Pipelines 2007: Advances and Experiences with Trenchless Pipeline Projects

In 1998 and 1999, the United States Environmental Protection Agency (EPA) and Georgia Environmental Protection Division (EPD) completed settlement negotiations associated with two complaints against the City of Atlanta for various violations of the United States Clean Water Act and Georgia Water Quality Act. This resulted in the recording of the Consent Decree (CD) related to Combined Sewer Overflows (CSOs) and the First Amended Consent Decree (FACD) associated with Sanitary Sewer Overflows (SSOs). They mandated improvement of the City wastewater collection and transmission systems including wet-weather control for combined sewers, and rehabilitation and relief of capacity-limited sanitary sewers. The City's seven existing CSO control facilities experience a combined 300 discharge events per year. Additionally, over 550 SSOs (unpermitted discharges and spills to dry land) are experienced annually. The City wastewater collection and transmission systems include approximately 1600 miles of sewer mains and approximately 37,500 manholes. Fifteen percent of the system is comprised of combined sewers while 85 percent of the system consists of separate sanitary sewers. Six other governmental entities contract for wastewater treatment by the City including the Cities of Hapeville, College Park and East Point, and DeKalb, Clayton and Fulton Counties. Fifty-five percent of the sewage flows are generated by Atlanta and 45 percent by the wholesale agencies. The total benefiting population is 1.2 million. The 14-year phased approach under the FACD includes evaluation and rehabilitation of the sanitary system, and construction of capacity relief sewers that is estimated to cost approximately $2.2 billion. Additionally, the CD requires a $1.0 billion capital investment including disinfection improvements, new tunnel conveyance/storage and treatment facilities, and sewer separation in three combined sewer basins. Additionally, the FACD requires the preparation and implementation of management, operation and maintenance ("MOM") programs for the sanitary sewer system as a measure to help control SSOs. Full compliance with the CD and FACD is required by November 7, 2007 and July 1, 2014, respectively. Over 200 miles of small diameter sewers have been rehabilitated to date for the most part utilizing cured in place pipe. The City anticipates escalating its rehabilitation program to an average annual expenditure of $100 million over 8 years. This paper will overview the City's challenges with negotiating complex consent decrees with EPA/EPD and complying, to date, with some of the scheduled 900 interim and final consent decree compliance milestones. The paper will also describe the formation of the improvement program, locally known as `Clean Water Atlanta', that was formed to meet the requirements of the FACD and will also introduce the three other papers in this track relating to SSES and Rehab Selection Process (Paper Two), The GIS Hub (Paper Three), and Hydraulic Modeling (Paper Four).

Paper One noted, along with several other requirements, that the FACD includes a task to evaluate and rehabilitate the City of Atlanta's sanitary system. This paper — Paper Two — provides an overview of the City's approach to Sewer System Evaluation Surveys (SSES) and the Rehabilitation Selection process within the terms of the consent decrees. The mission of the SSES and Rehabilitation Selection Task is to establish a comprehensive and accurate inventory of the assets of the City's wastewater system; to identify sources of inflow and infiltration within the system and to perform a condition assessment of wastewater system assets, incorporating sewers, manholes and laterals. The City's wastewater system has been conveniently split into six sewer groups for the purposes of demarcating areas of the City to be studied over the 14 year period of the FACD. With the findings from this study an appropriate prioritized list is scheduled of sewers, manholes and laterals identified for remedial action. This procedure will be repeated for each of the six sewer groups in turn with the intention of implementing the work in a timely, low impact and cost effective manner. Reporting requirements include the submission of a report to EPA/EPD at the conclusion of each of the six SSES studies. Although not a prerequisite of the FACD nevertheless a decision was taken by the City of Atlanta at the time the consent decrees were signed in 1999, that in order to address the widespread problem of spills — which, as outlined in Paper One, amounts to over 550 SSOs (unpermitted discharges and spills to dry land) annually — that the entire public sewer system would be targeted for evaluation, i.e., 100% internal sewer condition assessment and 100% internal manhole condition assessment. The paper discusses the process involved in synthesizing the huge volume of data arising from the SSES study through an in-depth QA/QC process ensuring that the data is complete, accurate, reasonable and exhibits full connectivity prior to upload to the GIS hub — see Paper Three — before being relayed in turn to the Hydraulic Modeling Group — see Paper Four — for micro-modeling analysis prior to the commencement of the Rehab Selection Process. The Rehabilitation Selection Process, using a specially developed GIS web-based tool, is reviewed in the paper. The tool integrates survey data, rehabilitation methodologies, sewer hydraulic modeling data and associated rehabilitation cost estimates. This allows program design engineers to efficiently determine suitable rehabilitation designs for each element of the system. To date, the tool has been used to generate sewer and manhole rehabilitation designs for just over 10% of the system. For the portion of the system evaluated thus far, various trenchless technologies have been identified as the appropriate solution for a significant percentage of the rehabilitation. High utilization of trenchless technologies is targeted for use throughout the program to provide cost effective system upgrade and at the same time minimal disruption to the community.

In 1998 and 1999, the United States Environmental Protection Agency (EPA) and Georgia Environmental Protection Division (EPD) completed settlement negotiations associated with two complaints against the City of Atlanta for various violations of the United States Clean Water Act and Georgia Water Quality Act. This resulted in the recording of the Consent Decree (CD) related to Combined Sewer Overflows (CSOs) and the First Amended Consent Decree (FACD) associated with Sanitary Sewer Overflows (SSOs). They mandated improvement of the City wastewater collection and transmission systems including wet-weather control for combined sewers, and rehabilitation and relief of capacity-limited sanitary sewers. The City wastewater collection and transmission systems include approximately 1900 miles of sewer mains and approximately 37,500 manholes. Fifteen percent of the system is comprised of combined sewers while 85 percent of the system consists of separate sanitary sewers. The FACD simply mandates the development of a mapping system which inventories the sanitary and combined sewerage systems. This paper will describe how the GIS task has gone beyond the requirements of the FACD to build an integrated enterprise database system explaining the benefits of doing so. In addition to GIS information, this integrated enterprise system also includes information pertaining to scheduling, project management and contracts, modeling, capacity permitting and Inflow & Infiltration (I&I), flow monitoring data and work management and planning. Under the FACD, the mission of the GIS task is to maintain and improve the City's GIS databases pertaining to the sanitary/combined collection system in addition to providing maps and spatial data to contractors, consultants, elected city officials, city employees, and the development community. To provide these services we implemented an enterprise-wide GIS system for the City of Atlanta, Department of Watershed Management, Wastewater Division, whereby GIS information can be accessed/distributed via the Internet using conventional web-based tools and ESRI's ArcIMS (Internet Mapping Service) and ArcGIS Server. The data are stored in an Oracle database and accessed through ESRI's Spatial Database Engine (SDE). The implementation of this system required the conversion of CADD-based sewer/manhole drawings to shapefiles/coverages and finally to a geodatabase format. In doing so, we designed a wastewater object model to best represent the City's collection system. Domains, subtypes, relationship classes and geometric networks all play a part in describing, modeling, and automating procedures to QA/QC the City's collection system. Specific project activities have included: 1 Conversion of CADD-based sewer/manhole drawings to a GIS format. 2 Updating GIS data with current survey data. 3 Assisting in QA/QC of the Sanitary Sewer Evaluation Survey (SSES) data and update the GIS with these data when appropriate (see details in Paper Two). 4 Developing an object-based data model to accurately represent the City's collection system. 5 Uploading and maintaining data in Oracle RDBMS using ArcSDE to access information. 6 Creating a GIS application framework to quickly deploy multiple interactive mapping websites for easier access of data and maps. 7 Developing an Intranet-based rehabilitation and cost estimate application to aid the City in its mandate to rehabilitate the aging collection system (see Atlanta Track - Paper Two). 8 Creating an address verification application in order to develop master address database to include City's dispersant address files used by different City departments. 9 Creating automated I&I credit reports by sewershed calculated from CCTV condition information together with completed rehabilitation. 10 Managing GIS links to Hydraulic Modeling software, creating tools to assist in the processing of flow monitoring data, developing tools to predict/calculate risk analysis for overflows using 40 year storm data (See Paper Four). 11 Developing traffic coordination website to provide the public information about projects in the right-of-way. 12 Developing a Work Order Management Website which allows a user to easily query list and display location of Hansen and Maximo Service Requests and Work Orders, fun reports and open, change status and close work orders all from one interface. 13 Developing real-time mobile applications using ArcGIS Server. The following pages will describe what an enterprise GIS is, what are some of the benefits and what are some of the key features which comprise our enterprise GIS database architecture.

Prior to 1915, the 19 square miles that comprised the City of Atlanta, and what is now the core downtown area, utilized a combined sewer system. As the City grew to its present total area of 132 square miles, the trend changed to a separate storm and sanitary collection system. Currently, the City is served by approximately 1900 miles of sewer mains, four wastewater treatment plants, six CSO control facilities, and one CSO treatment facility. The entirety of this collection system is subject to the mandates set by the SSO First Amended Consent Decree (FACD) and the CSO Consent Decree (CD). The CD and FACD ordered the evaluation and rehabilitation of the City's sewer collection systems through a number of plans. A Prioritization Plan was created at the onset to divide the city's ten sanitary sewer basins into 260 sub-drainage areas (sewersheds). Using the Criterium Decision Software, these sewersheds were then prioritized based on a number of parameters (i.e. structural integrity, capacity, risk to surface water, etc.) and assembled into six sewer groups. The Flow and Rainfall Monitoring Plan, which required both permanent and temporary flow monitors as well as a number of rain gauges, was implemented to gather data for hydraulic model calibration and to identify excessive infiltration and inflow. The Hydraulic Modeling Plan took these components and designated modeling parameters. Due to the immediate need for a hydraulic model, the City's modeling approach consisted of a three step process. Initially, a macro model was built for only the large trunk sewers followed by a micro model, which added the major outfalls, then the addition of the remainder of the smaller diameter pipes through SSES data — see details in Paper Two — as relayed through the GIS Hub to the Hydraulic Modeling Group — see Paper Three. Calibrated models are used for numerous applications, primarily the development of capacity upgrade proposals, e.g. pipe bursting — see Paper Two concerning the Rehabilitation Selection Process — as well as capacity relief projects. For this application, a design storm was developed using an analysis of historical rain data to characterize the "typical" storm observed in the City. Running a calibrated model under this design storm identifies system-wide capacity issues. In other applications, many Requests For Information require model analysis to determine cause of overflows, solutions to capacity issues, amounts of infiltration/inflow, and it can also be used to verify the amount of flows attributed to the six inter-jurisdictional municipalities that feed into the City's system. In October 2005, the City began to convert all sewer models from XP-SWMM to Infoworks for reasons that included GIS compatibility, enhanced model output reporting, ease of use, stability and reduced run times for very large modeling simulations. Amidst this software change and review of modeling criteria the task is on schedule with currently 954 of the City's 1600 miles incorporated into the model. This paper will discuss the hydraulic modeling related CD and FACD requirements, the City's modeling approach and project's successes as well as lessons learned.

Internal pipeline inspections can often lead to observations of distress and emergency action must be taken to get the pipeline back into service. In many cases, the pipe does not wait for an inspection to demonstrate signs of distress. The San Diego County Water Authority has first hand knowledge of these situations and has needed to act quickly in several cases to get the pipeline back into service. On several occasions, the fastest and most viable technique was Carbon Fiber Reinforced Polymer (CFRP) strengthening. When a pipeline needs to be strengthened quickly, few alternatives have proved as fast as CFRP lining. The design and installation of these materials must be done by specialized engineers and contractors using systems that have been thoroughly tested. Many projects have been completed that presented unique challenges. This paper will review the project details, specification requirements and lessons learned from the completed installations.

The Boston Water and Sewer Commission is a public agency created in 1977 by the Commonwealth of Massachusetts. Its enabling legislation gave them ownership of the water, sewer and drainage systems within the City of Boston. Since its inception the Commission set several goals for improvements to those systems through a clearly defined annual Capital Improvement Program. Since 1978 the water, sewer and drainage systems in the city have seen substantial improvements in the areas of water quality and reductions of Combined Sewer Overflows to Boston Harbor and its tributary rivers. Hundreds of miles of water and sewer pipe have been replaced or rehabilitated. More than eighty miles of new drains have been installed for the purpose of sewer separation. New larger sewer interceptors have been constructed along the waterfront and many sewer and drain interceptors have been cleaned and inspected. The results of the inspections have revealed that most of the systems large pipes are in good condition with the exception of some of the old brick sewers and drains that have exhibited various minor structural problems or infiltration due to degradation of mortar. Rehabilitation of odd shaped brick conduits presents a difficult challenge to provide adequate and long term repair to the conduit at the lowest cost and amount of disruption to the surrounding neighborhoods. Common rehabilitation methods are often not applicable to large or odd shapes and pipe replacement may not be a viable option. This paper presents the planning, design and construction of two projects in Boston involving the rehabilitation of large brick conduits.

As part of a sewer replacement project, the Town of Framingham, Massachusetts determined the most effective construction method to repair a failing 18-inch sewer located directly underneath a heavily traveled Massachusetts Bay Transit Authority (MBTA) and CSX Corporation (CSX) railroad, and located in a downtown area with high vehicle and pedestrian traffic. The rehabilitation of this sewer was made without any excavation, by slipping a new 12-inch replacement pipe inside the old failing 18-inch sewer, essentially creating a new pipe inside the old failing pipe.

Hampden Township (Township) is a growing municipality in central Pennsylvania. Although Pennsylvania as a whole has had a stagnant population in recent years, portions of the central part of the state are growing at a brisk rate. As with many New England and Mid-Atlantic communities, the aging sewer infrastructure is not able to withstand these growing pains adequately. The Township has been actively implementing a sewer system inspection and rehabilitation program to address the infrastructure deficiencies. Deteriorating sewer segments were identified in two distinct neighborhoods. Design documents were prepared to allow utilization of various trenchless pipe and manhole repair methods. Cured-in-place and fold and form alternatives were specified for sewer pipe rehabilitation. Epoxy and cured-in-place methods were specified for manhole rehabilitation. A case study highlighting the lessons learned during construction of the project will be discussed. Issues that had to be dealt with during construction included concrete in a portion of the existing sewer and excessive infiltration. This presentation will include an overview of the planning, investigation, design and rehabilitation construction component of the project.

The City of West Palm Beach constructed approximately 6 miles of effluent force mains in 1974 extending from 23^rd Street using 42" Pre-stressed Concrete Cylinder Pipe (PCCP) and from Congress Ave using 48" PCCP to the East Central Regional Wastewater Treatment Plant within the City. The force mains normally run below the prevailing water table or are subject to wetting and drying cycles and are generally now below multi-lane paved surfaces. The City had experienced failures and wanted a complete investigation into the cause and extent of any possible deterioration/distress while the force main remained in service. The City also wanted to get recommendations for a possible rehabilitation and replacement program. The Pressure Pipe Inspection Company (PPIC) led a team comprising of Jordan, Jones and Goulding (JJG), Jason Consultants and an excavation contractor to provide the City with a complete turn-key solution. This paper will discuss the methods used to determine the existing condition of the force main: Acoustic emission testing, historic H₂S readings, chemical dosing records, repair/maintenance records, local soil conditions, hydraulic model runs, as well as the stress and strain in the PCCP elements. Additionally, it will cover the recommendations made to the City for a rehabilitation and replacement program, and highlight the advantages of a turn-key solution.

Responding to worldwide failures of prestressed concrete cylinder pipelines (PCCP), the City of Phoenix initiated a program to inspect its entire 150-mile system of PCCP water transmission mains over the next seven years. This system serves 1.4 million people over more than 500 square miles and can only be inspected during low demand winter months. Most of the system has never been taken out of service. The inspection program began with development of a masterplan to prioritize each pipeline for inspection. The overall risk associated with the failure of each pipeline was assessed using readily-available data. The risk considered: 1 Pipeline diameter to predict the number of affected customers, 2 Nearby land use as a tool to assess potential property damage due to flooding, 3 Pipeline age to reveal quality of construction methods and materials, 4 Corrosive soil and groundwater conditions near the pipeline. This paper demonstrates the use of a risk-based methodology to prioritize inspections, the use of hydraulic modeling to predict and address shutdown impacts, and shutdown planning. Each step of the process is related to a 4-mile, 66-inch diameter pipeline in Phoenix. This 40-year-old pipeline serves a large portion of west and central Phoenix.

In today's competitive engineering design environment, most engineering firms engaged in pipeline design incorporate "labor-saving" technologies into their design process as a business strategy to improve the "bottom line". Although these tools are aimed at raising productivity, increasing profit, and streamlining design methods, there's often little consideration as to what is designed rather than simply the design process, as a means of increasing profitability. Simply put, when considering water and storm and sanitary sewer rehabilitation or replacement, it is time to rethink the traditional engineering design business strategy of designing the "same old thing, but faster". Integrating trenchless technologies into the engineering design process provides the opportunity to change the "what is designed" element of the design profitability equation. In this paper, the author presents the findings of his review of more than 50 US trenchless projects designed and bid in 2006 and then compares them to similar "dig and replace" designs. The author concludes that most "trenchless" designs were over-designed and frequently included unnecessary "dig and replace" details. When comparing "trenchless" designs to comparable "dig and replace" projects, the data illustrates that efficiently designing a trenchless project can easily result in significant savings in design time, a decrease in the potential for errors, and sizable increases in design profit (especially in Design-Build projects). The author also provides specific essential trenchless information to help design trenchless efficiently and to level the trenchless bid or evaluated proposal "playing field".

Many sewer agencies and consulting engineers still use older "tried and true" formulas, graphs, and guidelines for sewer hydraulic design. With increasing attention on system performance and the need to demonstrate capacity assurance, it is important to re-examine sewer hydraulic design criteria. The relevancy of standards such as 10 States Standards and individual state sewer design criteria, and sewer agency in-house design criteria should be reviewed relative to cost/benefit analysis considering infiltration and inflow (I/I) rates. The wastewater industry has been performing detailed flow studies for over 30 years. What has been learned can be applied for creating better sanitary sewer hydraulic design criteria to improve system performance by reducing the future occurrence of SSOs. In this paper, various design criteria are reviewed relative to the impact on sizing, cost, and system I/I.

The decision of how to accomplish the installation or repair of a buried pipe in an urban environment involves tangible and intangible parameters. This paper outlines the development and implementation of comprehensive, yet straightforward and easy to use interactive software for the evaluation of alternative construction methods that can be employed in the installation or replacement of buried pipes and conduits. The software emphasizes simplicity and practicality, and limits input data to those readily available to utility engineers at the design stage of the project. The program takes into account extensive performance data for 20 new construction methods and 6 in-line replacement methods commonly used in utility projects, and was designed to raise awareness and provide guidance to the utilization of trenchless technology methods across the buried utilities arena. This paper focus on the validation phase of the model development, reporting the results of a comparison of the model's predictions with the outcome of five case histories, which cover a wide range of project requirements, soil conditions and environmental constraints.

Specifying engineers already know the many benefits of fabricated steel pipe in the water transmission industry. The flexibility to design steel pipe to meet the needs of any project, in the most demanding of conditions, has evolved fabricated pipe into a highly focused industry. Water pipe customers should insist upon a quality product and at least minimum industry standards in their contract documents. Current industry requirements are trending toward quality steel pipe certification from a third party testing organization. These certifying agencies need to be familiar with quality manufacturing requirements. This discussion will look at the importance of fabricator certification. For example, what traits are desirable in a certifying agency? Why are third party auditor qualifications so important? What attributes/processes should be audited at the fabrication facility? And what kind of follow-up systems are needed to insure compliance?

Trenchless gravity sewer upgrade projects, whether through CIPP (cured in place pipe), pipe bursting, etc., tend to have one thing in common: the need for reliable pumping systems. Whether the source is overflow, collapse, construction, etc., gravity sewer projects typically require flow diversion. Once a gravity sewer line's flow has been diverted, reliable pumping is essential throughout the remainder of the project so that sewer contractors can devote their attention to the sewer upgrade.

The safe and reliable Installation of carbon fiber liners has many critical steps. When a single step is missed, the lining installation will suffer significantly. Development of a usable quality control standard for material selection, design, installation, and inspection are critical for a successful installation. Work in this area began in the 1980's with studies conducted by the University of California San Diego for the Department of California Transportation (Cal Trans) for the purpose of retrofitting highway bridge columns. The technology moved to the general building industry following the guidelines of ACI 440. During the mid 1990's this technology entered the pipeline industry for the retrofit of Prestressed Concrete Cylinder Pipe (PCCP) with broken wires. Initially, a quality control standard directly related to this application was unavailable. Initial methods drew from the column wrapping methods developed by Cal Trans, ICC and those outlined in ICC (International Code Council) AC 125. However, as this application became more popular both the Fyfe and Fibrwrap Construction companies made large advancements in materials, application, and quality control methods. In the year 2000, the Metropolitan Water District of Southern California, MWD, took a serious interest in carbon fiber liners for the retrofit of its 163 miles of PCCP and implemented a testing and review program for CFRP (carbon fiber reinforced polymer). Presented in the paper are the most recent methods developed for the safe and reliable installation of carbon fiber liners. Discussion of mobilization concerns, materal requirements and related verification testing, critical paths for installation, and inspection methods for both during and post installation are provided. A case history is discussed outlining program considerations for both owners and contractors. Discussion is also provided outlining the pitfalls owners should avoid in order to obtain an installation within their predetermined shutdown window. Areas of discussion are: access, dewatering planning, permitting, design coordination, mobilization, contract requirements, and field support.

In 2005, a non-destructive testing evaluation was conducted on a 36-inch Prestressed Concreter Pipe (PCP) line for a large water utility in Illinois using the patented Remote Field Eddy Current / Transformer (RFEC/TC) Technology. RFEC/TC determines the number and location of wire breaks in individual PCP pipe. Due to the small diameter of this line, both man-operated bicycle-type tool and the remote-operated tethered system were used for the inspection. Data collected from the two systems were both of good quality and comparable to each other. The utility recognizes the value of the RFEC/TC inspection and plans to conduct more inspections in other PCP sections. When possible, the remote-operated tethered system, known as PipeCrawler, will be utilized because of safety considerations and because PipeCrawler is capable of inspecting pipes in a water-filled condition. In November 2006, the same water utility used the RFEC/TC technology to inspect approximately 4 miles of another 36-inch line. This inspection was challenging because it contained seven 36-inch by 24-inch reducers. Consequently, it was not possible to use the man-operated bicycle tool. In addition, it would not have been possible to use the PipeCrawler tool in its normal configuration, because of its fixed length mast. To overcome this challenge, a controllable and extendable mast was designed to fit on the PipeCrawler to facilitate the RFEC/TC inspection of PCP mains with reducers. In this paper, we will discuss the practical aspects of this.

One of the key factors for better performance of sewer pipeline networks is proper monitoring of existing operational or hydraulic condition of pipes. The hydraulic performance of sewer networks involves many uncertainties and is dependent upon vulnerability and retention capacity of each pipe segment in the concerned network. Random inspections of pipes are expensive. This paper suggests an objective methodology for evaluating operational condition of pipes. A multiple regression model is developed on the basis of historic condition assessment data for predicting existing operational condition rating of sewers. The regression model produces a most likely existing operational condition rating of pipes by utilizing simple inventory data. The developed model is intended to assist municipal engineers in identifying critical segments influencing overall hydraulic performance of the system.

The "City" installed a sewer system as part of overall infrastructure improvements for the CFD1 project. The sewer system included 3650 m (12,000 ft) of Vitrified Clay Pipe (VCP) 20 cm (8 in) dia. to 30 cm (12 in) diameter main lines at depths from 3 to 7.3 m (10 to 24 ft), and 89 VCP 10 cm (4 in) service laterals. Within months of installation 35% of the service laterals had leaks, breaks, and misalignments. The contract identified the site conditions, extent and details of the work required to be performed in conformance with the contract drawings and specifications, the required schedule of 147 days, and the contractor's responsibilities for ensuring total quality control for the project on materials, and workmanship. The city engaged a company other than the engineer of record to provide site supervision, inspection, and monitoring similar to those outlined in the specifications. In addition, the company that had earlier carried out the geotechnical investigation was retained by the site supervision firm to provide geotechnical inspection services during construction of the project as required by the specifications. The senior author was engaged by the City's Attorneys to review the design, specifications, and construction practices including inspection and monitoring, and a current condition assessment on this project as part of an engineering evaluation of the deep sewer system. The review also involved identifying deficiencies in design, installation, inspection and monitoring, and parties responsible for such deficiencies and any negligence. This paper documents the lessons learnt.

The costs of trenchless projects can vary widely with many factors such as the project size, length, depth, location, surface and subsurface conditions, type of application, etc. Although there have been several studies regarding the cost comparison of trenchless with open-cut methods, practical examples of verifying the reasonableness of actual trenchless construction/replacement costs are still needed. In this paper, the cost of an actual pipe bursting project on the campus of Michigan State University (MSU) is described and compared to estimated costs of several traditional open-cut options. To verify the reasonableness of the MSU pipe bursting cost, a cost estimate based on the quantity of MSU pipe bursting project was prepared. To show the price range of pipe bursting projects, a cost comparison with two other pipe bursting projects is also made. Other project aspects, such as time and social costs are briefly mentioned as additional benefits of pipe bursting method. These analyses indicated that pipe bursting method is much more cost effective and approximately two to three times less costly than open-cut options.

Water and wastewater pipeline construction costs have consistently increased over the years. However, pipeline construction costs recently have seen significant increases. Because demand in rehabilitation of existing pipelines and construction of new pipelines continues to grow, design engineers face a challenging task when asked to prepare an opinion of probable construction costs. The purpose of this paper is to identify trends and/or major differences within the Dallas/Fort Worth (DFW) metroplex, as well as discuss some of the factors influencing the increased costs of water and wastewater pipeline construction. We collected bid tabulation data from the past five years for 8- to 18-inch pipelines from 17 cities around the DFW metroplex. This data was used to compare the cost of pipeline construction based on size of pipeline, type of installation, and population of municipality. The type of installation examined included open cut and trenchless technology methods.

The renovation period for a pipe is usually calculated by minimizing the sum of the renovation and maintenance costs. In this paper, the optimum period is calculated in a similar way although including additional costs of increasing importance that usually are not taken into account (water lost through leaks, social costs and opportunity costs). Additionally, the influence of the new trenchless technologies is also assessed. Finally, an example allows for the quantification of the influence of the new factors and the interpretation of the opportunity costs.

Stochastic finite element method (FEM) was applied to analyze the mechanical property of the corroded pipeline. Firstly, mechanical properties of the corroded steel were studied. Then, dynamic properties of the corroded pipeline were investigated; sensitivity analyses were performed on the effective factors respectively. Considering the distribution characters of the defects on the pipe surface as stochastic variables, a series of numerical investigations were executed on the corroded pipeline. Relation between the dynamic property of the submarine pipeline and the corrosion state of the material is achieved.

A large Florida Utility identified the need to develop and implement a wastewater collection system rehabilitation program. CDM provided services to provide technical and program management assistance to staff in developing and implementing a countywide Wastewater Collection System Rehabilitation and Replacement (R&R) Program. This project developed a systematic methodology to identify, rank and prioritize sewer system repairs and/or replacement projects. The process developed an initial project list and the development of a wastewater collection system rehabilitation program implementation strategies and tools. The program provided an evaluation of the gravity system, pump stations, and forcemains in order to prioritize R&R needs. In order to identify the immediate rehabilitation needs in the system and to provide a framework for a continuing future rehabilitation strategy, collection system components (gravity systems, pump stations, and forcemains) were evaluated based on both criticality (consequence of failure) and condition (probability of failure). Prioritizing pipes and pump stations in terms of their criticality and condition identified components that needed immediate inspection, rehabilitation, and continued monitoring.

Proper management of sewer pipeline networks involves fulfillment of many technical requirements under economic constraints. Therefore, cost effective solutions are required to assist municipal engineers in prioritizing maintenance and rehabilitation needs. This demands a systematic approach to condition assessment of rapidly deteriorating sewers. Performance evaluation of sewers through random inspections is expensive. Therefore, there is an urgent need to develop a proactive sewer pipeline condition prediction methodology. This paper presents a method for assessing a sewer's structural condition by utilizing general pipeline inventory data. Based on historic condition assessment data, condition prediction models for sewers are developed using multiple regression technique. The final outcome of these models produces most likely condition rating of pipes, which will assist municipal agencies in prioritizing pipe inspection and rehabilitation to critical sewers.

In order to assess the water pipe condition without excavating, artificial neural network (ANN) model was developed and applied to real-world case in South Korea. For the input in this ANN model, 11 factors such as (1) pipe material, (2) diameter, (3) pressure head, (4) inner coating, (5) outer coating, (6) electric recharge, (7) bedding condition, (8) age, (9) trench depth, (10) soil condition, and (11) number of road lanes were used; and, for the output, overall pipe condition index was derived based on 5 factors such as (1) outer corrosion, (2) crack, (3) pin hole, (4) inner corrosion, and (5) H-W C value. For the ANN computing, each factor was normalized into the range of 0 to 1. The ANN model could find better results than those of multiple regression model in terms of statistical correlation between observed and computed data.

With the rapid development of the economy in Shanghai—the metropolis in China, the density of the underground pipelines and the load of the pipeline network are increasing at a high rate. To guarantee the operation of the city properly, safety of Underground Pipeline. Network (UPN) must be one of the foremost considerations. In this paper, the authors present a method to assess the UPN safety in Shanghai by applying a newly designed Safety Grade Evaluation Model (SGEM). Furthermore, this paper provides a safety management system, which will optimize management of UPN, by applying a Rehabilitation Cost Model (RCM). At last, the authors design a roadmap for SGEM for future applications. The above models enhance efficient management of pipeline network in Shanghai which will be helpful to rapid development of the city.

After the 4.5-mile (7.2 km), 50-year-old, 2.6 m (102-inch) Olmsted Flowline Pipe was acquired from a power company, Central Utah Water Conservancy District (CUWCD) investigated ways to increase its reliability and reduce its maintenance. Its lower "Reach A", a 0.6 km (2000-foot) reach of pipe on a cliff, was failing due to punctures from boulder falls, steel trestle failures, concrete support cracking, pipe lining and coating failure, and inadequate maintenance access. CUWCD rehabilitated this pipe on a cliff in order to provide a spillway for a new regulating reservoir, provide hydropower reliability, reduce operations and maintenance (O&M) in a hazardous work area, and improve canyon aesthetics. CH2M HILL designed rehabilitated facilities for relocating the pipe (to "tuck" it into the cliff), textured concrete surfacing to aesthetically blend pipe encasements into the cliff, a drivable access for the cliff pipe, rock anchors to secure the pipe to the cliff, and vegetated reinforced earth slopes at non-cliff reaches. The Olmsted System spillway for a new 10 million gallon (MG) tank were maintained by the cliff pipe rehabilitation where flows were split between the hydropower system and CUWCD's municipal and industrial (M&I) system. Steep earthen cross slopes were soil nailed to allow for a buried pipe replacement of the Flowline. This approach eliminated talus buildup on an above ground pipe while stabilizing slopes uphill of trench cuts so they would not fail into the new buried pipeline in construction or in perpetuity.

Population growth and, consequently, increased demand on the water distribution system in San Marcos, Texas, created the need for increased water flow to the southeast section of the city. The City's Master Plan defined the size and established preliminary termination points for the proposed transmission main. Although the Master Plan defined the pipe size as 30-inch (762mm), it was the responsibility of the City of San Marcos's consultant, Carter & Burgess, Inc. (Engineer), to confirm the size and to provide a final design for the water transmission main. The project final design called for approximately 19,500 feet (5.9 km) of 30-inch (762mm) and 5,200 feet (1.6Km) of 24-inch (610mm) water line. Mitigating the impact to historical and cultural resources was paramount to this project. A major portion of the proposed pipeline alignment followed the El Camino Real, or Kings Highway, a trail from Monterrey, Mexico, to San Marcos, to the Caddo Indian villages in East Texas. This trail was used by the Indians of yesteryear and many Spanish explorers who traveled along the San Marcos River. One site within the project corridor was the Villa of San Marcos de Neve, established in 1808. Previous archeological excavations near this site found artifacts dating back more than 11,500 years. Today, the old Camino Real is one of Hays County's most valuable historical assets. To ensure preservation of this protected area, the Engineer specified horizontal directional drilling (HDD) for construction of the pipeline under the San Marcos River and through the area. The HDD installation portion of this project presented several unique opportunities and challenges. This paper will discuss several of these, including the world's first installation of twin parallel 30-inch (762mm) flexible restrained joint ductile iron pipelines, each approximately 1,200 LF (369m). The project also involved the Ductile Iron Pipe Research Association (DIPRA) and Corrpro, a leading provider of corrosion control engineering services, systems, and equipment, to evaluate the long-term effectiveness of polyethylene encasement applied to 30-inch (762mm) pipeline installed using HDD. Finally, this paper will provide designers and end users with information about the proper HDD application, design, and installation of flexible restrained joint ductile iron pipe.

Installation of combined sewer overflow (CSO) consolidation conduits in difficult waterfront conditions would have been no easy task as originally designed and bid, using cut-and-cover methods, yet an aggressive Value Engineering (VE) proposal was accepted and the installation accomplished using pipe jacking methods. Five-hundred-and-ten (510) feet of conventional pipe jacking was successfully accomplished to install 54-inch and 30-inch consolidation conduits as part of the Narragansett Bay Commission's (NBC) CSO Control Facilities Program. This paper will present site conditions, a comparison of the original cut-and-cover design and the VE pipe jacking proposal, provide construction details and challenges. The conduits were installed in a narrow strip of land between historic waterfront structures and the Providence River with a portion of the alignment beneath high-tension towers and transmission lines. The ground conditions consisted of urban fill, a soft organic silt deposit, and abandoned power tunnels, slips and wharfs. Bid documents directed an open cut with an Owner-designed secant pile wall support of excavation and installation of reinforced concrete pipe (RCP) for the conduits, and the Contractor's proposed VE largely eliminated open cut and included pipe jacking with sheeted pits. The VE proposal was negotiated and the Contractor successfully completed the pipe jacking using an open-face shield, ground improvement using chemical grouting, Permalok steel casing and high density polyethylene (HDPE) pipe. Several large obstructions, including concrete-filled vaults, abandoned tunnels, timber piles, and steel sheet piling were encountered and excavated from within the pipe jacking shield. Challenges and risks associated with open-cut excavation in a difficult waterfront environment were significantly reduced by implementing the pipe jacking VE change, but were not entirely eliminated.

Since its development in 1948, and its introduction by the industry in 1955, Ductile Iron Pipe has become the most widely used product for water line installations. In conjunction with water line installations, Ductile Iron Pipe has become often used for gravity and force main sewer applications. Following a tradition with hundreds of years of history, Ductile Iron Pipe was a logical progression from its predecessor, Cast Iron Pipe. Ductile Iron Pipe has been widely embraced due to its inherent strength, ease of field adaptability, and myriad of joint options. When the directional drilling method of pipeline installation was first introduced to the United States, members of the ductile iron pipe industry did not view their product as applicable to this method of installation. The reason; it was incorrectly believed that the directional drilling installation method required a pipe material with a uniform outside diameter throughout the entire pipe length. Consequently research and development efforts were put into action to design and test a ductile iron pipe restrained joint with a uniform outside diameter. During this time of Research and Development by the Ductile Iron Pipe Manufacturers, Horizontal Directional Drilling became a rapidly growing form of pipeline utility installation. There are several key reasons for this installation method growth. Some of the reasons are utility replacement in areas of well maintained landscape, residential areas with well maintained streets and driveways, as well as highly sensitive Historical areas. Open trench construction techniques can be very disruptive and controversial in these sensitive areas. Environmentally sensitive areas have also proven to be key areas where Horizontal Directional Drilling installation methods lessen if not eliminate impact on environmentally sensitive areas.

The 19-mile, Lower Northwest Interceptor (LNWI), consists of twin 60-inch and 66-inch forcemains. The LNWI construction required 12 twin microtunneled crossings including a crossing of the River City High School Campus. When the preliminary design called for the installation of the twin 60-inch steel force mains across the campus by open-cut methods, the School District placed severe restrictions on access to the site including time allowed for construction and restoration. The design engineers (CH2M HILL and Bennett/Staheli Engineers) then recommended tunneling to reduce cost and mitigate access and schedule restrictions. The contract as bid required two 1,200 foot microtunneled bores across the school campus and two 250 foot bores across a freeway operated by Caltrans from a common jacking shaft located immediately south of the freeway on the High School property. In order to further reduce schedule time, the Contractor proposed to combine the Freeway Tunnel and High School Tunnel into one tunnel push. Caltrans required a casing and two-pass installation but the High School Tunnel was only economical as a single pass tunnel. This required pushing two different pipe types in one tunnel push. It is believed that these twin, 1,420 foot tunnels are one of the longest 60-inch microtunnels completed to date. In addition to the 1,420 foot drive lengths, some of the additional challenges included microtunneling with shallow cover in close proximity to the high school's swimming pool, tennis courts, and running track. The contractor, Michels Pipeline, was able to complete both tunnels with minimal problems.

This paper provides an overview of Vacuum Technology and its use in exposing underground utility infrastructures safely and effectively prior to replacement or renewal of aging pipelines. The introduction includes an explanation of why the use of air is preferable over water when utilizing vacuum technology. Applications for use of vacuum technology and the procedures for avoiding conflict are discussed. Step-by-step instructions are provided on how to utilize vacuum technology effectively. Safety standards, conclusions, and acknowledgements complete this overview on the procedures for utilizing vacuum technology safely and effectively.

The City of Baltimore (City), Maryland has recently undertaken an extensive program to upgrade and rehabilitate their aging sewer system. The City, whose aging infrastructure has led to the necessity to replace and upgrade their existing systems, is under an Administrative Consent Order (ACO) to bring their system into compliance with state and federal regulations and to cease polluting the Chesapeake Bay. As part of the ACO, the City is required to upgrade the force main servicing the New Jones Falls River Basin. The work to be performed includes, in part, upgrading the existing pump station, upgrading the gravity sewer, and replacing the existing 36" force main. The replacement of the 36" diameter force main requires the installation of 42", 48" and 54" Prestressed Concrete Cylinder Pipe through city streets at depths well in excess of 20 feet and, in some instances, in excess of 30 feet. In order to complete this upgrade, the pipelines that are required to provide the City with sewer services are both larger in diameter and more difficult to construct than the existing ones. What is more, the presence of existing utilities makes it more difficult for engineers to find non-conflicting routes for the new pipelines. As a result, the new pipe lines are requiring extensive relocation of existing utilities; they are being constructed deeper and are becoming more costly to the owner. This paper will follow the New Jones Falls Force Main Project through the following phases: Design; Bidding; and Construction; with the main emphasis on the Construction Phase.

The first author has been practicing geotechnical engineering for primarily pipeline engineering projects for over 30 years and has amassed significant experience under varying site conditions from over 300 projects. The second author has been a contractor-engineer for over 40 years and has built over 200 pipeline projects. Both authors have seen many pipeline projects by either trenchless or open cut construction methods run into serious problems, disputes, arbitrations, mediations, and court proceedings when the engineer of record of the pipeline project failed to do an adequate baseline geotechnical investigation. Often the trench design, dewatering systems, shoring systems, soil support systems, bedding and backfill were inadequate due to the engineer of record not doing an adequate geotechnical analysis and existing utility mapping. These short-comings may result from too much emphasis on profit, too little time to perform all of the steps, or engineering firms allocating budgets that restrict quality engineering of the projects. The pipeline project may also fail due to soil migration. This is a common occurrence when no filter criteria are checked and when no suitable material is designed in the trench zone. Thus, the pipe loses its lateral support, becomes over-deflected, fails to meet the design criteria and in some cases even collapses. Although means and methods are the responsibility of the contractors, licensed engineering professionals simply cannot expect the contractors to construct projects properly when there are too many deficiencies in the engineers' designs, specifications, and mappings of existing utilities. It is not possible for contractors to perform miracles in the field when the engineers of record simply do not afford the standard of care expected of them by their clients. Unnecessary problems can occur when the engineering firm's revenue generation, company growth, and client relations take precedence over staffing pipeline projects with sufficiently qualified engineers. In summary, the success of the pipeline project depends heavily on knowing enough about what is in the ground, how ground conditions behave toward buried pipelines, and how to cope with difficult site conditions. The authors document some guidelines on the above issues using several case histories from their involvement in over 500 pipeline projects.

The City of Richmond is part of the Greater Vancouver Regional District in British Columbia, Canada and is located on a flood plain with elevations ranging from approximately 0.6 metres to 2.5 metres above sea level. These physical attributes present numerous challenges and opportunities with underground utility design and construction. Design and construction of water mains in combination with soft soil, river delta ground conditions in particular lends itself to trenchless construction opportunities. The City established an Asbestos Cement water main replacement program in the 1990's and the Shellmont watermain replacement project was designed to be undertaken using the conventional "open trench" procedure. The contractor proposed the use of HDD and segmented Cobra Lock PVC C900 DR18 pipe as an alternative, "trenchless" method as an innovative opportunity and one that would reduce costs and provide many tangible benefits to residents adjacent to the work. Implementation of this alternative method proved to be successful and was recognized as an opportunity for future water main installation work.

The Austin Country Club (ACC) and Davenport Ranch development needed to decommission its independent wastewater treatment facility and connect to the City of Austin's wastewater conveyance system. To support this initiative, the City of Austin developed a Master Plan to build a new Lift Station in the ACC area and discharge the wastewater to the city's Cross Town Tunnel. To implement their plan, the City would need to design and construct a 4,000 foot force main that crossed the ACC golf course and Lake Austin. Concurrently, the City partnered with Austin Energy, the local electrical supplier, to bundle the force mains with a series of electrical conduits, allowing Austin Energy to extend electrical service between the Davenport Ranch development and the Austin Energy transmission system on the other side of Lake Austin. This paper discusses the many challenges addressed during the design and construction phases of the project, ultimately resulting in a successful HDD installation, providing vital new wastewater and electric infrastructure to the residents and businesses surrounding Davenport Ranch.

A simplified methodology is presented to estimate the required pull loads on polyethylene pipe installed by a mini (or midi) — HDD process. A simplified procedure is also presented to evaluate the potential collapse tendency of the PE pipe during the installation or post-installation phases. The methodology and associated formulae are based upon approximations to the more complex set of equations and procedures provided in ASTM F 1962, Standard Guide for Use of Maxi-Horizontal Directional Drilling for Placement of Polyethylene Pipe or Conduit Under Obstacles, Including River Crossings. The objective is to provide a convenient means of identifying potentially problematic mini-HDD installations and/or to aid in the pipe (DR) selection process, in contrast to the extensive planning or analytical investigations characteristic of typical maxi-HDD projects. The proposed mathematical model reflects the major route parameters (bore length, planned bends) and buoyant weight for an empty PE pipe, and also accounts for unplanned curvatures (undulations) resulting from path corrections in a typical mini-HDD installation.

Regardless of the project delivery method (i.e. Design-Bid-Build, Design-Build, etc), trenchless rehabilitation is often overlooked as a solution to rehabilitate underground infrastructure. Pairing trenchless solutions with Design-Build project delivery, however, produces a powerful synergy that is virtually unequalled in construction. Design-Build (D-B) trenchless solutions bring numerous advantages regarding owner and design costs, design and construction schedules, critical path impacts and risk, and project profit that "dig and replace" alternatives do not. Trenchless solutions help allay some of the main owner "trust with verification" concerns while achieving 50-100 year performance. Additionally, trenchless solutions can provide sustainable design benefits that are increasingly important to customers, designers and the environment. The unique characteristics of D-B project delivery fully capitalize on these advantages. This paper overviews appropriate trenchless technologies and the D-B project delivery. Next, it examines the beneficial relationship between pipeline rehabilitation using trenchless technologies and the D-B project delivery method. It details the criteria for choosing Design-Bid-Build or D-B pipeline rehabilitation from the viewpoints of the owner as well as individual design-build team members. Most importantly, it offers: 1) Owners the "right questions to ask", 2) Engineers the latest in trenchless applications for design-build, and 3) Design-builders another, high-powered tool for ensuring project costs, schedule success and repeat business. Areas of opportunity and conclusions are presented. The primary position reiterates the beneficial relationship between Design-Build project delivery and appropriate trenchless solutions. The elements are far more successful and powerful when combined, than when trenchless is used in other project delivery methods or when Design-Build utilizes "dig and replace" alternatives.

Horizontal Directional Drilling (HDD) is a commonly accepted construction method for installation of pipelines throughout the U.S. and abroad. Most HDD installations are performed in rural areas where there are no significant structures under the alignment and where pipe laydown area and construction staging area are plentiful. However, HDD applications in urban settings have also been gaining increased consideration despite its inherent challenges with a built-out environment and sufficient drill side and pipe side construction areas. The Bellevue Pump Station Force Main is one such HDD project that will construct 5,300 feet of 24-inch diameter (ID) sanitary sewer force main just south of downtown Bellevue, Washington. The two main segments of the force main will be installed by HDD using a 32-inch steel casing pipe and 28-inch HDPE carrier pipe. The first HDD segment is a 3800 feet long, 200 feet deep crossing that will be installed under several residences, Bellevue High School, a condominium complex, and a courthouse building with only 650 feet of pipe laydown area. The second HDD segment is a 1000 feet long crossing under State Route 405 with a 70 foot elevation difference that will require a lane closure of a major arterial in Bellevue, WA. Construction is scheduled to begin in May 2007. This paper discusses the pipeline alignment alternatives evaluated, the selection of the final HDD alignment, the final pipeline design for the HDD crossings, permitting and easement issues, and lessons learned during design.

Buried municipal infrastructure is rapidly expanding due to increased urbanization. Subsequently, engineers and contractors are faced with having to designate the most effective method of installing new buried infrastructure while being mindful of cost considerations. In order to determine the most feasible underground construction method, various risks and cost factors must be assessed and analyzed. A comprehensive survey was conducted at Arizona State University to solicit input from twenty-eight contractors in various geographical regions throughout the United States and Canada. The intent was to determine specific risk factors and their inherent impacts, as well as to quantify cost comparison between Horizontal Directional Drilling (HDD) and traditional open cut construction methods. This paper identifies and describes risks and cost factors that were subsequently used to create a planning tool for small diameter pipelines in an urban environment.

The Greater Vancouver Water District (GVWD) is constructing the $600 million Seymour-Capilano water filtration project to enhance drinking water quality in the Vancouver metropolitan area. The project comprises the Seymour-Capilano Filtration Plant, the Capilano Pumping Station, the Twin Tunnels with associated shafts and the Capilano Break Head Tank/Energy Recovery Facility. The Twin Tunnels will convey untreated, raw water under pressure from the Capilano Reservoir to the Seymour-Capilano Filtration Plant and return treated water for distribution to the member municipalities. The tunnel system comprises twin 3.7 meter diameter tunnels approximately 7.2 km in length, the 11 meter diameter, 180 meter deep Seymour shaft as the main launch shaft, and two 4 meter diameter, 268 meter deep raisebore exit shafts at Capilano. Among the numerous complexities of a project of this scope was the selection of pipe materials, including the lined Twin Tunnels portion of the project. Steel pipe was the only tunnel lining material, of several that were considered, that offered the required combination of being completely water tight at the high water pressures associated with this application, capable of resisting the buckling loads, providing seismic properties required and providing acceptable constructability. The GVWD also has a long history and good experience of using steel pipe as the transmission water main material of choice. These items and high seismic design standard led the GVWD to select steel pipe for use on the Seymour-Capilano filtration project. Project construction commenced in 2003 and is expected to be complete by the end of 2008. Once completed, the GVWD will reliably deliver water of quality in full compliance with the Canadian Drinking Water Quality Guidelines and the Provincial Drinking Water Protection Regulation.

Since its formation in 1951, the North Texas Municipal Water District has been charged with developing a reliable water supply source for its 13 member cities and 46 other customers (some direct and some indirect), including more than 1.5 million people in portions of north Texas including portions of Collin, Dallas, Denton, and Kaufman Counties and all of Rockwall County. Recent long-range water supply planning efforts have identified significant increases in water demands that must be met through a corresponding increase in available raw water supply. Compounding the need for raw water is the fact that the North Texas region is currently in the second year of a drought that is the worst on record since the 1950s, with the District's primary water supply reservoir, Lake Lavon, falling some 17 feet in water surface elevation since mid-2005. In an effort to supplement available supplies, the District contracted for 50,000 acre-feet of water per year from the Sabine River Authority in Lake Tawakoni, located approximately 45 miles east of Dallas in October 2005. Given current drought conditions and ominous rainfall forecasts, the District has requested that the infrastructure needed to transfer this water from Lake Tawakoni to Lake Lavon be in service no later than October 1, 2007, to prevent further water restrictions and possible water rationing. The infrastructure needed includes approximately 30 miles of 54 and 60-inch-diameter transmission pipeline and two pump stations, each with a raw water pumping capacity of 75 MGD. The estimated project cost is $100 million. Critical path issues for meeting the highly accelerated schedule include overall project team coordination; route selection; environmental permitting considerations; easement and property acquisition; power supply; equipment delivery; and construction of multiple project components simultaneously. The focus of this paper is to discuss the critical path issues and offer lessons learned from fast-tracking the design and construction of a multi-million dollar water transmission project.

Black & Veatch Corporation is directing a project team that is designing a new $185 million supplemental raw water supply from Lake Nacimiento for San Luis Obispo County. The project consists of a multi-port sloping intake facility and pump station, two intermediate pump stations, three storage tanks, control center, and approximately 45-miles of transmission pipeline ranging in diameter from 36-inches to 12-inches. This paper discusses the planning and design of the intake facility, which is a 180-foot deep, 16- to 20-foot-diameter vertical shaft connected to the lake via a single 48- to 72-inch diameter microtunneled intake tunnel with a lake tap. A surface-mounted sloping intake with seven ports will allow water to be drawn from various depths of the reservoir for optimal water quality control. Also addressed are the intake alternatives considered during conceptual and preliminary design, and detailed construction planning with the use of a geotechnical baseline report (GBR) in the construction contract documents.

In the evaluation, planning, and design of pipes to serve as final liners for tunnels, the greatest emphasis during the design phase of the project is typically placed on the geological conditions to be encountered in the construction of shafts and the installation of the tunnel. The design of the shaft supports, selection of tunneling methods, initial tunnel supports, and control of the groundwater during tunneling become the most investigated elements in the design process. Often overlooked in the literature or in design guidelines are detailed descriptions of the processes necessary for proper pipe selection and pipe strength. If the wrong type of pipe is selected, damage during construction is possible and the system may have a less than planned service life. Using five projects as examples, this paper attempts to identify key criteria in the selection of pipe for tunnels constructed by tunnel boring machine (TBM) and microtunnel boring machine (MTBM) methods. In selecting the pipe for a given project, the following parameters must be considered: 1) Service fluid type (i.e. potable water, sanitary, or storm sewer), 2) Internal operating fluid pressure, 3) External ground and live loads, 4) External water load (groundwater), 5) Method of installation, 6) Material handling loads, 7) Owner history with pipe material, 8) Construction costs, and 9) Lifetime Expectancy.

Baytown, Texas is a highly industrialized city of oil refinery, rubber, and chemical industries located on Galveston Bay, approximately 30 miles east of Houston. Baytown population grew from about 20,958 in 1948 to about 66,430 in 2000, and its continued growth requires planning of city services including sewer service. In order to promote continued growth in the N. Main Street and Baker Road area, the City is planning to extend Baker Road, eastward from N. Main Street and provide sewer service to current and new businesses and neighborhoods in the area. The sewer project included 15-inch gravity sewers along N. Main Street, a duplex lift station, and a 6-inch force main crossing a flood control channel. N. Main Street is a five-lane roadway, constructed of reinforced concrete. As the street runs through the heart of Baytown, it experiences a steady flow of heavy traffic. It would be difficult and costly to close portions of the roadway for the construction of the proposed gravity sanitary sewer. The numerous utilities within the Right-of-Way also posed challenges for the installation of a new sewer system. Within the N. Main Right-of-Way, there are existing pressure force main, gas lines, water lines, over head power lines, and various other utilities. During design phase, it was determined that the most efficient and cost effective way to address these issues was to install the sewer system by open cut where feasible, and use the combination of augering and horizontal directional drilling to avoid existing utilities and minimize impacts on above ground features. This paper will present the challenges, planning and coordination efforts required to construction the sewer system describe the importance and benefits of trenchless technologies to Engineers during design and construction phases of infrastructure projects.

Beginning in 2007, the U.S. Environmental Protection Agency's (EPA) Office of Research and Development (ORD) is planning to support a new research program to generate the science and engineering to improve and evaluate promising innovative technologies and techniques to reduce the cost and improve the effectiveness of operation, maintenance, and replacement of aging and failing drinking water and wastewater treatment and conveyance systems. This research program directly supports the Agency's Sustainable Water Infrastructure Initiative. This paper will outline the plans for addressing condition assessment and rehabilitation needs for gravity sewer pipes in the U.S. In 2002, the EPA's Office of Water (OW) carried out a study to gain a better understanding of the challenges facing the Nation's drinking water and wastewater utilities. EPA published The Clean Water and Drinking Water Infrastructure Gap Analysis (EPA-816-R-02-020), also known as the "Gap Analysis" report. The report identified several issues that raised concern as to the ability of utilities to keep up with their infrastructure needs in the future: 1) Our wastewater and drinking water systems are aging, with some system components exceeding 100 years in age; 2) The U.S. population is increasing and shifting geographically. This requires investment for new infrastructure in growth areas and "strands" existing infrastructure in areas of decreasing population; 3) Current treatment may not be sufficient to address emerging issues and potentially stronger regulatory requirements; and 4) Investment in research and development has declined. This paper addresses two major research areas identified as critical by EPA; condition assessment and system rehabilitation.

Peddocks Island, located between the coasts of Hull and Quincy, Massachusetts, is one of the largest and most ecologically diverse islands in Boston Harbor. Located on the eastern side of the island, Fort Andrews is a magnificent example of Endicott Period military fortifications. However, since 1947, when it was abandoned by the U.S. Army, the fort has fallen into disrepair. Because of its history, Peddocks Island has been certified as an Historical and Archeological Landmark. Plans are in place for the rebirth of Fort Andrews into a vibrant family camp and eco-retreat that will be the gemstone of the Boston Harbor Islands. However, before the redevelopment of the fort complex could begin, reestablishment of utility service to the island was necessary. The previously existing 100-year old submarine water and electric services to the fort had been destroyed, and no water or electric service to the island existed, except for a small photovoltaic system. An aged sewer system that discharged directly to the ocean was also unusable. A feasibility study of alternatives to bring utility service to the island was conducted, with the selected alternative consisting of horizontal directional drilling approximately 2,000 linear feet beneath Hull Gut, a major shipping channel for Boston Harbor, from the Hull main land to Peddocks Island. A single 20-inch diameter steel casing within the drilled bore hole housed HDPE conduits that provided power, communications, wastewater and water service to the fort complex to fullfill the projected utility needs for the planned island buildout.

Engineering design and construction can be especially challenging in Alaska because of the harsh, remote, and sensitive environment. This paper focuses on the design and construction challenges of creek crossings of a large diameter potable water transmission main in the Municipality of Anchorage (MOA), in Southcentral Alaska.

The San Diego County Water Authority (Water Authority) selected CH2M HILL to design, construct, and operate its new 100 mgd Twin Oaks Valley Water Treatment Plant (TOVWTP). The project includes 21 major structures built around an existing 22 million gallon reservoir on 45 acres of land. By contract, the $157 million dollar project must be designed, constructed, and operational within 30 months. This requires a "fast track" design and construction schedule, multiple pre-purchase contracts with vendors and suppliers, and separate foundation packages for many of the structures. Mass excavation and earthwork, based on the 30-percent design package, began approximately three months after receipt of the Notice to Proceed. The design is complete and construction is moving at a very rapid pace to ensure that the 100-mgd TOVWTP will be operational by April 2008 to meet regional treated water needs for San Diego County.

The contractor installing a 48-inch steel water line filed for bankruptcy and vacated the project after installing approximately 90% of the pipe, but prior to any testing. The contractor's surety company hired another contractor to complete the project, which consisted of approximately 4,800 linear feet of tape coated and mortar lined steel pipe along the busy roadways of Almeda and Holcombe near Houston's Texas Medical Center. Upon arriving at the site, the completion contractor notified the City of Houston of potential problems with the pipe already installed, particularly, excessive deflection or "egging" along the vertical axis. Following this discovery, the City contracted with Lockwood, Andrews & Newnam, Inc., (LAN) and invited the pipe manufacturer to perform an internal inspection to assess the situation and recommend a repair solution. The inspection revealed approximately 141 of 235 pipe sections installed (approximately 3,035 LF, or 60% of the total pipe installed) had deflected beyond the 3% allowed by Specifications. The inspection also revealed several segments with dented cylinders, one with a puncture through the cylinder, and seven with severe longitudinal cracks which are indicative of damage to the cylinder. Pipe sections were observed to have deflected up to a vertical diameter of 44-inches, approximately 8.3%. City of Houston Specifications state that the maximum allowable deflection for mortar-lined steel pipe with a flexible coating is 3% of pipe diameter. This is consistent with AWWA M-11 requirements. (In this case: 3% of 48-inch = 1.44-inch maximum allowable deflection). There are two major reasons for limiting the amount of deflection allowed. First, the pipe relies on a circular shape to support the external loads. Second, excessive over deflection can cause cracking of the interior mortar lining which could lead to corrosion. However, because much of the project limits were within the roadway, and had already been repaved, correcting the pipe deficiencies would have a major impact to Texas Medical Center traffic. LAN and the City agreed on a variance in the maximum deflection, and accepted pipe with up to 4% deflection. A total of 58 pipe segments exceed this deflection. It was required that any pipe to be re-rounded would still meet the original specifications of 3% maximum deflection. The observed deficiencies also led to other concerns regarding possible pipe coating damage and the potential for long-term pipe and pavement settlement. This paper presents the results of internal and external pipe inspections, pipe embedment and backfill testing and discusses the likely causes of over deflection in this flexible pipe. The paper also describes the repair methods used, repair cost, and lessons learned in the process.

In 2001 Denver Water began its efforts to install a Recycled Water Distribution System to bring water from a newly constructed recycled water treatment plant to parks, golf courses, and other large users in Denver. The source water is taken from the effluent of the major wastewater treatment plant serving metro Denver. The water is then treated to bring the water's quality to levels suitable for irrigation and other non-potable uses. Phase 1 of the Recycled Water Distribution System became operational in 2004. In 2005, Denver Water began the design of Phase 2 of the Recycled Water Distribution System. The purpose of this expansion is to bring water to irrigatable portions of two large areas undergoing redevelopment; the former Stapleton Airport and the former Lowry Air Force Base. In addition to distribution piping, Phase 2 consists of a treated water reservoir and a pump station. Phase 2 is scheduled to become operational in the spring of 2008. The distribution piping installed during Phase 1 and Phase 2 consists of over 80,000 feet of large diameter pipelines (24" – 54") and over 11,000 feet of small diameter mains (6"–8"). The majority of the pipelines are being installed through relatively older and dense residential areas of the city. The pipelines cut across 3 golf courses and 6 park areas. There are 4 highway crossings and 4 railroad crossings. Relocation of hundreds of utilities, including gas mains, water mains, fiberoptic conduits, and sewers had to be performed ahead of the pipeline installation. This required significant coordination with many different private and public entities as well as an extensive public relations effort. A total of 12 contracts, totaling approximately $40 million, were used to construct the distribution system. The project was pieced out to facilitate limited design resources and a tight construction schedule. A number of special features are being added to the pipeline to help identify this pipeline as a recycled water pipeline. These include purple exterior, pentagon shaped valve nuts, and reversal of direction of operation of valves. Additionally, the pipe was not permitted to be lined with cement mortar due to concerns that it would cause the pH levels in the water to rise. The concern was that lime in the cement mortar would leach from the lining during the relatively slow velocities the pipeline would experience in the winter. Horizontal Directional Drilling was used to install portions of the smaller diameter PVC mains. This method of installation was allowed to compete against traditional open trench installation. This allowed Contractors to weigh the decreased permit and restoration costs versus the setup associated with directional drilling. This method also significantly reduced the level of inconvenience to residents and customers. The purpose of this paper is to describe the items specific to a recycled water pipeline as well address the coordination and planning required for a pipeline project of this scope.

The market for large diameter water pipeline construction in Texas has historically been a buyer's market compared to most of the remainder of the United States. Unit prices for pipeline construction in Texas have historically been very competitive, due to the large capacity of local contractors and pipe suppliers, low labor and material costs, and local construction practices. In the last four years, pipeline construction demand in Texas has increased significantly due to growth and drought. Local demand has begun to exceed local supply and prices have increased as much as ninety-six percent in four years. Some of the price escalation is due to the increases in costs for steel, cement, gravel, diesel and other raw materials of construction. Contractors are also raising bid prices to cover material price volatility and to increase margins in this Seller's market. Other inflationary factors include increased labor cost due to reconstruction after Hurricanes Katrina and Rita and fewer bidders due to the bonding companies tightening up on the bonding capacity of general contractors. Measures used to mitigate the price escalation include structure of the bidding packages, allowing longer advertising periods, using smaller construction projects, recruiting more out of state contractors, allowing lower qualification requirements, allowing alternate pipe materials, and providing incentives. This paper describes some of the escalation factors seen in the Texas market, measures taken to mitigate the price escalation, and lessons learned.

A contamination plume in the public water supply aquifer of the Town of Wilmington, Massachusetts threatens five of the Town's nine water supply wells. In early 2003, the Town took those five wells off-line indefinitely, which created a significant water supply deficit. The Town recently completed a Comprehensive Water Resources Management Plan that investigated various options for the Town to augment its water supply. The Plan identified constructing a permanent connection to the Massachusetts Water Resources Authority (MWRA) regional water system as a sound, long-term water supply strategy. Although the MWRA water system is located within only 3.2 km (2-miles) of the Wilmington town-line, in north Woburn, potential project routes are constrained by an active commuter rail and an inactive landfill on the west, Interstate-93 on the east, and a busy industrial area that contains the "Industri-Plex" CERCLA (Federal Superfund) Site in between. Past uses of the Industri-Plex Site include chemical manufacturing and manufacturing of glue from animal hides. By the late 1990's, approximately half of the Site was covered with a protective cap to prevent exposure to contaminated soils and portions of the Site were redeveloped. Investigations into the extent of the groundwater contamination and residual migration continue. In December 2002, the Town began investigations to determine alternative routes for the proposed water transmission main connection. Between 2002 and 2005, the Town coordinated extensively with numerous parties to gain an understanding of the limitations of this area and to identify the most feasible project route. The selected route proceeds through municipal roadways and a remediated portion of the Industri-Plex Site to reach the MWRA water system. The proposed pipeline installation within the Site required careful design considerations and various construction techniques to prevent disturbance to the protective cap, keeping in mind an overall goal of minimizing disruption to abutting businesses during construction.

Utilizing horizontal directional drilling for the installation of a river crossing water main saved the Caribou Utilities District in Caribou, Maine significant permitting requirements, construction time and money. The Caribou Utilities District in Caribou, Maine, recently transitioned from a surface water source to a new groundwater source. The District retained the services of Wright-Pierce of Topsham, Maine, to design the wells, pump station and transmission mains. A 12-inch ductile iron water transmission main was used to bring water from the wells and pump station to the distribution system, for the entire length except for a required river crossing, which was installed by horizontal directional drilling (HDD). This paper will address processes by which HDD was selected as the best alternative for the river crossing, the permitting benefits of selecting HDD, problems encountered during construction, and the lessons learned from this interesting project.

The Landfill Reclaimed Water Distribution System consists of two pump stations and two force mains. Pump Station No. 1 pumps into a 640 m (2100 ft) long 90 cm (36 in) diameter Force Main under a static head of 150 m (500 feet). Pump Station No. 2 pumps into a 1125 m (3700 ft) long 75 cm (30 in) diameter Force Main under a static head of 90 m (300 ft). Both pipes are Ductile Iron Pipes with TR Flex joints, wrapped in polyethylene sheets and were supplied by U.S. Pipe. The lines were tested under a static pressure of 2000 kPa (300 psi) after completion. Subsequently the pipelines were connected to the discharge headers and tested under a static pressure of 2000 kPa (300 psi), at which time significant movements were observed at the pump station piping at both Pump Station No. 1 and Pump Station No. 2. The authors were engaged by the Sanitation District to investigate movements observed on the pipe headers at both Pump Stations during the pressure tests. This investigation focused on the adequacy of the design of the entire system, and the installation procedures during construction of the project. The manufacturer's recommended installation procedures are also reviewed. This paper reports on the details of this investigation and how appropriate corrective actions were taken to stop further movements in the lines once the pipelines were put back into service.

Many of the most important measures to reduce pipeline risk management are made in the very early stages of formulating a pipeline plan. These decisions, if tempered by experience and judgment, will greatly facilitate the many actions that will follow to design, construct and operate a pipeline. Conversely, if knowledgable managers do not make these decisions and actions in a timely manner, the path to efficient operation and effective risk management will be an uphill struggle. The successful implementation of a pipeline facility plan entails a myriad of actions and decisions, beginning in the conceptual stage and continuing into the operation and maintenance stage. The purpose of this discussion is not to review the step-by-step procedures for pipeline planning, design, construction and operation; it is rather to highlight some of those early considerations and decisions that we have learned from experience are very important but often overlooked. Discussion will include these decisions that will be made in the planning and design stages of a pipeline project's evolution: 1) Early identification of pipeline project need, 2) Identifying high consequence areas, 3) Planning for outages, and 4) Planning for condition assessment.

Pipelines are pressure vessels used to transport products from one location to another and as such their operation falls under the US Department of Transportation. In principle, the Office of Pipeline Safety (OPS) has oversight on all transmission pipelines; however, in practice, regulations only exist for oil and gas pipelines. Spurred on by several spectacular and deadly pipeline failures starting in the 30's, the industry is now fully regulated. Present regulations include both risk management as well as mandatory condition assessment in high-risk areas. There are presently no regulations pertaining to risk management, pipeline assessment or pipeline safety in the water sector. It is not clear whether the fact that water transmission pipelines seldom cross state boundaries or the perception of lower consequence failures for water mains means that the water sector shall remain largely unregulated. It is clear that just as there is a strong desire to operate petrochemical pipelines up to and beyond their design life, there is a similar drive for water pipelines. The replacement value of water pipelines in the US is estimated at over $700,000,000,000. Comparing and contrasting approaches to condition assessment and risk management in these two sectors will certainly strengthen the emerging best practices.

The water utility industry has a unique perspective on corrosion and corrosion control as compared to other industries that regularly implement corrosion control, such as oil, gas or other hazardous materials. The hazardous materials industries are compelled by state, local and federal regulatory requirements to implement corrosion control in order to minimize the risk associated with failure of their piping systems and facilities. There is as yet no such compelling motivation for external corrosion control in the water utility industry. A water utility can, if it so chooses, do nothing to control corrosion, and accept the consequences. Currently the major motivating factors in the water utility industry are to provide uninterrupted water service with a high quality product, preservation of assets, reduction of operating costs (leaks), minimization of possible sources of contamination to the water supply, and pride of ownership. Corrosion leaks, just like any other pipeline "break", can result in contamination of the water supply. Reducing corrosion leaks reduces the potential for negatively affecting water quality and the possible public safety and. health effect issues associated with any contamination of the water supply. The growth of the pipe rehabilitation industry is evidence of the wastewater utility industry's dealing with the consequences of poor design assumptions regarding the risk of internal corrosion. Concrete pipes designed on the basis of corrosion rate assumptions, and force mains designed assumed to be full, for example, have had design lives significantly lessened by changes in flow regimes. Like the water industry, the wastewater industry is motivated by reduction of leaks that can lead to contamination of groundwater. The risks assumed by the utilities investing in rehabilitation of pipe and manholes lie in the assumption of design life extension of the buried assets.

The goal of risk management is to minimize expected costs over time where the costs are defined in some probabilistic fashion. Traditionally, total expected costs due to failure are summed for planning purposes over a meaningful spatial and temporal domain and assigned a weight based on the likelihood of occurrence. Expected costs are the product of the consequence of an event (e.g. failure) and the probability of the event occurring. This is the commonly applied definition of infrastructure risk; Risk = criticality x vulnerability. The total risk-based cost is then compared with expected life-cycle costs to take mitigation action to reduce risk. Actions may include insurance, inspection, monitoring, improved construction, or increased maintenance. Action is taken if the benefits in terms of avoided costs exceed the costs associated with risk reduction. Unfortunately the probability of occurrence of specific events is uncertain at best, and at worst the decision-maker is in total ignorance about the likelihood of an event occurring. In the face of uncertainty with respect to the probability of these events, guidance for prioritization of projects may be gained from ideas developed in portfolio investment theory, which is concerned with decision making under uncertainty. Common methods of benefit/cost-based decision criteria fail to account for uncertainty. An example risk-based calculation from the sanitary sewer field will be used to illustrate risk management at the planning level for pipeline rehabilitation projects using risk based decision criteria.

In 1996, Providence Water experienced a catastrophic failure of its 102" PCCP aqueduct pipeline. Subsequently, the main underwent an extensive assessment and repair and was returned to service with plans that the main would be re-inspected in approximately 5 years. In 2005, Providence Water re-inspected the aqueduct. Since the previous inspection, the state-of-the-art for assessing PCCP mains has progressed significantly. Non-destructive technologies, available for assessing and monitoring PCCP pipe have made significant strides. Providence Water implemented state-of-the-art inspection procedures to obtain the best possible assessment of the aqueduct. Following the assessment of 4.5 miles of the aqueduct, Providence Water opted to install a fiber optic acoustic monitoring sensor to continuously monitor the condition of the aqueduct and identify pipe sections experiencing ongoing wire break activity. Providence Water utilized the following technologies during the most recent 2005/2006 inspection/monitoring program: 1) Electromagnetic Inspection- to detect wire breaks in the prestressing wire, 2) Visual and Sounding Inspection- to inspect for cracks or delaminations, 3) Resistivity Testing- to detemine the actual number of wire breaks on excavated pipe sections (vs. the estimated number based on the electromagnetic inspection), and 4) Acoustic Monitoring- to detect future wire breaks as they occur in the operational aqueduct. Following the initial inspection, one pipe section was found to be in a state of incipient failure. As a result, several nearby pipe sections were strengthened and a decision was made to install the acoustic monitoring system. This paper focuses on the assessment and monitoring technologies used during this project and describes the capabilities and limitations of these technologies.

Criteria for rehabilitation priority are an important factor in planning the improvement of water supply systems. In this study, deteriorations of water pipes are discussed to evaluate structural stability of deteriorated cast iron transport and transmission pipes. For the purposes, safety factor is introduced and estimated by measuring tensile strength and analyzing stress caused by the internal-external loads working on buried pipe body. Prediction models of a residual tensile strength are presented using pit characteristics and fracture toughness. Related information is surveyed and collected in the fields up the pipe by digging and assessing its structural stability. The collected data is analyzed to evaluate the deterioration degree of the pipes including corrosion and pitting characteristics, fracture toughness, installation environment and water qualities etc. Assessment models developed in this study showed a little correlation for measured residual tensile strength. The results will very help water utilities to manage water pipes in the aspect of rehabilitation and assessment of structural safety.

The San Diego County Water Authority has over 400 kilometers of large diameter pipelines that provides up to 95 percent of the water to San Diego County's 3 million people. Of the 400 km of pipelines, 133 km is made of prestressed concrete cylinder pipe (PCCP) manufactured between 1958 and 1982, and ranging in diameters of 168 cm to 244 cm. In order to provide a safe and reliable supply of water to San Diego County, the Water Authority implemented the Aqueduct Protection Program (APP) in 1992 which includes the condition assessment of the Water Authority's PCCP. Part of the program consists of developing and researching new non-invasive/non-destructive inspection procedures to determine the condition of existing PCCP. In March 2006, the Water Authority installed 17.1 km of acoustic fiber optic (AFO) cable to monitor wire break activity and to provide critical information on the remaining service life of the pipeline. During the commissioning of the AFO system, there was a catastrophic failure on a section of the pipeline. This paper discusses the equipment, results and accuracy of the AFO system.

Prestressed concrete cylinder pipe (PCCP) tends to be of large diameter, making many failures of this type of pipe relatively catastrophic and costly. To date, most research has been focused on PCCP inspection technologies and performance prediction in order to minimize the risk to utilities from failures. The performance of Prestressed Concrete Cylinder Pipe has been an item of interest to water utilities for a long time. Fifteen years ago, AWWA Research Foundation (AwwaRF) and the Bureau of Reclamation initiated a study, "Performance of Prestressed Concrete Pipe" that was unfortunately never published. AwwaRF has also funded studies to develop software that uses fuzzy logic (Kleiner, et al. 2005) to predict future PCCP behavior useful if a utility has sufficient data from actual field experience with PCCP. Another AwwaRF report (Romer, et al. 2005), developed methodologies, techniques, protocols, and technology for identifying the specific conditions that lead to corrosion failures of PCCP. That study included testing the effects of cathodic protection on pre-existing notches in PCCP reinforcing wires, and compared the accuracy of similar internal investigative tools for the detection of broken PCCP reinforcing wires. This paper presents preliminary results of the most recent AwwaRF funded study, intended to collect, codify, expand upon, and disseminate the results of the previous studies on PCCP failures. The project began with a survey of a selected group of water utilities with a fair amount of PCCP in their systems, selected carefully to represent the range of conditions and variables that affect PCCP performance across North America. The survey results, combined with a pre-existing database of over 450 PCCP failures, were statistically projected over the installed PCCP base of North America, and provide a surprising indicator of failures and failure rate of PCCP.

Pre-stressed Concrete Cylinder Pipe (PCCP) offers a reliability challenge for owners and their public. In recent years, many PCCP have been found with de-grading pre-stress wires. Pre-stress wire integrity must be maintained in order for a pipeline to remain reliable. With out fully competent pre-stress wires, life safety, property, and commerce are threatened. As a result, owners are faced with making difficult repair decisions, and providing resources required to support t on-going operation of their de-grading infrastructure. Modern forensic technologies offer non-destruction methods to facilitate condition assessment of PCCP. These technologies allow owners to assess and categorize critical repairs with unprecedented accuracy. However, in many cases assessments have not captured all required repairs. This is due to incomplete or non-definitive assessment information, and misinterpretation of assessment data. To avoid this problem, one surefire solution has been to simply repair any suspect spools. Unfortunately, this approach requires funding that may otherwise been used for detailed investigations, more precise identification of critical repairs, or for other infrastructure improvements. Fortunately, a concise approach which utilizes modern technologies is available to assist owners with the identification of deteriorated PCCP, to make appropriate repair recommendations, and to provide appropriate monitoring for the capture of degrading performance characteristics before they become critical. Assessment recommendations may prove to be overwhelming. Generally, the impact of a challenging repair-program not only requires allocation of unplanned funding, but may also require resources already planned for different purposes. As a result, owner's are faced with making critical operational and repair decisions, while having to manage other essential aspects of their business with fewer than required resources. Fortunately, methods are available that streamline decision making, reduce costs, and require minimal resources, while upholding quality and safety. Assessment information for both immediate and long term pipeline-management can be joined with modern analysis methods to allow development and execution of a meaningful repair schedule. A program of this nature will relieve an owner of having to justify repairs based on vague information, and potentially sacrificing existing programs to support an overwhelming repair schedule. The goal of any PCCP management program should be 100% reliability. Anything less would be selling the public short on water delivery and safety. Through available assessment technologies a repair schedule may be developed which holds to the ideal of 100% reliability while addressing the owner's means. PCCP reliability is based on critical performance paths, and state-of-the-art inspection and analysis techniques. Appropriate use of these methods will allow owner's to maintain the public's trust through a reliable water delivery system while optimizing value. Presented herein, is a method of PCCP management allowing the identification and prioritization of repairs, as well as recommendations for development of long term monitoring efforts. PCCP reliability management can be a complicated subject. Fortunately, availability of new technologies and a broad experience base has greatly simplified the process.

A condition assessment of the City of Atlanta 72-inch buried welded steel raw-water pipeline was performed in 2006 by CH2M HILL/Williams Russell & Johnson Joint Venture Inc. and ATS Inc. on behalf of the City of Atlanta Department of Watershed Management. The pipeline is spiral welded with ½-inch wall thickness and double welded bell and spigot lap joints. It was fabricated in 1973 and 1974 to the standard of "Mill-Type Steel Water Pipe," AWWA C202-64T, Class B. This assessment focused on structural integrity, as the pipeline has a history of numerous failures since entering service in 1975. Past failures have been reported as full-circumferential brittle fractures through the bell at the toe of the internal fillet weld. In-situ and laboratory structural examinations were performed including extensive analyses on a 4.5-foot sample, including an intact bell and spigot lap joint, cut from the 72-inch welded steel pipe (WSP) alignment. This assessment did not include an investigation of an actual failure site. Data from this assessment indicates that the steel is extremely brittle within the cold-formed bell (Charpy V-Notch < 6 ft-lbs at 60° F). Past failures are likely the result of a high concentration of stress in the bell at the toe of the internal lap (fillet) weld of the fully stabbed joint, where the pipe steel is extremely brittle and where welding-induced notches were observed. All failures have occurred during winter months when water temperature is lowest, the steel is most brittle, and thermal induced longitudinal tension is maximized. The authors wish to translate the results of this condition assessment into recommendations—from the consumer's perspective—for the improvement of the industry standards for welded steel water pipe. Although AWWA has made improvements to their standards (M11-2005, C200-1997, and C206-2003) due to lessons learned from other WSP failures, gaps remain within these publications that may allow defects in design, fabrication, and installation of a new WSP.

The Greater Lawrence Sanitary District (GLSD) learned in 2002 that Prestressed Concrete Cylinder Pipe (PCCP) supplied to GLSD in 1974, was similar to pipelines experiencing a high rate of catastrophic failures throughout the United States. The District began an assessment program in 2005 to assess the structural condition of one of its PCCP lines. This paper discusses the approach GLSD used to assess the structural condition of the pipeline, including finite element analysis, acoustic and transient pressure monitoring, electromagnetic inspection, visual and sounding inspection, and material testing. This paper also discusses the emergency structural repair that was accomplished when one pipe section was found to be in imminent danger of failure. GLSD treats wastewater from Lawrence, Methuen, Andover and North Andover Massachusetts and Salem New Hampshire. The design capacity of the GLSD treatment plant is 52 MGD. During wet weather, the flow is increased to 110 MGD. Current plans involve raising the peak wet weather capacity of the plant to 135 MGD and in the future to 165 MGD. GLSD owns over 4 miles of PCCP ranging from 48 to 102 inches in diameter, which was manufactured by Interpace Corporation in 1973 and 1974. Much of this pipe is used in lower pressure applications. However, one GLSD pipeline, the Riverside Pump Station (RPS) 2700 foot long 72 inch diameter force main operates at higher pressures. Virtually all sewage received by GLSD is pumped to the treatment plant through the RPS force main. The force main route is through a residential neighborhood and crosses under an active railroad track that is used by Amtrak, commuter trains and freight trains. The majority of the force main is between 200 feet and 1000 feet from the Merrimack River, a major recreational, water supply and fisheries resource. Failure of this pipeline would have significant financial, environmental and operational consequences. The GLSD learned of the issues with its Interpace Class IV PCCP in June of 2002 while engaged in planning for combined sewer overflow abatement. In March 2003, the Middlesex County Utility Authority (MCUA) in New Jersey experienced a catastrophic failure of a similar 102 inch PCCP sewer force main. Representatives of the GLSD subsequently visited MCUA to learn about MCUA's response to the failure. MCUA's response included instituting a PCCP condition assessment program. Based on the uncertain structural condition of the GLSD force main, the District, in 2004 determined that it would be prudent to begin a program which would allow it to assess the current structural condition of its 72 inch PCCP force main. GLSD advertised and received proposals from engineering consultants and began its condition assessment program in 2005. GLSD hired CDM to lead the assessment program and they engaged specialty sub-contractors Openaka Corporation and Pure Technologies to conduct the condition assessment program.

Prestressed concrete cylinder pipe (PCCP) is often utilized in large volume circulating water systems for energy generation facilities. The circulating water system is essential to plant operations, and for many facilities, redundancy may not have been built-in; thus failure of a section of non-redundant PCCP could be disastrous. Evaluation of the physical condition of the circulating water system and assessment of the potential operational risk is deemed good engineering practice. At Great River Energy's (GRE) Coal Creek Station (CCS), a two unit 1100 megawatt pulverized coal generation facility, generation leaders worked with Golder Associates (Golder) to perform a condition assessment of the PCCP utilized in their circulating water system. This condition assessment involved the following: establishment of goals and constraints; review of documentation relating to pipe manufacture, installation, and operations; development of work plan; physical observations including visual, sounding, and remote field eddy current / transformer coupling (RFEC/TC); repairs including grout repair, joint seals, and exterior the Middlesex County Utility Authority (MCUA) in New Jersey experienced a catastrophic failure of a similar 102 inch PCCP sewer force main. Representatives of the GLSD subsequently visited MCUA to learn about MCUA's response to the failure. MCUA's response included instituting a PCCP condition assessment program. Based on the uncertain structural condition of the GLSD force main, the District, in 2004 determined that it would be prudent to begin a program which would allow it to assess the current structural condition of its 72 inch PCCP force main. GLSD advertised and received proposals from engineering consultants and began its condition assessment program in 2005. GLSD hired CDM to lead the assessment program and they engaged specialty sub-contractors Openaka Corporation and Pure Technologies to conduct the condition assessment program.

This paper reviews the results of the City of Baltimore's pilot large-diameter pipe inspection program, originally undertaken to develop and implement an inspection, condition assessment and asset management program for raw and finished water mains within the Baltimore Metropolitan Area. The transmission mains of primary concern are those of prestressed concrete cylinder pipe (PCCP), with a particular emphasis on those constructed in the early 1970's. Many of these PCCP transmission mains were fabricated with Class IV prestressing wire and such mains have had a significant history of breaking. An unexpected outcome of the inspections was the identification of a large number of 54- and 36-inch pipe sections in deteriorating condition which posed the threat of incipient main failure if returned to service. These findings required that the joint owner/operators of the system repair or replace the identified pipe reaches on an emergency basis, while at the same time maintaining adequate water supply for the system's customers. The paper describes the two types of internal inspections that were employed for this project, the action plan developed in response to the defective pipes identified, and the design and construction of repairs and replacements of the damaged pipes. It also discusses the careful coordination required between Baltimore City, and Baltimore, Howard, and Anne Arundel Counties in response to the inspection findings.

In order to protect their substantial investment in wastewater collection system infrastructure and to meet anticipated upcoming regulatory requirements, The Town of Milton, Massachusetts (Milton) has taken a proactive approach towards operating and maintaining the wastewater collection system by embarking on a comprehensive Town-Wide Sewer Investigation & Rehabilitation Program. This program is a phased approach to identify wastewater collection system deficiencies, evaluate rehabilitation options and follow through with design and construction on a continuous set schedule. Identifying and correcting problems will reduce inflow and infiltration (I/I) and immediately enhance the value of the system. Wastewater collection systems are constructed for the purpose of reliably transporting wastewater from each individual user to the wastewater treatment facility. A comprehensive annual investigation program ensures that the wastewater collection system properly serves this intended purpose on a perpetual basis. By following a regular program to investigate and repair the wastewater collection system, Milton will be in a better position for regulatory compliance, maintenance and management and addressing capital improvements.

This paper includes a case study for a baseline condition assessment conducted for the Erie County (N.Y.) Department of Environment & Planning (ECDEP), Division of Sewerage Management (DSM). This project was initiated when the County started looking for more efficient ways to develop their CIP for wastewater facilities, including wastewater treatment plants, pump stations, and collection systems. While the County had previously developed a GIS database for their wastewater collection systems that included information on some of their buried assets, the amount of information available for each of the 77 minisystems (defined as a sewershed or subdivision of a sewer district) varied greatly. For several minisystems there was a significant amount of useful information and for others, there was considerably less information. The baseline condition assessment approach was used to place all minisystems and trunk and interceptors on an equal-footing so that potential projects could be identified and prioritized, while still allowing more detailed information to be added in the future.

In these days of fiscal frugality, utilities struggle to get financial resources for pipeline rehabilitation. Once resources are dedicated, it is critical that they achieve the "best" results possible based on multiple objectives and criteria. These criteria reflect the often competing interests of different utility departments (e.g., planning, engineering, operations and maintenance), and they must consider the expectations of the utilities' customers and outside stakeholders, including the business community, regulatory officials, and environmental groups. Add politics and the media to this scenario, and the decision making process becomes complex. This paper presents a method of developing, applying, and defending a decision making process that is technically sound, practical to apply, and reflects the values and objectives of stakeholders both within and outside of the utility. The method sets rehabilitation priorities based on available information related to condition (probability of failure) and criticality (consequences of failure) criteria that are developed and weighted through a stakeholder's involvement process. The results provide a framework for setting priorities for immediate rehabilitation action items as well as priorities for collecting additional information in areas where it is needed to support better decisions. In coastal Wilmington, North Carolina, the need for sewer rehabilitation became a focus of the media and politically charged after several force main failures and system stoppages resulted in a series of sanitary sewer overflows (SSOs), one of which impacted beach areas on a holiday weekend. Quickly responding, the city initiated a priority-setting process using the methodology described herein that affirmed the importance of several sewer rehabilitation projects already ongoing and identified a number of high priority rehabilitation and condition assessment efforts to be started immediately. Several of the condition assessment efforts have been completed using techniques including zoom camera inspections in priority gravity sewers and ultrasonic thickness testing of several ductile iron pipe and prestressed concrete cylinder pipe force mains. These results demonstrate the successful application of this method in a politically-charged and high profile environment. The details of this case study are described in more detail later in this paper.

Over the last few years, The City of Houston has experienced failures of various large diameter water lines. Some of the most notable have involved 36-, 42-, 48-, and 60-inch Prestressed Concrete Pipe (PCCP), and 24-, 30- and 36-inch Cast Iron Pipe. Because of these failures, the City is concerned with the long-term performance and structural integrity of other large diameter water lines. The City requested Lockwood, Andrews & Newnam, Inc., (LAN) to prioritize the water infrastructure for evaluation under a Condition Assessment program. LAN's task is to prioritize existing lines based on the likelihood that they may have distress and the risk if a failure or water outage were to occur. The four pipe lines above were all constructed of prestressed concrete cylinder pipe (PCCP) between 1960 and 1996, however, each failed for distinctly different reasons. The causes of failure of these lines ranged from problems associated with hydrogen embrittlement of prestressing wire, internal corrosion to structural damage caused by transient surges, and failure of lead caulking of cast iron pipe joints. A list of criteria is organized into a GIS database in order to determine the theoretical condition of each pipe line. Physical assessment of the lines is to be scheduled based on criteria including: 1) Age, 2) Pipe Material, 3) Critical nature of line (Facilities served; schools, hospitals, industry, etc.), 4) Cathodic protection system, 5) Leak history, 6) Operational history, 7) Review of construction inspection records, and 8) Adjacent construction projects. This paper describes the criteria used by the City of Houston to prioritize their Condition Assessment program and some of the issues and constraints faced to fully inspect existing pipe lines.

The Inland Empire Utilities Agency (IEUA), formed in 1950, serves a 242 square mile area located in the southwest corner of San Bernardino County, approximately 35 miles east of Los Angeles. IEUA provides regional wastewater service and imported water deliveries to several contracting agencies. IEUA's Non-Reclaimable Wastewater System (NRWS) is a large diameter pipeline and force main system, about 55 miles long, conveying non-reclaimable wastewater or "brine." Over the years, records for this system became outdated and the condition of the pipelines and manholes were unknown. In the summer of 2005, IEUA contracted with PBS&J, an engineering consulting firm, to locate, inspect and assess the NRWS, including approximately 5 miles of force main, and 613 manholes. PBS&J teamed with Houston & Harris, PCS, Inc. (H&H) to inspect the sewers. Cecilia's Safety Services prepared the temporary traffic control plans, acquired the traffic permits, and performed the traffic control set up and take down for the inspection efforts. California Surveying Corporation located the inspected manholes using global positioning system (GPS) equipment to locate the manholes to the nearest 0.1 of a foot. The NRWS Capital Improvements Program Plan provided IEUA with recommendations for capital improvements, cleaning recommendations and on-going system maintenance efforts for the NRWS. The inspection and assessment work occurred between September 2005 and January 2006. The fast-paced schedule required the completion of the final report by March 1, 2006.

Sewer overflows pose a significant threat to public health and the environment, contributing to beach closures, contamination of drinking water, and other concerns. Knowing when and where they occur — as well as their duration, volume, and frequency — are important pieces of information needed to assess their impact and minimize their future occurrence. Sewer overflows are readily identified by evaluating flow monitoring data on a scattergraph. Practical examples from flow monitoring locations throughout the United States are provided, demonstrating the scattergraph signatures of sanitary sewer overflows (SSOs) and combined sewer overflows (CSOs) under various conditions. Techniques are also developed to estimate their duration and volume from flow monitor data.

The deteriorating highway culvert infrastructure has become a major challenge for the 21^st century. While more importance usually is given to highway embankments, pavements, and bridges, the maintenance of culverts has commonly been neglected. As many culverts reach the end of their design life, the state Departments of Transportation (DOTs) are in need of a model to track the existing culverts and forecast their conditions. Therefore, the main goals of this research is to develop a framework for culvert inventory and inspection by providing protocols and condition rating systems for culvert inventory and inspection, and validate the developed framework by conducting field pilot studies. Performance scores for the culverts are calculated using an analytical hierarchy process (AHP) to determine the magnitude of the deterioration and assist in short and long term planning. This study focuses on concrete, corrugated metal, and plastic culverts spanning less than or equal to 10 feet (3 meters). The developed model contributes to an effective culvert asset management strategy.

Most underground assets owners would like to know what the probability is for failure of a given pipeline asset as a function of material type, function type, age of the asset, geotechnical environment, and other factors, when we know past failure distributions, predominant failure mechanisms, and other attributes. While most underground utilities have collected voluminous data that could guide them into better buried asset management in the future, the use of suitable reliability analyses have been beyond their reach. Often the replacement and rehabilitation decisions have been based on simple rules of thumb rather than either good science or statistical analyses even when tremendous amount of resources and time are expended on benefiting from the use of state-of-the-art condition assessment techniques. When civil engineers struggle to convince the public and the legislators the dire need for increased rate of investments into buried assets, it is our obligation to engage the most suitable analytical tools to make the best use of past failure data and available infrastructure capex funds. This paper provides a methodology on how sound reliability analysis tools can be used in such management decisions to maintain and operate our underground assets better.

Arizona Public Service (APS) operates the Palo Verde nuclear facility in central Arizona. Palo Verde is the nation's number one power producer with a net generating rating of 3,875 megawatts that provides electricity for up to 4 million people in the Southwest United States. Reactors at the plant depend upon pre-stressed concrete pipes to transport the coolant water throughout the system. More significantly, Palo Verde is the only nuclear plant in the world not built on a large water source such as a lake, river or ocean. More than billion gallons a year of municipal effluent is recycled each year and travels through 35 miles of piping. Naturally, for a system this critical, a pipe failure would be disastrous, as would an extended repair outage. Engineers at the plant decided that the paper map and numerous different file systems that held the pipeline information were an inefficient manner in which to gather data and expedite decision-making. Deciding upon a GIS-enabled database, the APS engineers worked with Pressure Pipe Inspection Company (PPIC) towards an intuitive and dynamic GIS based system that provides users with timely information. Using GIS technologies effectively for a water pipeline requires a detailed data structure to address the jointing aspects specific to water pipelines. The data model needs to track individual pipe segments, from bell to spigot, with inspection and integrity information. Enabling this database for view through GIS software delivers a GIS with a high value data set that is very accurate at representing existing water pipeline infrastructure. Implementing such a system is not a trivial procedure; however, by utilizing resources from various departments (i.e. engineering, IT, GIS and database administration) at APS, completion of the project occurred within the budget and time period allotted. Applications within the GIS were built to enhance the casual GIS user experience. With these applications leveraging off the pipeline data model, APS pipeline operators can fully realize the advantages of maintaining their pipeline assets in a spatial database including 1) increased data availability; 2) identification of urgent repair needs; and 3) improved maintenance and capital planning.

During the course of a major harbor dredging project it was learned that three ten-inch diameter, high-pressure gas lines traversing the Federal Channel may not have been buried to the proper depths. After researching the plans of record on the subject gas line, the USACOE found that the originally permitted burial depths of the pipeline conflicted significantly with two more recent electronic surveys that had been performed. Several more surveys using electronic methods of locating the pipes were attempted; however, because of site constrictions and the pipeline configuration, functionally repeatable results could not be obtained. Because electronic surveys had not produced consistent results, the owner and the USACOE turned to the most reliable method — that of unearthing portions of the pipe, however the Channel depths, the pipe cover and port traffic made this a formidable task. The following case study documents how this task was accomplished.

The Washington Suburban Sanitation Commission (WSSC) has over 400 miles of prestressed concrete cylinder pipe (PCCP) in its transmission network for potable water, 150 miles of which is larger than 36 inches in diameter. WSSC has recently undertaken a condition assessment of several of their large diameter PCCP transmission mains, including the 96-inch Potomac main and the 60-inch North Adelphi Main. The assessments relied on the application of electromagnetic inspections combined with visual and sounding inspections and acoustic monitoring for the North Adelphi Main. Following the inspections, pipes deemed to be in a state of incipient failure were excavated to confirm the findings and repaired as needed. The focus of the inspections was to assess the condition of the prestressing wire for each pipe section, the structural component that provides the strength to PCCP. Electromagnetic inspections were used to test the condition of the wire. This type of inspection requires entering the pipe and traversing its full length with equipment that is capable of electromagnetically testing the prestressing wire wraps. The technology detects breaks in the prestressing wire and estimates the total number of breaks for each pipe section. Visual and sounding inspections are a reliable method of detecting pipes in an advanced state of distress. The visual portion of these inspections looks for indications of distress resulting from a lack of prestressing. The sounding portion of these inspections rely on impacting the interior surface of the pipe wall with a tapping rod and listening for hollow sounds indicative of a lack of prestressing. The inspection of the 96-inch Potomac main identified two pipe sections that required immediate repair. Excavations of these pipe sections revealed that the prestressing wire for these pipes was heavily corroded with numerous wire breaks. These identification and replacement of these pipe sections most likely avoided a catastrophic failure. For the North Adelphi main, following the inspection, a fiber optic sensor was installed in the main to permit continuous acoustic monitoring. The main was returned to service and is being continuously monitored to detect breaks as they occur in the prestressing wire. These wire breaks will be added to the wire break estimates from the electromagnetic inspection to update the wire break estimates for each pipe section. Using this data, the remaining useful life for each pipe section can be estimated.

The Greybull Water Transmission Pipeline (GWTP) was constructed as a steel line in the 1930s, but was replaced in late 1960s and early 1970s with 12 in. and 14 in. diameter asbestos cement (AC) pipeline because of steel corrosion and numerous leaks. Greybull, along with many other towns and municipalities, are faced with projected increase in future demand and the need to determine if the current infrastructure can safely and adequately meet the future demands. The condition assessment study was performed to determine if the line can continue to provide service under the proposed higher flow conditions. The scope of the work included review of available data, structural evaluation of the pipeline, determination of corrosivity of soil and ground water, and internal water to AC pipe, excavation and external inspection of the pipe, testing of AC pipe material, including three-edge bearing test, flexural test, and petrographic examination of the pipe wall. The results indicate that the AC pipe has not deteriorated significantly over the past 35 years, except minor to moderate acid attack that affected up to about 8% of pipe wall thickness in sporadic locations. There is no evidence of sulfate attack despite high soil sulfate content over most of the line, and of any other systematic deterioration mechanism. Structural evaluation for combined loads indicated that the pipe has adequate factor of safety and can continue to provide service under the proposed hydraulic modifications.

This paper discusses actual experience with independent (by owners or their consultants) corrosion evaluations of ductile iron (DI) pipelines. Included are evaluations of the extent of corrosion on DI in various soil environments, the effectiveness of polyethylene encasement for corrosion control, the effectiveness of the standard factory applied asphaltic coating for corrosion control, and the effectiveness of the 10-Point Method in predicting corrosion activity on DI.

Laser Radar (LADAR) enables a new generation of quantitative pipeline inspection techniques. These techniques differ from traditional inspection techniques including Closed Circuit Television (CCTV) and laser profiling systems by capturing 3-D range images that encode the local three-dimensional (3D) structure of the inspected pipeline. Individual range images thus obtained can be processed and integrated into a high-resolution geometric model of the inspected pipeline. Once the integrated pipeline model is assembled, techniques from 3-D computer vision and computational perception produce quantitative answers to pipe location, integrity, and performance questions. Three separate case studies that employed LADAR in quantitative pipeline inspection operations are presented: estimation of the effects of relining on pipe transport capacity within a culvert system, estimation of corrosion in Pre Cast Concrete Pipes (PCCP) and geo-location of two parallel segments of brick-lined sewer. In each case, an overview of the approach to data acquisition, processing, and sample results are provided.

The City of Atlanta, like many other cities, is currently facing the challenge of rehabilitation or replacement of much of its existing buried infrastructure. To confront this challenge, Mayor Shirley Franklin has led Atlanta on an aggressive system-wide capital improvement program. In order to make the most efficient use of available funds for pipeline renewal, the City's Watershed Management Department has committed to explore innovative and cost-effective options, including trenchless technologies. A significant step forward in this program has been a condition assessment and rehabilitation analysis for the system-critical raw water pipelines that connect the City's water source, the Chattahoochee River, to the Hemphill Reservoirs and Hemphill and Chattahoochee Water Treatment Plants (WTPs). The objective of this paper is to discuss the methods and results of this condition assessment and rehabilitation analysis project.

Trenchless methods are frequently utilized to install pipelines in some difficult conditions, such as loose sand, non-cohesive soil and fractured formations, which would cause hole-wall collapse, over-pull back force and/or even break the drill rods. It would be very troublesome and costly to use Horizontal Directional Drilling methods to construct underground pipelines in these kinds of strata. During the last several years the authors demonstrated practical applications of drilling using an electrically-heated graphite, tungsten, or molybdenum penetrator (subterrene drill) that melts a hole as it is slowly pushed through the rock or soil. The molten material consolidates into a rugged glass lining that prevents borehole collapse; minimizes the potential for cross-flow, lost circulation, or the release of hazardous materials without casing operations; and produces no cuttings in porous or low density formations. Because there are no drilling fluids required, the rock melting approach reduces waste handling, treatment and disposal. Because the penetrator does not need to rotate, steering by several simple approaches is considered quite feasible. Melting is ideal for making a hole in alluvium and other poorly consolidated soils since the formed-in-place glass liner stabilizes the hole. Because of the relatively low thermal conductivity of rock and soil materials, the heat-affected zone beyond the melt layer is very small, <1 inch thick. This paper will present the in-door experiments of the rock melting approach to make a hole and discuss the perspective of this hole-making method to be utilized in underground pipeline trenchless construction.

Condition assessment of Prestressed Concrete Pressure Pipe (PCCP) has evolved over the past 10 years mainly due to the development of the Remote Field Eddy Current / Transformer Coupling (RFEC/TC) inspection technique. By conducting RFEC/TC inspections to determine the actual condition of their pipelines PCCP owners and operators can make informed decisions regarding strategic repairs and selective rehabilitation. However, RFEC/TC inspections can, in some circumstances, be a challenge to conduct. Various designs of manned tools and tethered systems have been successfully used in the field but they require dewatering and/or depressurizing which can be costly and prevent the inspection of pipelines that can not be taken out of the service. To overcome these challenges a free-swimming tool for RFEC/TC inspection of PCCP in a live operating environment is currently being developed. This paper describes practical engineering considerations for such a development.

This paper is an overview of a joint product development program conducted by TDW and GTI in 2005. GTI originally contacted TDW in 2004 and indicated there was a need for hot tapping and plugging via keyholes. The term Keyhole, as used in the gas piping industry refers to small round or square access ports whereby buried pipelines can be accessed. The main goal of the project was to develop and demonstrate Hot tapping and plugging (stopping of the flow of the product in the line) could be done on buried pipes up to 6 feet below the ground via 18" cored holes in roadways, sidewalks, etc. This need was driven by increasing excavation and repaying costs, traffic problems, and safety issues. As stated, this technology would result in less job costs to the utility company by reducing the costs associated with pipeline excavation and street repairs. A safer system would also exist since personnel would not be subject to cave-ins.

Rehabilitation of medium and large diameter gravity pipes using traditional cured-in-place technologies often requires heavy, thick-walled liners, creating challenges for transportation and installation. A fiber-reinforced version of industry-proven CIPP technology has been developed as an innovative and reliable solution to these challenges. Using laminated composite design methodology, similar to that used in the aerospace and sporting goods industries, design engineers incorporate glass and carbon reinforcing fibers into the wall of a cured-in-place pipe. Optimal orientation of the reinforcing fibers allows the design engineer to achieve higher stiffness and strength than with traditional CIPP materials. The resulting laminated composite pipe provides full structural performance with approximately 40% less wall thickness than conventional CIPP materials, delivering the added advantage of increased flow area in the finished product. The increased physical properties of this composite material provide even more advantage when rehabilitating noncircular host pipes with large radii or flat profiles. This new product expands the technical envelope for cured-in-place pipe rehabilitation beyond traditional application boundaries. This paper discusses the design theory and product features of the composite pipe product. It also details industry standards testing and the application envelope for this technology. In addition, case studies of successful applications will be presented.

On January 21, 2004, a water main burst spilling over a million liters of water causing multi-million dollar damage. This incident affected the lives of a community significantly forever. The pipeline was directly underneath heavy traffic and was subject to frost loads during its life. This water pipe and a 128,000 volt cable installed in a duct shared a trench and the set back distance was a few centimeters. There was high water table in primarily glacial till and the pipe was made of PVC. The author served as an expert witness for the electric utility performing an independent investigation of the causes of the failure. While sharing rights of way and pipelines for multiple functions is an attractive proposition, the standard of care required of us engineers are more stringent compared to normal utility design, construction, and operation. There were many things wrong with the design, pipe material selection, construction, inspection, operation, and maintenance. This paper documents the lessons learnt for the benefit of pipeline engineers.

As an increasing number of large diameter pipe bursting jobs are attempted, more is being learned about the capabilities and potential of pneumatic pipe bursting. The large diameter pipe bursting project in South San Francisco is one of the most challenging and innovative bursting projects ever attempted in North America. Because the project's scope, difficulty, pipe diameter and tooling requirements it is being heralded as a landmark pipe bursting job.

This paper presents information on the investigation and lessons-learned during recent cured-in-place (CIP) lining project in which the host pipe was an asbestos cement (AC) sewer main. Due to deterioration of the main, swelling of the AC material resulted in reduction of the inside diameter of the pipe. Upon installation and curing of the liner material, wrinkles were noted during the follow-up inspection. Material testing and inspection were conducted to determine what, if any, impacts the wrinkling would have on the pipe's integrity. This paper examines the process of installing the CIP liner, examination of the final product and the resulting impacts of the wrinkles.

Many HHD installations utilize specialized drilling fluids, commonly called "drilling muds", which are composed of various organic and inorganic additives, polymers, lubricants, and wetting agents mixed with water. One common component in drill fluids which can be corrosive to metallic structures in certain environments is bentonite clay. This one year study investigates the corrosive effects of various commercial drilling fluids on Ductile Iron Pipe utilizing two widely recognized ASTM corrosion evaluation methods: ASTM G-59 (Standard Test Method for Conducting Potentiodynamic Polarization Resistance Measurements) based on electrochemical properties of metals, and ASTM G-162 (Standard Practice for Evaluating Laboratory Corrosion Tests in Soils) based on coupon weight loss. In addition to comparing the corrosive effects of various drill fluids, five different electrochemical test evaluation methods were compared to results obtained utilizing the weight loss method.

Applying cathodic protection can extend the life of an existing water main, but installing a cathodic protection system in an urban environment can pose significant construction challenges. The City of LaCrosse, WI Water Utility has implemented a demonstration project using horizontal directional drilling equipment to install a continuous linear distributed anode directly alongside an existing water main. The water main is approximately 20 years old, but has experienced significant external pitting corrosion. The results of the initial demonstration project suggest that a 40-year life extension of the water main may be achievable at a cost that is significantly less than the replacement cost of the pipe.

Cement mortar coatings have been widely used in the Western United States since 1935 to protect the exterior of large diameter welded steel pipelines (WSP). Applications include pipe up to 144-inches in diameter and a wide range of environmental conditions. The Metropolitan Water District of Southern California has had extensive experience with mortar-coated WSP and at present has over 150 miles of this type of pipe in its water transmission system. Characteristics of a recently installed 7-mile, 120-inch- diameter, mortar-coated WSP pipeline are described. Steel coated with cement mortar is normally protected against corrosion by a passivating iron oxide film that forms and is maintained in a highly alkaline environment of hydrated Portland cement. The potential of passive steel in concrete is several hundred millivolts more positive than the potential of bare or organically coated steel. This unique property makes it possible to identify areas of corrosion activity on mortar-coated WSP and areas where external currents are collecting or discharging. The long-term performance of cement-mortar coatings is dependent on pipe design, manufacture, and installation. The history of cement mortar coatings is discussed, and recommendations are made for application of mortar-coated WSP.

This paper presents investigations to ascertain the corrosion control benefits of polyethylene encasement for ductile iron pipelines in corrosive soil environments. Investigative procedures including cell-to-cell potential surveys, side drain technique measurements, in-situ and laboratory soil tests, pipe-to-soil potential measurements and excavation inspections. Included are testing results and the location sites of each investigation. These investigations demonstrate the effectiveness of polyethylene encasement as a corrosion control system for ductile iron pipe.

Three current corrosion strategies used for Municipal Metallic Transmission Pipelines (MMTP) (defined as concrete pressure pipe, ductile iron pipe, or steel pipe 24" diameter and larger) as part of a comprehensive Asset Management Program are: 1) Run to Failure, 2) Run to Failure and Repair as Required, and 3) Operate and Maintain to Provide an Indefinite Life (repair-free service life >100 years). The paper will discuss the short- and long-term impacts of each strategy and detail why the strategy of "Operating and Maintaining to Indefinite Life" provides the most reliable Municipal Metallic Transmission Pipelines with the fewest repairs at the lowest total cost of operation to the owner. It will be shown that the strategies of "Run to Failure" and "Run to Failure and Repair as Required" are overall more costly since both strategies accept corrosion, unscheduled repairs, planned failure of the pipeline and the resulting high replacement costs of the MMTP. The paper will focus on methods of design, corrosion protection, maintenance and installation which allow all MMTP materials to be equally operated and maintained for an indefinite life.

The San Diego County Water Authority (Water Authority) is currently constructing the San Vicente Pipeline connecting the San Vicente Reservoir to the Second Aqueduct Pipeline. This project is a key component of the Water Authority's Emergency Storage Program (ESP) to provide greater water reliability in the Water Authority's delivery system. The San Vicente Pipeline is approximately 11-miles in length and is being constructed as a 12.5 to 14-foot (3.81 to 4.27-meter) diameter tunnel through varying geology. The depth of the tunnel varies from 50 feet (15.24 meters) to over 500 feet (152.4 meters) below ground surface. There are four access sites to the tunnel. Each of these access sites has a unique set of parameters, site restrictions and expected groundwater inflows. It is difficult to predict the volume of groundwater that will be encountered, but 1000 gallons per minute is the upper limit in the project's Geotechnical Baseline Report. In addition, the current discharge regulations require high levels of groundwater treatment for discharge to surface waters. The majority of the groundwater that is currently being encountered is being treated and discharged to a local streambed. The cost of the treatment of groundwater is expensive and has led the Water Authority to look for other cost effective means of disposing groundwater. This paper addresses the other means of disposal and the various processes such as permit, community, and contract requirements that govern their implementation.

First introduced in the United States in 1995, Pilot Tube Microtunneling (PTMT) has been increasing in popularity year after year. This trenchless method of installing sewer pipe is essentially a hybrid of three trenchless boring techniques: 1) Having a slant faced steering head similar to that of a directional drill, 2) Utilizing the guided accuracy of a conventional microtunnel machine, and 3) Using an auger type spoil removal system similar to a horizontal bore. Among the reasons for the popularity of this system are; low equipment costs, relatively small topside footprint, and small jacking pits. Each year more contractors are purchasing these inexpensive and easy to operate tunneling machines from three equipment manufacturers: Akkerman, BohrTec, and Wirth-Soltau. Initially, pipe sizes ranged from 4 inch to 12 inch with maximum drive lengths up to 250 feet. Currently, the largest diameter (in the U.S.) installed by the pilot tube microtunnel method is 27 inch I.D. /32 inch O.D. and maximum drive lengths are now just over 400 feet. Larger diameters and longer drive lengths are due to the development of better optics in the guidance system and more powerful hydraulics in the jacking frame. This paper will explain the method of how sewers are constructed using PTMT in detail (two pass and three pass methods), as well as briefly discuss in a case study manner, showing reasons the installation method was chosen, project statistics, and difficulties or challenges of numerous completed and current vitrified clay pipe pilot tube microtunnel projects.

Concrete (reinforced and non-reinforced) and asbestos cements pipes represent a significant percentage of the storm and wastewater collection systems in many cities across North America. A significant percentage of these pipeline networks are approaching or have already exceeded their 50-year design life. These pipes are in various stages of deterioration, generally due to microbiological induced corrosion or mechanical loading (either external or internal). Open-cut replacement of these pipes, many placed beneath busy streets, is costly and involves a lengthy disruption to normal traffic and business activates. Common rehabilitation techniques for such structures include lining using a thermoplastic or thermosetting liner product or coating using epoxy-based or cementitious-based materials. The latter is in many cases the most economical approach, but the durability of most cementitious lining products in harsh environments limits their useful design life. Hybrid materials, such as polymer concrete, provide superior performance but at higher costs. Geopolymers are inorganic alumino-silicate polymers that come from chemical reactions under highly alkaline conditions between an active puzzolanic material (such as fly ash or metakaolin) and an activator solution (based on a molar mixture of sodium hydroxide and an alkaline silicate, e.g., sodium or potassium silicate). Geopolymers are usually referred to as inorganic alumino-silicates, and are known for their excellent mechanical properties, high corrosion resistance and chemical stability. Another promising cementitious material is Zeolite, a crystalline puzzolanic aluminosilicate material with uniform molecular sized pores. At present Zeolites are used as catalysts, separation media, ion exchangers and antimicrobial agents. Zeolites can be mixed with sand to form mortar blends that are highly stable in acidic environments. The paper provides a state-of-the-art review of these two cementitious materials and their chemical and mechanical properties. Thereafter, an experimental testing program undertaken at the Trenchless Technology Center to explore the suitability of these two novel materials for use as coatings for wastewater conveyance, storage and treatment structures is described and its preliminary results reported. Specifically, the effect of various mix design parameters (AS/FA ratio, curing temperature, type of silicate used and NaSiO₂ to NaOH ratio) on the compressive strength of geopolymer mortar cubes are reported and discussed.

This paper describes an innovative method for mitigating microbial induced corrosion (MIC) in concrete sewer pipes by driving nano-particles containing an antimicrobial agent into the wall of the steel-reinforced cementitious pipe using electrokinetics, an electrical deposition method. Electrokinetic coating involves the application of a weak electric field between the pipe reinforcement and a properly charged solution of nanoparticles. The electrical potential difference drives the nano-particles in the solution into the hardened concrete paste via its pore structure, simultaneously transporting the antimicrobial agent(s) into the pores. This new method of coating creates a mechanical anchorage between the coating liquid and the host matrix, which has inherent advantage over traditional brush or spray-on coating operations. The paper provides a brief overview of recent advances in spray-on coating and lining methods for protecting concrete pipe used in wastewater conveyance systems. Thereafter, a brief description of electrokinetics is provided. Preliminary results of an experimental testing program involving electro-kinetically coating of 35 mock concrete pipe specimens using cuprous oxide, a heavy metal oxide known the have a toxic effect on sulfate reducing bacteria (SRB), are presented. The preliminary testing program focused on examining the effectiveness of using electrokinetics for the treatment of new pipes, partially deteriorated pipes and pipes that exhibited moderate-to-severe deterioration due to sulfuric acid attack. The design of the experiment and the execution of the electrokinetic coating process are also described. The results suggest that the approach could potentially serves as an effective method for coating of new and partially deteriorated reinforced concrete pipes.

Piercing tools are being successfully used everyday, in almost every area of utility construction including the most recent Fiber-To-The-Home (FTTH) or Fiber-To-The-Premise (FTTP) phenomena. Today's piercing tools are reliable, accurate and hard working, which makes them particularly well suited for last mile operations.

Accurate prediction of the magnitude and extent of ground movements caused by the use of pipe bursting is important if confidence in its use is to be enhanced. This paper presents a method for quantifying the three-dimensional surface displacements induced by pipe bursting, which was implemented using commercial GIS software. Most current analytical solutions for determining soil displacement are based on the plane or controlled strain approaches using the cavity expansion theory, and simulation results are presented in 2-D. In the methodology presented in this paper the ground surface is divided into a grid with a pre-determined mesh size and the coordinates of each node are represented in a spatial data format. A simplified fluid flow theory is used to manipulate the spatial data. As the bursting head advances, the vertical displacement of each node is computed. The profile of the ground surface at each time step (i.e., incremental advance of the bursting head) can be visualized and the predicted soil displacement contour at different elevations studied. The paper presents the model formulation, codification using Arc View GIS software and the results of a validation process, where model's predictions were compared with experiments results reported in the literature. The incorporation of an analytical geotechnical ground movement algorithm within Arc View provides a powerful analysis tool for utility and municipal engineers. The designer can now export a shape file with existing utility lines and other surface improvements data into the analysis module, run the analysis and obtain the predicted soil movement at various locations within the proposed alignment. Using Arc View's powerful spatial analysis capabilities, potential problem areas (i.e., displacement exceeding a pre-determined threshold in the vicinity of a buried structural element) can be then identified with ease.

Recent advances in minimal-disruption rehabilitation for water systems are increasing the willingness of utility owners and operators to consider these technologies. This trend follows the lead of trenchless sewer rehabilitation methods that have been established as viable options to mitigate the impacts of replacing aging infrastructure. Water system renewal is, however, a more complicated issue with unique requirements. Products must withstand the internal pressures inherent in distribution systems, while being suitable for potable water. The trenchless technology industry is dynamic, with new options frequently coming to the forefront. In this paper some of the major issues and concerns for consideration when selecting a water system renewal technology are presented and discussed. This paper focuses on recent advances for lining potable watermains with polyethylene and polyester-reinforced polyethylene (PRP) products in North America, the UK and Europe. It also discusses the implementation of a revolutionary method for internal reinstatement of service connections. Further, the paper reviews the future of water system renewal, discussing outstanding hurdles as well as the next logical steps in industry evolution.

Pipe ramming continues to be one of the most versatile and capable trenchless pipe installation methods. The method is proven effective for horizontal, vertical, and angled applications. In recent years, the method has set new records in large diameter casing installations and is becoming more and more common. Pipe ramming is a favorite installation method for contractors installing casings under roads and rail lines because the method provides accurate installation in a wide range of soils without surface slump.

Acoustic leak detection systems have proven to be an effective means for identifying leaks in pipelines. Recent technological advances have resulted in the development of a free-swimming acoustic leak detection device capable of surveying many miles of pipeline with a single deployment into a fully operational pipeline. The system can identify and locate small leaks in water pipelines larger than 10" diameter constructed of any pipe material. The device can also pass through in-line valves (including butterfly valves) and negotiate unlimited bends in the pipeline. These benefits provide a cost effective and timely approach to identifying and locating leaks in large diameter transmission pipelines.

City of Portland-Bureau of Environmental Services (BES) contracted with BC Construction Company (BC) to construct the NE Airport Way II-NE 138th Avenue to NE 181st Avenue Water and Sanitary System. The contractor did not complete works to the satisfaction of the city. The city was subsequently forced to incur additional expenses to bring the line to acceptable condition before putting into service. The city wanted to recover the added cost from the Contractor, and engaged the author as an expert to review the contract documents, reports and records to find out whether it had the foundations and technical basis for its case and legal action against the contractor. The author completed the investigation and this paper presents a summary of the lessons learned from this investigation.

The recently completed Lower Northwest Interceptor Program (LNWI) in Sacramento, California comprises, ten pairs of microtunnels totaling 14,417 ft, three horizontal directionally drilled bores totaling 3,154 ft, and two large diameter tunnels under the Sacramento River totaling 3,953 ft. This paper describes the problems encountered with each trenchless crossing, as well as lessons learned with respect to shaft construction, ground control at shafts during tunnel break-in and break-out, frac-out and heave, settlement, obstructions, coordination with permitting agencies, and application of geotechnical baseline reports.

Dallas Water Utilities employs an innovative leak detection program which utilizes a variety of technologies to detect, locate, and repair leaks in both their water distribution and transmission systems. Over the past twelve months, this program has located over 200 leaks in Dallas' water distribution system, for an annual savings estimated at 100 million gallons of water. Over the past 2 years, Dallas has expanded their leak detection program to include the use of the Sahara^TM leak location system on their large diameter transmission mains. This paper discusses the technology and methodology used in Dallas' leak detection program, outlining the results achieved, and plans for further use of this program. Specific cases will be discussed in detail, with a focus on the innovative use of new technology.

The City of Wichita Falls (City) has experienced several problems with Lift Station No. 65 and the related force main since being placed in service. Several overflows called for the retrofit of a grinder pump that was installed upstream of the prison site in 1996. Electrical problems were also experienced, which may have contributed to later failures of the 10-inch force main. Despite constructing a new force main and installing pump control valves, the problems experienced by the Wichita Falls lift station and force main have not been alleviated. The City consulted with Lockwood, Andrews & Newnam, Inc. to analyze the lift station and force main system and to address the issues they faced. Together with a local engineering firm, Cornerstone Engineering, the project team collected lift station and force main as-built drawings, O&M manuals, and other related system data. This data was utilized to build a computer model of the lift station and force main system for analysis. An analysis of the effects of transients on Lift Station Number 65 and the 10-inch PVC force main will be performed for three conditions: 1. Normal pump start-up, 2. Normal pump shutdown, and 3. Failure of all running pumps. Special attention was given to the size of the wet well and the frequency of operation of the pumps. Transient conditions will also consider failure of the pump control valves, and the minimum pressure criteria, based on information received from the force main manufacturer. The force main failures will be reviewed with several issues in mind. The pipe material may be experiencing fatigue if a cyclic stress condition occurs at a high frequency and magnitude on a continuous basis over a period of time. The fact that the failure mode was the same in all cases in the 1994 line and the 2002 line suggests that the integrity of the pipe material was likely a cause of failure. In addition, the size of the line will be addressed. Based on results of the transient analyses and data collected, the project team identified the cause of the force main failures and proposed the appropriate solutions.

This paper put forward a new method to determine the tensile loading during the installation of steel pipe using the horizontal directional drilling (HDD). There are several methods being currently used. Advantage and disadvantages of those methods are discussed. The paper describes a commonly used Finite Element technique along with sophisticated material model, which deals with softening and failure of geomaterials. It has been shown that using different meshes for different stages of progresses in installation by pulling the pipe through the bore, a reasonable variation of pulling force can be obtained along the length of installation. This method can be readily applied to any site by knowing its geotechnical characterization. The method of tensile force calculation along the pipe installation is initially developed in two dimensional geometric model, but it can readily be extended to three dimensional case as there is no complex geometric interaction between the pipe and the soil. In all stages of calculation, a new mesh is used with advanced stage of installation of pipe. The interface behavior of pipe and soil is modeled by a thin layer of weak soil constituting the smear zone. The distribution of pulling force along the line of installation is determined from the interpolation of mobilized displacements of each stage of pipe setting.

The Tarrant Regional Water District (TRWD) is a political 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, owns four reservoirs and over 150 miles of large diameter water transmission pipeline. 1.6 million people in North Central Texas currently rely on TRWD to provide reliable, clean raw water to its wholesale customer agencies. Engineers at TRWD discovered that the "real-world" conditions surrounding their pipelines had changed from that shown on their original "as-built" plans of construction. Additionally, routine inspection and analysis of the pipeline system and related aboveground features created numerous datasets necessary to accurately and efficiently plan capital improvement projects to maintain the pipelines and associated assets in a sustainable manner. TRWD was interested in leveraging their current investment in GIS technology to manage these critical assets and related features by utilizing the capabilities of the ESRI geodatabase. Given the complex nature of the problem, TRWD is utilizing a wide range of resources from various internal departments (Engineering and IT/GIS) and external consultants as well. GIS staff at TRWD created a detailed geodatabase that included information on aboveground features such as land use, soil conditions, utility networks, right-of-ways, parcel ownership, and aerial photography. For the underground pipeline information, TRWD contracted with the Pressure Pipe Inspection Company (PPIC) to develop the water transmission pipeline and add these features to this geodatabase. PPIC developed a detailed water transmission data model to track individual pipe segments, from bell to spigot, with inspection, integrity and repair information. Pipe segments were positioned using the inline inspection data collected by PPIC and the differential GPS data collected on aboveground features by TRWD.

Nonlinear finite-element analysis is used to evaluate the performance of lined-cylinder prestressed concrete pressure pipe with broken wires and thinning of the steel cylinder due to corrosion. The model includes nonlinear stress-strain relationships to represent yielding in steel and compressive crushing, tensile softening and cracking in concrete. A relationship between prestress loss length and the shape and the variation of thinning in steel cylinder was developed from inspection of failed and nearly failed pipes in a line. This relationship is used in the finite element model to represent the effects of corrosion of the steel cylinder in the performance of the pipe. Analyses are conducted for pipes with different prestress loss lengths. In each analysis, the pipe is initially subjected to prestress, self weight, water weight, and earth load. After the application of gravity loads, the internal pressure of the pipe is gradually increased to a point at which the radius of the pipe increases without any significant increase in the internal pressure. Analysis results show crack patterns, crack width, crack depth, pipe deflection, change in the stress in the wires, and concrete crushing as a function of prestress loss length. These results are used to define engineering criteria for risk analysis and repair priorities determination of pipes with broken wires.

Parallel-plate loading mechanism (ASTM D2412 standard test method) was used for investigating the long-term pipe stiffness values of HDPE, PVC and ABS pipes. The conventional and accelerated test procedures were both used. The nominal inside diameters of the test pipes were 300 and 400mm. S-type long-term deflection curve was observed for the test plastic pipes on a semi-log scale. Long-term pipe deflection is a function of pipe material properties, pipe geometry, and external loading conditions. Load deflection rate approximately increases as increasing the pipe diameter. However, the relationship between load-deflection and different plastic pipe materials is still unclear. Long-term pipe stiffness values decrease as increasing test duration on a semi-log scale. The elevated temperature test procedure can be used as an accelerated method for estimating the long-terra pipe deflection and pipe stiffness value in conjunction with the parallel-plate loading mechanism.

A series of pilot studies across North America have been held to demonstrate that the Sahara® leak detection system can be adapted to detect leaks in pressurized wastewater forcemains and siphons under typical North American operating conditions. Likewise, the Water Research Council (WRc) in the UK has demonstrated the applicability of the Sahara® leak detection system to similar environments in the UK. Sahara® wastewater is a new technology that allows utilities to assess the condition of critical wastewater forcemains and siphons, such as major non-redundant lines, waterway crossings, and lines through environmentally sensitive areas, while keeping the line in service; it is the first to allow full length inspections of in-service force mains. This paper discusses the need for inspections of wastewater forcemains and siphons, the Saraha® wastewater acoustic system, and the need for benchmarking of new technologies by third party organizations. The application of the Sahara system for the inspection of six wastewater pipelines in North America will also be discussed in detail.

Utilities have several options for protecting pipeline systems from the effects of transients and surges. The most common methods include installation of surge protection devices, such as surge chambers, air release valves, etc., and to design the system to withstand the stresses of transients (hardening of the system). The San Antonio Water System recently placed into operation an Aquifer Storage and Recovery (ASR) wellfield that both stores excess water underground (storage mode) and pumps stored water and native groundwater (recovery mode) for use in its distribution system. The system is unique in that it must operate in both directions. In the storage mode, the wellfield is connected directly to the distribution system and must be designed to withstand the tremendous pressure associated with receiving water from a pressure zone over 350 feet (107 m) in elevation above the wellfield's ground elevation. In recovery mode the wells pump to a treatment plant or ground storage tank at approximately 50 feet (15 m) higher in elevation. The high pressure experienced during storage operations and the low pressure experienced during recovery operations each have their own unique transient conditions. The 32-well wellfield will be constructed in three phases ultimately producing 80 million gallons per day (mgd) (303,000 m³/day), with the second phase currently in design and construction and the third phase in conceptual design. The first phase of the wellfield (30 mgd (114,000 m³/day) capacity) was constructed with PVC C900 and C905 for the laterals and small collection mains, and AWWA C200 mortar-lined steel pipe for the mains greater than 24 inches (61 cm) in diameter. The surge protection system included four surge chambers located on the main line designed to keep the wellfield under positive pressure during surge events. A surge analysis was performed prior to design of the second phase of the wellfield and included a concurrent analysis of the third phase surge requirements. The surge analysis recommended the installation of additional surge chambers, and to save costs, the allowable minimal pressure would be set at –7.0 pounds per square inch (psi) (–0.48 bar) throughout the wellfield. The cost to fully protect the wellfield exceeded $1 million for these options. In an effort to reduce costs further, the utility decided to harden the second and third phases of the system so that they could withstand pressures below –7.0 psi (–0.48 bar). The second and third phase piping only included laterals that would connect to the existing C905 and C200 mains. Therefore, HDPE pipe was selected for the second and third phase piping because it could withstand transient pressures down to full vacuum (–14.7 psi) (–1.0 bar). In lieu of using surge chambers on the new piping, the utility decided to use air release valves to maintain a pressure above –10.0 psi (–0.69 bar) in the HDPE piping. The cost to provide this level of protection approached $500,000. In an effort to further reduce costs, the utility applied a risk analysis to the wellfield piping and adopted a "wait and see" policy before investing significant resources into the surge protection system. The reasons for this decision are 1) the wellfield is not a critical water supply component and can be taken offline for repairs, 2) the expensive components of the wellfield, i.e., the wells and the C200 mains, are well protected with surge protection devices installed during Phase 1, and 3) with proper monitoring, the utility can detect and repair transient-damaged sections less expensively than to blanket the entire wellfield with surge protection.

Field-welded lap-joints were first successfully used in the 1920s to join sections of an all-steel pipe transmission line in Texas. This application was later improved using shielded metal arc-welding technology followed by other semiautomated arc-welding processes (i.e., flux-core arc-welding and gas-metal arc-welding) that currently dominate construction practices for field-welding water transmission lines. Pipeline designers agree that arc-welding processes provide a superior field-welded joint; however, there is considerable uncertainty regarding pipeline design loads and required field-welded joint details necessary to resist these loads. Field-welded lap-joints have proven to be very economical and are contractors' first choice; however, they are also the most vulnerable part of any welded lap-joint steel pipeline. There have been significant failures over the last 80 years since field-welded lap-joints were first introduced. With this in mind, it is unfortunate that design manuals fail to focus on this critical aspect of structural design. The longitudinal forces on buried, continuous, steel water pipelines can be extremely large (e.g., thermal force, Poisson's stress, differential settlement, hydrostatic thrust, seismic force, and soil drag force if pipelines traverse steep terrain) and even more so for large-diameter pipelines. These load requirements are not covered well in the common design standards and can be hard to quantify. Many designers believe that these longitudinal forces are relatively small. The authors recently reviewed a pipeline design criteria report that stated continuous, buried, steel pipelines are not subject to longitudinal forces greater than hydrostatic thrust. When problems with buried pipe joints develop, fixing or repairing them is expensive and disruptive. Dewatering and accessing a large-diameter main is a major undertaking. Using double-welded lap joints costs more than single-lap welds, but it is better from a corrosion and structural standpoint and allows pressure-testing to ensure that joints are water tight. Further, there are two welds to resist leakage, which are much like the difference between single-gasket and double-gasket joints. It's often a sound investment for infrastructure that you want to serve without problems for many years. There is a place for single lap-welded joints, but they are not a panacea to be used everywhere. When the stakes are high, the designer should consider double lap-welding or even complete joint penetration (CJP) welding. This paper proposes methods for determining welded steel pipeline forces and strategies for resisting these forces with field-welded joints. The application of field-welded lap-joints that are single-welded is compared with double-welded lap-joints.

In response to a voter referendum, the Metropolitan Transit Authority of Harris County (METRO) is committed to extending its highly successful initial 7 miles of Light Rail Transit system to more than 45 miles within a 4-year period. METRO'S plans call for all 30 miles to be under construction simultaneously in 5 different corridors. As a result of METRO'S aggressive schedule, the City of Houston has to relocate numerous critical underground facilities. These relocations include force mains, lift stations, and several large diameter water transmission mains including an extremely vital 66-inch water main. A major focus of the paper will be to present the issues associated with the 66-inch PCCP water main. This line is the sole source of treated water to the City's Southwest Pump Station. This station averages more than 75 MGD and its service area extends over 80 square miles, including two major employment centers and the Houston Galleria, the largest retail center in the southwest. The discussion will include how five miles of this vital PCCP water main will be impacted by the Light Rail Transit extension. Impacts, analysis, and alternatives evaluated and to be discussed include how to mitigate the system's electrical currents, providing access to the line while reducing impacts to the rail operations, and how to minimize the potential failures on this line. This paper will also present the difficulties caused by METRO'S aggressive schedule on the City's critical infrastructure. It will present how the City is dealing with the coordination necessary for the construction activities occurring simultaneous in five different areas.

This paper presents a number of case histories described in generic terms without disclosing the specific agencies involved in which cement mortar coated pipelines were damaged and how the extent of the damaged areas was identified. One project was in California, one in Texas and another in Oregon. Typically the mortar coating provides corrosion protection for the steel cylinder; however, once the mortar has become delaminated from the steel cylinder, it no longer provides the same level of corrosion protection. The close interval survey test method is a non destructive test method that uses electrochemical techniques to identify areas where corrosion activity is present. Areas of corrosion activity are expected to correlate closely with areas of Delamination. The electrochemical technique has the advantage of being able to locate areas of corrosion non-destructively. The close interval survey method requires the pipeline to be electrically continuous along the length of the survey. However, electrical continuity is not required to complete the evaluation. If a portion of the pipeline is found to be electrically discontinuous, a cell-to-cell survey can be conducted over that portion of the pipeline. A cell-to-cell survey is similar to the close interval survey but does not require electrical contact to the pipeline. If performed correctly, a cell-to-cell survey can provide data which is just as accurate as the close interval survey technique. The paper present data on cement mortar lined and coated steel pipelines however this test methodology can be used on dielectrically coated pipelines also.

Trenchless technology (TT) methods, including horizontal directional drilling, pipe jacking and pipe renewal are advanced methods for installing, repairing and renovating of underground pipes, ducts, cables, etc., with minimum excavation of ground surface. In China, the number of small-scale projects using horizontal directional drilling (HDD) equipment has increased quickly, while the number of large-scale project by pipe-jacking is increased slowly, and there are only a few projects using pipe replacement (renewal). One of the important obstacles in growth of trenchless technology is the difficulty in estimating the cost of trenchless construction, including the cost to general public, environmental impacts, damage to pavement and underground existing utilities and structures, when compared to the open-cut methods. This paper puts forward a disutility-cost assessing method combined with linear regression method. Firstly, the total disutility of trenchless construction can objectively be estimated by quantitative analysis on the factors related to trenchless construction. Then, on the basis of the assessment we derive a model to calculate the cost and obtain the characteristic parameters and empirical constant of the cost model by means of linear regression method. Finally, the cost advantage of trenchless construction will be worked out by comparing with other construction methods of underground utilities. This paper is helpful for engineers to make a rational decision among underground utility construction methods.

Yangtze-River crossing tunnel in Wuhan, a key project in China currently under construction, is a twin bore, two-directional, and four lanes tunnel, with outer diameter of 11.38 m (37 ft) crossing the Yangtze-river, the largest river in China. This project uses two Compound Slurry Shields with large section to cross the Yangtze-river. The total length of tunnel is 5,049 m (16,566 ft) so it has long continuous shielding distance. The site geological conditions and the surface environment is complex, because the soil conditions of river bed are consisting of sand stratum, gravel, and shale rock. Around the tunnel job site, there are different kinds of underground pipelines, which makes the tunnel construction more complicated. Other challenges are the requirements for surface settlement and soil deformation control and environmental protection which are very strict. So with the long drive, shallow depth, and high hydrostatic pressure, this project will be facing with many unexpected difficulties. This paper mainly discusses such parts as general features of the project, its major characteristics, and the construction scheme and safety measures.