron water mains, the most important of which is considered to be corrosion. The ANSI/AWWA C105/A21.5-99 10-point scoring (10-P) method is the most common method used to predict soil corrosivity potential, which is based on soil properties. For a given soil sample, each soil property is evaluated for its contribution towards the corrosivity of soil. The 10-P method uses binary logic to classify the soil, either as corrosive or non-corrosive. Fuzzy logic extends the binary logic in this context as it recognizes the real world phenomena in which each property has certain degree of membership between 0 and 1. The main objective of the present research is to develop a fuzzy logic expert system capable of establishing a criterion (such as corrosion rate or breakage rate) for predicting the deterioration of cast/ductile iron water mains using soil properties. The proposed expert system includes a fuzzy model consisting of a series of IF-THEN rules to determine soil corrosivity potential (CoP) based on soil properties. The fuzzy model contains the data of linguistic variables (database) characterizing various soil properties, and a rule base that constructs relationships among those properties and CoP. Subsequently, the expert system uses a linear regression model to link CoP to the deterioration rate of metallic pipes. A case study on cast iron pipes is examined to illustrate the application of the proposed expert system.

This paper describes two significant unexpected corrosion failures of Las Virgenes MWD facilities. The first failure was a 61-cm (24-inch) influent force main at a wastewater treatment plant from "grooving corrosion". The second failure was of a 20.3-cm (8-inch) sludge force main from "microbiological induced corrosion." In each case the failures were completely unexpected and resulted in significant damage and expense. The history of the facilities, failure mode, resulting damage, repair strategies and lessons learned will be discussed. This paper is intended to illustrate how unexpected corrosion failures can result in significant damage and expense. The focus is from the viewpoint of an owner/operator rather than a corrosion engineer but will address the need for owners and operators to understand the potential of unexpected corrosion failures and their impacts.

The results of a two-year study of corrosion and corrosion protection characteristics of ductile iron pipe are presented. Included are field and laboratory evaluations related to short term and long term polarization rates under varying conditions, corrosion rate reduction and corresponding cathodic current criterion, and the corrosion protection benefits of the traditional standard asphaltic shop coating. This information was then analyzed in conjunction with an extensive database from 1379 physical inspections of buried iron water lines. The result of the study is a risk-based corrosion protection design strategy for buried ductile iron pipelines.

The Ductile Iron Pipe Research Association (DIPRA), formerly the Cast Iron Pipe Research Association, has conducted research on iron pipe since 1928. The majority of this research has dealt with corrosion and corrosion control of gray and ductile iron pipe. The Association has conducted over 115 corrosion related research projects involving thousands of actual production pipe specimens. In addition, almost 300 inspections of in-service pipelines have been conducted along with other related inspection investigations. This paper presents the analysis of a large data base derived from the test programs and in-service inspections that pertain to bare, sandblasted, shopcoated and polyethylene encased gray and ductile iron pipe. A statistical analysis of the data is also presented with respect to corrosion rates of iron pipe in a variety of different soil environments.

Coating of Ductile Iron Pipe (DIP) for buried water mains has been and continues to be a contentious subject. Considerable number of corrosion engineers and civil engineers take exception to the claim that effective protection of DIP can be achieved economically by wrapping the pipe in loose polyethylene. There seem to be as many reports of failure as success. The authors recently completed a three-year study of external corrosion of water mains, under the auspices of the AWWA Research Foundation. One of the conclusions in the study is that polyethylene encasement (more familiarly "baggies") can be an effective system for protection of DIP water mains in many environments. However, there needs to be additional attention to design and installation beyond that described in the relevant national standards. Polyethylene Encasement is discussed in AWWA Manual M41 "Ductile Iron Pipe and Fittings." AWWA Standards C105-99 "Polyethylene Encasement for Ductile-Iron Pipe Systems" and C600-99 "Installation of Ductile-Iron Water Mains and Their Appurtenances" reflect the current ductile iron pipe industry understanding about what should be used for corrosion protection for their product. Unfortunately, should additional protection from what may be afforded by such installation be needed by the use of other protection systems (coatings), the ductile iron pipe manufacturers will refuse to bid your project. Ductile iron pipe has many characteristics that make it desirable for waterworks use. But it will corrode if buried unprotected. So if you use it, wrap the DIP in baggies, and take the additional steps that allow you to effectively monitor it and preserve your corrosion control options in the future. These steps detailed in the paper include, electrical isolation from attachments and appurtenances, intentional electrical continuity at joints, corrosion monitoring stations and, if necessary, cathodic protection.

Isolation of dissimilar metals in corrosive environments using dielectric insulators is a well-accepted corrosion control principal. However, dielectric insulators have other purposes in a well-planned corrosion control program for buried metallic pipelines and piping systems. This paper describes the traditional uses of insulators in the water industry and discusses where their use is critical and where they offer only minimal benefit. The practical considerations that influence the selection of the type, location, method of installation and level of testing are presented. Isolation concepts and practices in other industries are also briefly discussed.

Corrosion impacts water systems in many more ways and to a far greater degree than many of us regularly consider. The construction of water systems is frequently financed through public revenue bonds with a 30-year term. The systems are often designed for a minimum 40-year life, but neither the financial projections nor design life adequately account for the impact of corrosion. Expensive repairs and replacements of system components can financially cripple the water operator, and directly cost the consumer far more than necessary for an inferior product. An infrastructure study in New York determined that the direct cost of leak repair for the Water Supply Bureau was $7,323 per failure. An extreme case is the City of Winnipeg, where a $7.7 million program is required to reduce the leak frequency to 2200 annually, which is equivalent to 1.8 leaks/mile of pipe/year.

The Calleguas Municipal Water District (Calleguas) is a water wholesaling agency that provides water to over 500,000 customers in Ventura County, California. As a large water purveyor, Calleguas owns and operates approximately 193 km (120 miles) of pipelines ranging from 0.61 meter (24 inches) to 1.98 meters (78 inches) in diameter. Much of the largest diameter pipe is pre-stressed concrete cylinder pipe (PCCP), with the remainder primarily concrete mortar lined and coated steel pipe. Several parts of the Calleguas service area have high groundwater and highly corrosive soils. Calleguas has faced a number of corrosion and cathodic protection issues, including the failure of appurtenances on PCCP and improperly applied cathodic protection causing embrittlement of the PCCP's pre-stressed wires.

The City of Phoenix has installed over 64 kilometers (40 miles) of unlined concrete sewers ranging in size from 60- to 230-centimeters (24- to 90-inches) in diameter. These large diameter sewers are subject to flat slopes and warm temperatures which favor the conversion of hydrogen sulfide into corrosive sulfuric acid. Most of the pipelines are key interceptors where there is a high consequence of failure and all of the pipelines are over 35 years old. In order to maintain system operation, the City has proactively investigated these sewers since 1992 to assess the condition and identify rehabilitation needs. This paper identifies the unique conditions being experienced by the City's collection system and the impact that rapid corrosion is having on the life of the system.

The EPA sulfide and corrosion models can be used to evaluate sulfide related odor and corrosion potentials in sanitary sewers and structures. The models take into account the in-line biologic processes; sewer hydraulics; sewage characteristics; localized turbulence; and the sewer pipe physical characteristics to determine hydrogen sulfide odor potential; corrosion potential; corrosion rates; or the degree of corrosion protection required for aparticular gravity sanitary sewer or sewer structure. The model has proved equally valuable in predicting sewer failure locations before the failure occurs. The model may be used to evaluate the corrosion potential of a proposed interceptor sewer system prior to final design. Based on the corrosion and odor potential predicted by the models, appropriate pipe sulfide corrosion protection can be selected based on predicted risk, costs associated with potential failure, and costs of corrosion protection, for various alternative alignments and system configurations. The use of the models to evaluate design alternatives for new sewers, identify potential odor and corrosion problem areas, and to evaluate the life expectancy of existing unlined concrete sewers is discussed. The model corrosion data are an important but often ignored component in sewer condition evaluation. Using the corrosion rate information, it is possible to prioritize and budget sewer rehabilitation needs on a realistic basis, rather than more simplistic models and methods that have been used in the past. Some of these methods have resulted in multi-million dollar rehabilitation projects on sewers with a calculated remaining life expectancy of 50 years or more. In other cases, pipe failure has occurred ten or fifteen years after installation due to a lack of understanding of the sulfide corrosion process.

We were retained to investigate two failures on a 12-year old, 76.2 cm (30-inch) diameter ductile iron wastewater interceptor pipeline, termed an outfall line, that traveled across hilly terrain towards a wastewater treatment plant. In both cases, the catastrophic failure resulted in significant property damage due to the large volume of sewage that escaped from the failure location. The interior of the pipe was lined with coal tar epoxy and the claim was that the protective coating failed; purportedly the fault of the manufacturer. The pipeline contained a large siphon and the designers anticipated elevated concentrations of hydrogen sulfide (H₂S) gas generation at the outlet of the siphon; and thus, incorporated a sulfide control station at this location. The method of sulfide control was to inject liquid hydrogen peroxide into the siphon upstream of the outlet to neutralize the liquid-phase hydrogen sulfide. In an effort to reduce operating costs, far too little hydrogen peroxide was added to the pipeline resulting in catastrophic failure due to sulfuric acid attack of the coating and pipe. The crown of the pipe was essentially missing in the downstream section of the pipeline following the siphon. This type of failure and the age of the pipe coincide with changes in the regulatory framework governing wastewaters, notably, the Clean Water Act of 1980. This act resulted in a reduction in the allowable metals concentration in sewage. The net result was increased sulfate reduction and corresponding sulfuric acid production, which increases the corrosive environment within sewage pipelines. For this reason, operators need to be more diligent in protecting their pipelines from the catastrophic effects of internal corrosion.

A 36-inch (900 mm) diameter high pressure bar-wrapped concrete cylinder pipe (CCP) water transmission main for the City of Prescott, AZ was successfully tested to 500 psi pressure. This CCP pipeline utilized double-gasketed steel joints in non-thrust areas, and double-welded lap joints in thrust areas. A brief history of the steel bell and spigot joints with single and double confined gaskets will be presented. The sealing capacity of gaskets in rigid, semi-rigid, and flexible type pipe joints will be reviewed. Design concepts, procedures and gasket designs utilized to ensure the water tightness of the 36-inch (900 mm) diameter CCP joints of the City of Prescott's high pressure pipeline will be discussed. Recommendations and conclusions for the use of double gasketed joints will be presented.

Gaskets have been used for sealing pipelines for over 100-years, but the vast majority of these projects have been with O-ring gaskets for cast iron and concrete pipe. The advent of new pipe materials such as PVC, HDPE and composite products have resulted in new and more complex gasket profiles. Since most of these new pipe materials have unique cross-sections, gaskets are customized to each pipe section. There is very little information on the performance of these gaskets and their relative design in comparison to the standard O-ring gaskets. With the use of new deformation and compression testing equipment, the performance of even the most complicated gasket profile can be modeled and tested relative to its installed condition. This paper will provide guidelines for designing and testing the new gasket profiles used in corrugated polyethylene pipe. Individual performance curves will be developed and analyzed for each joint configuration to determine key performance limits at not only nominal but also minimum and maximum joint openings. Their performance relative to the standard O-ring gaskets will also be illustrated as a reference point for developing national standards for use by organizations such as AASHTO, ASCE and ASTM.

Failure of a pipeline is an unpleasant event for all parties. Significant research has been applied to reduce failure risk through improvement in the design and manufacture of the pipe barrel for all types of gasketed concrete gravity and pressure pipe, but little in regard to the joints. Yet joints are the source of a significant proportion of reported concrete pipe installation problems, pipe failures, and subsequent litigation. Design of gasketed concrete pipe joints is left up to the pipe manufacturer. For example, AWWA Manual M9, Concrete Pressure Pipe, includes "Guide Specifications for Purchasing Concrete Pressure Pipe." The Guide Specification states: "The pipe design details...shall be prepared by the manufacturer for the contractor's submittal to the purchaser." AWWA and ASTM concrete pressure pipe standards require that the manufacturer submit, when specified, joint details for the purchaser to approve. There is no AWWA standard for concrete pressure pipe joints. Beyond illustrative figures in Manual M9 and performance requirements in ASTM C443-02 Standard Specification for Joints for Concrete Pipe and Manholes, Using Rubber Gaskets, and ASTM C361-99 Standard Specification for Reinforced Concrete Low-Head Pressure Pipe, there is little guidance available for the purchaser upon which to base approval of the joint design. This paper presents a new model, or paradigm, for specifiers of rubber gasketed concrete pressure and gravity pipe. Discussion of the state-of-the-art in rubber gasketed concrete pipe joints is followed by recommendations for gravity, low- and high-pressure joint design applications, and a challenge to the concrete pipe industry for more research.

When subjected to heavy external loads, buried flexible pipes are sometimes encased in concrete. The encasement holds the flexible pipe in its circular shape and supports most of the external load. The pipe is an impermeable liner in a concrete conduit. The flexible pipe is designed for internal pressure by classical methods. But design for internal pressure does not assure that the flexible pipe is designed for external pressure or internal vacuum. If a groundwater table is above the conduit, over a period of time, water pressure reaches the pipe through the permeable concrete encasement. The build-up of water pressure on the pipe is hastened if there are cracks in the encasement. And there usually are. Basic design requires that ring compression stress in the pipe must be less than yield strength. But if a flat spot occurs in the pipe (increased radius of curvature), ring compression stress increases. If yield strength is exceeded, the pipe inverts. Therefore, placement of encasement requires control of the shape of the pipe. If the pipe is plastic, under external pressure, the circumference shortens over time (creep) and a gap opens on one side of the pipe. Radius of curvature at the gap is greater than the circular radius of the pipe. Ring compression stress increases. Performance and performance limits for concrete encased pipes are identified, and design procedures are described.

A common finite element modeling approach for buried pipelines is the combined use of beam and spring elements. Typical loads are soil settlements, temperature variations, internal pressures, neutral topsoil loads and traffic loads. The beam elements represent the pipeline; assemblies of spring elements represent the surrounding soil comprising an elasto-plastic bedding and friction. The choice for such finite element models is a pragmatic one. The models are relatively easy to construct and the analyses can be performed within reasonable calculation time on an average PC. From a mechanical point of view the problem of a buried pipeline subjected to subsidence, or an offshore pipeline subjected to sand waves, is of a full 3D nature. Beam elements and spring elements only partly incorporate full 3D effects. In practice the common finite element models are therefore enhanced to take into account 3D effects that would be missed otherwise. A major point is the distinction between beam action and cross sectional behavior of pipes in straight and curved sections and their mutual interaction.

Pipe bursting in hard to medium rock presents significant cost advantage in addition to many other known advantages compared to open cut pipe replacement. However, the owners of nearby utilities and structures and all the involved parties in the project have valid concerns about the ground movements in these conditions due to pipe bursting. Theoretically, in tight rock trenches, the bursting head applies considerable amount of energy to create a pathway for the new pipe. Ground movements resulting from that energy may be considerable and may cause significant damage to nearby utilities, structures, and pavement. These concerns may unjustifiably prohibit the utilization of an economical option with less risk and disturbance than open cut. Bowling Green State University (BGSU) with the support of the pipe bursting and the Ohio construction industries conducted a research project to evaluate the ground movement associated with pipe bursting in rock conditions to investigate the safe distance for building and utilities from pipe bursting operations. This paper presents the measured ground movement within the theoretical wedge of ground movement due to the bursting process under several variables such as trench width, bedding material, degree of up-sizing, and proximity to existing services. The research also considered the ground movement associated with the pneumatic and static pull bursting systems.

This report includes an emergency engineering / construction case history for a failed underground 6.5 foot steel pipe with an approx. 8,000 gpm flow rate, under 11 feet of head. Emergency measures required quick response to analyze the failed conduit, the water control system, water diversion, and a continuous effort to stabilize pipe foundations in a soil, with high potential for "piping." Two abandoned underground steel pipes, 5 ft. and 6.5 ft diameter were not being utilized, but were located below a 6 ft. flexible steel pipe installed above ground carrying 170cfs. During an expansion reconstruction effort a couple years prior, the 6.5 ft steel pipe was left exposed to hydrostatic water forces from a connecting concrete mid-tower structure, which controlled the constant flow of 170 cfs for approx. 2000 ft. distance. The water source was from a natural spring and the system did not have any by pass or diversions to maintain the fish farm operation and divert water from the ruptured pipe. The seams of the pipe burst under the pressure and began to unzip at the radial seams. The pipe foundation and roadway was washing away due to the water spraying and gushing from the failed pipe. This became a major concern for the stability of an adjacent 6 ft. pipe in use. Temporary diversions, relief pipes and 3000 gpm diesel pumps were installed over several days to convey the water to settling ponds adjacent to the scenic Snake River near Twin Falls, Idaho. Further temporary water control measures were implemented to avoid potential disaster from pump (mechanical) malfunctions. Extra precautions were taken (i.e. light plants, backfill material, back-up pumps, etc.), to mitigate the potential disaster if failure at another pipe seams occurred.

This paper describes the development and deployment of Sahara - a non-destructive condition assessment technology that pinpoints the location and estimates the magnitude of leaks in large diameter (12 inch (300mm) and above) water transmission mains of all construction types. Developed in the United Kingdom by the Water Research Center (WRc), Sahara is now being delivered in North America, and in selected international markets, by the Pressure Pipe Inspection Company (PPIC). In operation, the system is inserted into a live pipeline through any 2 inch (50mm) tap. Carried by the flow of water, the tethered sensor head can then travel through the pipe for distances of up to 6,000 ft. (1,850 m) per survey, notifying pipeline operators of each leak as it is found. The leak's position is then marked on the surface, facilitating subsequent repairs. Over 1,000 individual surveys of large diameter water transmission mains have already been performed using this leak location system. Operators have eliminated an average water loss of 57,000 gallons/day/mile surveyed (134,000 liters/day/kilometer surveyed) using this system. This paper describes some of the challenges that were overcome in the development of the system and uses case histories to illustrate a variety of applications.

The City of St. Petersburg, Florida, receives all of its potable water supply through two concrete pressure pipe water transmission mains. The 900 mm (36-in.) and 1200 mm (48-in.) diameter water transmission mains are both approximately 40 km (25 mi.) long and were constructed in 1929 and 1963, respectively. Rapid growth in the Tampa Bay area has necessitated relocation of portions of these mains 17 times, ten of which occurred in the last ten years. Most of the relocations were required to facilitate transportation projects. Two of the relocations have been relocated a second time. In each case, time has been a critical factor, as water can be supplied to the City only through the remaining transmission main with some temporary supplemental supply from neighboring municipalities. An accident occurring on the remaining transmission main or a significant delay in the tie-in construction could have a dramatic adverse effect on the City including health impacts and fire flow deficiencies. Protocols have been developed over the years that assure the success rate of tie-ins and connections. Typically, the replacement segments of transmission main are constructed, tested, disinfected and cleared by the Health Department before tie-ins are constructed to place the new segment in service. Preparation for transmission main shutdown to allow construction of tie-ins begins approximately two weeks before and culminates in the confirmation of the checklist items. The day before the shutdown commences, the final checklist is reviewed and if everything is not ready, the shutdown is postponed.

The City of Fort Wayne, Indiana, periodically experiences problems with its older combined sewers. A failure in any of these sewers is problematic, but a failure in some of these lines, such as the Taylor Street Combined Sewer, would be catastrophic. Located beneath a busy multi-lane road near downtown Fort Wayne, the 1,830 mm (72 in) brick Taylor Street sewer is vitally important during high flows caused by rainfall events. Not only would a collapse create enormous environmental repercussions, it could also result in loss of life. Because the line includes a 90-degree bend beneath the road, a collapse would, at minimum, require expensive and disruptive street and sewer repairs. The City of Fort Wayne retained Greeley and Hansen to assess the Taylor Street sewer from a structural and hydraulic basis, and to provide a technical memorandum for its rehabilitation or replacement. The firm's assessment found poor structural integrity in critical sections of the 100-year-old sewer due to settlement, corrosion and natural deterioration. To repair or replace the sewer using conventional methods would be expensive, disruptive and require closing the street. Instead, the consultant recommended the city rehabilitate critical sections of the sewer using glass reinforced plastic (GRP) panels. After contract documents, including contractor qualification requirements, were prepared, the project was awarded to the low bidder, Affholder, Inc.

The County Sanitation Districts of Los Angeles County (Districts) own, operate, and maintain a wastewater treatment and collection system that includes approximately 2100 km (1300 miles) of sanitary sewers ranging from 150 to 3660 mm (6 to 144 in.) in diameter. A portion of the Districts' Joint Outfall "A" Trunk Sewer was constructed as a cast-in-place reinforced concrete conduit having a semi-elliptical cross-section. This paper describes the rehabilitation of approximately 2210 m (7250 ft) of this 2900- and 3200-mm (114- and 126-in.) semi-elliptical sewer using a flexible polyvinyl chloride (PVC) liner embedded in a structural grout. The 2900- and 3200-mm Joint Outfall "A" Trunk Sewer was constructed in 1927 and included an interior lining of vitrified clay tiles for corrosion protection. The sewer is located immediately upstream of the Districts' Joint Water Pollution Control Plant in the City of Carson, California. Over the years, the majority of the tiles above the low flow level became dislodged and debris accumulated in the sewer to a depth of approximately two feet, significantly reducing the capacity of the sewer. Moreover, physical inspections adjacent to manholes indicated the exposed concrete had corroded up to four inches. The Districts awarded an $8.5 Million contract to remove the debris and rehabilitate the sewer in May of 2001. The contract documents specified three acceptable rehabilitation systems to be installed by person-entry methods. The selection of the contractor was based not only on the overall bid price, but also on the contractor's proposal and approach to the project. The selected contractor elected to rehabilitate the sewer with a flexible PVC liner.

The Salt Creek Sewer Basin encompasses a significant portion of the developed and developing eastern part of the City of Chula Vista (Chula Vista) commonly referred to as the Eastern Territories. This area includes large parcels within the East Lake, Otay Ranch and Rolling Hills Ranch developments. Portions of the Otay River Valley, as well as portions of the unincorporated area north and east of Otay Lakes Road are tributary to the Salt Creek Sewer Basin. Furthermore, the Salt Creek Sewer Basin also encompasses a smaller sewer shed known as the Wolf Canyon Sewer Basin. Originally, a water reclamation plant was proposed for construction in the Otay River Valley to treat sewage flows from these developments under the City of San Diego's system (METRO) Clean Water Program. However, when METRO received a waiver of secondary treatment requirements for its Point Loma Wastewater Treatment Plant, plans for the Otay River Valley Reclamation Plant were scrapped.

In 1988 the Oak Creek Storm Drain, a 2450-millimeter (mm) (96-inch) diameter concrete pipe, was designed and constructed as part of a subdivision development in Murrieta, California. The pipe was specified as reinforced concrete pipe (RCP) with a cast-in-place concrete pipe (CIPCP) alternative as allowed by Riverside County Flood Control District specifications. The contractor chose the CIPCP alternative because it was more economical. The site soils were classified as compressible alluvials over weathered bedrock with some groundwater. The geotechnical engineer specified removal of the alluvials, placement of a subdrain, and replacement of the removal with engineered fill. The contractor excavated and constructed the specified subdrain and then excavated for the CIPCP construction. The contractor did not excavate and remove all the alluvial materials within the CIPCP structural envelope. This resulted in a soil environment not competent for CIPCP construction. Expectedly, after backfill, the pipe experienced structural cracking with some displacement. This paper describes the rehabilitation investigation, design, and construction that restored the existing pipe to function as designed for the expected service life.

The City of San Diego's South Mission Valley Trunk Sewer (SMVTS) was originally constructed in 1947, with alignment modifications made in 1959, 1960, 1969, 1979 and 1990. The original installation was along dirt roads, through agricultural farmland and within undeveloped areas along the San Diego River. The trunk sewer is now located in one of the busiest areas of San Diego, along Hotel Circle North, Hotel Circle South, Camino Del Rio North and Camino Del Rio South. The total length of the SMVTS is 9,556 meters. The trunk sewer collects flow from approximately 971 hectares primarily along the southerly side of the Interstate 8 corridor and extending up into the Mission Hills, North Park and San Diego State University communities. The existing trunk sewer collects flow from the Fairmont Trunk Sewer at the easterly end and terminates near the interchange of Interstates 8 and 5, where it joins with the 2700 millimeter (mm) North Metro Interceptor. The SMVTS is primarily comprised of vitrified clay pipe ranging in size from 450 to 750 mm diameter.

Developing bid forms for conveyance projects requires careful consideration in order to be fair to the project owner, the bidders, the successful contractor, the various subcontractors, and the suppliers who provide materials for the project. Bid items may be unit price, lump sum, or a combination of unit price and lump sum. The bid form may have deductive alternates, additive alternates, cash allowances, owner-selected items, or adjustments for various materials and equipment. Occasionally, the measurement and payment method selected can have unintended consequences. The paper will discuss these topics and offer recommendations to make the bid form as fair as possible for all participants in the bid process.

This paper discusses the development of a comprehensive Contractor Outreach Program to address a lack of bidders for the City of San Diego's water and sewer pipeline replacement and rehabilitation projects, called "Group Jobs." The Engineering & Capital Projects Department recognized that these projects were receiving only a limited number of bids that were above the project cost estimate; these higher bids meant that the City was paying more than anticipated to complete Group Jobs. This prompted the City to explore ways to inform contractors about Group Job bidding opportunities, and encourage them to bid on these jobs.

The Tarrant Regional Water District is apolitical subdivision of the State of Texas formed in 1924 with the purposes of water supply and flood control. One of the largest raw water suppliers in the state, the District serves over 30 wholesale customers, including Fort Worth, Arlington, Mansfield, and the Trinity River Authority of Texas. The District owns four reservoirs and utilizes three others for terminal storage. The District's activities span a 10-county area of North Texas from Jack County to Freestone County. The District operates in excess of 160 miles of PCCP, and experienced the first of a series of failures in 1981. Since that time, the District has implemented a number of condition assessment and risk mitigation measures that have resulted in an improvement in the reliability of the pipeline. These measures also resulted in the collection of a diverse range of data sets. In order to utilize this information, the District turned to the Pressure Pipe Inspection Company. This paper describes the development and implementation of a GIS system, created for owners and operators of PCCP lines for use as an Asset Management System. The system incorporates custom variable sets to provide an up-to-date view of an operator's existing water pipeline infrastructure. The system further integrates inspection / integrity information while maintaining the hydraulic modeling capability of typical pipeline models, providing a foundation for informed decision making.

This paper introduces the keystone and the applications of GPS technology. Summarize the present applications of GPS technology in water supply engineering. Describes GPS applications in the fields of pipeline information collection, establishing of water network GIS, establishing of real-time dynamic model of water distribution system and application in SCADA. By analyzing the development of GPS technology and the GPS application directions, this paper gives a foreview of GPS applications in the future days in the field of water supply engineering.

One of the greatest potential hazards and liabilities in pipeline design and construction is related to utility crossings. Pipeline projects may encounter crossings with electrical, fiber optic, natural gas, and a host of other utilities. When poorly identified, each utility crossing poses a liability to engineers and a threat to the safety of contractors. Although this thesis is well established by case history, steps may be taken to avoid new utility related construction disasters.

This paper presents three analytical solutions to the heat transfer problem where an insulated pipe transports fluids in an environment with a longitudinal temperature gradient. The first solution is for steady fluid flow condition. Closed form equations for temperature profile in the longitudinal direction and total heat transfer across the insulation are presented. The second solution is for fluid flow start-up process. A transient solution for temperature distribution in the pipe is presented. The third solution is for the process of changing flow rate (shutting-down is a special case). Again a transient solution for temperature distribution in the pipe is presented. Results of sensitivity analyses are presented.

Under the sponsorship of the New York State Energy Research and Development Authority (NYSERDA), a project is now near completion to assess the technical and economic feasibility of using pneumatic capsule pipelines (PCPs) for underground transportation of freight in New York City. Four kinds of applications, using different sizes of PCPs, have been examined. They include using PCPs for: (1) tunnel construction, (2) delivering goods on pallets, (3) dispatching containers from seaports to an inland inspection/transfer station, and (4) ferrying trucks with their cargoes. The fourth application, using large conduits (tunnels) to ferry trucks, has been examined for possible use in a particular area of New York City — Hunts Point. Success in this project can lead to future use of PCPs in New York City and other places in the nation, resulting in a significant reduction of the number of trucks on streets and highways, thereby reducing traffic jams, accidents, and air pollution caused by trucks. It may also reduce the chance of any terrorist attack using truck bombs and containers, and hence improving transportation security in overcrowded cities and ports. The need for federal assistance to demonstrate this advanced new freight pipeline technology for underground freight transport is also addressed.

In most onshore gas transmission systems, hydrate formation is controlled using a line heater to maintain the flowing mixture temperature above the hydrate formation temperature. The aim of this study is to describe a new correlation for predicting hydrate-forming conditions, produce a simple and easy-to-use method for computing the gas temperature profile, and thus provide an estimation for the appropriate location of the line heaters. With the use of an example, it is shown that the proposed technique can be used for the design of the heating system of a gas transmission pipeline.

In a destructive earthquake considerable damage occurs in buried structures such as urban water supply system. The preliminary action after an earthquake happens, is the repair of network and water supplying to the damaged area. Since pipes are mostly buried the damages not be found by digging even a long path. The most difficult part of the work is to find the damaged locations. In this paper an artificial neural network (ANN) is used to detect pipelines damage in water distribution systems due to earthquake. The states probable failures have to be computed. The amount of output discharge from the tanks is obtained by direct analysis of mathematical model for different states of pipe failure. The failure points are obtained by using the amount of water discharge from the tanks. Which could detect the damaged pipes through a back analysis. Since there are various types of failure, therefore, the ANN has been applied. Through a parametric study, different geometry, shape, diameter and pressure of the water network are surveyed and the best network architecture for each case is obtained. The peak responses and phase delays are assumed to be the network outputs. The network is trained in a supervised manner by the data obtained from direct analyses. The study shows the efficiency and capability of the ANN for modeling the observed nonlinear behavior.

Interceptor sewers, with diameters generally greater than 1½ meters (5 feet), traverse long distances from their terminating sewage treatment plants as well as cross varied geologic materials and numerous physical features. Routing of portions of pipelines often positions their alignments in lowland, flood plains which typically contain unconsolidated alluvial deposits, and adjacent to watercourses to minimize impacts on existing improvements. Invert grades can be deep when compared to other utility grades and at times pipelines must be located within local groundwater aquifers. Pipeline design in seismically active areas requires that combinations of potential earthquake shaking, high groundwater levels and granular foundation soils be evaluated for the potential of pipeline settlement or buoyancy. This paper presents the conditions and methodologies used for such predictions for portions of the Lower Northwest Interceptor (LNWI) project to be constructed in Yolo County, California. The total length of the LNWI project is approximately 31 kilometers (19 miles). A Standard Penetration and Cone Penetration Test subsurface program involving exploration spacings of 152½ to 305 meters (500 to 1000 feet) along the planned pipeline permitted the gathering of much subsurface soil and groundwater information as well as soil samples for characterization of material types, grain size characteristics, and fines contents. A summary of alignment subsurface conditions is presented for the portions of the LNWI alignment and methods used for determination of potential levels of earthquake shaking, liquefaction potential, and estimates of settlement are evaluated.

The East Bay Municipal Utility District (EBMUD) is located in the east portion of the San Francisco Bay Area, serving water to over 1.3 million people. The water system includes a network of reservoirs, aqueducts, treatment plants, and other distribution facilities stretching from the Sierra foothills to the Bay Area. The main source of water is the Mokelumne River watershed in the Sierra foothills located about 90 miles northeast of the Bay Area. Mokelumne River water is collected in the Pardee Reservoir and flows from Pardee to the Bay Area via the Mokelumne aqueduct system consisting of three large diameter steel pipelines. The Bay Area has high seismic risk, with numerous earthquake faults throughout the region. EBMUD's Water Supply Management Plan completed in 1993 identified that the aqueduct system is vulnerable to damage in a 14-mile reach located In the San Joaquin-Sacramento River Delta Area, possibly causing unacceptable outage duration. Recognizing this danger, EBMUD has undertaken a $39 million project to upgrade Aqueduct No. 3 and increase its seismic reliability. The EBMUD upgrade performance goal is to limit damage such that it can be repaired within six months following a 500-year return period earthquake, with terminal storage located within the service area being used to provide water to customers during the six month repair period.

The Olmsted Flowline is a vital link in delivering the Central Utah Water Conservancy District's (District's) municipal and industrial (M&I) water. In the last 20 years, three active landslides have interrupted the service of the Flowline and one of its branches, the Alpine Aqueduct (AA-1). For each landslide crossing, the District has determined the causes, identified solutions, engineered remedies, and constructed replacement facilities to improve the reliability of these aqueducts. The causes of the three landslides were similars—weak geologic formations and groundwater—but their movement rates varied from under 3 mm (⅛ inch) per year to over 6.1 m (20 feet) per day. Accordingly, design approaches for circumventing or crossing the landslides varied with their movement rates. Constructed facilities included a tunnel (horizontal and vertical realignment in bedrock), two above-ground pipes, surface and groundwater removal, slope buttressing, and soil nailing. This paper presents how the reliability and maintenance problems of multiple active and inactive landslides under two major aqueducts were addressed through the design and construction of various types of replacement conduits and slope stabilization facilities.

The Bureau of Water Works, City of Portland, operates and maintains the City's water supply system. The main components of the system include the Bull Run Lake and Reservoirs east of the City, and the reservoirs, well fields, and distribution systems in the Portland metropolitan area. Linking these two components, and serving as an important component itself, are the three water supply conduits that run the approximately 40 km reach from the Head Works at Bull Run Dam No, 2 to the Mt. Tabor Reservoirs in Portland. The system has provided water supply for almost 100 years for the city's inhabitants. The pipes were constructed of locked bar, riveted, and welded steel pipes and are approximately 93, 76 and 50 years old. Given the age of the existing system, studies are underway concerning the future water supply needs of the metropolitan area and the Bureau's operating and maintenance requirements. The Bureau hired the authors to conduct a thorough investigation of these 3 pipelines. Specifically, the investigation included the following: a) Determine the hydraulic capacity of the conduits with various terminal reservoirs, b) Calculate the hydraulic grade line under varying flows, c) Do a structural and seismic analysis of the conduits based on today's design standards along with adequate geotechnical assessments, d) Address specific engineering issues of interest to Bureau staff, e) Identify potential locations for installation of control valves, and f) Recommend operational, structural, and other improvements to increase hydraulic and structural capacity of the conduits. Those community water bureaus and their consulting engineers involved in asset management will find this paper useful.

The Olmsted Flowline was initially built in the early 1900s as a 7.24 kilometers (km) wooden flume and was replaced in 1948 and 1952 with a thin-shell, above ground, 2590 millimeter (mm) diameter (10-foot) steel pipe. It conveyed water from the Provo River within a narrow canyon in Utah to a hydropower plant. The Central Utah Water Conservancy District (District) assumed responsibility for operation of these facilities in 1987 and over the past 18 years gained considerable experience operating and a great deal of respect for the durability of these old facilities. The District has improved and replaced the majority of these facilities through a $63 million capital improvement process that is being completed in 2004. The facilities had many risks and problems, including landslides, excessive corrosion, rock falls, creep, talus buildup that "jacked" the pipeline on its supports, thermal expansion/contraction cycles, snow avalanches, and hydraulic constrictions. The completed facilities now have been significantly improved to fulfill the District's goal to reliably and safely deliver municipal and industrial water to a major population within Utah. This paper presents a summary of how the District proceeded with the capital improvement program and how each replacement project was formulated and constructed. It shows how long-term planning is important and valuable when sufficient time is available to evaluate and determine alternatives but it also presents the reality of solving immediate problems which faced the District in fulfilling its obligations to reliably deliver water through these old facilities.

In order to achieve compliance with their Consumptive Use Permit for groundwater withdrawals, Tampa Bay Water, a regional water supply authority on the west coast of Florida, needed to implement a new surface water supply by December 31, 2002 in order to reduce pumping from their stressed well fields. This was accomplished by a fast-track design and construction program that built two new surface water intakes and pump stations that connected to a new treatment plant via 14-miles of 72 and 84-inch transmission mains. The alignment of the new pipelines required the acquisition of over 120 separate easements. Because the land acquisition was ongoing during the design phase, access was not available to certain properties for collecting geotechnical data prior to bidding and awarding the construction contract. Only after the Contractor was mobilized and under construction was it determined that one of the designated wetlands that needed to be crossed consisted of muck and peat extending to depths ranging from 50 to 70 feet below land surface. It immediately became apparent that it would be cost prohibitive to remove and replace the unsuitable material with backfill capable of supporting the 72-inch steel pipe. Installing the pipe in the native material was the only available option. Because of the unsuitable nature of the soil, settlement of the full pipe during dry periods and flotation of the empty pipe during wet conditions were factors that had to be quickly evaluated and addressed without delaying the Contractor.

The construction of a pipeline project requires significant scheduling efforts to ensure a timely completion without cost overruns. Traditionally, pipeline projects are scheduled in a very similar way as other construction projects: either by the critical path method (CPM) or the line-of-balance method (LOB). Despite the wide acceptance of these two methods, they are less than satisfactory in scheduling pipeline projects. In this paper, the author addresses the deficiencies of these two classical methods and presents a new scheduling system, repetitive scheduling method (RSM). The author demonstrates the application of RSM in performing what-if analysis for alternatives to expedite a real-life pipeline project.

Horizontal Directional Drilling (HDD) is a trenchless construction method which has gained rapid acceptance in the pipeline engineering and construction industry. Once considered a small, specialized segment of the industry, HDD is increasingly being used for a broad spectrum of pipeline projects, including both pressure and gravity installations, and under difficult and diverse surface and subsurface conditions. Like many other trenchless construction methods, the feasibility and operating parameters for HDD are determined in large part by subsurface conditions along the pipeline alignment. While the pipeline industry has generally accepted the need for thorough geotechnical investigations on HDD projects, the quality of geotechnical reports is quite variable as is the use of geotechnical reports by both design engineers and contractors. Commonly, geotechnical reports do not provide the basic data necessary to make critical design and construction decisions. Similarly, designers and contractors often do not know how to interpret the findings of a geotechnical investigation and use them effectively for their HDD projects. This paper presents general guidelines for geotechnical investigations for HDD projects in soil environments, including a discussion of the subsurface information that is most useful for design engineers and contractors such as soil grain size distribution, soil plasticity, soil density/consistency, soil strength, vertical and lateral variability of soil deposits, presence of natural or man-made obstacles, etc. This paper also explains how the findings of a geotechnical report can be interpreted and put to practical use for a HDD project, including an examination of how subsurface conditions effect bore path design, risk of hydrofracture, drilling fluids design, drilling rates, tooling selection, etc.

A 224m (735-ft) long segment of steel casing was successfully installed using conventional pipe jacking methods in complex ground conditions located in a highly congested section of downtown Boston. The 1370mm (54-in.) outside diameter permalock steel casing, was installed in two reaches with lengths of 133m (435 ft) and 91m (300 ft) located at depths of 10.7m (35 ft) and 7.6m (25 ft), respectively. Ground conditions ranged from hard clayey soils with boulders to fine sand to sand and gravel below the water table to silt to stiff clay. The installation passed beneath both an active transit station and numerous near surface utilities. This paper will present the successful installation of the steel casing and include a discussion of the many challenges faced during construction. Challenges included siting of jacking and receiving pits, running ground that was stabilized by chemical grouting, unanticipated ground and coordination with various City Agencies. All construction activity was conducted at night and required that this critical thoroughfare be open to all stakeholders during daylight hours.

This paper presents the implementation of an artificial neural network to predict surface heave resulting from shallow subsurface utility installations conducted with horizontal directional drilling. Data gathered from a full factorial field experimentation examining the effects of drilling techniques is utilized in the network development, with the attempt to understand the relationship between construction techniques and resulting surface heave. The developed model is compared to a multivariate linear regression analysis conducted on the raw data, and a sensitivity analysis utilizing the trained network connection weights is conducted to determine which factor has the greatest effect on surface heave development. Further examination of the behavior of the system is provided through a trend analysis which studied the effect of each drilling factor on the predicted surface heave. The results indicate that a neural network would adequately model the relationship between drilling techniques and the resulting surface heave.

In 1997, the California Regional Water Quality Control Board, San Francisco Region issued a Cease and Desist Order for discharges from the Cities of South San Francisco and San Bruno Water Quality Control Plant requiring expansion of this treatment plant and the collection system upstream. Among the necessary improvements was the installation of two new sewer force mains. Due to the existing utilities, subsurface conditions, and surface activities including heavy traffic, several trenchless technologies were evaluated for portions of the force main pipelines. Pipe bursting was chosen for a portion of one pipeline due to the availability of an existing, deteriorating sanitary sewer that was scheduled for replacement and because it provided minimal surface disruption. Microtunneling was chosen for portions of another pipeline because it provided a means of crossing major thoroughfares and areas heavily congested with utilities with minimal surface disruption.

The Novato Sanitary District (District) is rehabilitating their 27-inch and 36-inch diameter Main Interceptor Sewer using trenchless rehabilitation methods that do not require bypass pumping. A portion of the project was completed as a pilot project, using a machine spiral wound poly vinyl chloride (PVC) liner that was installed through existing manholes without any excavation, bypass pumping, or significant impacts to residents. This paper will summarize the evaluation of various alternatives for rehabilitation, design considerations, options for bidding, and present photographs of the rehabilitation construction. Specific issues to be addressed during the project include limited site access, crossing an existing railroad track that constrains bypass pumping, construction through easements across a nicely landscaped residential property, coordination with the City of Novato's (City) pavement project, and utility relocation requirements for some of the rehabilitation methods.

During the past few years, trenchless technologies have been gaining popularity in the area of buried infrastructure rehabilitation due to economic and environmental factors. The gap between infrastructure spending and needs, which was presented in the USEPA GAP report and was supported by the 2001 ASCE Report Card, prompted the need for non-traditional approaches to the rehabilitation of buried infrastructure assets. In addition, those technologies have been becoming more and more familiar to engineers and practitioners in the field as more projects are constructed. An analysis of selecting the most suitable construction method for the rehabilitation project will be presented. The Water and Sewer District of Clermont County, Ohio has implemented various trenchless technologies for both water and sewer projects. The projects varied from a water main river crossing, a main sewer trunk replacement in a creek, highway crossings, and water and sewer deteriorating pipes. This paper will discuss the replacement of a sewer trunk using microtunneling and the construction of a water distribution interconnection under a river using Horizontal Directional Drilling (HDD). The respective trenchless technology was deemed the most suitable method over traditional methods of open cut for both projects. The County utilized a Geographic Information System (GIS) and a Supervisory Control & And Data Acquisition system (SCADA) to aid in the identification of needs, design efforts, and management of the infrastructure. The need for a decision support system to aid in the rehabilitation projects of buried infrastructure has become urgent as more of such systems proved to be beneficial. The role of GIS to select the appropriate construction method will be discussed. Data presented in this paper will aid in providing a strategy for the rehabilitation of water and sewer projects.