Pipelines 2015: Recent Advances in Underground Pipeline Engineering and Construction

The Sugarloaf Pipeline is part of the Victorian Government’s strategy, “Our Water Our Future – The Next Stage of the Government’s Water Plan”. The strategy outlines infrastructure projects to address the worst year of drought and lowest stream flows in the State’s history. The Sugarloaf Pipeline project involves the construction of a 70 km (43.50 mi) pipeline from the Goulburn River, located approximately 3 km (1.86 mi) north of Yea, to the Sugarloaf Reservoir at Yarra Glen. This paper presents the challenges associated with the design and construction of one of Australia’s longest single drive pipe jack tunnels, the 828 m (2716.54 ft) long KP41 Tunnel. The tunnel was designed to avoid open excavation through the Toolangi State Forest where steep slopes, up to 40 degrees above the Melba Highway, would have required significant benching and excavation to facilitate construction. The tunnel was excavated using a Slurry Tunnel Boring Machine (TBM) at a continuous uphill grade of 0.5%. The tunnel was constructed with a two-pass tunnel lining consisting of a 2000 mm (78.74 in) ID reinforced concrete jacking pipe (200 mm (7.87 in) thick) primary lining and a 1750 mm (68.90 in) OD MSCL (Mild Steel Cement Lined) pipe (12 mm (0.47 in) thick, 19 mm (0.75 in) cement lining) secondary lining grouted in place.

The Santa Ana River Interceptor (SARI) Line is a 23-mile-long wastewater pipeline that extends from the boundary of Orange and San Bernardino counties in Southern California to the Orange County Sanitation District (OCSD) sewage treatment plant. Several segments run adjacent to and under the Santa Ana River and nearly 4 miles of the pipeline were in jeopardy of failure during heavy rainstorms. To ensure the long-term integrity of the pipeline, protect public health and safeguard the environment, the Orange County Flood Control District, in cooperation with other stakeholders, embarked on the Santa Ana River Interceptor Relocation Project to relocate and replace the SARI Mainline with a new pipeline. A portion of the project consisted of 4,000 feet of 101.5-inch OD microtunnel completed in four drives including installation of 2,900 feet of 84-inch ID reinforced concrete pipe and 1,100 feet of 99.5-inch ID steel casing. This design also required excavation of several deep shafts in difficult locations. Ground conditions along the four alignments were an extremely abrasive mixed face combination with soft to stiff silt and loose sand, gravel, sand, and clay exhibiting a flowing behavior with cobbles and some boulders. The groundwater table ranged from the tunnel invert at the lowest point to approximately 17 feet above the tunnel invert at the highest. Originally designed as a traditional conservative microtunnel project with several short, straight drives, the SARI Mainline offered an ideal opportunity for an innovative value engineering proposal. By suggesting a standard curve microtunnel drive and a compound curve microtunnel drive utilizing an innovative hydraulic joint the project contractor was able to eliminate shafts and combine multiple drives on the project. Reinforced Concrete Pipe (RCP) with Carnegie style bell and spigot joints was designed for use on the sections of the project being considered for the curved drives. After revising the design and incorporating appropriate changes to the standard pipe, the RCP manufacturer concurred that the pipe would perform through the curves, an important step in the value engineering (“VE”) process. Preliminary sketches of a curved alignment were prepared to determine the potential curve radii. Based on the sketches and load calculations it was determined that RCP with the incorporation of the hydraulic joint was more than sufficient to handle the potential joint deflection. The coordination and cooperation between the agency, contractor and manufacturer resulted in a savings to the project of over $1 million and offered a 20% reduction in the tunneling schedule.

In 1994, 2001, and 2009 Fairfax County completed spot inspections and testing (i.e. visual, petrographic examinations, wire testing for tensile and torsional strength) at different locations along an existing one mile 0.91 m (36-inch) PCCP which traversed an environmentally sensitive area. The purpose of the testing and evaluation was to assess the pipe integrity and determine if replacement or repair was required. The results of these tests indicated that the pipeline remained in serviceable condition. However, concern regarding any extended leakage into the surrounding environment led to a decision for installing a new, parallel 0.91 m (36-inch) pipe, with the existing line to be available for redundancy. Due to the proximity to natural wetlands open trench installation was not plausible; therefore, the use of trenchless technologies was evaluated for its viability in this application. Based on the analysis, it was determined that microtunneling (MT) was the most viable technology for installing the new force main in order to minimize environmental impacts to the wetlands and disturbance to the neighboring communities. Microtunneling proved to be the best available technology in this application as the new ductile iron force main has been in operation for two years and had minimal impact on the wetlands and neighboring communities.

A preliminary hydraulic analysis and transmission main routing study was completed by Burns & McDonnell in 2008 to plan for projected growth in the southeast section of the City of Lawrence, KS (City) and to provide an additional water service feed to North Lawrence. The analysis recommended addition of a future 36-inch water transmission main to meet the City’s needs. The nearly six mile water transmission main would connect to the Kaw water treatment plant (WTP), supply water to North Lawrence and ultimately provide service to the southeast section of the City to meet projected water demands beyond 2020. The City chose to design the first phase of the water transmission main project to connect the Kaw WTP to an existing 12-inch water main located in North Lawrence. The major challenge with serving North Lawrence is that the Kansas River separates this service area from the rest of the City. In addition to the Kansas River crossing, other design challenges associated with this project included a US Army Corp of Engineers levee crossing, two railroad crossings, a creek crossing, and work in the Burcham Park area which is a high use park enjoyed by the residents of Lawrence. Fusible polyvinylchloride pipe (FPVCP) was selected and bid for the transmission main. At the time of installation, the 2,400 foot Kansas River crossing was the longest FPVCP horizontal direction drilling (HDD) installation in the world for 36-inch diameter AWWA C905 Dimension Ratio (DR) 21 pipe, which is currently the highest rated pressure class available in 36-inch FPVCP.

The Denver Metro Wastewater Reclamation District (MWRD) is installing a 10-inch pressure pipeline to carry potable water from the Robert W. Hite Treatment Facility located in Denver, Colorado to the MWRD facility. The pipeline alignment crosses beneath both the Burlington Ditch, owned and operated by the Farmers Reservoir and Irrigation Company (FRICO), and the Union Pacific Railroad (UPRR) trestle, both of which have specific and stringent requirements for trenchless pipeline installations. Furthermore, the pipeline traverses Denver Water right-of-way, thus triggering the necessity to adhere to another set of trenchless installation requirements. This paper presents challenges encountered during design and construction of the horizontal directional drill, focusing on how the design and construction was influenced by FRICO, UPRR, and Denver Water requirements. Discussion of the settlement and hydrofracture analysis performed during design is presented and compared to what was observed in the field during construction. Furthermore, this case study details the morass of permitting requirements encountered and how, as a whole, the requirements actually dictated the overall risk profile of the project.

Competitive Power Ventures’ Woodbridge Energy Center is a new 700-megawatt, dual energy, high efficiency power generating plant being built in central New Jersey. Located in Woodbridge, New Jersey, the plant will supply electrical power to the New Jersey metropolitan area, meeting the growing demand for power and providing increased reliability for the local grid. When plant construction is complete, power generated at this new facility will be transmitted to Jersey Central Power and Light’s existing Raritan Substation, approximately three miles away. The required three mile transmission alignment between these two locations included some critical crossings, including two environmentally sensitive wetland areas and the longest one, a crossing of the Raritan River. Use of traditional installation methods such as overhead towers and direct burial of conduit were not feasible in these sections of the required alignment. For these three critical locations horizontal directional drilling (HDD) was used to install more than one mile of transmission lines. Each of the three sections included dual parallel installations, resulting in six separate drills of 30-inch casing and conduit pipe installations that would eventually house three 230 kV electrical cables each. In all, over 11,000 feet of HDD installation was completed for these sections. Fusible polyvinylchloride pipe (FPVCP) was used for both the casing and conduit piping. The 30-inch FPVCP casings housed four 8-inch FPVCP conduits to carry the transmission cables, two 2-inch HDPE conduits for ground and fiber optic lines, and two 3-inch HDPE grout delivery tubes. The entire assembly was grouted in place using an engineered thermal grout for heat dissipation. Local suppliers provided the materials that were tested and used for this project. This paper will discuss the design and construction elements of the HDD sections, as well as the lessons learned for these key ‘underground’ sections of the Woodbridge transmission project.

Pipelines have been traditionally constructed in short 20-40 feet (6-12 m) long segments. The pieces are shipped from the factory to the job site and stored on site until they are joined together. This process leads to delays in projects due to the time required to build the pipe segments, and high transportation charges for delivery of the pipes to the job site. Once connected, the joints are a major source of leakage and maintenance expense that continue for the life of the pipeline. The pipe materials require protection against corrosion and the heavy weight of the pipes is a safety concern, making pipeline construction one of the most dangerous trades. In view of the above limitations, the author has developed an onsite-manufactured pipe that allows construction of a virtually endless pipe of any diameter and pressure rating onsite. Unlike conventional pipes, the walls of this pipe are made of a lightweight core that is encapsulated between layers of Carbon or Glass Fiber Reinforced Polymer (FRP). The thickness of the core and the number of layers and type of fibers, i.e. carbon or glass, are determined based on the project loading requirements. This paper focuses on the development of the first prototype of the Mobile Manufacturing Unit (MMU) that was completed in October 2014. Within the MMU, layers of resin-saturated fabrics are wrapped around a mandrel and cured to create the pipe. As the MMU travels along the roadway, it produces a continuous pipe at a rate of 2 miles (3 km) per week. Various aspects of the MMU that were considered and the lessons learned as part of this R & D are presented. A hand-made version of this pipe can be produced with minimal equipment, providing safe drinking water to remote sites and villages worldwide.

Lake Travis is located northwest of the City of Austin, Texas. Due to explosive population growth in the area, the Austin Water Plant No. 4 was designed and constructed in the “hill country” to pull water out of the lake through an intake vertical shaft and tie-in the tunnel located approximately 230’ underneath the lake. The project was designed and bid with one contractor doing the shaft and another installing the tunnel and Cut-In Outlet. This paper discusses from a manufacturer and specialty installation perspective how and why the cut-in outlet was required for this installation between the Intake Shaft and Tunnel. Also discussed is how a standard AWWA Manual M11 Design Procedure for Crotch-Plated Fittings in the original bid documents was not applicable for this installation. The paper will go into the design procedure and methodology used and discusses the changes that took place between the design and approval process and the final installation. The first half of this paper will discuss the Pipe Manufacturer’s Perspective including the design, bid and approval process for this installation. The second half of this paper will be the Specialty Installation Perspective which will discuss the installation process including the outlet fit-up, welding and NDE practices used for this installation.

This is a case study presented on the Big Lake (W14) Gravity Sewer Microtunneling Project in Edmonton, Alberta. The gravity sanitary sewer project was designed as a direct bury application with PVC and RCP pipe. It was expected that the subsurface conditions were to vary considerably within the proposed depth of proposed pipeline. The subsurface conditions within the pipe zone were expected to include water bearing peat, fill, and saturated silt and silty sand, all of which were extremely soft, with blow counts as low as 2. To address these conditions, the design included special bedding and embedment envelops to ensure the installed pipe is adequately supported to prevent pipe settlement and structural failure of the pipe. This design component was more essential to the longevity of the PVC Pipe than the Concrete Pipe. As an alternative, Michels Pipeline proposed to install the pipe by means of microtunneling in lieu of direct bury. In addition they proposed the use of fiberglass jacking pipe for this installation method. The project construction began utilizing 48” diameter FRP jacking pipe, but due to the unfavorable subsurface soil conditions the project was not able to be completed with this pipe material. As a solution to the installation difficulties, the pipe material was changed to 48” FRP Lined Reinforced Concrete Jacking Pipe. This is the first installation of FRP Lined Reinforced Concrete Jacking Pipe in North America.

The I-5 / 164th Martha Lake Gateway Sewer and Water Improvement project, completed in November of 2014, provides a new gravity sewer system and water transmission main for the Alderwood Water and Wastewater District (AWWD) in the vicinity of Interstate 5 (I-5) and 164th Street SW just north of Seattle, Washington. An earlier study performed for the District determined that the most desirable method of providing sewer service to the sewer basin would require a 532-foot trenchless crossing under I-5 as well as a 200-foot crossing of 164th Street Sw. This paper examines the trenchless crossings of I-5 and 164th Street SW with respect to the geotechnical conditions and explores how these conditions influenced the design of the crossings as well as the execution of the contract once construction was underway. The first section focuses on project history and design of the crossings and discusses how the soil conditions directed the trenchless evaluation and selection of the trenchless method for each crossing. The second section focuses on the geotechnical baseline report (GBR) and examines how specific baselines were determined through a collaborative process between the District and design consultants. This process allowed the District to apportion the various risks between themselves and the trenchless contractor. The final section discusses the execution of both trenchless crossings and examines how various elements of the GBR were utilized during construction.

Predicting the borehole pressure during Horizontal Directional Drilling (HDD) is a significant part of HDD. Borehole stability means that pressure on the bore-face must be less than formation fracture pressure and more than the collapse pressure to avoid fluid losses or borehole breakouts. The proposed research is aimed at an analysis comparison between the mud pressure data collected in the real field and the ones the mathematical model predicted. Then the optimal model will be applied to predict the allowable maximum borehole pressure during HDD. Borehole stability during drilling consists of evaluating the drilling fluid weight to maintain the borehole wall integrity. The tensile failure (hydraulic fracturing) and dog-ear shape breakout are two main failure modes around boreholes during HDD. The cavity expansion model was used to calculate maximum and minimum allowable drilling fluid pressure in a bore. Both 2D and 3D finite element (FE) models of maximum borehole pressure were developed by the Drucker-Prager and Mohr-Coulomb theories using ANSYS Parametric Design Language (APDL) to support the customized parametric study. The result showed the maximum mud pressure closely matched the estimation obtained using the Delft equation in this field experiment for shallow layers within clay. The FE modeling procedure used was able to capture the volumetric compressive behavior of the soil around the borehole.

The Victory Pipeline project is a $30 million dollar, 27.5 mile pipeline located in Duchesne County Utah. This gravity fed pipeline was constructed using HDPE pipe with sizes ranging from 22”–30” that will deliver treated potable water to 7 different water companies and cities. This paper will discuss the pipe material selection process, pipe fusion, and installation techniques including open trench, and HDD and the benefits of using HDPE pipe. Several obstacles were encountered in the design and installation of this project which forced an alignment change. These obstacles include environmental assessments, endangered plant species, migratory birds, easements of over 50 property owners, state land, federal land, the Bureau of Indian Affairs property easements, and coordination with US Fish and Wildlife, and the US Bureau of Reclamation.

Large diameter pipelines are a critical component of a utility’s infrastructure. Design and construction of pipelines in an urban environment is a difficult task. Weaving a large, critical piece of infrastructure through city streets, easements, and existing infrastructure has unique challenges that must be studied in the planning, routing and preliminary design of the project. This paper will present an outline for the planning, design and construction of a large diameter pipeline in an urban area based on lessons learned from previous projects. The lessons learned during construction provide valuable insight into how better planning and design can greatly reduce the challenges faced in future construction projects. Pipeline construction can impact businesses, bring traffic to a halt and jeopardize public safety. To limit these impacts to the community, engineers must consider public involvement initiatives, traffic control and project phasing. Route selection is a critical part of the process and can ultimately have the greatest influence on how challenging construction and maintenance of the pipeline will be. Additionally, engineers can work within the framework of the triple bottom line to balance, environmental, economic and social impacts. This process can be used in evaluating open cut construction versus tunneled construction as well as selecting the best route for the pipeline. Construction of large diameter pipelines is slow and expensive. Working with contractors to identify work space requirements and construction methods is very important. As a part of this paper, several contractors were contacted to discuss these challenges and a summary of those discussions is included in the paper. Pipelines, due to the large investment and criticality of service, must be reliable and resilient with a long service life; therefore, they must be engineered with robust design criteria and with operations and maintenance in mind. This effects route selection, pipe material selection, backfill and embedment design and appurtenance layout. The earlier these factors are considered the better off the project will be during construction.

Box culverts are an essential component of highways and railroads since they transfer storm runoffs from upstream to downstream. Box jacking (BJ) is a trenchless technology method to install box culverts under embankments of existing highways and railroads with minimum surface disruptions. Over excavation (overcut) during box jacking operations is required to facilitate steering and reduce friction forces. Surrounding soils may collapse into the annular space during or after project box jacking and cause soil movements. Soil movement is reduced away from top of the box due to arching effect. Arching is a mechanism where soil particles are prevented from collapsing completely above the installed pipe/box and consequently less load is applied to pipe/box. The objective of this paper is to investigate the applicability of available empirical methods to estimate soil vertical displacements in box jacking projects and compare their results with a case study. Finite element modeling (FEM) using PLAXIS 2D is used to simulate box jacking operations. Data is collected from a box jacking project to validate the FEM model.

Placing material in the hard to reach places underneath a pipeline called the haunches, is very difficult to do and very labor-intensive. This is one of the most important tasks when installing a pipeline. The main objective of pipe haunching is to provide firm uniform support to the pipe that will not change over time due to consolidation, moisture ingress, collapse etc. This is the main reason for specifying the use of a well-graded free-draining sand-gravel type of material in the pipe haunches. The purpose of this paper is to evaluate the effect of different haunching techniques (i.e., placement and compaction of material underneath the pipe in the haunches) on the predicted structural responses and performance of buried pipes using a non-linear finite element analysis program. Results are presented for the following typical installation conditions: (1) No haunching (i.e., loose/dumped support such as 50% Standard Proctor density), (2) Haunching (i.e., firmer support such as 85% Standard Proctor density), (3) Placing silty sand (i.e., AASHTO A-2-4) material in the haunches, (4) Placing well-graded sand-gravel material (i.e., AASHTO A-1-a, A-1-b) material in the haunches, and (5) Using flowable low-strength soilcrete (i.e., 700 kPa compressive strength) in the haunches. Results reported herein include predicted pipe structural responses for a DN1200 steel pipeline such as deflection, wall thrust, normal pressure and bending moment. Lastly, the importance of proper pipe haunching and the beneficial use of soilcrete are clearly demonstrated from the results of the parametric study.

Grottoes, Virginia discovered severe corrosion in portions of their stormwater system during a routine annual inspection in 2013. A large set of elliptical CMP culverts didn’t pass inspection. The culverts were in poor condition with severe corrosion. Individual sections were failing and misaligned, and the town’s consultants recommended replacement. Complicating the issue, the failing pipes were four parallel culverts which are all are quite large, 70” by 44”, running directly underneath Dogwood Avenue, one of Grottoes’ two main thoroughfares. The town obtained cost estimates for trench-and-replace from Brunk & Hylton Engineering, Inc. and, as expected, the price was high and the plan called for significant and lengthy traffic disruptions. Fortunately, Grottoes Town Manager Jeff Nicely had seen a trenchless rehabilitation process called CentriPipe that looked like it could be useful in this situation. In researching the solution, Nicely discovered the project cost was 15 percent less than the dig and replace estimate they had received, and had the added benefit of eliminating weeks of traffic disruptions. This paper will review the breadth of aging infrastructure situation that state and local agencies in the United States are facing, the engineering considerations in addressing failures, and the process, quality control measures, and results of the critical project in Grottoes, Virginia.

The tunneling industry involves countless number of variables and complexities that have to be considered when selecting the construction method to be applied in different types of projects. In addition, the availability of different trenchless technologies makes it difficult to select the most suitable trenchless technology to be used. This paper introduces a framework for developing a Trenchless Technology Decision Support System (TTDSS) using a newly-introduced technique “Hierarchical Artificial Neural Networks (ANN)”. The system integrates the concept of hierarchies with the ANN, taking into consideration the direct effect of the factors on each hierarchical selection. Sixty projects were introduced to the HANN, 80% of them were used as training cases and the remaining 20% were used for testing. Results indicated the potential of TTDSS in supporting trenchless technology specialists in their selection decisions, where the error percentage did not exceed 5%.

The use of polyethylene (PE) pressure pipelines is increasing in international significance and therefore being used in increasingly challenging conditions. The reasons for this are manifold, including the excellent corrosion resistance of the material, the flexibility of high-density polyethylene 100 (PE 100) pipes, and the resulting installation and cost advantages. The construction of a80 km long water pipeline through the Mediterranean sets new standards in water supply. Requested by the Turkish Republic of Northern Cyprus (TRNC), it runs from the Turkish mainland (Mersin Province) to the Turkish part of the island of Cyprus. For the project, individual lengths of 500 m (1600 ft) PE 100 pipe were produced and installed so that they float 250 m (918 ft) below the surface of the Mediterranean. In 2011, a dam was built in the mountains of the province of Mersin which directs water from the Dragon River to the north-east of the town of Anamur. The dam is also to be used for generating hydroelectric power, as well as for storing the water for the pipeline. The prerequisite for the success of this project was the development of an ultra-demanding and innovative flange design for a stub end that can durably join steel and PE 100.Due to the excellent communication and cooperation between Reinert-Ritz GmbH and the project managers, a high level of confidence was generated for the long-term tightness and safety of the flange connection.

The Valley Transit Authority is working with the Bay Area Rapid Transit (BART) to ultimately expand BART’s existing light rail system south to San Jose. Several new stations are proposed as part of the Light Rail Track extension. However, two of the new stations will impact two existing large diameter water pipelines, owned by the Santa Clara Valley Water District. These existing lines have to be relocated away from the new stations. This paper will discuss the technical design aspects of installing new pipe and fittings into an existing 66” concrete pressure pipe raw water main and into an existing 42” steel pipe treated water main in order to properly relocate both lines. A key consideration in this modification to the existing lines is the thrust forces generated from the realignment. The thrust restraint of the old 66” line posed a number of challenges since the original pipe in this area did not have longitudinal thrust forces. Additionally the owner, the Santa Clara Valley Water District, has their own specialized thrust restraint procedure that is based on a 1960s paper. This approach is different than what is recommended by the AWWA in the pertinent AWWA design manuals. Other challenges encountered during the relocation design included a number of pipe design considerations such as internal and external load, buckling, and fittings design. Further complicating the relocation effort is the need to account for a special “rattle box” casing to protect existing gas lines under a new “floating slab” for the Light Rail Track at one location. Included in the discussion will be recommendations on a few “lessons learned” from the relocation design efforts.

In 2009, the City of Corpus Christi (the City) moved forward with the preliminary design phase of the Mary Rhodes Phase 2 Pipeline. This 42 mile, 54-inch pipeline is integral to bringing water from the Colorado River to Lake Texana and eventually to the City’s citizens. Because the City utilized a Water Infrastructure Fund deferred loan, the engineering feasibility report and environmental permitting were completed prior to the beginning of the final design phase. Environmental permits were secured in December of 2012 and final design began immediately after. With the USACE permitting conditions, trenchless construction methods were required for two large Waters of the US crossings, the Navidad River in Jackson County and the Tres Palacios River in Matagorda County. Horizontal Directional Drilling (HDD) was selected for these crossings due to the reliable accuracy, ability to drill below the water table and through wet soils, quick construction timeline, and minimal environmental impact. Multiple factors are considered in horizontal directional drilling design. Some of the key design parameters include entry and exit angles, analyzing soil conditions, and ensuring minimum depth below the river bed. The pipe material, pipe lining and coating, and pipe size are all critical components to how the HDD will be designed and constructed. The Mary Rhodes Phase 2 Pipeline HDDs were unique design challenges due to the large diameter of the pipeline, limited pipe materials available, the depth and length required, and limited working area. The HDD sizes were re-analyzed and changed during the construction phase due to coating application limitations caused by the original pipe size. Various alternatives were analyzed for coating application alternatives. The City, the Engineer and the Contractor were able to work together to secure a good solution for all parties. At present, the construction of both of these HDDs has been completed on schedule with minimal challenges. The detailed design process, construction process, and lessons learned will be discussed in this paper.

Anne Arundel County is currently in the process of replacing approximately 25,000 linear feet (LF) of sewer forcemains (FM) using horizontal directional drilling (HDD) for trenchless installation. The County has initiated a small diameter sewer FM replacement project to rehabilitate and/or replace small diameter sewer FMs that have reached the end of their useful life and/or have a history of breaks/failures. The County decided to use HDD to protect existing infrastructure and minimizing environmental disturbance and to streamline regulatory reviews and approvals. This paper focuses on six individual contracts in Anne Arundel County, Maryland that have utilized HDD. The challenges encountered on each of the contracts are highlighted and then summarized as lessons learned for general HDD installation. The conclusions from the lessons learned are summarized below: (1) The more information that is gathered in the design phase the smoother the construction phase will be. (2) The clearer the contract documents are the less room for change orders during construction. (3) A good public outreach program is essential.

This paper discusses a 30” HDPE new water main installation project installed by the horizontal directional drilling process under a river. It will discuss the challenges of the installation including a steep angle of entry, significant elevation variances from one side to the other, varying soil conditions along the path of the bore, environmental challenges and more. Additionally, the new line was installed in a corner where 3 municipalities met and benefits related to good communications between all involved will be discussed. It will prove how the right material, the right equipment, and partnership between all with a staked interest in projects can overcome challenges and produce a quality product for the end users. It will also point out how bore fluid choice, hydraulic pressures while boring and soil condition as well as terrain assessment prior to beginning the project are instrumental to a successful project of this nature. Also, dealing with 3 municipalities, 2 state agencies and a developer of an assisted living facility within the confines of the jobsite brought additional administrative and physical challenges that will be discussed. Additionally, the owner’s needs and desires including, but not limited to, time constraints, environmental concerns, public relation concerns, and the ultimate need for this line as a substantial and important feed for a growing territory will be discussed. Ultimately, this paper will clearly exhibit that planning, cooperation, communication and executing to plan can lead to a very successful project even though many challenges are encountered along the way.

The Silver Lake Reservoir Complex located in Burbank, CA is one of several projects to replace open storage reservoirs in the Los Angeles area. This complex included replacement of the open reservoirs with enclosed reservoirs plus tunnels and open cut pipelines to accommodate the upgrade. One of the main components to the project included construction of a segmented concrete tunnel casing under Griffith Equestrian Park to the Silver Lake Complex and installing a 96” × .563” × 3,200’ butt welded steel tunnel liner which is the subject of this paper. The project was performed during the hot season (August) and mandated expedited/around the clock installation due to a delay of the preceding work. The design disallowed the use of welded pipe attachments for temporary support and blocking during installation which in turn dictated the use of block supports independent to the pipe. There were also no expansion joints or means to accommodate thermal contraction expected during the installation. Following the expedited pipe installation approximately 2,000’ of pipe was installed within the first 11 days and supported on nonorganic/plastic lumber intended for dead load support. During installation the pipe butt joints were stabbed into a steel backing ring and tack welded or root welded to provide a temporary connection. The project Specifications required SMAW welding (stick/manual welding) which limited the finish welding progress rate and therefore welding lagged considerably behind the installation. While in process and after installing about 2000’ the temporarily tacked/rooted joints began to pull apart as a result of thermal contraction. This paper explores the tunnel liner installation execution means and methods, the resulting thermal contraction causes and the suggested options to avoid future occurrences of this type to future tunnels.

The application of nondestructive examination (NDE) for welding of steel pipe and steel cylinders is a topic that requires forethought and knowledge. Specifically, when to use a certain NDE method, how to determine the frequency of examination, and the acceptance criteria to apply. NDE methods often vary from project to project, and understanding each method will help the engineer determine which process or combination of processes to use for a specific project. These quality assurance checks are useful for confirming weld quality in the final product before it is put into service. A weld that looks great on the outside is often seen as high quality and this is hopefully the case. Unfortunately, surface appearance alone cannot be used to verify good workmanship or internal weld quality. Many pipeline owners operate on limited budgets and need systems that can perform for many years with minimal or no maintenance. Water main and other pipeline ruptures almost always make front page news, which is why following good design practices in combination with the use of secondary checks to verify fabrication quality are important. Most pipe fabrication standards require some NDE, typically in the form of hydrostatic testing and visual inspection. These tests are useful for locating leaks and surface defects, but they will not confirm that a weld has complete joint penetration or that individual weld beads are free from objectionable defects. Additional forms of NDE must be specified by the engineer and are often needed for critical applications and projects that involve field welding to confirm weld quality. This paper will provide an overview of Visual Inspection responsibilities and additional NDE methods specified by engineers. A description of what each NDE method is capable of detecting, its benefits and limitations is also included. Specific NDE methods that will be discussed include: (1) Radiographic Testing (RT) (2) Ultrasonic Testing (UT) (3) Magnetic Particle Testing (MT) (4) Liquid Penetrant Testing (PT)

This paper discusses several recommendations for preparing, reviewing, and responding to contractor’s submittals for water and wastewater conveyance projects. These conveyance projects typically involve submittals for pipe materials, pipe fittings, pipe joints, pipe lining, pipe coating, welding, manholes, valves, and pumps. The paper includes perspectives from the supplier’s, contractor’s, and designer’s involvement in the process. At times, the submittal process can be time-consuming and frustrating for all participants. Suggestions are presented to improve preparation of submittals, to speed up the processing of submittals, to minimize re-submittals, and to generally streamline the submittal process.

The East Bay Municipal Utility District (EBMUD) is a major water utility providing water to over 1.3 million people on the eastern side of the San Francisco Bay Area. EBMUD has approximately 4,200 miles of treated water distribution and transmission pipelines within a 332 square-mile customer service area. System data are managed using a comprehensive Geographic Information System (GIS) geodatabase of pipeline characteristics, spatial location, and seismic hazards involving liquefaction, landslide, and fault crossing severities. Due to the proximity of active faults such as the Hayward, Calaveras, San Andreas, and Concord Faults, the EBMUD service area is prone to earthquakes and susceptible to secondary effects, such as liquefaction settlement, landsliding, and other permanent ground deformations. Previous studies (Prashar et al., 2012, and 2014) documented the susceptibility of these secondary effects. Permanent ground deformation was estimated from liquefaction induced settlements. The magnitude and spatial distribution of differential settlement were established in a GIS database for areas of Alameda and Oakland. Significant damage was predicted in all pipelines intersecting and also within: 1) Artificial Fill, 2) Merritt Sands, 3) Holocene Alluvial Fan Deposits, and 4) Pleistocene Alluvial Fan Deposits. This paper summarizes the results of a pipeline structural analysis to identify pipeline segments with the potential for failure due to liquefaction induced settlement, using GIS. A detailed pipeline structural analysis was performed for the varying pipeline characteristics including diameter, length, pipe material type, and joint connection to evaluate the relative settlement estimates for four distinct soil deposit and geologic formation types. The goal of the study was to determine which pipelines would most likely fail in the event of an earthquake, with future steps to develop a plan to replace, reinforce, line, or install flexible connections at strategic locations of liquefaction induced differential settlement.

The backbone of the DC Clean Rivers Project includes the construction and operation of 23-foot finished diameter tunnels. The tunnel alignments total almost 15 route miles, and traverse underneath existing sewage and water pipes that are paramount for the residents, federal government offices, and businesses in Washington, DC. These existing pipelines have to serve the rate payers for many decades; therefore, serviceability of these existing pipelines cannot be impacted adversely by the construction and operation of the tunnels. The authors undertook a detailed investigation of anticipated impacts on several pipelines by two of the tunnels. This paper presents the data and methodology used, and the results obtained. Based on the outcome of these analyses, the ground movement monitoring plan was designed and implemented. A summary of how the design-build bidding process benefited from the above risk management-based impact analyses is also presented.

Fragility functions (or fragility curves when presented graphically) are a well established tool to assess seismic risk to infrastructures. Given a sustained level of ground motion intensity, seismic fragility functions of sewerage pipelines are used for predicting earthquake-induced physical damage to sewer pipes. However, existing fragility functions of sewerage pipelines refer to a limited number of pipe types and material categories. Therefore practitioners often draw upon fragility functions specifically defined for potable-water pressure pipelines available in the international literature, for foreseeing earthquake-induced failures on sewerage gravity and pressure pipelines. The discrepancies between existing fragility curves and the observed physical damage data collected after the Canterbury (NZ) Earthquake sequence in 2010-2011, evidence that the fragility functions defined for potable-water pipelines tend to underestimate the physical damage to sewerage gravity pipelines. This paper proposes fragility functions for sewer gravity and pressure pipelines, categorized by pipe materials and liquefaction zones. The proposed fragility functions are developed using maximum likelihood estimation by correlating peak ground velocity with damage ratio (defined as number of faults per km) for sewer gravity pipes and with repair rate, defined as number of repairs per km for sewerage pressurized pipelines.

The 2010 and 2011 Canterbury earthquake sequence left Christchurch City’s wastewater network severely damaged. This study undertakes an investigation into the performance of buried wastewater pipes after the Canterbury earthquakes adopting and integrating two different approaches, namely: 1) a statistical analysis of the repairs undertook by the pipes; 2) the classification of the observed vulnerabilities after field inspections. The aim is to assess how physical factors, including geometrical and constructive characteristics of pipes, along with the sustained seismic permanent ground deformation, have all contributed to the pipes’ seismic performance. A database combining pipe physical factors, along with ground deformation measures, and repair rates (defined as number of repairs per km) was created and analyzed through statistical analysis, regressing repair rates against ground deformation respect to the physical factors. Then, the main factors identified via field visual inspections, are summarized. Finally the outputs from the two different approaches were comparatively discussed in the paper. The possibility to use the findings from this paper for the preliminary seismic vulnerability evaluation (e.g. screening and relative ranking) of buried wastewater pipelines is finally discussed in the paper.

In Japan, the main irrigation pipeline network is increasingly getting older and losing its function due to deterioration. The concept of in-situ rehabilitation for aging pipelines, which can improve the performance of a damaged pipe by installing new pipeline inside of the existing aging pipeline, has gained increasing attention. However, the seismic mechanical behavior of pipeline rehabilitated by this method is not substantially clear. In this study, to clarify the effect of damaged outer pipe on the inner pipe, shaking table tests were conducted for the buried pipe in liquefied ground. To model the inner pipe, polyvinyl-chloride (PVC) and polyethylene (PE) pipe were used. To model the outer aging pipe, different types of concrete pipes in length were used. The test results indicated that the amplitude of the bending strain in PVC pipe sharply increased due to the stress concentration at the gap between outer pipes. Additionally, the deflection mode of the pipe was categorized into two main types; bow-shaped deformation and pendulum-shaped deformation.

The desalination project with 54 million gallon per day (MGD) capacity in Carlsbad, California, which is under construction, includes a 54-inch diameter, 10-mile long high-pressure steel pipeline for the conveyance of the desalinated ocean water from the treatment plant to the San Diego County Water Authority’s water system. The steel pipeline is lined with cement-mortar and coated with polyethylene tape and cement-mortar topcoat. The design criteria and parameters for the pumped flow system pipeline, which included seismic analysis, were stringent due to the operating conditions. The steel pipeline and its field double lap-welded joints were designed for a maximum design and surge pressures of 537 psi and 662 psi, respectively. The preliminary lap-welded joint design was based on ASME’s joint efficiency factors and the final joint design was based on the joint stress analysis. The preliminary and final design criteria, which included limiting the maximum design circumferential stress at surge pressure to 50% of the minimum yield strength of the steel, will be reviewed and presented. The steel cylinders, with thicknesses varying from 0.50 inch up to 0.70 inch for 64% of the total length of the pipeline, were fabricated from coiled steel by the spiral forming and welding process. The remainder of the steel cylinders, with thicknesses varying from 0.72 inch up to 0.90 inch, were fabricated from plate steel by the rolling and welding process. The weld-seam fabrication tolerances and allowable repairs were more stringent than AWWA C200 standard requirements. In addition, 100%of the weld seams of the steel cylinders were radiographically tested. The fabrication and testing requirements of the steel cylinders will be reviewed and presented.

The Carlsbad Desalination Project uses a pipeline to deliver water from a seawater desalination plant located near sea level to the San Diego County Water Authority’s Second Aqueduct connection facility located at an elevation of about 560 ft above sea level. The approximately 10-mile long steel pipeline is 54 inches in diameter, has a wall thickness varying from 0.500 to 0.895 in., and is joined with double lap welds. Along the pipeline alignment there are simple bends, compound bends, and tees. In addition, certain parts of the pipeline are installed within a steel casing in a tunnel. The authors analyzed the stress states of the pipe walls and of the double lap welded joints, assessed the thrust restraint behavior of the pipe, and analyzed the stresses and strains in areas where the pipeline is shielded by tunnel casing and incorporates a tee connection. These analyses accounted for the effects of combined loads resulting from internal working and transient pressures, temperature change, and seismic longitudinal strains and curvatures of the soil on the pipeline. This paper discusses the analytical procedures used in the stress analyses, including material nonlinearity and pipe-soil interaction, for pressure pipelines subjected to seismic wave propagation effects.

Using advanced finite element simulation tools, which account for both geometric and material nonlinearities, the bending capacity of welded lap pipeline joints is investigated. Following the analysis of plain pipes, numerical results are reported for two steel typical grade 40 pipes, single-welded or double-welded, with D/t values equal to 150 and 240 respectively. Internal pressure effects are also examined, as well as the effects of bell-spigot gap. The results of the present study focus on the value of local strains developed at critical locations and are aimed at providing better understanding of welded lap joint behavior under extreme bending loading conditions. This may allow for the development of design methodologies in geohazard areas where welded joints are required, in order to safeguard the structural integrity of steel water pipelines imposed to severe ground-induced actions.

Polypropylene (PP) corrugated pipe is one of the newest products for sanitary and storm sewer applications in North America. Polypropylene pipe has been used for decades in Europe, but was not used in United States and Canada until the past 5 years, when new ASTM International, AASHTO and CSA standards were developed and approved for the applications more typical to North America. Polypropylene offers unique benefits over previous plastic materials used for sanitary and storm sewers. It has very high stress crack resistance, essentially negating any concerns with the type of stress cracking associated Stage II plastic pipe failure. It also has very good impact resistance and a high modulus of elasticity giving it both better performance at low temperature installations and a higher pipe stiffness. This increase in modulus also provides corrugated PP pipe with better beam strength, which helps to mitigate field deflection. In a very short period of time, corrugated polypropylene pipe has been specified and installed on numerous major sanitary and municipal drainage projects. This paper will cover the specific aspects that make polypropylene a unique material for pipeline construction. The various national standards shall be discussed with the emphasis on the performance criteria that these products must be tested to and meet as part of their certification. Some large infrastructure projects will also be highlighted to demonstrate its current acceptance and use.

As the use of Fiber Reinforced Polymers (FRP) in the rehabilitation of aging pipeline grows globally, so also does the adoption of various accepted industry ideologies of FRP design. While many municipalities in the waste water pipelines industry have used the rehabilitation of water mains standard (American Water Works Association Manual 28(AWWA M28)) and the American Society for Testing and Machines (ASTM) F1216 to develop standalone rehabilitation designs,the referenced design criteria does not account for all the loads that the pipeline may encounter in its lifetime. In addition, this criterion was not written assuming the use of an anisotropic material, such as FRP. This paper will highlight the different design practices used for FRP and Cured in Place Pipe (CIPP), as well asprovide recommendations to modify both the AWWA M28 and the ASTM F1216standard, which reflect some of typical buried pipeline load conditionsnot defined in either manual.

The author was retained by the DC Clean Rivers Project team while designing the relocation of a critical water main of PCCP with bends to minimize the adverse effects from the construction of a 75-foot in diameter and 100-foot deep shaft. In this project, the client sought multiple pipe materials considered for the new bends. The author used most of the thrust restraint design methods presented in the AWWA manuals of practice with ease, but stumbled into many issues in Chapter 9 of M9. The author examined: (1) The details of the new thrust restraint design method (2) The content of Zarghamee et al. (2004), as well as the discussions and the closure, Zarghamee et al. (2005) that were written in response to this paper (3) The experimental verification of the new design method by ACPPA and the AWWA concrete pressure pipe committee before implementing Zarghamee et al. (2004) in Chapter 9 of AWWA M9. This paper summarizes the lessons learned from the birth and the life of Chapter 9 in M9 and the associated software TRDP. This paper’s most significant contribution to the profession is outlining changes that would encourage wider use of the contents of AWWA M9 Chapter 9.

The ASTM standard C12 “Standard Practice for Installing Vitrified Clay Pipe Lines” gives recommended methods for installing vitrified clay pipe (VCP). C12 was significantly modified for the 2014 version (C12-14). Three of the most notable changes were: (1) Use of uncompacted soil for the bedding (2) Adoption of uniform soil groups (3) Recommended gradation for the bedding soil. The current standard includes several bedding classes for proper support of the pipe with corresponding Load Factors. The Load Factors reflect the amount of support the bedding soil gives to the installation. While the basic trench configurations and Load Factors have not changed, the 2014 version incorporates various improvements including: (1) Discontinuation of the concrete arch bedding class (2) Adoption of Uniform Soil Groups for Pipe Installation (3) Recommendation for methods of improving the foundation to provide proper support for the pipe when the foundation is deemed not suitable (4) Updates to bedding standards, including: (1) Use of uncompacted soil for the bedding (2) Recommended gradation for bedding soils (3) Specifying the appropriate amounts of fractured faces for Class II soil particles (4) Limiting the maximum soil particle size for bedding and initial backfill materials to 1-inch and 1½-inch particles. (1) Requiring shovel slicing of haunch area soil to occur before the bedding height is 0.25 of the outside diameter of the pipe. (2) Replacing subjective language with more definitive language (3) ASTM specialized standards relating specifically to Controlled Low Strength Materials (CLSM) bedding for VCP. In 1995, C12 became the first pipe installation standard to give CLSM bedding as a viable option. Requirements for flowability when placed, 28 day compressive strength, and set time prior to backfill load are now referenced to the ASTM CLSM standards. One advantage of using VCP is that it will not float during CLSM installation.

The pipe-in-pipe proposed in this paper is an innovative structural material with more flexible and ductile bending performance than that shown by usual steel pipes. A pipe-in-pipe structure comprises double thin-walled pipes with granular material such as sand filled between the outer and inner pipes. The filling material prevents local failure known as the Brazier effect by transmitting the interactive stress between the pipes. As a result, smooth and flexible bending deformation is realized even under a large bending moment. In addition, when the sand filled in the pipe is frozen, the flexural rigidity of the pipe increases, but the pipe maintains its high ductility. To adopt such a pipe-in-pipe as a practical pipeline material, a numerical method must be established to evaluate the elastoplastic bending behavior. This paper proposes numerical methods for the bending behaviors of pipe-in-pipes and examines the difference in bending behaviors due to the filling materials using the proposed models.

The Blue River Pipeline conveys water from Montgomery Reservoir near the Continental Divide over 70 miles by gravity to reservoirs on the north slope of Pikes Peak. The original transfer system from the Blue River Pipeline, constructed in the early 1950’s, consisted of parallel 14-in. and 16-in. steel pipes to South Catamount Reservoir, crossing North Catamount Creek in the process. In about 1959, North Catamount Dam and Reservoir were constructed, inundating the North Catamount Creek crossing of the transfer pipeline with up to 75 feet of stored water. Over the ensuing decades, the pipeline deteriorated, resulting in leakage to the point that water could no longer be effectively transferred to South Catamount Reservoir, and replacement or rehabilitation of the pipeline was required. Due to seasonal and other constraints, design-build procurement was selected. The recommended pipeline alternative was 36-in (DIPS) DR11 HDPE, placed across North Catamount Reservoir using the float-sink method. In this method, the HDPE pipe is floated into position with the ends capped and with concrete ballast spaced along the length of the pipe to achieve about 50% buoyancy. Once the pipe is floated into position, it is filled with water, causing it to sink to its final position at the bottom of the reservoir. The project construction was facilitated by historically low reservoir levels as a result of drought, which shortened the length and depth of float-sink required. A long, relatively straight access road to the reservoir crossing allowed the entire length of HDPE to be fused prior to launching. Ballast consisted of single-piece concrete blocks placed beneath the pipe, affixed with stainless steel straps, rather than the more conventional two-piece concrete ballast. Sinking was completed in mid-November 2013, just prior to ice formation on North Catamount Reservoir. Total length of HDPE placed beneath the reservoir was 2,450 feet.

Most utilities are faced with replacing aging infrastructure while experiencing an ever reducing repair and replacement budget. Determining cost effective ways to repair and replace infrastructure in a cost effective manner led the South Seminole & North Orange County Wastewater Transmission Authority (SSNOCWTA) to explore multiple pipe installation methods on one project in order to reduce construction costs and disruptions to customers and businesses. SSNOCWTA replaced 8,200-feet (2,500-meters) of existing class 200 PVC pipe due to age and the high probability of failure. Pipe bursting was the first method reviewed to replace the existing force main. During right-of-way permitting coordination it was determined pipe bursting was not permitted in certain locations by the agency controlling the right-of-way. Therefore, supplementary pipe installation methods were required. Following the design process, a total of five (5) HDPE pipe installation methods were chosen. This paper will discuss the applicability and benefits of the five (5) HDPE pipe/fitting installation methods. By utilizing different installation methods, engineers can provide value to their utilities by producing a more constructible project that minimizes disruptions to customers, businesses and the environment. The additive value of all the advantages incorporated into the project saved SSNOCWTA over $215,000 and two months of construction time.

The City of South Bend’s Consent Decree specifies capture and conveyance of overflows from all of their Combined Sewer Overflow (CSO) locations, which was issued in 2012. The Long Term Control Plan (LTCP) in the Consent Decree, which was developed from 2002 to 2008, has a cost of almost $600 million. There are several retention treatment basins (RTB) and storage/conveyance pipes planned in the Long Term Control Plan (LTCP) as part of the Consent Decree. After the City of South Bend went through the first phase of their LTCP, they found that affordability was an issue. At the same time, the City was completing a feasibility study which ultimately included looking for options to reduce the cost of a specific area of the CSO program based on new technology. As a result of finding significant savings in that study and with the recent development of integrated planning, the City elected to contract a consultant to reevaluate their Consent decree LTCP. This paper describes the process for re-evaluating LTCPs through the use of new design technologies, integrated planning, and the value of advanced affordability calculation methods and how it is being applied to find the right answer for the City of South Bend.

The City of Myrtle Beach has become one of the number one beach vacation destinations in the United States. Known as the Grand Strand, Myrtle Beach hosts over 15 million beach and golf visitors each year. For several years, the City had been plagued by adverse publicity associated with high bacteria counts in the surf zone. Recommendations were made for replacement of many beach outfall pipes and combining the outfalls into a single deep water ocean outfall. Successful implementation of the Ocean Outfall master plan was imperative because stormwater treatment upstream of the existing beach outfalls must be designed, permitted and installed to justify combining the individual beach outfall pipes. Water quality discharge requirements are identified and best management practices discussed as related to the design of the deep water ocean outfall. Pipe hydraulics, including dynamic wave analysis, is presented. Critical design elements presented are evaluation and qualification of pipe material types, jointing methods, pipe bedding, backfill and armor stone sizing for proper performance within the surf zone.

Using the traditional design-bid-build (DBB) project delivery system, the T-Bar Ranch Well Field Development & Delivery System project would likely have taken upwards of three or four years to complete. With the City of Midland, Texas, deep in a severe drought, an alternative delivery system was a necessity. The City was facing the probability of being cut off from their primary source of water in less than fifteen (15) months. By means of the design-build (DB) delivery system — in this case, design-build-finance-operate (DBFO) — the Project Team took tasks that, using the DBB system would have been completed in a linear manner, and overlapped them, tackling them in conjunction with one another, significantly decreasing the overall project schedule and ultimately the cost to build. Diligent management of the land acquisition, design, material manufacturing, and construction resources delivered this project ahead of schedule and under budget.

Dallas Water Utilities (DWU) supplies treated water to 2.3M people in the Dallas-Fort Worth Metropolitan area (DFW). The East Side Water Treatment Plant (ESWTP) is a 440-MGD plant that has the capacity to meet nearly half the City of Dallas’ customer demands including its wholesale customer cities. A regional large diameter pipeline project called the Southwest 120/96-inch Water Transmission Pipeline Project (Southwest Pipeline) will provide redundancy and increase service capacity to meet the growth of current and future DWU customers in Southern Dallas County. The Southwest Pipeline will serve multiple jurisdictions over its 32 miles of urban area. During the planning stages of the project, multiple roadway expansion projects were identified along the pipeline corridor that would overlap with the pipeline project and involve coordination with multiple jurisdictions and agencies. In many cases, joint construction contracts were deemed the best delivery method for both the roadway and the pipeline projects. The coordination between the multiple agencies for joint construction contracts presents both challenges and opportunities. This paper will discuss the challenges and opportunities facing joint pipeline and roadway construction projects and will cover lessons learned during several phases of the project, including planning, design, bidding, and construction.

The San Diego County Water Authority (Water Authority), in conjunction with a private development team, is nearing completion with the construction of the Carlsbad Desalination Conveyance System (Conveyance System). A series of projects will deliver water from the new 54-mgd Carlsbad Desalination Plant to the Water Authority’s Aqueduct System. The Conveyance System consists of four separate projects, three of which are being implemented through separate design-build (DB) contracts. The fourth is being implemented through a design-bid-build (DBB) contract. The fifth project, which is the desalination plant itself, is included herein for clarity, but is not considered as part of the conveyance facilities. The projects include the following: (1) Carlsbad Desalination Plant—50 mgd seawater desalination plant (2) Carlsbad Desalination Product Water Conveyance Pipeline: (DB) Ten (10) miles of 54-inch steel pipeline with operating pressures up to 550 psi. (3) Pipeline 3 Relining (DBB): Five (5) miles of existing 75-inch and 72-inch pipe are being relined with 69-inch and 67.75-inch steel liners. (4) TOVWTP Improvement Project (DB): Approximately 1,500 feet of 54-inch steel pipeline, clearwell improvements, a flow control facility, and chemical injection facilities. (5) San Marcos Vent Desal Modifications (DB): Includes connections between Pipelines 3 and 4 of the Water Authority’s Second Aqueduct. This paper addresses multiple challenges associated with the implementation of the Conveyance System. Specifically, it will address the challenge of coordinating design and construction of interrelated projects, handling simultaneous reviews of numerous pipeline headings, and establishing design criteria and resolving conflicting recommendations.

Large urban highway widening projects will have many water and wastewater pipeline conflicts. Those conflicts are caused by various aspects of the highway project including the following: road pavement widening through lane addition, new/realigned storm sewer, new bridges, new retaining walls and proposed grading changes. This paper presents the challenges and advantages of water and wastewater pipeline relocation design as part of the design-build large urban highway project with Public-Private Partnership (3P) funding and project delivery. This paper also addresses possible ways to improve the process for future work. The utility relocation portion of the project consisted of eliminating all possible water and wastewater conflicts with the aforementioned design components of the roadway. The project scope consisted of three large highway corridors in Tarrant County, Texas. Tarrant County is the third most populous county in Texas according to the 2010 U.S. Census and the county seat is Fort Worth, TX. Approximately 150 water and wastewater conflicts were analyzed throughout the project. This equates to 106 miles (170 kilometers) of water, wastewater and franchise utilities impacted by the project. The total construction cost for these three urban highway reconstruction projects was $4.1 billion.

When a pipe reaches 60-inches in diameter, there are few materials of choice for designing a water transmission main. When the use of prestressed concrete cylinder pipe (PCCP) or bar-wrapped concrete pipe (BWCP) is not allowed, the choices become even more limited. Ductile iron is arguably the pipe material most recognized and utilized by municipalities for their potable water infrastructure (on the East Coast), especially for smaller diameter lines; however, at 60-inches in diameter, PCCP and spiral-welded steel pipe (“welded steel”) are more prevalent. When adding in the requirement for a full cathodic protection system, an analysis is required for selection of an appropriate material for the project. So, under what circumstances does the scale tip in favor of ductile iron at these larger diameters? How about for welded steel? This presentation focuses on reviewing the characteristics, advantages and disadvantages to using both pipe materials on large diameter transmission main applications through the lens of a ductile iron/welded steel materials analysis that was completed for a 60-inch diameter transmission main for the Washington Suburban Sanitary Commission (WSSC).

AWWA C303 pipe has been known as Pretensioned Concrete Cylinder Pipe and Bar Wrapped Concrete Cylinder Pipe, without having made any changes to its structure. While this can be confusing, it relates to the hybrid nature of the product. While it has been used extensively in some of the western states and in most of the far western states (those west of the Rockies), it is a new product to the eastern market, where it is currently being promoted. This paper will address the complexity of the nature of the product, relate to its history and provide an insight to its manufacture and design. Although not a new material by any sense of the word, it is new to many potential users; owners, engineers and contractors. Also, the eastern market will almost certainly involve some variations to the product’s historical experience. These variations should not cause undue concern as long as they are recognized. History, experience and knowledge are essential ingredients in providing a beneficial new tool in the pipe industry’s tool box.

Three workshops were held as part of a Water Research Foundation (WaterRF) research project to investigate durability and reliability of large diameter HDPE pipe (WaterRF Project #4485). As stated in this paper, the use of large diameter HDPE pipe for water applications is currently very limited, as most water utilities are not fully familiar with characteristics and capabilities of this type of pipe. The objectives of these workshops were to explore issues and concerns about use of HDPE pipe in large diameter transmission mains. The workshop participants were from water utilities, design consultants, project team members, and pipe manufacturers and installers. Through innovative brain storming sessions, the issues and concerns regarding use of large diameter HDPE were identified and subsequently ranked. This paper provides details of these workshops, topics discussed, concerns and issues with use of HDPE pipe, and strategies to resolve these concerns and issues. As results of these workshops, a set of strategies for water utilities, design consultants, and pipe manufacturers were developed and presented in this paper.

Maintaining uninterrupted service and fire protection to customers is always a top priority for water providers. When a major transmission main begins to show signs of failure, addressing the cause and fixing the problem also become a top priority. When Howard County, Maryland began to experience multiple wire breaks in a major 30-inch Prestressed Concrete Cylinder Pipe (PCCP), they recognized the potential for a major service interruption to their customers and began to take steps to protect that asset. Howard County faced a unique challenge in that a new pipeline was needed that had to be resistant to stray current, installed through rock (directly adjacent to an existing failing PCCP main that was to remain in service during construction), and cross the Little Patuxent River. The result was the installation of 2,200 linear feet of a 3-inch thick 30-inch diameter HDPE water main that including blasting through rock and an open cut installation under the Little Patuxent River.

Corrugated high-density polyethylene (HDPE) pipes are an attractive product for culvert and drainage applications in the railroad industry due to their resistance to corrosion and abrasion, long service life, and flexibility. Railroad specifications currently require these pipes to be manufactured with 100% virgin materials. However, due to the push for more sustainable and cost-effective engineering materials and practices, the railroad industry would benefit from using pipes made with recycled content provided their long-term performance was equivalent to pipes made with virgin materials. To evaluate the performance of corrugated HDPE pipes made with recycled content in rail applications, a pilot study was conducted with the Southeastern Pennsylvania Transit Authority (SEPTA). The study was funded cooperatively by SEPTA and the National Cooperative Highway Research Program (NCHRP) Project 4-39. Two 30-inch diameter corrugated HDPE pipes, one manufactured with 100% virgin materials and one manufactured with post-consumer recycled content, were installed underneath a regional commuter rail line in northeast Philadelphia with 2 feet of cover from the top of the pipe to the bottom of the railroad tie. The pipes were instrumented with strain gages and extensometers to record live-load data and monitor the pipes over time. A laboratory study was also developed to assess the long-term durability of pipes made with recycled content with regards to cyclical live loads. The pipes have been in service for over 1 year and are performing as designed, with no change in performance since the date of installation. This was a groundbreaking study as it included the first corrugated HDPE pipe manufactured with post-consumer recycled content installed underneath one of SEPTA’s regional commuter lines. The research project is a key component of SEPTA’s ongoing sustainability initiatives.

Large diameter water transmission pipelines are critical elements of water supply systems, because a failure can be catastrophic. Extended service interruptions for many customers, along with high costs of emergency repairs, inconveniences to general public, and associated water quality concerns can be results of large diameter pipeline failures. This paper presents a survey of water utilities for using large diameter (16 in. and larger diameter) high density polyethylene (HDPE) pipes for water transmission applications as a part of a wider-scale research project on durability and reliability of HDPE pipes (Water Research Foundation (WaterRF) #4485). While a full evaluation of a particular pipe material requires many parameters to consider, the main goal of this paper is to present the overall experience of water utilities with large diameter HDPE pipes. The survey of water utilities indicated that majority of respondents were satisfied with the durability and reliability of large diameter HDPE pipe, while five percent were unsatisfied. Survey respondents expressed concerns about tapping, repairs and joints. They considered permeation and oxidation to be minor concerns with no failures reported due to oxidation or permeation in large diameter HDPE piping systems. They also mentioned that some measures are required to improve construction techniques.

The choice of initial wall thickness in welded steel pipe design is accomplished by following an empirical formula with the objective of managing stresses and strains in the pipe wall during handling. Stresses and strains during handling are due to a number of factors, including lifting with slings, placement on supports, and shipping to name a few. Although the avoidance of cement mortar lining (CML) cracking before or during stull installation is of primary interest in this paper, the need to manage the strain level in steel to prevent having an adverse impact on the integrity of CML is also discussed. With a flexible lining, the design engineer has more latitude. To avoid excessive stresses and strains, for decades, design standards and manuals have provided empirical formulae as a diameter to thickness (D/t) ratio criterion. Given that water pipes carry relatively low internal pressures in many projects, the choice of initial wall thickness often ends up as the final thickness of the steel pipe. The question that has not been asked by engineers for over eight decades is “Can a Design Engineer Rely on D/t Ratio as a Rational Indicator to Manage Stresses and Strains in Welded Steel Pipe during Handling?” The authors of this paper embarked on an investigation to answer this very question. The authors share their methodology, results, findings and suggestions for improvement in current practice.

Large diameter steel water pipe is typically supplied with temporary internal bracing or “stulls” that have been shown to prevent damage to the pipe, particularly rigid lining and coating systems such as cement mortar lining and coating, during transportation and handling. They are also provided to assist with maintaining the shape of pipe ends to within AWWA C200 requirements for field jointing. Stulls are typically manufactured from rough cut lumber and on occasion, steel angle or poles. Stull sets are typically placed at pipe ends and at mid points, depending on diameter and thickness of the pipe. Stull sets typically consist of a minimum of one to three sets of stulls with various stiffeners, and may include shoes and blocks to assure the internal bracing will retain functionality during the handling process. Manufacturers may have variations in their stulling means and methods but all have the same goal of providing pipe integrity during handling and transport, and pipe-end roundness at the ditch, ready for joint assembly, installation and backfilling. Stulls may assist holding the pipe shape until side fill support is developed during backfill placement. Loads on top of the pipe, including construction loads, are distributed to the soil envelope around and adjacent to the pipe. The assumption that pipe stulls will limit or eliminate deflection has lead to misunderstandings, false expectations and even improper pipe installation due to over reliance on a stulling system’s ability to limit deflection of the pipe. Pipe stulls are not in themselves designed to withstand the unknown loadings generated by depth of soil cover or various construction equipment and vehicles during installation. This paper will illustrate the installation of stull sets at the factory, review their intended function, discuss flexible pipe deflection control methods and review installation requirements of the AWWA C604 buried steel pipe installation standard.

There are cases where excavations in hard rock must occur very close to existing pipes that must remain in operation. These cases include new gas or water pipes in existing Rights-of-way (ROW) where separation between new excavation trenches and existing pipes is very limited. In other instances, hard rock or mass concrete must be excavated to install new pipes or other facility upgrades near critical utility pipes or operating penstocks at hydroelectric plants. In these cases where excavations in hard rock must occur very close to existing pipes, the use of blasting methods is not possible when standard vibration criteria or restrictions based on pseudo-theoretical calculations are applied to the work. However, mechanical methods are often impractical when the rock is too hard, volume of rock is too large, or excavation geometries prevent their use. This paper focuses on systematic methods that can be used to develop customized blasting programs based on existing pipe(s) condition, strain failure modes, ground characteristics, and close-in blasting experience. The application of these methods is demonstrated in two case-history summaries including blasted rock excavations located within 1 m of steel penstock pipes and 2.4 m from steel water mains.

Over the last decade, the Central Utah Water Conservancy District (CUWCD) has designed and constructed 13 projects to complete 32 miles of large-diameter pipe and flow control structures for the Utah Lake Drainage Basin Water Delivery System (Utah Lake System), which represents over $200 million of constructed facilities. The Utah Lake System is a component of the Bonneville Unit of the federal Central Utah Project, which delivers municipal water to major cities in northern and central Utah. Water is collected within the Colorado River Basin on the east side of the State and conveyed via reservoirs, tunnels, and pipelines to the Great Basin along the Wasatch Front. The Bonneville Unit is comprised of three major projects: 1. The 40-mile long Strawberry Aqueduct Collection System which collects water from numerous drainages extending from Stillwater Reservoir on Rock Creek to Strawberry Reservoir through a system of tunnels and pipelines; 2. The 19-mile long Diamond Fork System which is a transbasin diversion that conveys water collected and stored in Strawberry Reservoir within the Colorado River Drainage to the Great Basin via tunnels and pipelines up to 660 cfs capacity; and 3. The Utah Lake Drainage Basin Water Delivery System which conveys and distributes water conveyed from Strawberry Reservoir to municipal water users along the Wasatch Front. In addition to municipal water deliveries, water is delivered to some of the streams and rivers within the Great Basin to provide supplemental flows for fish and wildlife. In the spring of 2015, two of the three branches of the Utah Lake System will be substantially completed and brought into service, which will result in a 124-mile gravity flow system from Stillwater Reservoir via Strawberry Reservoir to water users in Salt Lake City. This paper presents the to-date completed Diamond Fork and Utah Lake System aqueducts and the project’s unique challenges related to planning, design, and construction. Two of the three major pipeline branches of the Utah Lake System are constructed at this time. The completed portions of the Utah Lake System includes 26 miles of 96-inch and 60-inch–diameter welded-steel pipe at 280 to 450 psi pressures and 6 miles 54-inch HDPE pipe. The project includes six major flow control structures designed to deliver up to 120 cfs and break pressures of 420 psi to atmospheric conditions. Other major facilities include pig launching and receiving facilities for the 96-inch and 60-inch pipelines, a 6.7-MG rectangular concrete regulating reservoir, and 15 separate turnout vaults designed to deliver water to existing flood irrigation and municipal secondary systems with the option to convert to pressurized delivery in the future. Topics discussed include crossing and construction near the Wasatch fault, landslides, cavitation control at high-head turnouts, flow and pressure control between the upper and lower delivery systems, and maintaining system capacity with pigging facilities.

Proper buried pipeline installation relies on support for the pipe in the haunch area. This is necessary for all types of pipe material. One method of obtaining haunch support is by using a cohesionless soils and providing compaction by using saturation and internal vibration (jetting and vibrating). The method uses internal concrete vibrators and enough water to lubricate the soil particles. The method has two significant advantages: (1) the soil in the pipe haunch area can be effectively compacted to a high density, and (2) the compacted lift thickness can be several feet thick, limited by only the length of the vibrator. Denver Water has been utilizing this method since the 1960s. US Bureau of Reclamation has been using the method since the 1950s and at one time saturation and vibration was their only acceptable compaction method for pipe embedment. This paper will describe research investigations and present case studies on the use of compaction of cohesionless soils by saturation and internal vibration.

Proactive management, monitoring, and rehabilitation of pipelines are common phrases used in the water and wastewater industry today. Over the last 10 years, tools and techniques have rapidly evolved, providing utilities with a plethora of options for pipeline assessment and management. Because proactive management and monitoring are only recently being widely implemented across the industry, few long-term case studies documenting the success of these practices are available. This paper will discuss the monitoring and proactive management of the 102-inch Sayreville Relief Force Main, which has been actively monitored and routinely inspected for the last 10 years. When the Sayreville Relief Force Main experienced its second failure in March of 2003, many of the common techniques for condition assessment and asset management were just being introduced to the industry. Due to known deficiencies associated with Interpace PCCP manufactured in the 1970s, aggressive soils, and an environmentally sensitive surrounding area, the force main’s owner and operator, Middlesex County Utilities Authority (MCUA), began a program of inspection, assessment, and active monitoring. Over the 10-year management period, monitoring evolved from a surface-mounted sensor (SMS) system to an acoustic fiber optic (AFO) monitoring system, and the assessment techniques grew from visual and sounding inspections and electromagnetics to include sonic/ultrasonic testing, and advanced structural analysis. Through this program, MCUA has proactively rehabilitated deteriorating pipes, preventing catastrophic failures. A study of the evolution of the program for the Sayreville Relief Force Main can serve as a resource for other water and wastewater utilities, who will benefit from the lessons learned and the advantages gained over 10 years of proactive management.

This paper presents the recent enhancements to Tarrant Regional Water District’s (TRWD’s) geographic information system (GIS)-based structural evaluation tool, how this tool is used to improve asset management capabilities, and lessons learned from development of TRWD’s GIS for use in pipeline asset management. TRWD now utilizes a GIS and a GIS-based tool capable of performing structural evaluation of non-distressed pipes, failure margin analysis and repair prioritization of each distressed pipe, and pipeline diagnostics as a part of their asset management program. TRWD recently updated their GIS and enhanced their existing tool to be able to identify pipes that have high rates of distress progression, add flexibility for projection of distress into the future, and plot analysis results for easy visualization. TRWD periodically performs electromagnetic inspection of their pipelines, and the GIS-based tool provides the ability to update the risk of failure of distressed pipes based on the latest electromagnetic inspection results and identify the pipes at highest risk of failure for remediation. A GIS and customized GIS-based structural evaluation tools provide TRWD with the ability to effectively aggregate pipeline data and perform the analyses needed to evaluate the structural safety of each section of the pipeline system and failure margin and repair priority of individual distressed pipes.

The majority of cast iron (CI) pipelines were installed in the United States in the early to mid-20th century. Most of these pipes are in a sustainable working condition; however, any failure of these pipelines could be catastrophic due to the social, political, and environmental impacts of the failure. To facilitate better decision making for capital expenditures and to address the risk associated with these assets, the failure mechanisms of CI pipe must be understood. In addition, for planning and capital budgeting, it is important to determine the current condition of a deteriorated pipeline and its risk of failure. In this study, the structural evaluation of damaged CI pipes is discussed considering corrosion of the pipe (the most common failure mode of CI pipe). This paper provides a clear and concise picture of how to determine the current condition of damaged CI pipelines. This will allow decision makers to enhance their asset management strategy based on inspection results and advanced computational modeling.

Over the last several decades, San Antonio has experienced rapid population growth. The San Antonio Water System (SAWS) currently serves more than 1.6 million people in Bexar County Texas as well as parts of Medina and Atascosa Counties, and has over 460,000 water customers. With the integration of the Bexar Metropolitan Water District, regulatory withdrawal limitations, and increasing drought restrictions that have put a strain on the Edwards Aquifer, SAWS has had to increase its water supply and system flexibility. SAWS has been working to meet the increased water demand through a strategy of conservation, reuse, and investments in new water supply resources, and will increase system flexibility with the Water Resources Integration Plan (WRIP). Currently, the Twin Oaks Aquifer Storage and Recovery (ASR) facility in South Bexar County allows SAWS to store excess Edwards Aquifer water from the east side of San Antonio. That water can then be recovered from the ASR during periods of high demand, significantly increasing SAWS operational flexibility. The ASR Pipeline, completed in 2004, is currently the only conduit between the ASR and SAWS’ distribution system; moving water into the distribution system during production mode and reversing flow to inject water into the ASR well field in recharge mode. Since future water supply facilities will produce a constant base flow, additional flexibility is needed for continued recharge of the ASR. The WRIP will provide that flexibility. The WRIP consists of approximately 45 miles of 48” to 60” diameter steel pipe and two associated pump stations, extending from the ASR to west San Antonio. The WRIP will be constructed in two phases and will ultimately convey up to 75 MGD of potable water from four different sources: treated water from the Brackish Groundwater Desalination Facility (Wilcox Aquifer), Local and Expanded Carrizo Wells (Carrizo Aquifer), and recovered ASR water (Edwards Aquifer). Similar to the ASR pipeline, the WRIP pipeline will also be used to recharge the ASR well field using reverse gravity flow. The WRIP pipeline will work in tandem with the ASR pipeline to offer operational flexibility and provide water where San Antonio needs it most. This paper will describe the WRIP and specifically discuss design concepts that allow the WRIP to give SAWS additional flexibility in managing their water supply.

The Henry J. Mills Water Treatment Plant (Mills plant) is one of five water treatment plants owned and operated by The Metropolitan Water District of Southern California. Located in Riverside, California, the Mills plantreceivesvirtually all of its raw water from the East Branch of the State Water Project (SWP), either by gravity from the Department of Water Resources’ (DWR’s) Santa Ana Valley Pipeline or via pumping from Lake Perris, another DWR facility. Because of the current state-wide droughtin California, and resulting low allocation of SWP supplies, Metropolitanrecognized thatsufficient quantities of SWP water may not be available to meet demands at the Mills plant and that another source of supply was needed.Metropolitan staffreviewed several options and ultimately proposed using Metropolitan’sDiamond Valley Lake (DVL) as a source for the Mills plant, even though at the time, Metropolitan’s infrastructure did not allow the Mills plant to access the water in DVL. Metropolitan’s solution was to modify the existing infrastructure, including a pressure control facility, a pumping facility, a tunnel, and two pipelines, so that water stored at DVL could be supplied to Mills Plant. This paper will describe the required modifications, discuss the design and construction of the interconnection, and address the methods used to expedite the project delivery so that a project that would usually take 30 months to complete was completed in just 10 months.

In 1992, the American Water Works Association (AWWA) introduced a new standard for the design of prestressed concrete cylinder pipe (PCCP) designated as ANSI/AWWA C304. The ANSI/AWWA C304 Standard introduced a new design philosophy for PCCP based on the concept of evaluating and satisfying certain serviceability, elastic and strength limit-states criteria using various combinations of factored and unfactored design loads and internal pressures. When the C304 Standard was first introduced in 1992, many potential users voiced concerns related to the complexity of the design provisions contained therein that continue to date. Upon performing a detailed review of the C304 Standard, it is apparent to the authors that some of the provisions currently incorporated in the document can be simplified without any significant corresponding consequences relative to the final overall design solution. This paper addresses some of these overly-complex design provisions and provides alternate or simplified provisions for a few of them. In the near future, the authors anticipate performing a more comprehensive evaluation and preparing additional supplementary publications with the intention of providing further justification for simplifying future versions of the ANSI/AWWA C304 Standard.

The City of Fresno (City) serves approximately 513,000 residential customers and 35,000 commercial and industrial accounts. The City’s water demands are approximately 145,000 acre-feet annually, which is met by 88% groundwater and 12% treated surface water. In order to address overdrafting of groundwater, the City has embarked on a major CIP that utilizes surface water allocations to reduce groundwater supply source from 88% to 36%. Construction of new 80 MGD treatment plant, several large diameter raw water pipelines, and approximately 40 miles of large diameter potable water regional transmission mains (RTM) has been recommended. The first phase of transmission mains initially included 25 miles of large diameter pipelines to connect to existing grid mains and distribution piping. Schematic design of the initial route for these and other alternative pipeline routes was completed concurrent with the optimization study. The approach to the optimization study was to take the information developed during schematic design and perform repetitive hydraulic modeling to determine the lowest cost alternative. The initial budget for the first phase of the CIP which included 25 miles of 48-inch to 24-inch RTM was estimated at about $88 million. After completing in excess of 700,000 hydraulic model runs, the optimum solution resulted in a recommendation of 13 miles of 66-inch to 24-inch pipe with a total cost estimate of $43M. The total cost to perform this optimization analysis was about $150,000 and resulted in about $45M in cost savings without compromising service objectives.

S4 testing per ISO 13477 is a lab-based procedure to determine the critical pressure above which a fracture will propagate in a given pipe material after initiation. The test was developed for the natural gas industry using air as the test medium because only compressible fluids can provide enough energy to propagate fractures after an initiation event. Recent industry discussions have focused on water applications as well. A small amount of testing using water was performed in the 1990’s on PVC pipe extruded in the UK to the standards in place at that time. Until now, no testing had been completed on AWWA C900 PVC pipe using the S4 test method as prescribed in ISO 13477. Instead of speculating with outdated and ill-fitting data, actual testing has now been done. The test results show the differences in results between AWWA C900 PVC currently extruded in North America and the PVC pipe on which some testing had been done in the UK in the 1990’s. This paper discusses the test methodology, test results, and the accurate and updated conclusions for modern PVC pressure pipe made to AWWA C900.

The drinking water infrastructure in the North America requires a durable and reliable water transmission pipe material. However, there is no known standard to evaluate large diameter high density polyethylene (HDPE) under cyclic loads to investigate its fatigue performance, as it a major concern for water utilities. As part of a wider-scale research project to investigate durability and reliability of large diameter HDPE pipe (Water Research Foundation (WaterRF) #4485), a testing protocol was developed at the Center for Underground Infrastructure Research and Education (CUIRE) at the University of Texas at Arlington to test a large diameter (16 in. and larger) HDPE pipe under cyclic surge pressures. This paper presents details of test setup, and results of testing for a 16-in., DR 17, 15-ft long pipe sample with a fusion joint in the middle. The testing consisted of two phases. The pressures used for the first phase were between 125 and 188 psi (1.5 times pressure class) for 2 million cycles. The 2 million cycles are equivalent to 50 pressure surges per day for a 100-year design life. A second phase was later added using the same pipe sample to evaluate occasional surges between 125 psi to 250 psi (two times pressure class) for 50,000 cycles. The testing was completed with pipe sample’s minor dimensional changes primarily due to limited relaxation allowed during the pressure cycles.

Providing adequate capacity to drain stormwater runoff during heavy rainfall events can be a challenge for many communities in Ohio and the Midwest. Even for the Municipal Separate Storm Sewer Systems (MS4) communities, flooding is common for rainfall events as short as two years. A number of methods are applied towards solving this problem, and they can be divided into three groups, which include gray infrastructure, green infrastructure (GI), or the combination of both. As an alternative method, trenchless pipeline rehabilitation by lining can provide a significant capacity increase to existing storm sewer systems by reducing the roughness of the storm sewer pipes. This study investigates the use of a semi-structural spray applied lining system to improve the hydraulics of a 42-inch (1,070 mm) stormwater pipeline that is comprised of reinforced concrete (RCP), brick, and corrugated metal (CMP) pipes.

Accurate hydraulic analysis and head loss calculations are essential for conveyance pipeline design. Flow modeling tools significantly expedite the hydraulic analysis steps, but estimating nominal pipe characteristics may result in considerably erroneous results. This paper presents critical design requirements to estimate flow area reduction and quantify excessive roughness effects in aged pipelines. Correction factors shall be applied to the Hazen-Williams equation for turbulent flow to reflect the actual flow area and corrected roughness coefficients. Two scenarios of an actual design will be presented to illustrate the order of magnitude of erroneous results when the design is based solely on nominal flow area and basic roughness factors. In addition to defining extreme conditions, this paper describes experimental methods, boundary conditions, and field measurements required to develop hydraulic characteristics specific to aged systems. This paper also presents general corrective actions required to improve hydraulic performance of existing systems.

This paper will benefit those interested in regional water supply planning to replace a substantial portion of existing groundwater supply. Excessive pumping of ground-water from an aquifer can greatly accelerate the consolidation of clay strata resulting in subsidence – the permanent loss of elevation at the surface or ground level. The authors outline the regional planning to substantially reduce subsidence in a heavily developed and rapidly growing region. Most attention is on the North Fort Bend Water Authority (Authority). The Authority’s groundwater reduction plan (GRP) provides the benefit of regulatory compliance while reducing and equitably sharing the costs of compliance. To implement the GRP, the Authority has issued $283 million in bonds to construct more than 50 miles (80 km) of 12- to 48-inch (30.5 to 122 cm) water lines including steel, bar-wrapped, PCCP, ductile iron, and PVC. Approximately 17 million gallons per day (mgd) (0.75 m³/s) of surface water are delivered to 28 water plants throughout the Authority. The Authority successfully met the initial regulatory requirement to reduce ground-water use. Planning is ongoing to meet the 2025 deadline to further reduce ground-water use to no more than 40% of total water demand (i.e., a 60% reduction). The Authority is a participant in three regional water supply projects and will construct more than 30 miles (48.3 km) of water lines to complete its internal transmission system. The Authority’s estimated cost for these four projects is more than $700 million of the total estimated cost of more than $3 billion.

Modern urban societies depend greatly on water supply systems for economic prosperity, public health, security, and quality of life. Uninterrupted water supply is even more important during times of natural calamities such as earthquakes. Seismic hazards during past earthquakes have caused significant damage to buried pipelines rendering the water systems dysfunctional. This paper presents a flow-based metric for assessing and enhancing water supply resilience against the seismic hazard of liquefaction-induced settlement. The proposed resilience metric is demonstrated considering a water supply network in a coastal region in South Carolina. Seismic settlement is evaluated using an available liquefaction potential map. Evolutionary optimization techniques are employed to identify the optimal set of pipeline replacement strategies to enhance seismic resilience of the selected water supply network. The computational tools employed include the igraph package in R software, the EPANET and its toolkit, and the MATLAB programming environment. The presented framework along with the results will be useful to utility departments that manage pipeline systems in earthquake-prone regions.

There are countless possible benefits of real-time modeling, including model calibration improvement, advanced alerting of system abnormalities, forensic analysis, and real-time evaluation and predictive optimization of water quantity, quality and energy usage. All the pieces are available to connect real-time water system information to hydraulic models, making these benefits a reality. The pieces include advanced computing hardware and software, accurate GIS and hydraulic models, increasing amounts of real-time data about water system performance, and database and communication protocols ready for integration. The process of integrating and implementing a real-time modeling system can seem daunting, especially without the right tools, and one must consider if the value and potential improvements are worth it. The tools are increasingly available, and water systems are beginning to see the potential values of real-time implementation. This paper will discuss the benefits of real-time modeling, implementation challenges and successes, as well as two successful implementations at a medium and large-sized water systems. In particular, these water systems implemented the Innovyze IWLive real-time modeling software platform. CH2M HILL provided implementation assistance and coordination between the water system and the software provider, Innovyze. Some of the challenges included incoming data quality, database integrity and robustness, hydraulic model readiness, and each of these will be discussed, along with the solution to achieve success.

Performance prediction modeling is a crucial step in assessing the remaining service life of pipelines. Sound infrastructure deterioration models are essential for accurately predicting future conditions that, in turn, are key tools for effective maintenance, repair and rehabilitation decision making. The objective of this research is to develop a wastewater pipeline performance deterioration model for predicting the remaining economic life of wastewater pipe for infrastructure asset management. Under Water Environmental Research Foundation (WERF)’s Strategic Asset Management (SAM) Challenge, there was a planned three-phase development of a pipe deterioration model. Only Phases 1 and 2 were successfully completed under the SAM Challenge. In the Phase 1, the research team identified and developed: life cycle of wastewater pipe; failure modes and mechanisms; consequences of failure; data structures; data collection protocols and methodologies. In the Phase 2, research team developed a standard procedure for rating the performance/condition of wastewater pipes. This paper presents the current progress on Phase 3 research for developing a wastewater pipeline performance deterioration model. This paper demonstrates the research methodology and current progress for update of phase 1 and phase 2 efforts and development of the new phase 3 deterioration prediction model. This research will provide utility managers with a practical and efficient model for the predicting wastewater pipeline performance and estimating end of the remaining life deterioration curve for decision making.

The operation of water transmission systems and recurring nature of pump cycling at wastewater pumping stations contributes to pipeline fatigue and stress and can impact a pipeline’s structural integrity and useful life. Pressure and transient monitoring of water transmission pipelines and wastewater force mains provides information that can be useful to a Utility’s system operations and Asset Management. When compared to design values, and historical system records, analysis of pressure and transient data can provide additional quantified information to help determine the risk or likelihood of failure associated with a pipeline or force main to be applied to an overall asset management plan. This quantified operational information can also be used to support implementation of or changes to standard operation procedures (SOPs) and maintenance and repair programs. This paper will include a brief overview of various available pressure logging /monitoring technologies and how the technologies have been implemented in several different applications. Up to five case studies will be presented (water transmission pipeline & wastewater force mains) and will include the implementation, analysis, and results of the associated pressure and transient monitoring, including impacts to the associated pipeline and system, and recommendations.

The minimum pressure criterion (MPC) is considered as the minimum standard for delivering water pressure when designing water distribution systems (WDSs). This criterion is established by political jurisdictions and is different around the world. A low value of the MPC may reduce water consumption (e.g., faucet, showers, and lawn watering) and also lead to efficient operation through reduced energy use, leakage, and frequency of pipe breaks. However, if this criterion is too low, the system may be more susceptible to low pressure failures, either hydraulic (e.g., an inability to supply the required flow) or safety related (e.g., increasing the risk of an intrusion event and pipe bursts associated with hydraulic transients). Thus, although it may not have been part of the original intent, there is a direct connection between MPC and transients that should not be ignored. This paper looks specifically at the role of MPC and how it affects the system response in transient conditions to raise the awareness about issues that can arise from changes in MPC. First, the definition of MPC and the possible effects of changes in the MPC on WDSs during transient events are briefly explained. Then, two case studies are developed to explore the role of MPC in transient pressures. The results show, not surprisingly, that using surge control strategies is more efficient than increasing the MPC to prevent unwanted surge pressures.

Concepts relating to energy transformations within built and natural systems have been some of the most fruitful in the history of science and engineering. The property of energy summarizes essential changes both in a system’s state and key interactions with its environment. Traditional unsteady flow analyses, based on momentum and continuity relations, have been dominated by considerations of wave mechanics, such as unsteady fluid friction which is typically accommodated via adjustments to the momentum equation. The current paper demonstrates how conventional analyses can be supplemented with metrics that can provide a complementary understanding of transient flows. Specifically, this study considers the classical Joukowsky equation, mass oscillations, and the role of energy in analyzing the performance of transient protection devices. The goal is to gain insight by considering energy transformations and interactions.

Extending the safe service life of aging pipeline infrastructure requires an understanding of the actual structural integrity of the asset, as well as the loading imposed on the pipeline through, amongst other factors, the way in which the pipeline or system is operated. A change in the steady state operating condition of a fluid system, by means of valve or pump operational change, or due to system failure, is communicated to the system by pressure waves, propagating from the point of the origin where the change in steady flow condition was imposed. The system attains a new state of equilibrium, after some time, if the change has not reached destructive proportions. The terms “surge”, “water hammer” and “transient flows” are used synonymously to describe an unsteady flow of fluids in a pipe system. Various transient modeling software packages based on proven mathematical and numerical solutions are commercially available today. Confidence in modeled results can however be improved by comparing actual field measurements with modeled results. This paper describes the hydraulic modeling, field verification and comparison of modeled and measured results achieved on the Rietspruit-Davel-Kriel bulk water supply pipeline for the Department of Water and Sanitation in South Africa. The hydraulic assessment was performed as part of a comprehensive risk based condition assessment project.

Fluid transients causing pressure surge or water hammer are well known to create damaging effects on pipeline systems. It is common for pipeline designers to evaluate transient surge scenarios for their pipeline projects by looking at the pipeline in its entirety from end to end. Any pump facilities located on the pipeline are often considered as a point on the pipeline, with little attention given to the specific piping details of the pump station at a local level. Pressure transients passing through a pump facility can encounter many piping elbows, risers, and piping segments that have small bore attachments for instrumentation, vents, and drains. As the transients pass through the facility, high vibration on the main lines and their associated small bore attachments can lead to fatigue failures with damaging consequences. This paper highlights the importance of considering liquid transient effects on facility vibration for main pipes and small bore attachments using test data from field measured vibrations during known transient events.

Water managers are becoming more aware of the impacts of hydraulic transients on their systems in terms of structural integrity, water quality and operations. In the past, transient analysis was typically completed as part of individual pumping or pipeline works design. Distribution systems have likely evolved considerably since transient protection equipment was designed and constructed, in terms of water demands, infrastructure expansion and operations. A comprehensive system-wide transient assessment provides managers and operations with a better picture of the transient impacts of both routine and severe operations at pumping facilities and within the distribution system. It facilitates more intelligent decision making as to the best transient management practices. Case studies of system-wide assessments for several medium sized municipalities are presented. These municipalities desired a review of existing protection and operations of the systems in their entirety. The studies critically evaluated protection effectiveness and whether they benefit or are detrimental to the system. This evaluation determined the criticality and benchmarking of protection for all facilities and evaluated protection enhancements and maintenance priorities. Operational and process control procedures were evaluated from a transient standpoint. This led to the development of a transient management strategy for the system as a whole from both a planning and operations perspective, including short and long term best practices related to transients.

An extended period calibration was performed for Sydney Water Corporation in Australia, a regional utility which serves 4.6 million people and manages 13,000 miles of water mains. The purpose of the project was to calibrate existing models to maintain an accurate representation of the water distribution system, customer demand patterns, and controls. The calibrated models would then be able to be used by the utility for many purposes including future growth planning, operations optimization, water quality modeling, and incident management. The calibration process consisted of updating models based on the most recent geospatial data of the network assets, updating the demands from the customer usage database, and updating the controls from the SCADA system. The calibration tolerance of +/- 1 m difference between observed and measured hydraulic grade over a 24-hour period was achieved for the majority of calibration points. In order to achieve calibration, the boundary conditions and initial settings were updated based on measured data, the control settings were updated, and the demands were updated to match the demand patterns observed on the calibration day. In some cases additional modifications were needed to achieve the calibration tolerance, such as: pump curve adjustment, valve diameter adjustment, pipe roughness coefficient adjustment, and valve operational status. Identifying these operational issues as a result of the calibration process provided a benefit to the utility and allowed them to focus field efforts on particular areas, such as underperforming pumps and water mains with potential closed valves or other restrictions.

Over the last decade, United Water Toms River (UWTR) implemented an aggressive capital improvement program to incorporate several new facilities into the water distribution system. With the new assets in place, UWTR initiated a pump energy usage analysis to optimize the water distribution system operations. The primary objective of this study was to conserve energy by improving the distribution system pumping efficiency. Using a hydraulic model database, service area boundaries were developed to automate water distribution system operations, improve pumping system efficiency, and maintain network connectivity. New control valves (check, flow control, pressure reducing, and pressure sustaining) and isolation valve closures were identified to delineate the boundaries. The new boundaries provided the framework necessary to update the water system operations for the production facilities and the booster pump stations to reduce the energy required to maintain a uniform level of service. As a result of our hydraulic modeling efforts, the overall system delivery costs decreased by seven percent. The conclusions associated with this analysis are based on model simulation results. UWTR is currently designing the infrastructure necessary to integrate the proposed service area boundaries. Following the service area boundary integration, UWTR plans to implement the recommended water system operations. The project team will be positioned to compare actual field data to the model simulation results following the operational adjustments.

The Pipeline Assessment and Certification Program® (PACP ®) is an international standard that has been used for many years for assessment of pipelines, manholes, and laterals. Since 2002, over 20,000 people have been PACP certified. In 2015, NASSCO released a new, improved PACP Version 7.0. The development of Version 7.0 included an unprecedented review by over 100 collections professionals, who collectively, raised the bar on PACP industry standards. The new manual includes technical updates, educational benefits, and a more user friendly format. Technically, there are more detailed explanations of deterioration mechanisms, descriptions of current inspection technologies, and the simplification of Level 1 MACP requirements. Educationally, the manual includes an enhanced color coded chart for Header Codes, as well as a section dedicated to pipe shapes and materials. Finally, a new Asset Management Appendix provides basic guidelines to use PACP to develop Likelihood of Failure, Consequence of Failure, and Risk.

WaterOne of Johnson County, Kansas provides potable water to over 140,000 service connections with a production capacity of 200 million gallons per day. A 30-inch unwrapped ductile iron highly critical transmission main was nearing its 50 year life expectancy for this very corrosive soil area. Before replacing the entire 30-inch water main in 2014, WaterOne decided to perform a condition assessment of this pipeline to determine if the full replacement could be delayed for a significant savings to the utility. Remote Field Technology was utilized to determine the corrosion locations and the remaining wall thickness on the transmission main. After verification of the inspection data, WaterOne determined 10% of the pipeline should be replaced within a year, 10% more in five years, and the remaining 80% in 2025. This staggered delay of full replacement led to a $1.8 million total savings based on the time value of money.

Recent developments in inspection techniques/technologies now make it possible to collect condition data for the entire length of pipeline that can then be evaluated with analytical and engineering techniques to provide a targeted strategy of repair, replacement and management. One specific research and development effort of inline screening technologies began with field trials as part of a 2008 EPA study on innovative condition assessment technologies for water mains. The initial phase of the development of pipe wall assessment (PWA) tools used acoustic pulse technology in qualitative manner to assess the wall strength of a pipeline by determining the change in hoop stiffness over short intervals. On a parallel path, a second PWA technology was developed that measures the change in the self-generated magnetic field produced by ferromagnetic materials in stress. This paper will discuss the development of both technologies.

The San Diego County Water Authority operates and maintains the San Diego region’s aqueduct delivery system, which consists of approximately 483 kilometers [300 miles] of large-diameter pipelines, more than 1,400 aqueduct-related structures, and over 100 flow-control facilities. These facilities occupy approximately 567 hectares [1,400 acres] within the Water Authority's right of way, and deliver water for over 3 million residents. This paper will examine some of the steps taken by the Water Authority to continue the development of its asset management program. With many years of focus on managing prestressed concrete cylinder pipe (PCCP), the program is now progressively including other pipe types. Utilizing state-of-the-art technology, the Water Authority is actively including the comprehensive assessment of critical components of its 204 kilometers [127 miles] of welded steel pipe (WSP) and making long-term projections of remaining life based on data gathered. The paper will describe the process of undertaking comprehensive condition assessments using high-resolution magnetic flux leakage technology, lessons learned, and improvements that were made between projects. The paper will also describe how the Water Authority funds such ventures, and how it uses the collected data to determine remaining life in the context of its entire asset management program.

Condition assessment projects for large diameter pipelines can be very expensive andoperationally complicated. Costs not only include the condition assessment effort, but additional costs for preparation of the project, pipeline shutdown/isolation, engineering, coordination of the project with the public, and non-revenue discharged water. Owners are finding condition assessment projects expensive and difficult to justify to their board of directors and governing bodies. This paper will cover the San Diego County Water Authority’s typical large diameter pipeline condition assessment costs inclusive of all aspects of the project. In addition, the paper will describe the Water Authority’s justification for condition assessment projects with four main cost benefits: preventing failures with a proactiverepair approach, maintaining a reliable water supply, extending the life of pipelines, and efficient useof replacement and repair funds.

This paper presents a case study for the examination of one of the City of San Diego’s oldest and most critical water transmission pipelines, a 36-inch (900 mm), 7-mile (11.3 km) long lock-bar steel pipe. A history of the original installation and subsequent maintenance improvements (addition of cathodic protection and re-lining with cement mortar) is discussed, and the results of recent field examinations are presented, along with conclusions. The paper also discusses a number of condition assessment methods and techniques that were utilized on this pipe, including internal video inspection and leak detection; external broadband electromagnetic scanning, guided wave testing, and ultrasonic thickness testing; corrosion testing; transient monitoring; and assessment of valves and appurtenances. Additionally, the paper briefly covers the methodology and results of a risk analysis that was conducted for prioritizing potentially required repair and rehabilitation improvements. The finding of this case study is of direct benefit to other agencies that own and maintain this unique type of steel pipe.

In 2009, a 60-inch (1500-mm) prestressed concrete cylinder pipe (PCCP) transmission main carrying potable water failed. This break and the hundreds of thousands of dollars in damages inflicted was the impetus for Louisville Water Company’s (LWC) PCCP Condition Assessment Program. The program covering 105 miles (169 km) of PCCP pipe was approved as part of LWC’s 2010 Capital Improvement Budget and contained two pilot projects that were selected. A 5.2-mile (8.4-km) section of 48-inch (1200-mm) pipe and an 11.5-mile (18.5-km) section of 60-inch (1500-mm) pipe were selected as the two pilot projects based on their perceived criticality, lack of redundancy, damage-causing capability, and the availability of electromagnetic inspection technology. These two projects were inspected with a variety of electromagnetic inspection platforms, high definition (HD) video, and acoustic leak detection technologies. The inspections identified several pipe sections that required a variety of testing, replacement, and rehabilitation options. LWC utilized multiple contractors to employ a variety of repair methods including external steel bands, external post-tensioning tendons, full joint replacement, internal carbon fiber-reinforced polymer (CFRP) linings, and internal hybrid fiber-reinforced polymer (FRP) linings. With the completion of both pilot projects, the paper will discuss all of the issues encountered, items that worked well and those that did not, a comparison of the multiple structural repair methods, data storage issues, LWC’s future implementation of the program, and how the program best serves LWC’s customers going forward.

The Department of Water and Sanitation is the custodian of South Africa’s water resources and is responsible for meeting the country’s current and future water needs. In 2014, the Department of Water and Sanitation undertook a comprehensive inspection and subsequent risk assessment of two of their most critical pipelines. The pipelines total 90 kilometers in length and are comprised of Non-Cylinder Prestressed Concrete Pipe. The assessment included specification development, material testing, hydraulic steady-state and transient analysis, a corrosivity survey, a flown lidar survey, leak and gas pocket detection surveys, electromagnetic inspection, structural analysis, engineering assessment, and risk evaluation. As a result of the assessment, the risk of failure for each of the over 14,000 individual pipes that comprise the transmission mains was quantified and reported to DWS in a geospatial asset management platform.

The Santa Clara Valley Water District (District) manages an integrated water resources system that includes the supply of clean, safe water to local water providers who deliver drinking water to homes and businesses in the heart of Silicon Valley. This paper describes the District’s large diameter pipeline management and rehabilitation strategy, including corrosion control, and provides some examples of what we’ve learned over the past 10 years. The District manages a 142 mile large pipeline infrastructure. The first pipelines were constructed in the 1950’s. These initial pipelines were reinforced concrete pipe and steel, followed by a major period of Prestressed Concrete Cylinder Pipe (PCCP) construction, followed up in the latter years by coated steel pipe. Beginning in early 2000, concerns regarding PCCP reliability raised the need for establishing a long-term program and strategy for managing the inspection and rehabilitation of all existing pipelines. The first component of the District’s strategy is corrosion control. The design lives of early pipelines were usually not more than 50 years. Currently, we are looking at extension of asset life to 100, 150, and possibly 250 years depending on the existing condition of the pipelines. The next component is vigilant semi-annual monitoring and preventative maintenance activities. Thorough in-pipe inspections are scheduled on a 5 to 10 year window depending on pipe condition and are usually coupled with pipeline rehabilitation and repair activities. Pipeline rehabilitation and repair activities incorporate a comprehensive assessment of the current pipeline and appurtenant condition. Based on the condition during rehabilitation, appurtenances are usually replaced, civil, mechanical, control system, and electrical upgrades and modifications to existing structures undertaken, and any internal pipe repairs or other enhancements completed. Over the past 10 years, 70% of the District pipelines have been inspected and undergone rehabilitation.

Arizona Public Service Company’s Cholla Power Plant has four units with circulating water lines made of 66 in. to 72 in. diameter prestressed concrete cylinder pipe (PCCP) in Units 2, 3, and 4. PCCP in these three units has been in service for thirty-four to thirty-seven years. Inspections over the years have shown a high level of distress throughout the pipelines due to widespread corrosion of prestressing wires. A condition assessment and repair program has been developed and performed over multiple outages with the goal of minimizing the risk of failure of the pipeline and avoiding unscheduled shut down. This paper presents a unique condition assessment and repair program implemented over the past six years.

Sanitary sewer overflows (SSOs) continue to be an issue for collection system managers, and performing additional cleaning without knowledge of the pipe condition results in a significant waste of resources. Rapid acoustic inspection technology can quickly determine the extent of blockage in a pipe and enables the user to deploy cleaning resources much more effectively. Municipal wastewater utilities struggle to effectively manage the vast underground network of pipes that handle the transportation of raw sewage through our nation's cities and towns. Capital investment needs for wastewater and stormwater collection systems are estimated at $298 billion over the next 20 years (ASCE, 2013), further squeezing operating budgets. Condition based maintenance (CBM) can assist by efficiently targeting maintenance to locations prior to an overflow or other failures. This requires cost effective/timely information to implement. A CBM program for collection system operations can substantially lower operating costs, but until recently obtaining the required assessment information was cost prohibitive. There are two key factors influencing a CBM program's viability: inspection cost, and the fraction of pipes requiring maintenance. A novel acoustic inspection technology (recently commercialized and evaluated by the EPA) is an enabling technology that allows for economical pre-cleaning assessment of sanitary sewer lines. The acoustic inspection technology is cost effective with inspections costing 1/10th the cost of CCTV inspections. In addition, based on acoustic inspection (and validated by CCTV during pilot projects) on average 50-70% of the pipes in a system do not need immediate maintenance or further detailed inspection. It's important to note that the acoustic inspection does not replace CCTV, it helps to prioritize where and when to use more expensive CCTV resources. Using acoustic inspection to prioritize cleaning operations could provide a breakthrough enhancement for moving collection systems maintenance towards efficient CBM programs. Economic analysis and productivity measurements will be presented that evaluate the effectiveness of using a preliminary inspection tool. Multiple case studies will be discussed, while also evaluating the substantial financial and operational impacts of using acoustic inspections to prioritize cleaning operations.

Stormwater infrastructure asset management is becoming increasingly popular in the United States, with emergent government regulations and knowledge of the risk posed by deteriorating stormwater pipelines to the environment. Performance assessment of a stormwater pipe is an essential aspect of utility asset management plans. This paper presents a weighted factor framework to determine the performance of stormwater pipes. A list of about 50 parameters effecting the performance of stormwater pipelines was prepared based on literature review, study of existing stormwater asset management plans and feedback from utilities. The list was divided into essential and preferential parameters, due to a lack of readily available pipe parameters with utilities. A two-level hierarchical representation of degradation of stormwater pipeline infrastructure was developed, constituting five failure modules and the essential parameters. On the basis of survey replies obtained from ten utilities across the EPA regions, the essential parameters were combined into a performance index. The index is a scale of one to five, similar to National Association of Sewer Service Companies’ (NASSCO) Pipeline Assessment Certification Program (PACP) grading system. Furthermore, a prototype of the performance index was developed using real utility data.

The key to implementing infrastructure asset management strategies is to have a comprehensive understanding of the asset performance, and how this performance changes over time. The rate of deterioration of pipes is affected by a number of factors. Although there are many condition assessment technologies and accelerated testing methods available, these techniques do not provide all of the required data on the factors effecting deterioration. Earlier efforts have been made to capture data on pipe failure and as described in the literature, these data have been used to develop of some prediction models. However, failure data alone are limited in terms of understanding pipeline deterioration. Forensic analyses of pipe samples extracted while in service as well as after failure are crucial in acquiring a comprehensive understanding of the rate of deterioration over time. Water sector utilities need feasible and sound protocols to analyze these pipe samples. This paper presents methods and protocols for failure and forensic analyses and collecting data on the deteriorated or failed pipe samples. These proposed protocols contain guidelines on capturing the environmental (soil, groundwater, climate, etc.), and structural (corrosion, fracture, fatigue, etc.) data for drinking water and wastewater pipelines with field and laboratory tests. Furthermore, a Web-based and GIS driven platform called PIPEiD (Pipeline Infrastructure Database) has been developed to collect and share the data produced following these failure and forensic analysis. The objectives of the PIPEiD is to unite the nation’s water pipeline infrastructure data and information, to make it universally accessible and useful, and to provide access to the data sources, tools, and models that enable the analysis, simulation, visualization, and evaluation of the behavior of water pipeline infrastructure systems for advanced asset management. PIPEiD is envisioned to be “a Living Database Platform for Advanced Asset Management” addressing all three major asset management levels including strategic, tactical, and operational that will assist drinking water and wastewater utilities of all sizes to sustain targeted levels of service with acceptable risk.

Of the 1,300 miles of sanitary sewer lines owned and operated by the City of Baltimore, approximately 16 miles is 6-inch diameter, which is not included in the 2002 Consent Decree. While these pipes represent a small portion of the collection system, they generate a disproportionate number of service disruptions because they were constructed in the early 1900s using vitrified clay pipe and substandard construction methods by today’s requirements. Faced with the question of how to deal with these problematic small sewer lines, Baltimore City decided to perform a comprehensive condition assessment, followed by the renewal of the assets depending on the results of the assessments. The 16 miles of 6-inch sewers was prioritized for condition assessment based on history of complaints and pending street rehabilitation projects. The intent of this project is to improve the level of service these assets can provide, thereby minimizing service disruptions and potential public health impacts associated with SSOs and basement back-ups.

The Boston Water & Sewer Commission (BWSC or Commission) with the help of consultants CH2M developed a systematic and robust approach to asset management for BWSC’s wastewater and storm drainage system. BWSC is moving their infrastructure assessment and rehabilitation program from reactive to proactive responsiveness. BWSC has set a goal of completing (closed-circuit television) CCTV inspections for approximately 10% of its sanitary sewer system (90 miles) each year to establish a baseline condition of their system. To achieve this, BWSC’s inspection program was re-engineered. This included: 1. Implementing tools for automation, data analysis, and reporting 2. Implementing a risk-based approach to planning future inspections. The re-engineered inspection program has allowed the Commission to meets its goals related to collecting, storing, and analyzing condition assessment data. SCREAM reports enable BWSC to document trends related to maintenance and condition of sanitary and storm drain system. The major findings of the program to date include: (1) Structural condition of most inspected pipes was better than anticipated. (2) The age of the pipe is not a good indicator of its structural condition. (3) Pre-cleaning surveys found that significant amounts of sediment had accumulated in many pipes. (4) The most frequently identify remedial measures for the inspected pipes are cleaning and maintenance rather than rehabilitation or replacement. As the Commission continues to progress through its system on an annual basis, the re-engineered inspection program and tools are expected to help the Commission focus future investments to provide the most benefit for the City of Boston.

The Southern Delivery System (SDS) is a regional project that will bring water from the Arkansas River to the City of Colorado Springs, the City of Fountain, Security Water District and Pueblo West Metropolitan District. Core components of the project consist of connection to the Pueblo Dam, 45-mi (72-km) of 66-inch (1.7-m) diameter raw water pipeline, three pump stations with total connected horsepower (hp) of 26,750 (19,947 kw), 50 MGD (189 ML/D) water treatment plant and finished water pump station, 4 miles (6-km) of finished water pipeline, and environmental mitigation to meet regulatory requirements. Although integration of SDS is part of a comprehensive integration plan, the primary emphasis of the paper is on the raw water pumping/pipeline operational strategies, including: (1) Integration planning (2) Asset hierarchy (3) Commissioning/startup (4) Operator training (5) Warranty (6) Optimization (7) QR technology. Through the use of these integration strategies, SDS will deliver water to customers in the spring of 2016.

In 2013, the City of Aurora engaged Wilson & Company Inc., Engineers and Architects (Wilson & Company) to conduct a comprehensive inspection and condition assessment of their stormwater Corrugated Metal Pipe (CMP) sewers. Approximately 41,000 LF of existing and abandoned CMP conduits,ranging in size from 12-inches to 120-inches in diameter, were evaluated and prioritized for rehabilitation or replacement. Wilson & Company completed an engineering report that included a summary of all CMP assessment findings, infrastructure evaluations, budgetary level cost estimates, priority rankings and recommendations for rehabilitation improvements. The report also specified final design recommendations for conduits that were deemed to be in eminent failure. Wilson& Company observed that a pair of 96-inch CMP pipes under a major arterial roadway, which Aurora’s Public Works Department had already de-rated for traffic-loading, were severely deteriorated. Wilson was commissioned to review applicable rehabilitation techniques that had minimal public impacts. The consultant recommended Centrifugally Cast Concrete Pipe (CCCP) as the repair method that would meet all the City’s objectives. This paper will discuss the development of the design for the CCCP, installation and lessons learned in the first CCCP rehabilitation project for Aurora Water.

Laser profiling is a non-contact inspection method used to determine a pipe wall profile. A remote control tractor unit with a CCTV camera and attached laser profiling head are guided down the pipe to record defects, excessive deflection, cracks and holes. When the tractor reaches the end of the pipe run the unit is retracted in the rotating laser system, while projecting the laser onto the interior of the pipe to complete optical triangulation. In a non-rotational projection system, the 360 degree laser ring is video recorded as the camera and the laser projector are retracted. A real time report including video, three dimensional wireframe and deflection analysis are immediately available for review by contractors, engineers, owners, and state inspectors. Given that the laser profiling can deliver the deformed shape of the pipe cross section, at a pitch of as small as 0.2 inch, the use of Spangler’s equation and the E’ is likely to fall out of favor. Two ASTM standards F3080-14 and F3095-14 have been written while the third is in progress within ASTM F36. The authors are encouraging wider use of this novel technology within the pipeline industry.

Over the past several years, multi-sensor technology has provided the tools to finally overcome many of the obstacles that were previously encountered inspecting large diameter interceptors. There are countless combinations of collection system materials, sizes, shapes, and conditions that require innovative inspection technologies. Continually, more engineers and municipalities are utilizing these technologies to make more informed, cost-effective rehabilitation decisions. Inspections can now be economically performed using high definition (HD) cameras and a variety of sensors for above-water and below-water data collection. While inspection costs are a fraction of rehabilitation costs, the condition assessment provides invaluable information in the design process. However, different rehabilitation methods require different types of data to make informed design decisions. When all of these data sensors are contained on a single delivery system, the inspections can be economically performed in a single inspection run, but what sensors do I need? What is the difference between standard CCTV and HD CCTV? Do I need 2D or 3D laser data? What are the different types of sonar technologies? Do I need to measure gases and temperature in the line? What does an inclinometer tell me? There is no “one size fits all” when it comes to multi-sensor inspection technologies, so it’s important to understand the basic mechanics of different sensors and how the collected information will benefit the design engineer. With all the new innovative technologies in the market today, it’s important to understand the benefits, not necessarily the features. Using actual case studies, the presentation will provide information on the operation of the different data collectors and delivery systems by different manufacturers. Identifying conditions prior to the inspections to enable planning of the most effective means of performing the work and those conditions that may be encountered that could cause problems are discussed and illustrated. Sample reports and typical illustrations will also be presented.

Pipe Penetrating Radar (PPR) is the underground in-pipe application of GPR, a non-destructive testing method that can detect defects and cavities within and outside mainline diameter (>18 in / 450mm) non-metallic (reinforced concrete, vitrified clay, PVC, HDPE, etc.) pipes. The key advantage of PPR is the unique ability to map pipe wall thickness and deterioration including voids outside the pipe, enabling accurate predictability of needed rehabilitation or the timing of replacement. This paper presents recent advancement of PPR inspection technology together with selected case studies. Two case studies are discussed in detail. The Del Norte Trunk Sewer in Stockton, CA is a 36” reinforced concrete pipe with a 0.7” thick fiberglass liner. The objective of the PPR survey was to determine the condition of the approximately 55 years old lined RC pipe by mapping its wall thickness, rebar cover and detecting voids and/or other anomalies within or outside the pipe wall. The pipe experienced failures in the past and the fiberglass liner has at places also separated from the original RC pipe wall. PPR results confirmed 3.9 to 4.5 inch remaining wall thickness including the grouted fibreglass liner with little variation over the inspected length. Rebar cover appeared to be sufficient with no void type anomalies on any of the inspected lines. A 120 inch diameter brick lined combined sewer pipe was inspected with PPR. The pipe was built in 1906 and experienced wet weather overflows. In order to design the most appropriate rehabilitation strategy the knowledge of voids outside the sewer was critical. Over 6,000 ft of high resolution line data were collected via manned entry. PPR data revealed voids both outside and within the pipe wall and thus provided engineers the information needed to take the appropriate approach to rehabilitate the pipe. With limited available funding and budget constraints becoming more prevalent, timing of rehabilitation and overall intelligent asset management is more critical than ever. PPR provides engineers and utility owners the information to accurately estimate the remaining life left in a pipeline, refine timing of repairs, and ultimately better allocate funding for asset management.

Advanced condition assessment technologies for buried municipal pipeline applications have been gaining significant attention in recent years. This paper presents a case study from the recently completed pipeline condition assessment project employing Ultra Wideband (UWB) radar system integrated with CCTV camera. Recently, a storm drain was rehabilitated using the trenchless slip lining technique. Following rehabilitation, a non-destructive testing (NDT) based QA/QC analysis was performed to evaluate the quality of rehabilitation. Prior to the field test, laboratory based feasibility study was conducted using pipe specimen with artificially created defects. Results from both laboratory and field evaluations are presented in this paper. The results indicated the possibility of employing UWB radar as a tool for detecting quality control issues in the trenchless slip lining projects including grout blockage within the annular space, uniformity of grout thickness and proper alignment of liner pipe.

Many regulatory agencies around the world requiretheir municipalities and water utilities to routinely assess and report the condition of their water and wastewater assets. Condition assessment standards and protocols exist for wastewater and gas pipelines as well as for other civil infrastructure systems such as pavements, bridges and buildings. However, no standard defect coding and condition grading protocolsexist for potable water pipelines. The development of a standard coding and condition classification system for water distribution mains is challenging because there is no single inspection technology that can detect and characterize all pipeline flaws, defects and features. Therefore, the codes and classification protocol ought to be independent of inspection technology. This paper introduces the development of a standard defect coding system for drinking water distribution pipelines. Common anomalies, defects and failure modes for metallic (cast iron, ductile iron, and steel), plastic (PVC and PE), and asbestos cement water mains arebriefly discussed. The paper also highlights the challenges related to water main condition assessment and discusses existing specifications and standards from gas and petroleum industry that can be adapted bythe water industry to develop an objective condition assessment protocolfor water mains.The proposed standard defect coding systemis being developed with the support of Water Research Foundation and in collaboration with over a dozen municipalities and water utilities from Canada and the USA, as well as major technology providers and international water experts.It willprovide a common nomenclature and language for water main defects and features. Other benefits will include facilitation of effective and efficient asset management, support forbenchmarking and establishment of minimum acceptable condition levels or levels of service, and improved operation, maintenance and renewal of water distribution systems.

The Public Works Department of Shawnee County, Kansas recently completed the first project phase of a program to clean, televise and evaluate the pipes of their sanitary sewer system. The current project consisted of the cleaning and televising of approximately 105,000 ft of sewer pipes in 1,350 acres of four of the County’s sewer districts. The pipes were inspected and defects were identified and rated using the National Association of Sewer Service Companies (NASSCO) pipeline assessment and certification program (PACP) scoring system. In addition, all of the pipe segments and their associated defect data were linked to the County’s geographic information system (GIS). Bartlett & West developed computation algorithms to calculate overall rating scores for each pipe in all four sewer districts. The pipes in all districts were then ranked for their comparative condition. Based on the pipe score, each pipe was recommended for improvement consisting of either replacement, point repairs, or lining. The costs associated with each pipe improvement were also automatically calculated using current cost factors. The website has provisions for multiple and nested queries. However, a standard set of queries was developed to allow rapid evaluation and computation of repair and rehabilitation costs. These standard queries can be made with as little as three clicks of the computer mouse. This “easy button” capability allows for rapid collection system understanding by County decision makers for use in planning their capital improvement plan (CIP) and assessing the need for rate increases.

A team lead by ARCADIS, U.S. (ARCADIS) was retained by the City of San Diego (City) to determine the condition and remaining useful life of the City’s 75-year old raw water transmission main, the El Monte Pipeline. As this pipeline ages, the City has taken a proactive approach to investigate this critical infrastructure in numerous phases. This is the first time the pipeline’s condition has been evaluated and the assessment consists of various non-intrusive and intrusive assessment and inspection methods along its 12.2-mile long alignment. Assessment involves performing acoustical testing at 300-foot intervals along a 2-mile section of 48-inch diameter pipe, internal inspection on accessible reaches of the pipeline that varies from 48-inch, 68-inch, and 72-inch diameter. Assessment also includes external excavations at locations of concern determined from the acoustical and internal inspections, and limited core sampling where the pipeline is easily accessible.

Prestressed concrete cylinder pipeline (PCCP) condition assessment methods include an acoustic wave propagation testing technology (ePulse) to identify sections of pipeline with reduced structural stiffness. A recent innovation, ePulse, is a survey level test that uses acoustic sensors to measure the velocity of an acoustic wave in a pipe segment. The wave speed in the pipe is a function of the wave speed in an infinite body of fluid and the pipe stiffness; therefore, changes in wave speed may indicate changes in the pipe wall stiffness along the test segment. Reduced pipe wall stiffness may be an indication of broken prestressing wires, lower prestress, deteriorated mortar coating, cracked concrete core and others. This paper presents a brief description of acoustic wave based pipe stiffness testing and the structural and failure risk analyses and external pipe inspection to evaluate the ePulse predicted pipe stiffness in several pipelines. Results of a case study including pipe stiffness testing on several sewer forcemains are evaluated based on variability of the measured pipe stiffness within a given pipe class, and comparison of the measured and nominal calculated pipe stiffness. We discuss parameters that may affect the results such as entrapped air, pipeline design properties and layout, appurtenances and other features. We discuss observations from the external inspection of excavated pipe to evaluate the results of ePulse predictions. Results of field inspections indicate correlation of observed distress with predicted reduced pipe stiffness and show that the use of this technology, coupled with structural analysis of the pipeline properties, can identify sections of pipeline with structural deterioration for further investigation.

The Easterly Wastewater Treatment Plant (WWTP), located on the northeast side of Cleveland between Lakeshore Boulevard and Lake Erie, provides wastewater treatment services for 334,000 residents and various businesses in northeastern Cleveland and the surrounding suburbs. In addition to treating wastewater from homes and businesses, the Easterly WWTP also receives and treats stormwater from combined sewers. Over 94 million gallons of wastewater per day (mgd) are treated at the Easterly WWTP. The Northeast Ohio Regional Sewer District (NEORSD) awarded the contract to Shook Walbridge Joint Venture. The Sustained Secondary Improvements Project includes expanding the Easterly Wastewater Treatment Plant’s 330 MGD capacity to 400 MGD. The project included improvements to the plant’s existing aeration tanks and final settling tanks, construction of six additional final settling tanks, improve hydraulics to support the capacity increase, and implement various miscellaneous improvements. More specifically, as part of the improvements, the project required auger-cast—piles to support new structure foundations, but also to support pipe cradles for the final effluent piping. These piles were part of the original design to support the 60”, 72” and 84” diameter effluent pipe, which was designed with Prestressed Cylinder Concrete Pipe (PCCP). As a way to solve some constructability issues, Shook-Walbridge proposed a pipe material and pipe foundation substitution in lieu of the PCCP pipe and auger-cast–piles. Their substitution included the use for large diameter fiberglass pipe along with a continuous concrete ballast slab to address floatation concerns. As part of the substitution review process, various aspects of the alternative installation method had to be reviewed prior to acceptance of this alternative. This paper will review the different key components considered during the substitution review process.

Padre Island is part of a barrier island complex that runs along the Texas coastline, from Galveston to Brownsville, Texas. It is bounded on the east by the Gulf of Mexico and by Laguna Madre on the west. A portion of the island is located within the limits of the City of Corpus Christi (City) and the water supply to the island is operated and maintained by the City. Prior to this project, the island was served by a 650 mm (24-inch) steel water transmission main that was constructed across the Laguna Madre in 1968. Survey and assessment of the existing pipeline indicated that it was nearing the end of its useful life. In order to increase the reliability of their water distribution system the City decided to pursue the design of a redundant water transmission main. To minimize impact to the natural resources in the area it was decided to locate the alignment on the south side of the John F. Kennedy Memorial (JFK) Causeway and to construct the pipe line using horizontal directional drilling (HDD) and conventional trenching methods. HDD was used to span the two major water crossings and conventional trenching was used to install the pipe through the dredged materials. During the design phase the City also decided to construct a 200 mm (8-inch) gas line and a 120 mm (4-inch) communications conduit along the same alignment as the water transmission main, allowing them to extend gas and communication service to the island. The final project consisted of 3,290 m (10,800 feet) of conventional trenching installation and 1,905 m (6,250 feet) of HDD installation for a 495 mm (18-inch) water transmission main, a 200 mm (8-inch) gas main and a 120 mm (4-inch) communications conduit. The first and most difficult HDD segment extended approximately 1,645 m (5,400 feet) from the mainland to the eastern side of the Humble Channel. A second 260 m (850 feet) HDD segment was constructed under the Gulf Intracoastal Waterway. This paper will discuss the design and construction of the Padre Island Water Supply project, focusing on the unique project challenges presented by the close proximity to the coast and important natural resources, as well as the very long and challenging HDD sections utilized.

The development of reliable lifecycle intervention plans for water distribution systems depends on better understanding of water main degradation behavior. Traditionally, water main failures have been studied as Weibull/Exponential processes. This paper investigates the application of log-linear model for assessing metallic water main structural degradation. A comparison of the proposed model with the existing Weibull/Exponential based model is presented. Water mains inventory, operational and performance data from a Canadian municipality are used in the analyses. Conclusions concerning the adequacy of existing models and the applicability of proposed models are made. Municipalities and water utilities can use the method provided herein as a tool for desktop condition assessment and risk based failure analysis.

The East Layton Pipeline is a critical aging potable waterline of the Weber Basin Water Conservancy District’s (District or Owner) delivery system that serves as a major source of drinking water supply for the cities of Layton, Kaysville, Fruit Heights, and Farmington, which are located along the Wasatch Front just north of Salt Lake City. The original East Layton Pipeline was constructed in 1955 and includes segments of 30-inch-diameter bar wrapped pipe (AWWA C303) and nonstandard 27-inch-diameter centrifugally cast, reinforced-concrete pressure pipe with rubber gasket joints. Starting in 2010, the pipeline experienced an increased number of leaks requiring emergency repairs, which severely jeopardized the District’s ability to provide a reliable water supply. The pipeline operates with limited system storage and could accommodate shutdown periods of no more than 24 hours during low demands. This paper documents the condition assessment of the existing pipeline, evaluation of alternatives for rehabilitation and replacement of the pipeline, and design and construction of the East Layton Pipeline using a Construction Manager/General Contractor (CMGC) arrangement between the owner, engineer and contractor. The rehabilitation and replacement evaluation resulted in replacing the existing pipeline with a 36-inch-diameter welded-steel pipeline on a separate parallel alignment through residential streets and slip lining the existing pipeline with a 24-inch HDPE pipe to provide system redundancy and ability to meet future demands. Key attributes of the project include construction of a major pipeline in narrow residential streets, crossing of a canyon with steep side slopes and potential landslide material, coordinating utility relocations, surge analysis of existing and future pump stations connected to the pipeline, easement and right-of-way acquisitions, and a significant public involvement effort prior to and during construction. This paper provides a detailed discussion of key issues and project challenges associated with the rehabilitation and replacement of aging infrastructure from the viewpoint of the Owner, Engineer, and the Contractor and also discusses the use and benefit of a CMGC alternative project delivery method.

Trenchless technologies similar to Cured in Place Pipe (CIPP) continue to be embraced for pipeline repair and rehabilitation since the first installation in the early 1970’s. The varying levels of repair from corrosion mitigation, leak protection, to semi-structural and fully structural repair systems require alternating levels of strength, stiffness and durability properties under loading conditions. ASTM F1216 is widely used in water and wastewater pipelines to determine the required thickness of composite liners for semi structural (class II and III) and fully structural (class IV) repair/rehabilitation systems as defined in AWWA M28 Appendix A. It is important to understand the initial assumptions and limitations of these design guidelines. The ASTM F1216 was developed for felt-epoxy CIPP systems that demonstrate quasi-isometric properties. Likely because of this, longitudinal loading is not considered in this design process. As CIPP products continuously develop to resist increasing external and internal loading conditions, stronger materials are used in specific orientations to meet those increasing demands. When unidirectional glass and carbon reinforced polymers (GFRP and CFRP’s) are used to meet the demands of high internal and external loading conditions, additional design criteria are required to cover both hoop direction and longitudinal loading. These additional design criteria extend beyond ASTM F1216. Thus, theoretical calculations from existing and developing pipeline standards, and experimental validation is required to demonstrate the capabilities of new technology utilizing high strength and high stiffness materials like CFRP. This paper will address the additional design considerations appropriate for CFRP pull-in-place rehabilitations and the validation of a fully structural CFRP in situ pressure barrier for small diameter (six to fourteen inch) pressure pipe.

According to ASCE’s “2013 Report Card for America’s Infrastructure”, the United States received a D+ for an overall “below average” rating. Drinking water and wastewater utility infrastructure both received a D rating. Comprehensive utility asset management is becoming increasingly important as aged and degrading infrastructure begins to fail. Managers of these utility systems constantly face funding and scheduling challenges to meet the demands of the country’s growing population. However, effective utility infrastructure asset management does not always have to involve daunting or expensive processes. Integration of engineering technologies — such as geographic information systems (GIS), global positioning system (GPS)-enabled devices, advanced spreadsheet applications, pole-mounted viewer/recorders (pole cameras), and web-based user interfaces, yield a multitude of dynamic data and statistics to end users at the touch of a button during and after infrastructure condition assessments. This paper details a unique approach to infrastructure asset management in which managers of small to medium-sized utilities (generally less than 500 miles of linear assets) can decrease cost and increase productivity through selection and integration of appropriate engineering technologies.

For many water utilities, the true amount of non-revenue water is a mystery, or at least a guess. With the growing use of tools like the AWWA Free Water Audit Software, many utilities are beginning to have a better understanding of how their water system is operating. But with this realization, comes the next question, which is how to economically reduce water losses. There are many things that can be done, but which should be done, and to what level of implementation are the tough questions. The concept of economic level of losses is important, but most water systems will not be close to determining this level after first assessing their non-revenue water. This paper will go describe the approach to identifying the quantity and components of non-revenue water through an initial audit, bottom-up activities, evaluating, selecting and prioritizing corrective approaches, and implementing water loss control activities for effective results. The ability to change course in mid-stream is also important, and so accurate progress reporting is critical. A comprehensive non-revenue water reduction program integrates and informs with other utility management functions, such as asset management. In particular, the level of rehabilitation and replacement of pipelines is related to the non-revenue water goals and economics. This relationship between asset management and non-revenue water becomes the cornerstone for ongoing planning and improvement.

Gulf Coast Water Authority (GCWA) and the City of League City, Texas were faced with the need to renew a critical 39-inch PCCP water transmission main. The 39-inch PCCP water main, owned by GCWA and operated by League City, required replacement of approximately 6,800 feet along Calder Road. This paper will outline the design phase and selection process as traditional slip lining was considered including an alternate for a compressive tight fitting HDPE pipe. The design criteria required a fully structural solution capable of 125 psi operating pressure. The Swagelining™ process was selected over slip lining due to the additional flow capacity and the contract was awarded to Murphy Pipeline Contractors. This paper will also outline the construction phase, including the Swagelining™ process, the pipe installations performed by Murphy Pipelines, and the challenges associated with the installation of a 1000 mm (39.4 inch OD) DR 17 HDPE pipe. The 2.32-inch wall thickness pipe was pulled through a single swage die in four pulls ranging from 1,250 feet to 2,100 feet in length. The Calder Road Project represents the largest diameter, fully structural pipe installed to date in North America utilizing the Swagelining™ technology. The utilization of this technology with HDPE pipe allowed the owner to meet all design parameters and increase the flow capacity. Swagelining™ offers a solution for pressure pipe renewal that is unique in today’s trenchless pressure pipe market as it meets both internal and external loading requirements.

In 2009 a CCTV/sonar inspection revealed that many areas of Baltimore’s Southwest Diversion Sewer (SWDS) were in need of repair. Following this inspection, the City of Baltimore divided the Southwest Diversion sewer repairs into phases for the purpose of retaining consulting engineers and prioritizing repairs. For the Phase III repairs, the City and their consulting engineer, Rummel, Klepper & Kahl (RK&K), worked for several years on project planning and analysis to determine the most effective options to repair the RCP gravity and PCCP pressure segments of this major sanitary sewer conveyance system. A Cured-In-Place–Pipe (CIPP) repair system was selected for the gravity portions and Carbon Fiber Reinforced Polymer (CFRP) for the repair of the pressure portions because each system could provide the necessary repairs with minimal loss in the system’s hydraulic capacity. Carbon fiber systems have been typically used by water and wastewater pipeline owners across the United States to provide full structural repairs to distressed and damaged pipeline segments. These specialized materials are designed to meet a variety of installation conditions, including stand-alone repairs where all internal pressures and external loads are assumed by the CFRP without relying on the existing structure for strength. The CFRP scope of work for the SWDS Rehabilitation Project represents the largest continuous installation of carbon fiber completed to date for an internal repair of a large diameter pipeline in the United States. The project required extensive planning, design and an expert installation crew trained and certified for installation of carbon fiber materials. In addition, a comprehensive inspection and QA/QC process was used throughout the installation process to insure the long-term success of the repair. This paper will address the successes and challenges of the SWDS Rehabilitation Project throughout all stages of the project, including options analysis, design, bidding, best installation practices, collaborative design approaches, coordinating large-scale trenchless repair system installations and inspection.

In 2010, Miami-Dade Water & Sewer Department (MDWASD) implemented a comprehensive asset management program to increase the reliability of their large diameter pipeline system. The program includes inspection, prioritization and targeted replacement or rehabilitation of pipeline segments as needed. MDWASD utilizes several methods to address damaged or distressed pipelines including targeted fiber-reinforced polymer (FRP) structural repairs. Several critical Miami-Dade pipelines have had FRP systems installed at numerous segments as fully structural repairs. FRP repairs are trenchless and involve the use of carbon fiber and glass fiber-reinforcing fabric saturated in an epoxy matrix, then installed on the interior of the pipeline. Once cured, the FRP provides a standalone structural upgrade of the pipe, extending the lifecycle equivalent to replacement. Traditional FRP systems are typically used for segmental repairs when single or multiple non-contiguous pipe sections require rehabilitation. To address extended runs of pipe in a more cost-effective manner, a hybrid system has been designed utilizing continuously wound high strength steel reinforcement embedded in epoxy along with layers of FRP to form a structural upgrade system inside the existing pipe. In the summer of 2014, following an inspection, 13 pipe segments in need of structural upgrade were identified across a 3.5 mile stretch of Red Road. The 54-inch prestressed concrete cylinder pipe (PCCP) segments were selected as the most at-risk through MDWASD’s risk ranking and prioritization process. The repair method elected for the 13 segments was installation of FRP as a stand-alone structural upgrade. Also, as part of the project, Miami-Dade set aside 3 of the 13 segments for installation of the Hybrid FRP System, also implemented as a stand-alone structural upgrade. The Hybrid FRP System installation process includes surface preparation, application of FRP and installation of the steel tensile reinforcement. The steel is installed using specialized equipment which places the reinforcement in the hoop direction onto the pipe’s interior surface. The general design approach utilizes the steel reinforcement for resisting hoop direction design requirements and the FRP component of the system for resisting longitudinal design requirements. The steel is typically placed between layers of FRP with the steel reinforcement set into an epoxy putty for system continuity and protection. The Miami-Dade Hybrid FRP installation was implemented successfully within the allotted schedule. Readers will learn detailed information about MDWASD’s experience selecting and implementing the Hybrid FRP repair at three (3) segments of 54-inch PCCP. The benefits and limitations of the system will be explored including design, materials selection, installation and the appropriate quality control measures.

Fiber Reinforced Polymer (FRP) composite lining systems are used by major municipalities throughout the United States to structurally rehabilitate and upgrade large diameter pipelines. For internal Carbon Fiber Reinforced Polymer (CFRP) lining systems addressing prestressed concrete cylinder pipes (PCCP), there are two design approaches utilized relative to interaction with the host pipe structure. These approaches are referred to as stand-alone and composite. For a stand-alone design, the carbon fiber takes 100% of the loads acting on the pipeline system with no reliance on the host pipe for structural integrity. Composite designs rely on the carbon fiber lining system and inner concrete core of the PCCP to interactively provide a structural system to resist the loads. A composite design approach relies on the inner core to resist bending and buckling due to external loads such as soil cover, water table, vehicular loads and vacuum pressure. When applicable, this type of design can be more cost-effective because the amount of carbon fiber materials utilized can be less than stand-alone design. This paper presents design limit states and includes information from recent research, development, and testing. It discusses factors to be considered, potential challenges and best practices for determining stand-alone versus composite designs for carbon fiber lining systems.

This paper describes the development and successful applications of a CCTV, LIDAR and sonar based pipe inspection system that is robust to gather quantitative data for critical underground pipe condition assessment. The system that can be deployed on a ROV or on a float and produces accurate cross-sectional analysis and sediment volume. This capacity is increasingly critical in large diameter pipes with high level of flow. The system employs a time of flight LIDAR that is accurate to 1/16^th of an inch. Results from recent projects are discussed in detail. The Huntington Trunk sewer in Abbotsford, British Columbia, Canada is a critical line in the municipality’s waste-water system. It is a PVC and HDPE pipe that also carries sewage from Sumas, WA. Pipe diameters vary between 10” and 27” with highly variable flow conditions. Hard to access, off street manholes located in a swamp and on a railway right of way created challenges during deployment. The robust, yet modular SewerVUE multi-sensor pipe inspection system (MPIS) was repeatedly reconfigured during the project to accommodate the challenging site conditions. The sonar results provided accurate sediment volumes and cross sectional restrictions. The Quai George Gorse combined sewer in Boulogne-Billancourt, a southerly suburb of Paris, France is a critical interceptor in the SEVESC operated collection system. This 2200 mm wide and 2700 mm high, irregular shaped (“cunette avec banquettes”) reinforced concrete pipe runs parallel to the Seine river and experiences wet weather overflows during extreme rainfall events. The primary objective of the survey was to quantitatively measure sediment volume and distribution within a 1275.8 m long section. This paper presents the methodology and the results of the inspection. Advanced pipe condition assessment technologies, such as the CCTV, LIDAR and sonar system described in this paper are cost-effective, non-destructive methods that are able to help better refine estimated remaining life of an interceptor, accurately determine overall severity of pipe degradation, as well as provide a basis for improved cost allocation and timing of rehabilitation efforts.

Stainless steel liner, as an emerging method, is being used with increasing frequency for trenchless renovation of damaged water mains in China. In this paper, the application of rehabilitating water mains and laboratory testing of stainless steel liners are described. Practices prove that this new trenchless technology can be effectively and low-costly utilized to renovate damaged water mains and meet the utility owner’s requirements. And considering that there have been little studies on the buckling performance due to external pressure of this new thin-wall structure, the buckling strength of stainless steel liner is studied by laboratory tests. The research shows that the buckling resistance of the DR445 liner is more than 7.25 psi. This conclusion demonstrates that the stainless steel liner meets the requirement in Chinese national standard GB 50332-2002.

We propose a novel pipeline rehabilitation technique that uses particles of a reactive, multi-layer metallic foil to repair internal cracks of a pipeline with minimum on-site effort and no downtime. The principle of this repair technique is as follows: when cracks are detected during routine pipeline maintenance, the particles are introduced into the fluid flow in the pipe, then manipulated by an external magnetic field to fill the cracks or pits. Once the particles are in the site of interest, induction heating is externally applied, causing the reactive metallic foil to undergo an exothermic diffusion reaction and sintering the particles in the crack. In this paper, we experimentally confirm the feasibility of such a reaction within a pipe repair system. We investigate the reaction and bonding strength for various simulated crack sizes, particle sizes, and particle mixture compositions. We observed stable reaction propagation in 30 mm long, 100 μm diameter glass capillaries at velocities of 80-100 mm/s. Shear tests were also performed on the reacted particles. A maximum shear stress of 3 MPa was applied between sintered particles and a simulated crack in carbon steel, demonstrating the ability of reactive particles to repair small pipe cracks.

While a combination of condition assessment and pipeline rehabilitation is used extensively for wastewater sewer mains, this is not true for water mains. One reason is the greater difficulty of assessing water mains than sewer mains (a simple video inspection does not suffice). Another reason is the lack of guidelines for selecting and designing a rehabilitation system which considers the condition of the old water main. This paper summarizes recently completed Water Research Foundation Project 4473, “The Assess-and-Fix Approach: Using NDE to Help Select Pipe Renewal Methods”. This report makes the case for employing condition assessment as part of rehabilitation projects, selecting and designing the final lining only after first scanning the pipe for defects. To develop useful guidelines, the study investigated the essential properties for structural lining systems, and how various linings might be applied to impaired mains. Application of the assess-and-fix approach is feasible today, but requires knowledge and diligence on the part of utilities. Guidance is now available through this recently completed study. Utilities are encouraged to adopt this approach.

In the past five years, EPA and other agencies have been talking about sustainability and resiliency. Each of these areas has received attention on an individual basis. There are parameters and interdependencies which cross all three areas; performance, sustainability and resiliency. This paper will present the research to date on development of the governing parameters associated with each of the three areas. The basic asset management plan shall be viewed under the following distinct categories, performance management, sustainability management, and resiliency management. Parameters for performance will be selected which are the major contributors, based on: Industry Standards, Standard Practice, Research, Wide Use, Data Reliability, and Data Sustainability. Based on the evaluation matrix a performance index will be assigned. Each area will receive an indicator index of 1 (one) to 5 (five). The results of the research will be presented at the conference.

Large amount of manholes in the United States are suffering from serious structural decay and are in need of immediate rehabilitation. Among various candidate techniques, spray-on-place lining is one of the promising techniques for manhole rehabilitation. Based on a new manhole rehabilitation classification system proposed by the authors, epoxy liner is considered as semi-structural material and relies on residual strength of existing manhole structure to withstand external loads. In this study, a two dimensional axisymmetric finite element model for concrete manholes is developed using ABAQUS and calibrated to an existing full-scale manhole experiment. The calibrated FEM manhole model is then used to model the structural behavior of the manhole with epoxy liner under in-situ soil pressure. Results show that concrete residue strength is needed for deteriorated manhole repaired with epoxy liners to resist in-situ soil pressure load.

Asset owners and engineers throughout the U.S. and the world are in search of cost-effective and environmentally friendly solutionsthat serve infrastructure issues. One of the most critical areas of concern is wastewater piping and structures. It is well known that corrugated metal pipes used in storm-water structures are corroding and microbial induced corrosion of sanitary sewers of various materials results in structural concern.Geopolymers have long been known to provide enhanced physical performance to traditional cementitious binders with the addedadvantages of significantly reduced greenhouse emissions and superior chemical resistance. Geopolymers are ceramic polymertechnology that creates a chemical material similar to natural stone that is superior to traditional Portland cement and shotcretematerials. However, they have not generally been contractor-friendly. This paper reviews a geopolymer mortar system that has been used in the U.S. since 2011 and is becoming a preferred solution fortrenchless rehabilitation. The system is spray cast either by rotary nozzle or via traditional shotcrete delivery systems inside ofexisting structures to create whole new structures which do not depend on the existing structure, just using it as formwork. This paperdiscusses competitive advantages over other trenchless repair solutions such as spiral wound, slip-lining and CIPP through specificcase studies including a corrugated metal storm drain rehabilitation in Hidalgo, Texas along with the repair of a stone sewer system inCincinnati, Ohio.

There are numerous point repair solutions in the pipeline industry. These can be broadly grouped into internal joint seals, mechanical sleeves, CIPP short liners and other. The pros and cons of available methods are not always clearly understood by the owners, engineers and installers. Some widely known brand name manufacturers of joint seals and mechanical sleeves are: WEKO-SEAL®, In-Weg seal, Quick Lock, Link-Pipe, LMK, HydraTite, Amex 10, and other. These products can be used for storm, potable water, wastewater and industrial pipes, conduits and drainage culverts. Materials for these types of repairs are specified based on anticipated exposure conditions after installation. When owners are in need of an economical solution for the maintenance of pipelines, the point repair solutions present an attractive alternative to more extensive repair or replace options. Quick Lock that meets ASTM F3110 is new in North America although it has been used for over 20 years in other countries. This paper introduces its features that no other point repair solutions offer. In addition, given that the suitability of the technology for a particular application shall always be jointly decided by the owner, the engineer and the installer, this paper provides an evaluation of available methods during this decision making process.

A water utility located in the Southern US provides water to over 16,000 customers and wastewater service to over 13,000 customers across two counties. In order to serve a growing population, the utility is in the process of upgrading its water treatment plant from 51 MGD to 62 MGD. As a part of the construction process, soil nails were installed for excavation on the property. During the implementation of these soil nails, two 6-inch diameter punctures were made in a 54-inch Prestressed Concrete Cylinder Pipe (PCCP) and 45-degree steel elbow respectively. Given that this pipeline is the main raw water line for the treatment plant, and that the damage occurred during peak summer demand, the need to repair the line was urgent. The proximity of multiple bends and steep slopes adjacent to the distressed regions of the pipelines posed significant challenges for replacement. After extensive research and a site visit to a large municipality pipeline project utilizing similar technology, the utility proposed an internal structural repair using carbon fiber. The owner’s options analysis process, implementation of the bypass system, as well as the internal repair will be detailed in this paper.

The Central Arizona Project (CAP) operates and maintains three (3) 21-foot diameter pre-stressed concrete non-cylinder pipes (PCP) as part of the aqueduct system that delivers almost 1,950 million gallons of Colorado River water per day, to Maricopa, Pinal, and Pima Counties in central and southern Arizona. The pipelines, installed in the late 1970’s, have experienced pre-stressing wire breaks and have been repaired several times since the early 1990’s. The wires have broken primarily due to defects in the wire. One of the pipes, the Centennial Wash Siphon, conveys water beneath Interstate-10 and the Centennial Wash, about 80 miles west of Phoenix, AZ. The siphon is upstream of CAP's first customer turnout, and as such is critical in the aqueduct's conveyance and delivery system. An internal electromagnetic inspection in January 2013 discovered several pieces of the pipe comprising the siphon had many broken prestressing wires, prompting a closer inspection and assessment of the siphon. The case study described herein examines inspections, assessment, monitoring, and subsequent repair using post-tension tendons of the Centennial Wash Siphon. This paper further discusses the ongoing efforts of monitoring, assessing, repairing, and maintenance practices for the largest prestressed concrete pipes in the world. A brief history of the siphons includes manufacturing of the 252-inch diameter prestressed concrete pipes, installation of the pipelines, and early investigations and repairs. The focus of this paper is on the assessment and monitoring since the last repairs in 2006, specifically newer technologies that have emerged to assist CAP in monitoring and making decisions in the repair methods and locations. Relevant points include a discussion on the excavation of the pipes requiring repair, the repair work (post-tension tendons), and maintenance practices. A brief discussion will follow on new technology recently installed in all three of CAP’s prestressed concrete siphons.

This paper presents a case study covering design and construction phases of sliplining the outlet pipe of the Motts Run Dam in Spotsylvania County, Virginia. The reinforced concrete outlet pipe had been previously lined with an HDPE liner in order to allow the outlet pipe to be used for pumping water back into the reservoir. However, the liner did not perform as expected. An investigation of the liner determined that the existing HDPE liner had experienced major deformation. The County decided to remove the failed HDPE liner and replace it with a steel liner. The paper provides an overview of the challenges encountered during design and construction. The project was successfully completed in 2015.

Construction is ongoing of a 100-year service life 5.25-mile 42- and 48-inch welded steel pipeline, conveying raw river water from the Potomac River for a 40 MGD water supply system in an urbanizing county in northern Virginia. Ductile iron pipe (DIP) and welded steel pipe (WSP) were specified to create price competition. Transient modeling incorporated material-specific celerity values and showed that vacuum due to surge was more severe than positive surge. Air vacuum relief valves were located at each high point and 4 non-high points where transient surges were predicted. Cathodic protection was designed, consisting of a bonded coating and galvanic anodes. All bids received were for WSP. Lay schedule and shop drawings review assessed alignment, joint types and pulls. Constrained easements prompted reduced radii elbows. The heat shrink sleeve dissipates heat from joint welding after backfill. Daily lay production of 250 feet is planned. The strength of single lap welds was considered. Each weld is to be magnetic particle tested.

The Tarrant Regional Water District (TRWD) and the City of Dallas Water Utilities (DWU) are engaged in the planning, design and implementation of a 350 MGD raw water transmission system. Referred to as the Integrated Pipeline Project (IPL), the system consists of approximately 150 miles of 84- to primarily 108-inch diameter pipeline, a 5 mile 120-inch diameter tunnel, six 100—350 MGD pump stations, one 450 MG balancing reservoir, and ancillary facilities. When complete, the “integrated” system will provide a critically important source of water for the rapidly growing Dallas-Fort Worth Metroplex for the next five decades and beyond. After years of study, followed by design and construction of a 2 mile, 108-inch steel water pipe demonstration project, the Line J Project, the first segment of the pipeline, Section 15-1, bid in February 2014 and was awarded in March 2014. Steel pipe was chosen for the construction. Pipelines of this diameter and length are not common and come with their own set of challenges from the design, manufacture, shipping and installation standpoints. This paper will review design of this piping material and the practical aspects of furnishing and installing a line of this magnitude, with particular emphasis on lessons learned on both the Line J and the Section 15-1 Projects from the view point of the Owners, Engineer and Manufacturer.

Soil liquefaction has long been recognized as one of the greatest hazards for the integrity and performance of water transmission systems during and after major earthquakes. The effects of soil liquefaction include relatively large magnitudes of permanent ground deformations (PGD) in the form of vertical settlements and horizontal movements (lateral spreading). The effects can also include loss of soil strengths and flotation. Pipeline performance during previous major earthquakes showed that flexible, durable, strong pipes and joints can tolerate some degree of the liquefaction induced deformations. Welded steel pipe is considered one of the better seismic performing pipes. In some degrees, steel pipe can withstand plastic yield but still maintain integrity and service during and after earthquakes. For steel water transmission system planning and design, overall assessment of liquefaction hazards, appropriate route selection, pipe thickness and weld selection are the crucial elements. For deep pump stations and vault structures, foundation failure and flotation of the liquefiable soils should also be considered. At some locations pipe supports or ground improvements can provide some advantages in liquefaction mitigation. Flexible/extendable joints can also provide additional benefits. However, these additional mitigation features are typically associated with relatively high costs. In some significant PGD zones (i.e. forefront of the lateral spreading zone) with prohibitive mitigation costs, considerations can be given for planning emergency repairs and bypass at controlled, accessible location. This paper/presentation explores necessary geotechnical and liquefaction hazards assessments, steel pipe and joints evaluations, and mitigation method selections to optimize construction cost and seismic resiliency requirements for an approximately 30 mile long water transmission main project for the City of Hillsboro and Tualatin Valley Water District (TVWD) in Washington County, Oregon.

This paper discusses the challenges associated with the rehabilitation design and construction of the 36-inch ductile iron pipe (DIP) Underwood Creek force main. Based on the condition assessment and risk analysis, the Milwaukee Metropolitan Sewerage District (MMSD) minimized the risk of continued pipe failures by rehabilitating the force main. The rehabilitation design was based on a review of the currently available technologies and methods to identify those that appeared to be feasible. The four methods selected for further evaluation were cured-in-place pipe (CIPP) (for pressure), swagelining, tight liner (rolldown), and fold and form rehabilitation technologies. The final design documents included the use of two methods, CIPP and high density polyethylene (HDPE) liner, allowing the contractor to select the method and provide MMSD with the most cost-effective solution. The challenges that were addressed included minimizing the number of pits for construction of the liner because of location and constraints, the need to minimize impacts on the Underwood Creek Parkway and crossing a railroad and highway. This paper also discusses the challenges associated with implementing the design during construction and the coordination with many stakeholders, including the full reconstruction of a U.S. Highway 45 interchange by the Wisconsin Department of Transportation (WisDOT), and the construction of overhead high voltage trans¬mission lines by the American Transmission Company (ATC).

Culverts which are typically located under roadways and embankments for the passage of water are designed to support the super-imposed earth and live loads from passenger vehicle and trucks as well as the internal hydraulic loading from the stream flow. Many of the existing culverts in the U.S. are in a deteriorated state having reached the end of their useful design life, making them vulnerable to failures with potentially catastrophic consequences. Traditionally, deteriorated culverts have been replaced by the conventional open-cut construction method. Due to higher costs, adverse environmental and societal impacts associated with open-cut method, particularly in high population and busy roadways, transportation agencies are increasingly looking to adopt trenchless techniques for addressing their culvert problems. This paper reviews several trenchless rehabilitation and replacement techniques investigating their suitability to address different defects, and their compatibility with various host pipe materials and diameters. With focus on reinforced concrete pipe (RCP), corrugated metal pipe (CMP) and high density polyethylene (HDPE) culvert materials, easy-to-use decision-making flowcharts are presented in this paper. State transportation agencies, U.S. Forestry Service and other local government agencies that manage culvert infrastructure will benefit from this paper.

As water pipelines and sewer force mains reach the end of their service life, leaks and uncontrolled line failures become more common. These failures may result in unacceptable environmental incidents and lack of adequate potable water and sewage service. This paper will discuss how hot tapping and plugging is used as an effective enabling procedure that allows the replacement or rerouting of concrete pressure water lines and sewer force mains while maintaining operations. The discussions in the paper will include: the tapping and plugging concept and sequence; engineering principals involved; forces developed in the application of the procedure and the need to address those forces with adequate thrust block designs. Two specific projects will serve as case studies to highlight the use of the technique. One case studyis about the relocation and replacement of a prestressed concrete cylinder pipe sewer force main in an urban area. The other case study is the replacement of a municipal concrete pressure pipe (non-cylinder) water supply pipeline.

Monochloramine loss was studied in two, approximately 70-mile pipelines within the Tarrant Regional Water District (TRWD) raw water supply and transmission main system. Both bench-scale studies and full-scale sampling were used to determine the impact of several factors that may affect monochloramine loss in the pipelines. The conditions of bench-scale study were representative of the range of water quality conditions encountered at the pump stations. Bench-scale results were compared to full-scale samples taken along the pipeline. Samples collected along the 70-mile pipeline were measured for chloramine concentration, pH, dissolved oxygen, as well as parameters known to indicate nitrification such as nitrite and free ammonia. Samples collected along the pipeline were also filtered with a 0.2 μm filter. Filtering the samples removed any nitrifying bacteria potentially present. Comparing the chloramine decay between the filtered and unfiltered samples allowed the affect of nitrification in the pipeline to be observed.

The Baltimore City Sewer Root Control Program was launched in 2007 to reduce root-related sewer overflows and basement flooding by using maintenance and chemical treatment activities. In mid-2014 the City had the third treatment cycle already scheduled, which prompted the execution of an effectiveness study to evaluate root regrowth, reduce the inventory of pipes in the Program, and establish future planning parameters. Due to the large number of historical inspection data in the study, a simplified analysis was adopted. The approach established a combined root condition classification using the National Association of Sewer Service Companies (NASSCO) Pipeline Assessment and Certification Program (PACP) terminology that included both the oldest and most recent inspections. The results of the study were useful for calculating a root control effectiveness value, as well as other significant indicators such as the percentage of pipes with no history of root problems and the percentage of reoccurring root balls.

This paper discusses the inspection tools, procedures and field operations performed in 2011 for the in line condition assessment of a 30 year old, 13 mile long, 24 inch diameter gas transmission line, operating between 250 and 300 psi, that had not been inspected after being placed in operation. Since the line supplies an important part of a suburban area of a large Midwest city with natural gas for domestic, commercial and industrial consumption, the assessment was important to determine whether the line conditions were adequate for continuing operational safety. Additionally the assessment would serve as a comparative baseline for future assessments while the associated cleaning would help improve line flow. Project challenges included limited work areas, public activities adjacent to the tool launching site; load restrictions; limited access to the transmission line easement and right of way, that traversed both residential and environmentally sensitive areas; and commercial and light industry activities close to the gas venting lines at the launching and receiving site.

When a natural gas pipeline ruptures, the adjacent upstream and downstream automatic line break control valves (ALCVs) should close quickly to prevent significant as leakage. The rate of pressure drop (ROD) setting and ROD duration time are the important parameters that determine whether an ALCV closes in time. This study used transient hydraulic software to evaluate the effect of parameters such as flow rate, operating pressure, distance from a rupture to a valve, and rupture diameter on maximum ROD values of ALCVs installed on the second Shannxi-Beijing gas pipeline. In addition to analyzing the effects of pipeline ruptures, the study also evaluated the effects of valve closing. The study found that pipeline flow rate has little effect on the maximum ROD value caused by a rupture. Operating pressure, distance from a rupture to a valve, and rupture diameter have large effects on the maximum ROD value caused by a rupture. Flow rate and operating pressure have the greatest impacts on the maximum ROD value caused by a valve shutdown. In addition, the greater the ROD duration time, the smaller should be the allowable maximum ROD setting.

During a cross-country steel pipeline hydro-static test, pressure changes throughout the test, as a result of temperature fluctuations of the steel & water, air in the system or the presence of a leak in the system. Petroleum releases can occur if the thermodynamics of the test mask a pipe or construction related defect. Using precise measurement techniques, it is possible to evaluate the effects of temperature fluctuations in the system, and greatly improve the ability to identify a small leak during the hydro-static test. When the pipeline being tested is buried for many miles, it is critical to be able to identify leaks without visual inspection. This technical paper will present a brief description of common hydro-static testing measurement equipment in use today. Second, a description of the digital instrument and automated data collection measurement system recently developed by the authors will be presented. Third, a brief description of hydro-test thermodynamics will be given. Then the process of conducting the leak test portion of the hydro-static test will be explained. Finally, a comparison of the relative error between the common hydro-static testing measurement equipment in use today and the digital instrument and automated data collection measurement system recently developed will be presented.

In a batched pipeline, the transient pressure due to a rapid valve closure depends on batch sequences, batch interface locations, and batch volumes. Since an infinite number of potential batch scenarios exist, it is necessary to identify a worst-batch scenario where the maximum transient pressure occurs for the transient event of the valve closure. This study demonstrates that the worst-batch scenario is the densest fluid filling the pipeline between the closed valve and its upstream boundary and the least dense fluid filling the pipeline between the closed valve and its downstream boundary. For a surge-dominated transient event, the worst-batch scenario could be a smallest batch of the densest fluid placed just upstream of the closed valve with the least dense fluid filling the remaining volume of the pipeline.

Electrochemical Impedance Spectroscopy, EIS, measures how the frequency dependent electrical impedance of a coating film changes during its exposure to corrosive media. The technique is fairly rapid, often non-destructive and is sensitive to changes in the coating and can also be performed in the field. The electrical properties of the paint film are measured through its thickness between the metal and an exterior electrode which is usually a reservoir of a conductive salt solution on the outer surface. Polymer pipeline coatings and linings are designed to be barriers to water and dissolved salts that would otherwise corrode the steel water pipes. High values of impedance are characteristic of coatings without defects and that do not absorb water or salts. Diminished values of impedance show that either a defect has formed or that the coating has absorbed electrolyte that may eventually corrode the metal pipe substrate. The technique was used to compare the performance of modern epoxy or polyurethane coatings with coat tar enamel that is known to have a much extended service life, if undisturbed. Results show that, after one and a half years, all the coatings are performing well although the polyurethane coatings are performing better than the epoxies.

Hydrostatic pressure tests of prestressed concrete cylinder pipe (PCCP) with bands of broken wires and lined with carbon fiber reinforced polymer (CFRP) have shown that certain CFRP laminates used as liners for remediation of distressed PCCP may not be watertight. Such test indicated the need to investigate the watertightness of CFRP laminates without expensive hydrotesting of full lengths of CFRP-lined distressed pipe. To address this need, the authors developed a special watertightness pressure chamber that allows testing of curved CFRP laminates, similar in geometry to a segment of CFRP liner installed in a rigid pipe, to pressures up to 500 psi. The pressure chamber simulates the stress state in the CFRP liner installed inside a pipe degraded to the extent that it does not resist the radial motion of the CFRP liner within a window. A number of watertightness concepts were developed, and CFRP specimens were built and tested. The results of the watertightness tests are presented along with the provisions for watertightness of CFRP liners. The procedure for qualification of different laminates for watertightness is discussed.

Failure in oil and gas pipelines due to leaks has led regulators to require operators to implement ever more rigorous inspections. However, advances in inspection technology developed for oil and gas pipelines have not been fully utilized for water and wastewater pipelines. ANSI/NACE Standard Practice 0502 — Pipeline External Corrosion Direct Assessment Methodology has been developed to ensure safe operation of pipelines and prevention of external corrosion in non-piggable pipelines. This standard requires a minimum of two indirect inspections to confirm the most susceptible locations on a pipeline for external corrosion to occur. While legacy technology requires a technician to first locate and map a pipeline, then to conduct individual inspections for coating faults, cathodic protection, and soil data, external line inspection (XLI) technology combines up to 10 different inspection techniques into one integrated inspection. A case study is provided to show the potential and limitations of this advanced inspection technology.

Concerns about the durability and elevated consequence of failure associated with asbestos cement (AC) water main breaks has led utilities to increase focus on the management of AC water mains. This paper synthesizes results from the collaborative project between East Bay Municipal Utilities District (EBMUD), HDR, and the Water Research Foundation (WRF) titled “Development of an Effective Management Strategy for Asbestos Cement Pipe”. This study has expanded water industry knowledge regarding AC pipe performance and recommended a: (1) Method to quantify factors that drive pipe deterioration and useful life (2) Appropriate level of renewal investment at EBMUD (3) Condition assessment approach most useful in focusing renewal investments (4) Method to identify and prioritize particular pipes for renewal. Note, these recommendations are dependent on utility specific variables including but not limited to desired level of service, cost of service constraints, geographic influences, loading influences, and construction practices. While the conclusions may vary by utility, the approach to answering these questions is meant to support all utilities in the development of effective management strategy of the AC pipe they own.

The City of Casselberry completed its $10.3 million asbestos cement (AC) pre-chlorinated potable water main pipe bursting project in April of 2014 which replaced approximately 35 miles of AC pipe. City staff has worked closely with the contractor, engineers and regulators from local and federal government to fully understand the applicability of the National Emissions Standards for Hazardous Air Pollutants (NESHAP) to pipe bursting of asbestos cement pipe. The Environmental Protection Agency and industry representatives have recognized the need to understand the potential environmental impacts of AC pipe rehabilitation and have tasked the Water Research Foundation and the Battelle Institute with studying the various methods of AC pipe rehabilitation. The environmental impacts of pipe bursting AC pipe have been analyzed with the Casselberry Water Quality Improvement Project as its pilot project. Results of the WRF study indicate that bursting AC pipe is more environmentally friendly than removing the existing AC pipe while providing the option to rehabilitate the existing pipeline in place. This paper will present the results of WRF Project #4465 while clearly describing how to burst AC pipelines and meet all existing regulations. This paper describes the challenges and successes of implementing a pipe bursting project, from field application of pipe bursting technology to working directly with regulators and right-of-way controllers who may be skeptical about pipe bursting AC pipe. A potential path forward through submission of a potential Administrator Approved Alternate to EPA that accepts a streamlined AC pipe bursting process is also presented.

There are concerns that asbestos cement (AC) pipes have reached or are close to their design life. These pipes have been extensively used around the world, and estimates are that 15 to 18% of the pipe in the ground in the United States is AC pipe. The Water Research Foundation has engaged in a few recent studies regarding the management of AC pipe that have provided some surprising results. Supplementing this recent research work with a careful literature review and interviews with some key utilities managing large quantities of AC pipe, we will provide a brief overview of the state-of-the science on AC pipe management. While AC Pipe was found to be at or near failure in some case study utilities, in the majority of the case studies the pipe had many years of expected remaining life. For management of high consequence pipe We discuss the method developed to assess the expected remaining life of AC pipe for use on high consequence pipe, and discuss the use of breaks and leaks for management of low consequence pipe. The case is made that AC pipe should not be targeted for removal unless it is performing poorly or is assessed to have little remaining life.

The aging water infrastructure is one ofthe main causes of the increasing water pipe breaks nationwide, resulting in significant social and economic costs. To sustain water infrastructure assets in good condition, it requires a proactive decision making process for capital improvement project planning, maintenance, rehabilitation and replacement. Because physical inspections involve extensive labor and financial resources, it is not always a feasible option to cover entire water pipe inspection and condition assessment. This paper presents two statistical water pipe failure prediction models developed forwater system managers to assisttheir long-term decision making process using Weibull distribution and binary logistic regression. The models presented are developed based on water pipe failure data from approximately 100 years old cast iron pipesfroma municipality in the Midwest, United States.

This paper introduces the use of cluster analysis in pipeline asset management. It utilizes the pipeline geographic information and the historical pipeline break data to test if the pipe breaks are randomly distributed in space and time, and whether any hot zones can be detected. The results contribute to risk analysis and decision-making under a pipeline asset management program. When additional pipe information is available, the cluster analysis can eliminate the impact of different pipe attributes to break rates and reveal the existence of the hot zones due to the complex environmental and hydraulic conditions. The application is demonstrated on a medium-size water distribution network in North America.

With at least 28 existing prestressed concrete cylinder pipe (PCCP) failures in the water system and little history of preventive maintenance, the City of Baltimore (the City) must take significant steps to manage the PCCP in its system. This year, the City is implementing a strategic and comprehensive assessment, monitoring, and repair program for its inventory of PCCP. In this initial ten-year program, the City is strategically prioritizing pipes for inspection through a detailed risk assessment model and maximizing the inspection of high-risk pipes in the program’s early stages. Condition assessment is performed for each inspection zone using a combination of acoustic, visual, and electromagnetic technologies. Acoustic fiber optic systems will also be installed to effectively monitor pipe segments for wire breaks in high-risk pipes, allowing the City to respond to damaged pipe before a catastrophic failure occurs. In parallel, the City is carrying out an outreach plan to proactively share the approach with stakeholders.

This paper provides a presentation of a life extending system (“Anode Retrofit Program”) for existing water mains by examining the planning, design and specification requirements. Included is a case study from the District of Columbia Water and Sewer Authority (DC Water) in Washington, DC. First, a discussion of the proper design and construction considerations for cathodic protection (CP) of water and wastewater transmission pipelines is basic to any asset management strategy. This includes the importance of understanding: (1) Environmental conditions, (2) Interior and exterior pipe conditions, and (3) CP design considerations. The second part of this presentation of an Anode Retrofit Program for cathodic protection of an existing steel main in Washington, DC. DC Water conducted an anode retrofit project as part of a water main repair on a 48-inch steel water main at the Brentwood Reservoir. The prime objective of corrosion control is to maintain a pipeline system free of corrosion at the lowest cost thereby extending the life of the asset. Washington, DC’s corrosion control program have proven to be beneficial in the reduction of leaks while extending the useful life of the asset. In recent years the question regarding the use of linings or cathodic protection alone, or in combination, has been evaluated for the best economic choice, especially when viewed in terms of the life cycle of the asset. When corrosion protection is added to an existing pipeline asset that has a documented leak history, as part of an Anode Retrofit Program (ARP), it is possible to estimate the additional expected life. This provides decision makers with valuable data that can be used as part of a life cycle cost analysis for making informed decisions.

Broken prestressing wire wraps are known as the primary cause of failure in a pressurized prestressed concrete cylinder pipe (PCCP) due to dissolution corrosion or hydrogen embrittlement. The effects of internal hydrogen sulfide attack to the concrete core can lead to delamination, spalls or pipe thinning and weakening of the concrete. The severity of the damaged concrete core typically increases from springline to the crown of the pipe. In some cases, it was observed that the interior concrete core at the crown of the pipe has completely deteriorated and the steel cylinder was exposed at the crown and corroded. For the case study, nonlinear finite-element analysis (FEA) is used to investigate the performance of a 30-inch and 48-inch Lined-Cylinder Prestressed Concrete Pipe (LCP) with a thinning and weakening concrete core. To understand the effects of concrete spalls and delamination, the stress and strain in the various components of a damaged LCP were investigated by applying the realistic loading while varying the number of broken prestressing wire wraps. The results were calculated for the aforementioned 48-inch diameter LCP design with 5, 35, 70, and 100 broken wire wraps and 30-inch diameter LCP design with 5, 25, 50, and 75 broken wire wraps. Based upon the results obtained, a comparison was performed between the effect of the broken wire wraps in the LCP with the deteriorated concrete core and a fully intact concrete core.

Past and recent earthquakes have highlighted significant seismic vulnerability of utility lines, including water and wastewater pipelines, at bridge crossings. After the Canterbury Earthquakes (2010-2011), severe impact on utility lines at bridge crossings was reported. To identify the risk mitigation strategies for these systems, a performance based approach for the seismic assessment of integrated bridge-utility systems has been proposed. This paper focuses on findings from the first stream of the proposed framework, by presenting the product of the exhaustive data collection and collation, as seismic vulnerability indices. Firstly, an overview is presented highlighting performance of pipelines mounted on host bridges during the past earthquakes. Subsequently, the methodology employed to evaluate the seismic vulnerability index for pipelines at bridge crossings is presented. The methodology is based on data collation, which employs Geographic Information Systems (GIS) overlays of: the bridge and utility inventory in the Canterbury region; damage observations to bridge and utilities during the Canterbury Earthquakes (2010-11); and, the sustained ground shaking and ground deformation maps. The seismic vulnerability index will provide an initial basis for asset managers for pre-disaster screening and prioritization of existing potable water and waste water pipeline installations on bridge crossings, in seismic prone regions.

Distributed Optical Fiber Sensing is a mature technology given its strong record of over 20 years. Nevertheless, underground utilities are yet to embrace it as an everyday tool despite its enormous capability. One dimensional long buried utilities and tunnels offer the best application for the use of this technology. Research studies around the world offer the promise of this technology in monitoring the impact of ground movements on underground utilities and tunnels. No application standards existed that governed the use of this technology within any jurisdiction in the world in September 2012. A global task group on optical fiber sensing systems (OFSS) was born to become a unique pool of talent and experience on the subject with over 40 leading experts from 17 countries, which went on to author two companion standards American Society for Testing and Materials (ASTM) F3079-14 and F3092-14, within ASTM Technical Committee F36. This paper provides a brief overview of how OFSS work, what is in these standards, why OFSS is poised to become the most versatile innovation among all measurement tools for field monitoring, what problems the task group faced during the development of the standards and how the members of the task group resolved these problems, what the benefits are of such global standards and the future plans for the global OFSS task group. The most paramount goal of the authors is to share the lessons they learned during the development of the standards with the delegates of this conference.

Corrosion significantly impacts the reliability and safety of metallic pipelines, which is a leading cause of metallic pipeline failure. A real-time update for the pipeline corrosion status and a timely alert for corrosion induced pipeline damages would contribute to an appropriate plan for pipeline maintenance and repair and reduce the frequency of pipeline failures. To assess the pipeline corrosion, various technologies exist and the most common approach is to measure the pipe-to-soil voltage potential. However, to date, few techniques can yet achieve remote and real-time corrosion assessment for pipelines. Fiber optic sensors, with unique advantages of real-time sensing, compactness, immunity to electromagnetic interference and moisture, capability of quasi-distributed sensing, and long life cycle, is a potential candidate to meet this challenge. This study, therefore, an integrated fiber optic sensing systemis developed to assess the corrosion of on-shore buried metallic transmission pipelines in a real time manner. The sensing principle, development of embedment technique, and laboratory accelerated corrosion tests will be discussed in detail.Upon validation, the embedded integrated fiber optic sensing system could potentially serve the purpose of corrosion monitoring on numerous metallic pipelines and would possibly reduce the pipeline corrosion induced failures.

Exposure of aromatic polyurethane (PUR) elastomers to UV irradiation and moisture is known to cause changes in color and physical properties. This paper will discuss mechanisms by which these changes occur and the degree to which they affect bulk physical properties. Several studies have questioned the detrimental effects on the long-term performance of PUR coatings used on the exterior surfaces of water transmission pipelines. In this study, Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM), Differential Scanning Calorimetry (DSC) and Dynamic Mechanical Analysis (DMA) was utilized to determine the depth and extent of the damage. Steel panels were coated with two experimental standard AWWA C222 compliant systems and weathered for 2000 hr in a Xe-arc Weather-o-meter. Validation of the analytical results was accomplished by analyzing weathered and non-weathered panels.

Simplified pipe design relies overwhelmingly on the empirical modulus of soil reaction, E’, as a measure of soil stiffness which is back calculated from actual test results (Howard, 1977 and 2011). It is therefore not a measurable soil property. The relationship between the modulus of soil reaction, E’ and true soil properties such as Young’s modulus, Es, or the constrained soil modulus, Ms, has been investigated by a number of researchers. There seems to be a growing consensus that the modulus of soil reaction, E’ can be directly replaced by the constrained soil modulus, Ms (McGrath 1998, and McGrath et al. 1999). Equipment for the triaxial compression test is not readily available to all soil testing laboratories especially temporary site laboratories, and the testing is relatively complex, expensive and time consuming. A relatively simple alternate to the triaxial test is the one-dimensional compression test or constrained modulus test. Although Ms is becoming the design soil stiffness of choice, very limited published data exists for buried pipe design whilst laboratory testing procedures are not well documented. It would be very beneficial to the pipeline industry to have a comparable set of soil stiffness values (i.e., Es and Ms) as a function of soil type, based on similar testing procedures and using the same soils. This paper presents the findings from an extensive geotechnical investigation conducted for a bulk water pipeline project involving over 390 triaxial tests and twenty constrained modulus tests. Following months of testing, data analysis and modifications, detailed guide specifications were developed for constrained modulus testing. Lastly, actual Ms values are presented for different soil groups and as a function of compaction density and stress level including recommended soil types for buried pipe backfilling.

The Tarrant Regional Water District (TRWD) with the City of Dallas Water Utilities (DWU), are currently engaged in the planning, design and implementation of a 350 MGD raw water transmission system, which will run across north central Texas from Lake Palestine to Lake Benbrook, with connections to Cedar Creek Reservoir, Richland Chambers Reservoir and a Dallas delivery point. Collectively, the system consists of approximately 145 miles of 84-inch to 108-inch pipeline, a 5-mile 120-inch diameter tunnel, three 150 to 275 MGD lake intake pump stations, three 200 to 350 MGD pump stations two of which include 80 MG suction reservoirs, one 450 MG balancing reservoir and ancillary facilities. The program developed by TRWD and DWU to accomplish these improvements is called the Integrated Pipeline Project (IPL). At the onset of the IPL, the project teams were given the mission to deliver this complex program in a sustainable manner by balancing the triple bottom line of “people, planet and profit” or “social, environmental and economic”. As part of the efforts to optimize design functionality against the “profit” component a series of value engineering studies were conducted at key milestones along the project delivery schedule. Formal value engineering workshops were held at the end of the program’s conceptual study to help guide further definition of project components and design scopes. The project was considered in three major areas: pipeline, booster pump stations and balancing reservoir facilities, and lake intake pump station facilities. Value engineering workshops for each of the components of design were conducted at preliminary design and progress design stages. Informal value engineering for each sub-project was collaboratively conducted through component concept reviews and milestone design reviews. The paper discusses the use and results of Value Engineering for a cross country water transmission line project with particular attention to the balancing reservoir sub-components of this system which through “VE” realized a range of savings of 30% to 50% of project budget on a delivered unit basis.

Due to a series of high impact failures of prestressed concrete cylinder pipe (PCCP) in its water distribution system, the Washington Suburban Sanitary Commission (WSSC) has developed an aggressive program of field condition assessment to identify pipes in danger of failure. However, it found that it was not able to apply these techniques to the two parallel PCCP pipes located within its primary water treatment facility, the Potomac Water Filtration Plant, because the flow demands would not permit the existing 78-inch line to be removed from service for condition assessment. A Business Case evaluation was convened to develop and compare alternatives for installing a full capacity redundant transmission line to carry finished water from the plant, which was complicated by the severely congested nature of the facility, which had grown and been added to multiple times in its history. The alternatives were evaluated using Triple Bottom Line techniques for cost, societal and environmental impacts. Alternatives considered included a tunnel, multiple near surface alignments, and pump station reconfigurations, plus the “No Action” and “Status Quo” options.

The City of Baton Rouge/Parish of East Baton Rouge (C-P), Louisiana has designed and is implementing a sanitary sewer overflow (SSO) abatement program that involves conducting comprehensive rehabilitation and capacity improvements to the collection system as part of an EPA/DOJ Federal Consent Decree. The C-P developed the Program Delivery Plan (PDP), with a current estimated cost of $1.6 billion. In order to manage costs, value engineering (VE) has continuously been a critical component of the Program. Initially, projects in design that had a construction cost estimate of $25M or greater underwent VE. The savings realized from this VE effort was approximately $93M, with the largest savings at the South WWTP ($85M). For all remaining conveyance system projects in design, VE proposals were made by the Program management team (PMT) that could be generally applied. The VE proposals, resulting in $25M in savings, typically involved reduction in scope such as consolidation of buildings, deletion of valve vaults at pump stations, and changes to conduit materials. In order to execute projects to immediately alleviate SSOs in the system, the initial phases of implementation involved making decisions with the limited information available at the time. As components of projects were brought online, a VE committee comprised of staff from the PMT and the C-P was formed to challenge the initial design criteria and evaluate the impact of projects to ensure that each project was delivering the highest value for its construction cost. The VE committee used additional system information, as well as lessons learned from the initial projects. The committee reviewed the proposed pump station capacities and pipeline segment sizes as individual components and their function in the system, in relation to the existing infrastructure and anticipated future development. If a planned pump station or pipeline segment upgrade was questioned, a VE review of the C-P’s hydraulic model was requested. If the future system model showed that the existing pump station or pipeline segment had no SSOs, and the C-P advised that the portion of the system did not have a history of SSOs, then the pump station or pipeline segment was removed from the project. Other examples of proposals include technical review to ensure that a pump station and its associated force main will operate at an optimal point on the pump curve and modifications at pump stations (e.g. lower wet well inverts to allow for future tie-ins). This VE review is ongoing and has resulted in over $20.5M in savings as of February 2015. Many improvements in the system’s future operational ability have also been made. Through VE reviews, the C-P has captured over $138M in savings as of February 2015. This paper will present a variety of specific examples of technical modifications that were made within the SSO Program, in order to achieve the Program’s overall goal through the ever-changing economic climate, in a method that could be utilized on other large wet weather programs.

Underground projects for civil infrastructure continue to become more complex. Engineers and contractors are increasingly being asked to design and construct projects that expand the operating envelope in terms of pipe diameters, project lengths, ground conditions and other new factors outside of prior constructed projects. When assessing the complexity of the project, all parties need tools to identify and assess project risks. Risk management should be part of the planning, design and bidding process. It should occur early in the project life cycle to maximize the ability to influence the project’s outcome. Frequently the focus of risk management is only on technical risks. Along with technical risks, financial, contractual and third-party risks also need to be assessed. The project team needs to assess who is the best party (e.g., owner, engineer, contractor or insurance provider) for assigning and then managing the risk. Early decisions in a project have the most ability to influence project objectives and cost at a lower investment. As the project progresses, decisions made later in the project life cycle have less ability to influence the final project cost while implementation becomes more expensive. Underground construction is inherently risky. The more risk which is passed onto a contractor through contract documents, the higher the contingency will be during contractor pricing and bidding. This paper will discuss the three major stages of risk management – 1. Risk Identification, 2. Risk Analysis, 3. Risk Management and Mitigation. For every risk, the potential impact of the risk needs to be studied. One can then assess the probability of the risk occurring, the impact of the risk and the urgency of the risk. The combination of these factors can provide a relative risk index for making comparisons between risk items. Techniques used for evaluating, quantifying and comparing risks will be presented. Specific examples will be shared from past risk management programs related to pipeline, trenchless and tunneling projects. When all things are considered, the project team needs to evaluate is the risk greater than the benefit that could be achieved by taking on this action.

There are uncased aging pipes crossing major interstate freeways and congested railroad corridors throughout the United States. In the case of the Portland water system, more than 100 uncased crossings have been identified. These pipes are what many consider “high consequence” pipes as they potentially pose greater financial impacts than those in the general pipe population, not only to the utilities that manage them, but to the public as well, as the effects of failure may be felt widespread throughout society. To capture the full effects of such an event, Triple Bottom Line (TBL) impacts to society are quantified in the risk management methodology. Understanding the failure modes and root causes of failure, condition, and consequences of failure of pipes crossing major transportation corridors will assist utilities in better managing these high consequence assets. The likelihood of failure can be refined by obtaining knowledge regarding the pipe’s operational and environment conditions, and historical performance. Estimating the financial consequences associated with main breaks has been facilitated by the development of transportation disruption models. By refining the likelihood and consequence of failure estimates, Portland Water Bureau (PWB) has been able to establish the business case for mitigation measures, including the potential for continued monitoring, additional valves, or pipe rehabilitation or replacement options.

The East Bay Municipal Utility District (EBMUD) is a major metropolitan water district with approximately 335 miles of large diameter pipelines (LDP) defined as any pipeline 20 inches and greater in diameter. EBMUD’s past approach for selecting LDP replacement candidates has been based solely on analysis of leak history data. In order to shift from this reactive approach to a more proactive replacement program, EBMUD recently completed the Large Diameter Pipeline Master Plan which prioritizes replacement pipelines based upon a risk model. The risk model ranks each LDP segment based on its risk score which is a product of the individual pipe segments likelihood and consequence of failure scores. The likelihood of failure criteria includes the LDP condition (age, material, joint type, lining, coating, and leak history) and hazards the pipeline is exposed to (seismic activity, liquefaction, landslide, floods, tsunami, and sea rise). The consequence of failure criteria includes collateral damage concerns, access issues, customer impacts, and system hydraulic importance. The risk model was calibrated and verified based on input from Operations and Maintenance (O&M) staff. Hydraulic modeling and planning criteria were used to cluster individual pipe segments into practical replacement projects. The risk model will be updated on an annual basis. The updated results will be compared against the previous year’s results to determine if a change in replacement priority is recommended. The risk model is a more comprehensive, proactive method of selecting LDP replacement projects for the capital improvement program.

The Regional Municipality of Peel, Canada (the Region), a suburb of Toronto, through its growth projections will be tasked with supplying over 2.5 million residential and commercial customers with drinking water over the next twenty years. In response to this, the Region has undertaken a review of its transmission and sub-transmission infrastructure to ensure it can continue to deliver drinking water services that meet its customer’s needs. This project consists of undertaking a risk and resilience assessment in order to understand and proactively manage threats and opportunities to key components of the Region’s water distribution system and to ensure continued and reliable delivery of water service to its customers. The key focus for the project was to develop a long term strategy to manage and reduce risk through capital improvements and operational planning. In addition, it was necessary to link corporate asset management objectives to risk impacts and resilience enhancements to ensure they are translated into, and support the appropriate business planning processes and life cycle management strategies for the critical assets. The AWWA 7-Step RAMCAP risk management process was used to meet the overall project objectives. Existing and planned protective measures were used to generate alternative options for managing critical asset risks. Risk mitigation options included repair, rehabilitation, replacement, adding redundancy and other operational procedures.

Cobb County-Marietta Water Authority (CCMWA) is the second largest drinking water supplier in Georgia, providing service to nearly 800,000 people. Two of CCMWA’s key objectives are to be financially viable and to reduce vulnerabilities by improving redundancy and implementing a comprehensive asset management program. A large portion of CCMWA’s large-diameter pipeline inventory is made up of PCCP. In 2012, CCMWA was in a similar situation to many predominant PCCP users; past failures on these critical assets had led to the decision to replace the majority of PCCP assets to avoid the risk of future failures. To date, CCMWA has replaced 46% of its PCCP inventory through capital improvement programs and emergency responses. Since 2012, CCMWA has been proactively managing the remaining PCCP within their inventory through a comprehensive condition assessment program. This paper will discuss the various methods utilized by CCMWA to manage their PCCP inventory including the financial and operational impacts of these approaches.

Baltimore Metropolitan Water District (BMWD), which provides water to 1.8 million people, decided to undertake a risk-based prioritization for the network of large diameter mains that is the backbone of the system. This includes 86 miles of PCCP. The goal of the prioritization is to provide the BMWD with a transparent and defensible action plan to minimize the risk of catastrophic failure associated with PCCP mains. The prioritization was conducted by grouping pipelines into a logical approach for the overall asset management strategies the BMWD is currently implementing. This desk-top prioritization effort is a planning level tool, based on the current knowledge of the system that will be used to guide the inspection sequence. The resulting model can be easily updated on a semi-annual or annual basis as actual field data is collected and the true knowledge of the system improves. This paper will present the methodologies used to conduct the prioritization and the results of the prioritization demonstrating the importance of a cohesive plan.

The Washington Suburban Sanitary Commission (WSSC) is among largest water and wastewater utility in the United States serving over 460,000 customer accounts including approximately 1.8 million residents in Montgomery and Prince George’s County Maryland (suburban Washington D.C.). Of the nearly 5,600 miles of water mains, approximately 145 miles are comprised of large diameter (greater than 36-inches in diameter) Prestressed Concrete Cylinder Pipe (PCCP). These PCCP mains make up the backbone of WSSC’s large diameter water transmission system therefore placing a high consequence of failure for these pipelines. For more than five years, WSSC has successfully implemented a PCCP condition assessment program using state-of-the-art inspection, condition assessment, and monitoring techniques. Since its inception, the Program has evolved from a conventional PCCP condition assessment and engineering approach to an integrated, near-real-time pipeline monitoring and management system. This system has been built upon an online GIS based management system of the large inspection data sets (including live monitoring data) and engineering analysis allowing WSSC to manage their transmission mains in a dynamic manner. WSSC’s data management system also goes beyond the node to node (valves, appurtenances, pressure zones, etc.) resolution and drives down to a pipe-by-pipe basis. Pipe by pipe resolution of the data allows detailed and directed analysis, statistical modeling, prediction, and planning where the individual pipe segments form the basis of the statistical samples. Automated alerts and up-to-date reporting have been incorporated into the online GIS based management system providing almost instantaneous access to all its pipeline information. This paper will provide an update to WSSC’s PCCP management program including its recent evolution into an online GIS based information approach.

Many municipalities have the same concerns when it comes to infrastructure planning. Whether it is condition assessment, budgeting or general planning concerns, most similar sized agencies face the same dilemmas throughout the U.S. The knowledge gained through active communication between those sharing a similar interest can be vast. It is likely that challenges being faced by one owner are also being experienced by many more similarly sized agencies. Howard County Department of Public Works (DWP) recently completed a condition assessment for over 44,000 LF of distribution main in one of its oldest planned communities. The Wilde Lake area, which was established in the mid-1960’s, has experienced numerous water main breaks in recent years. In an effort to remain pro-active, Howard County DPW launched a comprehensive study into the cause of the water main breaks, with the intent of developing an overall replacement strategy for the community. As the project developed, it became apparent that this community’s distribution system was a good representation of the County’s system as a whole and the studies completed as part of this project could be applied comprehensively to the entire system. As such, the Wilde Lake condition assessment became a pilot program which could be used to develop a larger asset management program for their distribution system. As the project continued, it became apparent that other local agencies were facing a similar dilemma of how to evaluate and manage their distribution systems. In an effort to gain an industry-wide perspective, the County developed a “Pipeline Management Working Group” that included representatives from Baltimore County, Baltimore City, DC Water and WSSC. These agencies met both in person and via webinar to discuss topics such as: (1) Various inspection techniques (2) Desktop pipeline risk analysis (3) Data Management (4) Replacement strategies (5) Operational strategies. Following the successful outcome of the local information sharing session, the program was expanded to include other North American utility owners, when Howard County hosted a Pipeline Management Working Group at the 2014 ASCE Pipelines Conference in Portland, OR. This session was attended by owners from the US and Canada, all of whom shared a common interest in learning how each other handled their distribution systems. The idea of information sharing, although not a new concept, it is typically done only on a local level. However, by expanding the circle of participants to those outside a local region, additional perspectives can be gained. As the mixing bowl continues to grow to include additional participants, the level of quality knowledge being exchanged is sure to reach new heights!

The United States is critically dependent upon more than 5 million miles of pipeline (lifeline) infrastructure systems to transport water, natural gas, oil, and nuclear facility coolant and waste. Pipelines provide the lifeblood to society by transporting energy, water, waste, and other critical services; yet, the pipeline infrastructure in North America is inadequately prepared to support a growing economy dependent on sustainable growth, public health, and community resilience. Approaching pipeline systems installation, operation, and retrofitting by continuing to use the same 20th century processes, practices, technologies, and materials will likely yield the same results: increasing instances of service disruptions, higher operating and repair costs, and the possibility of catastrophic, cascading failures. How a nation operates, retrofits, and expands its pipeline infrastructure will help determine the quality of life for future generations and that nation’s competitiveness in the global economy. If a nation is to meet important challenges of the 21st century, a new paradigm for the building and retrofitting of critical pipeline infrastructure system is required, one that addresses the conflicting goals of diverse economic, environment, societal, and policy interests. This paper presents the workshop outcome focused on transforming the nation’s capability to plan, design, install, monitor, control, retrofit, and asset manage energy and water pipeline infrastructure systems to be both resilient and sustainable.

In a cooperative agreement, the Tualatin Valley Water District, its partners, and the cities of Hillsboro, Beaverton, Tigard, and Tualatin, Oregon have begun development of a new water system to provide greater redundancy and resiliency in a seismically active region. The new water supply as part of the Willamette Water Supply Program (WWSP), will take water from the Willamette River, and convey it to the terminal reservoir approximately 26 miles away. To move the water from the source to the connection points, nearly 35 miles of transmission main, ranging in size from 72 to 48 inches in diameter, must be constructed. Due to the size of the project, a set of common standards was developed; this will assure consistency between projects designed and constructed by different professionals, resulting in improved efficiency and easier maintenance and operations practices. Consensus was achieved by assembling drafts of design guidance sections, details, and specifications, and by hosting a series of workshops with technical and operations staff. This paper outlines the challenges faced and presents innovative techniques used to help ensure a long-term and reliable water supply to customers in the Pacific Northwest.

Rather than implementing a traditional replacement program, several utilities are now opting to manage their pipeline assets using a more holistic approach with advanced engineering principles, condition assessment technologies, software, and multiple renewal strategies. Under this holistic approach, utilities are not only optimizing the life of the buried assets thereby reducing the capital costs of replacement, but also seeing other financial benefits. Many utilities under value their buried assets by simply stating the value of their systems based on typical straight-line depreciation. However, by implementing a more managed approach to their pipeline infrastructure utilities can increase their debt to equity ratio through recognizing the remaining life of their assets is greater than previously estimated in their existing depreciation model. This paper will present various analyses from holistic pipeline management programs providing several financial benefits over simple deferral of capital replacement. These analyses will focus on three main benefits: 1. The extension of the life of buried infrastructure; 2. prolong the costs of capital replacement and; 3. allow the utilities to determine a more accurate system value thereby increasing their financial standing.

The Willamette Water Supply Program (WWSP) has teamed with the Institute for Sustainable Infrastructure (ISI) to develop a “pre-certification” process for the Envision™ Sustainable Infrastructure Rating System (Envision). The “pre-certification” process is being used during the planning phase of a major water supply program to inform evaluation of pipeline routes, selection of reservoir sites, and development of design guidelines to provide a sustainable water supply project that fits well in the community. This first-of-its-kind approach will use Envision during the planning and preliminary design phase in order to expand the focus of the engineering team to consider criteria beyond just engineering. The WWSP has incorporated the Envision rating criteria into the process for determining the pipeline route and reservoir site location and for developing design guidelines. Envision criteria are being used to minimize disruption to the surrounding communities and design a sustainable infrastructure project.

To serve the customers of the City of Hillsboro and Tualatin Valley Water District, collectively over 400,000 customers, a new water supply system is in development in western Oregon, south and west of Portland. To select a route and secure a corridor for the critical new facilities, the team developed a holistic approach for evaluating routes that included evaluation of multiple corridors based on criteria developed for technical, social, economic, environmental, constructability, and cost factors. In addition to the evaluation criteria, the approach involved working closely with the partners’ public involvement, public outreach and property acquisition consultants to engage affected residents and businesses to help identify appropriate routes and get input. This paper outlines the challenges in identifying pipeline alignments that could be secured to enable the new water supply project be constructed and online by its critical need date of 2026.

In a recent construction, a new four story building was constructed over a 110 year old brick arch sewer (22’ wide and 23’6” high). DC Water learned of the construction after it was completed when the developer applied for water and sewage connection. The developer submitted a structural engineering assessment in an effort to prove that the building does not compromise the brick arch sewer tunnel. Developer’s engineer used a simple load-for-load comparison that computes vertical loads only to substantiate that the load of the wood framed building including excavation for basement did not exceed the previous earth load on the sewer. DC Water engineer rejected this simple arithmetic computation as the calculation failed to analyze the impact of the unbalanced load on the masonry arch sewer. Fully aware of the potential of its impact, DC Water’s engineers responded by immediately organizing a series of engineering evaluations that consist of in-house FEM (finite element model) structural analysis as well as a geo-structural FEM by a consulting engineer. In this paper, we discuss the results from the two independent FEM analyses. Both these analyses confirm a similar stress/strain mode (tension) on the brick arch sewer. Armed with the results of the analysis, DC Water engineers focused on the tension zones during the inspection and identified a crown fracture under the new building. This paper will provide details and owner’s lesson learned regarding the impact of the new construction on a conventional masonry tunnel with modern day engineering tools.

The City of Bellevue serves as a major financial hub in Washington state, and continues to experience high growth in its downtown and adjacent areas. The Wilburton sewer basin lies just east of downtown Bellevue across Interstate 405 (I-405), and its existing sewer system originally built in the 1960’s needs capacity improvements to support the anticipated growth in this area. After an initial condition assessment and pipeline alignment alternatives analysis, the existing sewer alignment was selected as the preferred route. However, after 50 years of development, this required designing 4,300 feet of new 12-inch to 30-inch diameter sewer through a peat bog and creek, adjacent to a new 30 feet tall retaining wall holding up I-405, across 10 lanes of I-405, through a Lexus car dealership, and under a major arterial. These various and distinct challenges required a full range of project solutions including auger-cast pile supported pipe, geofoam backfill, prescriptive shoring methods, trenchless techniques, complex bypass and construction sequencing, and mitigation of business impacts. This paper summarizes the key elements of the project; the alignment evaluation process; the numerous challenges and constraints along the selected alignment; and the toolbox of engineering solutions required to provide a constructible new pipeline for the City of Bellevue. Design was completed in April 2015, and construction is scheduled to begin in the summer of 2015.

Located in the City of Greenfield, Indiana, Potts Ditch is a partially encapsulated stream that was constructed over a century ago. The encapsulated infrastructure is constructed mostly of brick arches and is reaching the end of its useful life. Portions of the encapsulated infrastructure are located underneath and adjacent to existing buildings, thereby putting these structures at risk. Furthermore, the ditch is undersized and contributes to flooding in the downtown area. The project, currently under construction, includes installation of approximately 2,000 linear feet (LFT) of new 14-foot by 6-foot precast concrete box sections to reroute Potts Ditch within the City right-of-way. The stream was modeled in HEC-RAS. Design included a detailed sequence of construction to install the proposed facilities while maintaining existing operations, minimizing the need for bypass pumping, and minimizing the impact to the affected neighborhoods. The affected street corridors are being completely rebuilt and utilities are being relocated to accommodate the construction. Due to vertical conflicts between the existing gravity sewers and the precast concrete box, the City decided to proceed with a 24-inch sanitary sewer interceptor project through the project area to maintain gravity sewer service. Subsurface Utility Engineering Quality Level A was completed in strategic locations. At project completion, the City will have improved storm drainage, filled in a brick arch that is at the end of its useful life, extended a sanitary sewer interceptor, and reconstructed street corridors within the project area.