Pipelines 2024: Construction and Rehabilitation

The Potomac Interceptor (PI) is a 48-mi-long multijurisdictional large diameter sewer operated by DC Water. It conveys flow from surrounding counties to the Blue Plains Advanced Wastewater Treatment Plant. The PI is one of the DC Water’s most critical sewers with a peak flow of 90 million gallons per day (mgd) with no redundancy. Rehabilitation of this section is particularly challenging, because it is directly adjacent to the Potomac River, within a Northern Virginia (NOVA) Park, on federally funded land, and only accessible through private roads. This intersection of state, federal, and private land presented challenges that spanned the technical, political, and public spheres. The presentation will focus on why Progressive Design Build (PDB) was chosen for this high-risk and complex linear pipe rehabilitation. It will highlight how an experienced Design–Build Institute of America (DBIA)-certified Owner’s Advisor guided DC Water in Design–Build Best Practices, leading to the successful planning, procurement, and contracting of the project. The presentation also includes drivers for choosing of PDB, critical stakeholder engagement, building a high-performing team, risk allocation and mitigation during design development (integral to price negotiation), “in-the-dry” concept to maintain flow throughout construction without bypass pumping, flow conversion and final commissioning, utility owner’s experience during the PDB, lessons learned, as well as cost and time efficiencies using PDB.

The Washington Suburban Sanitary Commission (WSSC Water) selected the Lanham Station Road Water Main Replacement Project (Lanham Station or project), an approximately 3-mi upgrade, as a pioneering testbed for pipe bursting technology. Three construction techniques, such as pipe bursting, relocation, and re-lay (same trench replacement), were meticulously implemented for comparison. Different types [restrained joint and fusible polyvinyl chloride (PVC)] and sizes (6–12 in.) of C-900 PVC pipe were installed and evaluated during the pipe bursting process. With construction completed in 2020, the pilot project identified the pros and cons of pipe bursting compared to conventional open cut methods, evaluated the performance of select PVC products, and assessed the applicability of pipe bursting under differing site conditions. The project demonstrated the advantages of water main replacement using pipe bursting and highlighted challenges that require further examination. Ultimately, the pilot project confirmed pipe bursting as a viable alternative for water main replacement projects and provided practical recommendations for standard specifications, construction methodologies, material selection guidelines, and engineering/designer checklists.

In 2021, the City of Fayetteville (the City) performed a remote inspection of the 48-in. gravity sewer from Gregg Avenue to Sunshine Road. Installed in 2006 via hand tunneling, the pipeline is a 48-in. diameter centrifugally cast fiber-reinforced polymer mortar (CCFRPM) pipe inside a 72-in. diameter steel tunnel liner, originally designed with a grouted annulus. The tunneled segment is 913-ft long with fill cover up to 24 ft and runs under Interstate 49 and the Southbound Highway 112 Exit Ramp. The City’s inspection revealed a 100-ft section of localized cracking, damage, and high deflections under the interstate exit ramp, which required trenchless repair. The City retained the investigate-design-build team of Structural Technologies and their subconsultant, Simpson Gumpertz & Heger Inc., to investigate and repair the tunnel. This case study highlights the numerous challenges and multidisciplinary efforts of the project team to successfully implement trenchless repair, including setting up a bypass for the root cause investigation, discovery of unstable tunnel conditions, design of custom shoring solutions, and a three-stage tunnel stabilization effort to allow for installation of a CFRP liner. Thermal sensitivity of the carrier pipe also required a thermal control plan to limit the heat of hydration during grouting.

This project concerns approximately 7,200 linear feet of existing 21-in. to 24-in. wastewater main in the City of Irving, Texas. The main is proposed to be upsized to 30 in. to accommodate build-out conditions per a Wastewater Master Plan. However, the location of the main primarily within a private golf course meant that construction would be tricky. Additional site-specific coordination and constructability challenges also affected the potential replacement options. The original main was constructed in 1969 of vitrified clay pipe. An alignment study determined that no good possibilities existed for realignment around the golf course. A condition assessment indicated various defects throughout the study limits, with the most significant concentrated in two areas: one within the golf course and another outside the golf course proper. Evaluation of current flows by City staff indicated that although the Master Plan calls for upsizing, the existing pipeline has adequate capacity for the foreseeable future. Therefore, two separate packages were developed to address the pipeline segments with significant defects, with the remaining portions left as-is, thereby extending the service life of the pipeline assets and reducing immediate capital costs. The first package involved a 2,320-linear foot stretch with significant defects within the golf course. Because the existing pipeline has adequate capacity for the foreseeable future, the City elected to perform cured-in-place pipe (CIPP) rehabilitation, which substantially reduced the impacts to golf course operations in comparison to open cut replacement and to trenchless replacement options, such as pipe bursting. To further reduce impacts, the rehabilitation occurred during the winter. Additionally, the City elected to utilize BuyBoard, a purchasing cooperative, to contract the work, which reduced costs associated with bid and construction administration. The second package involved a 1,600-linear foot stretch with significant defects outside the golf course proper. Though not impacting play on the golf course directly, this portion had its own challenges. The existing pipeline meandered through a wooded environmental learning center operated by Irving Independent School District on land owned by Dallas County Community College District. To minimize impact to the learning center, the replacement pipeline was aligned along the golf course’s maintenance road, which lay between the wooded area and a pond, roughly parallel to a raw water line owned by Dallas County Utility and Reclamation District (DCURD) which was unable to be located in the field. Additionally, the project involved bored crossings below a bridge and past a forested wetland. The success of this phase was due to collaboration among the City, engineer, contractor, and various affected parties.

Design and construction on the new Valley Line West LRT which connects downtown to the west side of Edmonton are currently underway. EPCOR owns and operates a number of sanitary sewers along the new LRT alignment. Due to the location, depth, length, and other utility conflicts, the primary sewer was designed to be replaced primarily by microtunneling methods as it will conflict with the new LRT alignment. Shanghai Construction Group was awarded the project and began planning for the work. Due to the tight construction timeline, two drives were planned to occur simultaneously from both sides of an existing 1,500 mm diameter trunk at installation lengths between 400 m and 990 m. The anticipated jacking loads for the installations were identified as a concern as the existing deep trunk was not designed to take the laterally imposed 500 and 1,000 t. A finite element analysis of the proposed shaft design system and the loading imposed by the microtunneling was completed to determine if the potential impacts to the existing tunnel were in excess of what could be resisted. This paper discusses the steps taken to assess the structural impact of the construction loads on the existing deep sewer trunk.

The District of Columbia Water and Sewer Authority (DC Water) owns and maintains more than 1,900 mi of sewer that conveys over 300 million gallons per day (MGD) of wastewater to the largest advanced wastewater treatment facility in the world. DC Water has a proactive asset management and preventative maintenance program for inspection and rehabilitation of its sewer assets, including major or large diameter gravity sewer assets. This has led to the identification of high-risk assets for repair before potential catastrophic failure. The East–West Outfall Relief Sewer (EWORS), consisting of twin reinforced concrete rectangular gravity conduits, is a recent example of this management approach that became a collaborative delivery repair project. The upstream junction chamber of the EWORS conveys wastewater from a force main and twin interconnecting branch gravity interceptors, with flow rates up to 700 MGD. The EWORS was identified as a candidate for immediate repair, as its interior outer walls and top slab had severe deterioration, with missing sections of its shared channel midwall. The goal for the project was to return the asset to normal operation in less than 12 months through collaborative delivery between DC Water and its contracted service providers. Phase 1 of the tactical plan focused on diversion of flow with a temporary sheet pile open channel around the EWORS to facilitate the repairs. Phase 2 included evaluation of trenchless rehabilitation alternatives that could provide a long-term repair solution. A variety of repair solutions were evaluated, with the PALTEM Flow Ring system chosen. This innovative system had never been installed in the United States but selected due to its ability to meet the operating conditions, strength of the contractor installing the system, and ability to meet a fast-track schedule. This presentation summarizes the project drivers, timeline and logistical challenges, and an overview of the diversion, rehabilitation, and return to normal operation. It concludes with next step recommendations that prioritize corrosion control strategies for DC Water.

The City of Benicia, located in the San Francisco Bay Area, faced a critical emergency in March 2023 when a landslide severed its primary water supply pipeline. This 12.4-mi, 36-in. diameter bar-wrapped steel cylinder raw water pipeline, supplying over 80% of the city’s water demand was severed, effectively cutting off the community’s water supply and putting City’s residents and businesses at risk. Stantec Consulting Inc. (the Engineer) was retained by the City to implement an emergency bypass, with the knowledge that the City’s emergency water supply was only 1 month. A new manifold and a set of two 12-in. emergency bypass pipelines were installed within 1 week to meet immediate demands. An additional two 12-in. bypass pipes were added later to meet summer demands.

Lauderdale, located in north central Edmonton, has an 8 m deep 1950 trunk sewer system consisting of 750 mm diameter and 900 mm diameter RCP combined sewers, with several incoming lateral connections—including a 600 mm connection and seven sanitary manholes, one being a drop manhole. Following a series of inspection and condition assessment programs, the conveyance system was identified to be in poor-to-very poor structural condition. The wall loss alone was estimated to range between 50% and 80%, indicating a high risk of imminent localized failure. Additionally, 24 “Water Level Sag” defects were found along the trunk sewer. Wastewater samples revealed a high level of biological activity, possible anaerobic conditions, and high sulfide content, which were evident by the degree of H₂S-induced deterioration observed and the odor nuisance issues in the neighborhood. The technical viability and overall suitability of various renewal methodologies were evaluated. Consideration was given to sanitary flow bypass requirements, trunk sewer structure and hydraulic capacity requirements, site constraints, and service life extension. CIPP was identified as the most viable renewal option for the sewer and geopolymer and epoxy coating for the manholes. Some project “twists and turns” included: (1) an 8 m deep sinkhole due to collapse of a section of the trunk sewer during the planning phase, (2) the existing drop-manhole was to be relocated away from the right-of-way of the future LRT project and to be replaced with a new 2,400 mm manhole, (3) the 2,400 mm manhole was to be installed at the sinkhole location, and it was to house a Hydro Vortex Flow Insert system required to address drop flow and odor issues, (4) chasing competent concrete along the RCP sewer for reconnection on both sides of the 2,400 mm manhole, leading to ~20 m long unexpected excavation, (5) five sections along the sewer with significant sagging were earmarked for open-cut replacement prior to re-lining. Liquification and soil sloughing were encountered, causing the team to change course, and (6) the 600 mm service pipe and one of the 250 mm CB leads reside beneath the right-of-way of the future LRT project, triggering the need to comply with applicable railway crossing design standards. This article shows how the rehabilitation activities leveraged collaborative and adaptive team efforts, as well as industry best practices and innovative solutions. Multiple lessons learned will be shared, as well as rehabilitation options evaluation, design criteria, constructability constraints and considerations, stakeholders’ management, construction approach, and QAQC requirements.

The York Peel Feedermain (YPFM) is a critical watermain comprised of 1,800 mm (72 in.) diameter prestressed concrete cylinder pipe (PCCP) that is owned and operated by the Regional Municipality of York (Region) and supplies approximately 30% of the water demand for the Region. In 2022, two leaks were identified through leak detection on the YPFM, one near the West Humber River crossing and another near the East Humber River crossing. Before these two leaks, YPFM had experienced five other confirmed leaks that the Region repaired, including a pipe failure in 2009 just west of the East Humber River crossing that resulted in removal and replacement of several pipe pieces. The purpose of this paper is to present the investigation, analysis, and repair of the PCCP near the leak locations at East and West Humber River. Investigation included internal inspection of PCCP in the YPFM near the two 2022 leak locations, external investigation of PCCP removed in 2009, study of the steel cylinder of a pipe segment removed in 2021, and laboratory testing. Analysis included review of past studies that were performed during localized pipe replacements and pipe–soil-interaction finite element analysis of the pipeline. Repairs for the two 2022 leaks were performed using internal Carbon Fiber Reinforced Polymer (CFRP) that was designed to resist all internal and external loads including longitudinal demands from thrust and thermal loads with special details at the leak locations and at locations of suspected settlement.

The Brock Bridge Road Water Transmission Main is a 17,600 LF (3.33 mi) 20-in. ductile iron water main constructed in the 1990s which is the sole water supply for over 30,000 residents within the Maryland City community of Anne Arundel County, MD. Recent corrosion-related failures resulted in long-duration water outages prompting the County to develop a holistic assessment and comprehensive emergency rehabilitation approach. The primary goal of the assessment was to evaluate the condition of the main to develop an immediate rehabilitation approach. Phase I comprised of installing 3,000 LF of temporary 12-in. HDPE water main to provide bypass in the event of successive failures on the 20-in. transmission main. Phase II was comprised of open-trench excavating 3,200 LF of 20-in. Ductile Iron Pipeline (DIP) with Polyvinyl Chloride (PVC) C900. Phase III was comprised of the replacement of an additional 1,100 LF of 20-in. DIP with PVC and the Cured-in-Place-Pipe lining of over 5,200 LF of 20-in. water main. This case study presents a milestone update and lessons learned of the successes and challenges throughout the emergency assessment and design of over 3 mi of critical transmission main.

High Density Polyethylene (HDPE) is widely used for trenchless technology installations, such as horizontal directional drill (HDD), pipe bursting, sliplining, and compressive fit sliplining. HDPE is a viscoelastic material that allows for a generous allowable bending radius, ruggedness, and durability that are valuable characteristics during trenchless installations. HDPE’s material behavior is unique as its Modulus of Elasticity can vary under time dependent loading conditions which affects the allowable tensile strength of the pipe during installations. General data collection principles for successful design of trenchless technology installations will be provided. Calculations for the pipe installation such as net external loads, average radius of curvature for bore entrance and exit lengths, axial stress along bore path, allowable tensile load, and maximum pull force during HDD will be presented. The realistic construction equipment footprint will be presented for designers to understand equipment constraints that will aid in preparing constructable designs. The construction sequence for pipe bursting, sliplining, and compressive fit sliplining will be provided with discussion on potential points of failure of the process, including unexpected excavations due to repair clamps, changes in existing pipe material, or other items that would halt the advance of equipment. Terzaghi’s theory of soil arching will be presented in order to display how soil behaves during the pipe bursting process as the soil will strengthen as the expander head advances. Available references providing detailed information on calculations and installation procedures will be provided, such as ASTM F-1962 and the Plastics Pipe Institute’s Handbook on Polyethylene Pipe. Actual project examples will be provided in order to help the audience translate the analysis from equations to field installation conditions.

The increasing population growth in southwest Florida area, particularly the City of Cape Coral and Fort Meyers, has created the demand for the environmentally responsible treatment and reuse of the community’s wastewater. These two communities have collaborated to construct a state-of-the-art, tertiary wastewater treatment and reuse water transmission system. This reuse initiative will contribute to the reduction of over 50 t of excess nutrient loads in the surrounding environment and bodies of water. A key component of this system is a 1.5-mi long (2.3 km), 24-in. (610 mm) polyvinyl chloride (PVC) subaqueous horizontal directional drill (HDD) crossing of the Caloosahatchee River. Achieving such a significant engineering milestone within a mere 35-h pullback was made possible by the exceptional teamwork displayed by all project stakeholders from the project’s inception. This paper will detail the challenges and the innovative means and methods utilized to accomplish record breaking 7,630-ft (2,325 m) HDD installation of 24-in. (610 mm) DR18 Fusible PVC (FPVC) pipe.

Pipeline river crossings are challenging, require significant prior planning, and will still likely experience challenges during construction. Close coordination with project stakeholders, including regulatory agencies, customers, residents, community members, and business owners, during the planning, design, and construction stages is crucial to any project’s success, particularly with complex situations, such as pipeline river crossings. The Great Lakes Water Authority (GLWA) provides clean, safe drinking water to 88 member partners across 112 southeast Michigan communities, equivalent to nearly 40% of Michigan’s population. GLWA is in the design and construction phases of the relocation of a 96-in., 2.5-mi drinking water transmission main around a closed industrial landfill, near Shelby Township, Michigan. The 96-in.-diameter pipeline serves over one million people in southeast Michigan. The first phase of the project includes 2,220 linear feet of water transmission main (WTM) and roadway improvements across the Clinton River and through a major intersection and adjacent popular, seasonal business. The Clinton River crossing will be the focus of this paper. This paper will discuss the collaboration of the Project Team for the execution of this crossing: GLWA, Jacobs (the Engineer), and Kiewit [the Construction Management at Risk (CMAR) Contractor]. During the project planning phase, GLWA and the Engineer conducted an alternatives analysis to make the determination between open-cut and trenchless crossing of the Clinton River. In coordination with Michigan’s Department of Environment, Great Lakes, and Energy (EGLE), GLWA and the Engineer selected open-cut as the crossing method, to be discussed in the paper. Due to the extensive process and long permitting schedule, GLWA and the Engineer involved EGLE early in the planning and design phases to inform and coordinate prior to the permit submittals, including field visits and discussions. During the design phase, the Engineer developed a conceptual layout and technical requirements for the crossing and obtained the wetland and floodplain permit from EGLE. This included flood modeling, scour analysis, pipeline alignment (for pipe pre-purchase), and river restoration coordination. Once the CMAR Contractor was under contract, they used the Engineer-provided flood model, technical requirements, and permit-required analysis to design the cofferdam and crossing. The construction phase occurred between November 2022 and September 2023. As can be expected with river crossings, there were challenges that arose, and the Project Team worked together to solve the challenges. The resolution of these challenges along with lessons learned throughout the process will be detailed in the paper.

Quite often, buried pipelines connected to rigid structures or existing buried pipelines undergo differential settlements that, in addition to stress and strain from normal operational conditions, may impose significant stress and strain in the pipe wall. The pipeline should be capable of accommodating the imposed displacement due to settlement while maintaining its structural integrity and fulfilling its water transmission function without leaks. Currently, the use of couplings or joints that depend on gasket seating to maintain water containment after settlement is the typical solution for lesser amounts of differential settlement. The paper describes the expanded application of the engineered steel pipe solution identified as Geohazard Resistant Steel Pipe (GRSP) for use in differential settlement applications. The application of GRSP for absorption of ground displacement in a controlled and efficient manner allows for fully welded joints, eliminating the need for gaskets. GRSP has been introduced in previous ASCE Pipelines conferences and validated with a series of full-size physical tests backed with extensive rigorous finite element simulations. It was shown that GRSP can be used in seismic or ground fault areas where ground-induced actions are expected to occur. GRSP has also been applied in settlement or subsidence areas, offering a simple and economical solution for absorbing the deformation imposed by differential settlement or subsidence. This paper will provide design guidelines and design tables on the use of GRSP and, specifically the InfraShield Joint System (IJS), patent pending. The design tables and design guidelines are developed from the full-scale testing on 24-in.-diameter pipes and continued with extensive finite element (FE) simulations on 84-in.-diameter pipes under differential settlements. This paper will expand on this FE work and include 42-in. and 24-in.-diameter pipe simulations. Two primary cases are considered: (1) the soil settles, causing pipeline deformation, whereas the nearby structural system has negligible settlement, and (2) the structural system settles, while the soil next to it exhibits negligible settlement. The main parameters for the advanced FE work are: (1) soil types (stiffness); (2) diameter-to-thickness ratio (D/t); (3) level of internal pressure; (4) size of soil cover above the pipeline; and (5) amount of vertical or horizontal settlement. Using the results of these extensive studies, application tables for settlements of up to 4 in. for diameters of 24 in. through 96 in. are provided, accompanied by design and GRSP installation guidelines.

San Antonio, Texas, is one of the fastest-growing cities in the United States. To accommodate this rapid growth and to expand water supply resilience, the San Antonio Water System (SAWS) implemented the Water Resources Integration Program (WRIP) to expand their ability to transfer water between pressure zones. Phase 2 includes Pipeline Segments 2C and 3, connecting the Old Pearsall Pump Station to the Anderson Pump Station. This program allows SAWS to distribute desalinated brackish groundwater, fresh groundwater, and Edwards Aquifer water stored at the Aquifer Storage and Recovery (ASR) facilities into their system. In early 2010, SAWS initiated the WRIP Segment 3 Project design, including approximately 13.1 mi of 48″ water transmission line. The 90% design documents were completed in 2012, but then placed on indefinite hold due to the discovery of endangered species in the project area. Once mitigation methods were identified, design resumed in 2017. The 5-year hiatus required a re-examination of the transmission main alignment to locate significant commercial or residential construction that would impact pipeline installation. Pipeline alignment modifications were limited to the easement area previously obtained during Phase 1 of the project. The 100% design documents were completed in Fall 2018 but then placed on hold again due to budgetary constraints. The design was reinitiated in early 2020 to identify any additional changes that may have occurred during the 2-year hold. The project was issued for bid in July 2020, with a construction NTP issued in November 2020. Over the 10-year design period for the Phase 2 WRIP pipelines, commercial and residential construction transformed the project area necessitating multiple iterations of design changes. Additionally, the Project itself was located within an environmentally sensitive region presenting pipeline installation obstacles.

Utilities today are expanding their sewer collection systems into partially or fully built-out areas currently on septic tanks. This expansion is done as a practical means to grow the utility but also remove septic tanks, which have been identified by the State of Florida as a major source of nutrient pollution, from impaired watersheds. A common challenge associated with expanding into partially or fully built-out areas of a city is construction within a constrained right of way. This challenge can result in increased construction costs and extended construction duration. This paper will focus on how this challenge was met for the 44 West Sewer Expansion Project owned by the City of Inverness, Florida. For the purposes of this paper, the discussion is limited to the project elements located within the constrained right of way for State Road 44 West. There are other elements of the project that are located within right of ways owned by the City of Inverness which are not mentioned in this paper, because they are not relevant to the analysis or discussion.

The Bay Park Conveyance project is one of the largest current microtunneling and rehab projects in the United States. The completed project will convey treated water from the South Shore Water Reclamation Facility located in Nassau County, New York, which currently discharges an average of 50 million gallons per day (MGD) of treated water into Reynolds Channel, to the Cedar Creek Water Pollution Control Plant (WPCP) ocean outfall pipe. The 72″ pipe carrying treated water will be approximately 20–60 ft below the surface. This paper will focus on the 20,000 LF of microtunneling that was used to connect a 7.3-mi stretch of the aqueduct that was rehabilitated via sliplining as part of the project. Design–Build project delivery, pipe selection and design, and microtunneling construction methods will be discussed.

The Los Angeles Department of Water and Power (LADWP) designed and constructed the Green Verdugo Floating Cover Replacement Project to comply with the Environmental Protection Agency’s (EPA) Long Term 2 Enhanced Surface Water Treatment Rule. LADWP incorporated best practices utilizing data from computational fluid dynamic modeling, installing remotely operated hydraulic actuated valves, and relocating trunk lines to beneath the reservoir floor to maximize the longevity of the floating cover. The construction of the project was subject to two California regulatory agencies. Tie-in connection work was done within the footprint of the dam leading to increased structural requirements. Reinforced concrete encasement and additional steel thickness to the trunk line added to the longevity of the pipe while also providing corrosion protection. The project had a hybrid delivery process through a partnership with LADWP’s in-house construction division and a specialized geosynthetics contractor. All regulatory requirements have been met and Green Verdugo Reservoir is expected to go back into service in February 2024.

The Peace River Manasota Regional Water Supply Authority (Authority) formed a regional integrated loop potable water system to support the rapid population growth across Southwest Florida. The Regional Integrated Loop Phase 2B Pipeline, a critical segment of the integrated loop system supporting Charlotte County’s potable water demands, was advertised as a progressive design–build project for 13 mi of 42-in. water transmission main design and construction to be completed on an expedited schedule. The project included a total of 16 canal crossings; some with a maximum of 4 ft of grade over existing stormwater culverts with no clear way to squeeze in a 42-in. steel pipe without significantly impacting the budgeted cost. The pipeline also needed to cross the Myakka River, a 2,500-ft-wide river swathed with low-lying wetlands at both shorelines, to reach a termination point identified as the Charlotte County booster pump station. These challenges, as well as challenges associated with intergovernmental coordination and property acquisition, were approached as a united front with the Design–Build Team. This methodology allowed the team to quickly devise constructable, value-engineered designs with each member of the collaborative Design–Build Team to focus on pertinent aspects of the project that best compliment their unique and respective strengths.

This study investigates the application of flexible composite liners for repairing long-distance subsea pipelines with multiple bends. Employing a comprehensive methodology that integrates theoretical calculations and numerical simulations via ABAQUS, the research addresses the complexities involved in liner installation. Key findings demonstrate the effectiveness of these liners in complex pipeline configurations, highlighting the impact of factors like bend angles and inner wall roughness on installation forces. The study confirms the feasibility of this repair method, offering significant implications for enhancing the safety and efficiency of subsea pipeline maintenance.

The City of Dallas, Dallas Water Utilities (DWU) continued its comprehensive condition assessment program in 2022 by performing electromagnetic and leak detection inspection of one of its critical transmission mains, the Cedar Crest Water Transmission Main, which detected a large leak in the vicinity of one of the bends within the encased portion of the pipeline that crosses under the Trinity River. DWU retained the design–build team of Structural Technologies (Structural) and their subconsultant, Simpson Gumpertz & Heger Inc. (SGH) to investigate and repair the subject portion of the pipeline under the river using Carbon Fiber Reinforced Polymer (CFRP) lining. This paper discusses the criticality of the pipeline, investigation, repair approach, and challenges encountered during CFRP repair construction, such as a major flood event.

Safety, quality, and value were key drivers for the solutions-oriented project team when evaluating the rehabilitation of two 70–90-year-old concrete lined raw water tunnels experiencing distress and cracking. An “in-the-wet repair” solution, without interruption to the water supply, was developed to re-line the tunnels with custom stainless-steel inserts to extend the service life of the facility. Assembled by divers at the invert of the tunnel, the liner inserts would be transported over 700 ft down the tunnel for installation by a diver-operated transporter vehicle, integrating an electric over hydraulic power system. The transporter has two onboard underwater monitors and eight LED lights allowing divers to navigate the 25-ft-long transporter down the tunnel with a load capacity of just over 9,000 pounds.

Spray applied pipe lining (SAPL) is a recent pipe rehabilitation technology that can address the issues of pipe aging and failure; however, its usage as a fully structural lining as per AWWA structural lining system is still in the development phase. This paper presents methodologies to test the hybrid polyurea liner material for pressure integrity under internal hydrostatic pressure when designed as an AWWA Class IV lining system with no support from the host pipe. The test methodology includes testing of pipe samples with 8-in. diameters at different temperature conditions from 41°F to 150°F. The test results determined the burst pressure, mode of failure, and hoop stress on the SAPL due to internal pressure. The test results determined a relationship between the pipe thickness and pressure at different temperatures, which are required to determine the performance of the material under different environmental and loading conditions.

HDR has been a trusted advisor to Aurora Water and Louisville Water Company for decades. Both water utilities have aging water infrastructure, large conveyance systems, and serve metropolitan areas. HDR was called upon by each to assist with the renewal of critical transmission pipelines within their systems to continue dependable water delivery to their customers. Although completed independently, the two projects used similar trenchless rehabilitation methods. This presentation will provide an overview of the design, delivery, and construction approaches provided for the $17.5M Aurora Rampart Delivery System 54-in. (1,350 mm) PCCP Steel Slipline and the $25.5M Louisville Water Company’s Eastern Parkway 48-in. (1,200 mm) CI Steel Slipline rehabilitation projects. Project challenges, design criteria, and different sliplining construction methods will be highlighted for each project. The presentation will conclude with a summary of lessons learned from the two different approaches for the design and construction of the sliplining projects.

The discovery of a buckled steel penstock at the Brian J. Gallagher Generating Station in Almonte, Ontario, leads to repair involving removal of the damaged steel liner and installation of a standalone CFRP liner bonded to the concrete encasement. Repair work was completed in the fall of 2013, and annual follow-up inspections were performed in 2014−2016. A recent inspection was also completed in 2023 at the 10-year anniversary. This case study looks back at some of the initial challenges faced during the design and construction of this CFRP liner, discusses how these challenges manifested as distress in the final laminate, and tracks how these issues fared over a decade of in-service usage. This paper reviews the performance of the CFRP liner, in terms of both structural health and abrasion resistance, and monitors the changes in minor defects over the course of a decade of follow-up inspections.

The inevitable aging of pipelines has become a challenge in the underground infrastructure industry. During the pipe’s service life, corrosion can have a detrimental effect on the material and life span of the pipe. The corrosion effect increases with time, and in the worst-case scenario, corrosion can considerably reduce the effective internal pipe diameter, subsequently increasing the pipe roughness. The pipe roughness affects the friction factor and, consequently, has a negative impact on the pipe flow and pumping requirements. Therefore, spray applied pipe lining (SAPL) can be a potential rehabilitation process to reduce the impact of corrosion and improve pipe roughness. Lining the host pipe decreases the internal diameter (ID), which can affect the flow capacity of the pipe, especially in pressure pipes. Therefore, it is important to evaluate the flow characteristic of the lining system when applied to pressure pipes. The hydraulic flow test was designed to measure the friction factor of the lined pipe and then compare it with the friction factor of the bare new and corroded carbon steel pipes. The friction factor for all scenarios was calculated at a high Reynolds number. In addition, the test was aimed to measure the roughness profile of the liner and compare it with corroded carbon steel pipes. In the end, the head loss was compared for bare pipe, lined, and corroded pipes to evaluate the effect of the lining system on the internal diameter, roughness, and flow capacity of the pressure pipes.

Urbanized areas around the globe face an increasingly urgent need to rehabilitate aging sewer infrastructure. Challenging projects in dense neighborhoods have long been deferred for their difficulty and are now rising to the top of the list of priorities. The Boston Water and Sewer Commission (BWSC) is undertaking a multi-year, multi-phase program to rehabilitate one of its most critical sewer interceptors. The New Boston Main Interceptor (NBMI) conveys sewage and stormwater from more than 3,000 tributary acres, including downtown Boston and multiple other district neighborhoods. The 102-in. reinforced concrete pipe is experiencing significant corrosion from hydrogen sulfide gas. This paper focuses on the unique complexities faced in large-diameter sewer rehabilitations within a dense urban fabric—including working within congested utility corridors and major commuter transportation corridors, minimizing neighborhood impacts, and anticipating the needs of many stakeholders. The goal of this project is to achieve a robust structural rehabilitation solution while minimizing hydraulic impacts to the network, construction impacts to the neighborhood, and local traffic. Trenchless techniques are optimal for urbanized settings, because they minimize excavation which, in this case, would be an average 30-ft deep excavation along a major residential/commercial street and would cause significant neighborhood disruption. In this instance, sliplining and geopolymer application were the preferred rehabilitation methods for this vital venture due to the significant corrosion, large interceptor size, bypassing design, and barriers to excavation. By early 2024, Phase 1 rehabilitation will be completed, Phase 2 rehabilitation will be under construction, and Phase 3 design will be 50% complete. BWSC employed complex bypass strategies for varying flow conditions, adapted lining practices to suit this unique project (e.g., slipline grouting into a tight annular space and field measuring ovality of spray liner), minimized excavation and utility conflicts through the use of existing access points and structures, and minimized traffic impacts with a narrow work zone. We will highlight these and other strategies that can prove beneficial to owners and engineers undertaking similar rehabilitation efforts in highly urbanized settings worldwide.

The deteriorating state of North America’s pipeline infrastructure requires advanced renewal technologies that undergo rigorous testing, provide complete structural integrity, and ensure a swift return to service. Despite the vast amount of testing on polymeric spray-applied pipe liners (SAPLs) and the acceptance of SAPL as a structural solution, there is room for improvement within its testing requirements and certification. For instance, there is the absence of a systematic approach to the design experiments for SAPL testing. Addressing this gap, the study introduces a framework developed using the widely accepted Taguchi method. This comprehensive approach incorporates diverse SAPL characteristics, manufacturing factors, application and field conditions, and specimen preparation, effectively bridging the current sensitivity and improving the consistency of testing results.

The Big Dry Creek Interceptor (BDCI) serves approximately 90,000 residents with collection through five separate sanitary sewer districts in south suburban Denver. Through internal pipe investigations spanning nearly two decades, the Southgate Sanitation District (District), located in Centennial, Colorado, identified sanitary sewer manholes and main line segments on the BDCI requiring rehabilitation due to aging and deterioration. A multi-year, five phase rehabilitation program was initiated to rehabilitate all remaining unlined RCP segments in the District-controlled portion of the BDCI. The results of the evaluation, analysis, criticality, project grouping, and engineer’s opinions of probable construction costs (EOPCCs) were utilized to phase the BDCI Sanitary Sewer Rehabilitation Project (Project). Due to the criticality of the BDCI, several unique design and construction solutions were required to provide crucial rehabilitation of vintage infrastructure to serve communities and protect natural resources.

Legacy pipelines face challenges related to seasonal temperature change. The thermomechanical loading results in axial deformation and stress, especially concentrated at weak joints. Understanding the mechanical response of rehabilitated pipelines aids in the successful design of lining. This study presents variations in the force–deformation curves, elastic modulus, and irreversible strain values under displacement-controlled cyclic axial loading. Experimental tests measure the behavior of steel–cured-in-place-pipe (CIPP) host-repair specimen, featuring a full circumferential crack where the CIPP is exposed. An analytical approach based on elasticity theory was conducted to study the structure’s behavior and estimate potential levels of stiffness degradation. Results showed that the stiffness degradation process gradually occurs after each cycle of loading with interaction of several parameters. Debonding process and residual plastic strains are the most important parameters affecting stiffness degradation. Both full-scale experimental test and analytical method showed reasonable consistency in determining the mechanical properties of cured pipelines.

Managing large diameter pipeline reline projects poses significant challenges for project management teams. These complex technical infrastructure require robust planning to promote project success and limit impacts to the customers who rely on them. What are the primary challenges during initiating, planning, executing, monitoring, and closing of large diameter pipeline reline projects? Sharing lessons learned among project team members prevents an organization from repeating the same mistakes and allows them to take advantage of organizational best practices and innovative approaches, and good work practices should be shared with others. Large diameter pipeline operation and maintenance projects require careful management to overcome the associated challenges successfully. By utilizing tools and techniques, project management teams can navigate the complex nature of these projects, minimize risk, and achieve a successful outcome. This paper reviews example projects completed by Central Arizona Project and breaks down the lessons learned within each phase.

On July 16th, 2023, a 20-ft deep, 42-in. reinforced concrete sanitary interceptor sewer collapsed adjacent to a six-lane state highway within an urbanized area of the City of Omaha (City). The sewer collapse created an unstable soil condition resulting in a cave in, jeopardizing the state highway and several utilities. While developing an emergency repair plan for the collapse, the City inspected the surrounding sewers and identified significant deterioration of the infrastructure. As a result, the emergency repair expanded to include nearly 2,000 linear feet of cured-in-place pipe (CIPP) lining of adjacent interceptors ranging in size from 36 in. to 60 in. in diameter. To facilitate the repair work, temporary bypass pumping systems were installed to convey sanitary flows around the planned repairs. This included bypass system setups at 42-in. [10.8 million gallons per day (mgd) capacity], 36-in. (7.2 mgd capacity), and 18-in. (0.70 mgd capacity) interceptor sewers. The bypass force mains had to traverse a recreational trail, under a bridge, and through several private properties. This paper will review the sewer failure, the City’s expedited efforts to stabilize the site, and the emergency repair plan implemented to restore the City’s interceptor system.

Installing 36-in. Ductile Iron Pipe (DIP) by Horizontal Directional Drill (HDD) does not happen every day. Through a Design–Build (DB) project, Dewberry completed the relocation of 13,500 LF of large diameter pipe, including 6,800 LF of 36-in. DIP, of which 1,100 LF was installed by HDD under Bullfrog Creek. Project also included multiple 14–30-in. casings installed by Jack & Bore (J&B) under tunnels and major DOT roads. This paper provides an overview of the project design and construction with a focus on lessons learned during the 36-in. DIP installation by HDD. The challenges included the inability to shut down the existing system; initially dealing with a pipe believed to be pre-stressed concrete cylinder pipe (PCCP); staging and pre-reaming for the installation of the 36-in. DIP across Bullfrog Creek; determining the adequacy of flow and pressure to pig the 6,800 LF of pipe; and other construction sequencing challenges.

This paper discusses installing tapping and plugging fittings on concrete cylinder pipe for effective pipeline modification and repair. Rather than a technical discussion of a methodology to develop and analyze data, the author, based upon 10 years of experience as senior project manager for a global organization that, among other things, executed large diameter high pressure tapping and plugging projects, including concrete cylinder pipes, believed that it would be of interest to civil engineers to have additional information related to tapping and plugging the aforementioned pipe beyond that information usually available in some water works association publications. Topics included in the discussion are: tapping and plugging configuration and sequence; cylinder pipe cross sections; procedures and specifications for tapping and plugging; selection and design of appropriate fittings; proper fitting installation to achieve a positive seal on the pipe; and procedures for effective project execution. Except as otherwise indicated herein, the statements contained in this document are authoritative to the extent they reflect the above indicated experience of the author. This does not preclude that the experience and resulting conclusions of others may differ.

Capitol Hill is the seat of the US government, home to the United States Capitol, Senate, Houses of Representatives, and the neoclassical Supreme Court. Known for the Eastern Market, where vendors sell produce, meat, cheese, handicrafts, and antiques on weekends. The project consists of the installation of approximately 10,650 linear feet of small diameter water mains 3–12 in. and approximately 2,270 linear feet of large diameter water mains of 20–36 in. Project also includes the replacement of fire hydrants, valves, and service lines, including private side replacement of lead and galvanized pipe. Project will help improve water quality and system reliability and help maintain adequate flows throughout the system. Extensive coordination, open communication, cooperation, and collaboration were key to completing a successful project in this historic neighborhood. Coordination between various stakeholders such as the Architect of the Capitol (AOC), Advisory Neighborhood Commissions (ANC) 6A and 6C, Mayor’s Office of Community Relations and Services, Ward 6 Councilmember Charles Allen, District Department of Transportation (DDOT), Congress, Senate, Supreme Court, Supreme Court Police, and Capitol Police was critical to a successful project. They were at the mercy of the AOC schedule and the constraints of the DDOT Occupancy Permit, which limited work hours in the public right-of-way. Communication weekly with the contractor was critical to minimize misunderstandings that could delay construction, weekly meetings with AOC, and weekly newsletters and community outreach to ANC and surrounding communities. Collaboration between stakeholders focuses on a common goal. Due to ongoing challenges with the schedule of the Supreme Court, round-table discussions between DDOT, AOC, and the ANC commissioner led to an agreement to allow night and weekend work to decrease project duration, a shared goal. Cooperation had to be one accord with DC Water’s internal stakeholders, such as Design, Construction, Water Operations, Community Affairs, Safety, Meter Operations, and Legal Affairs. This was critical to the successful completion of this project. Painstaking effort in conjunction with Compliance, Program Services, Finance, and the contractor to meet an August 15, 2022, Water Infrastructure Finance and Innovation Act (WIFIA) loan spending deadline is a testament to the team’s commitment. Organized coordination, diplomatic communication, concerted collaboration, and shared cooperation between stakeholders and other government agencies made navigating a water main replacement project through the historic Capitol Hill neighborhood a success.

The North Charleston Sewer District initiated a program in 2021 to rehabilitate its largest force mains with cured-in-place pipe (CIPP) methodology. The force mains were associated with their regional pump stations: Ingleside, Northwoods, Turkey Creek, and Noisette. The oldest force main (FM), Noisette, was constructed in the 1960s and has exceeded its useful service life. The project was bid in January of 2022. The preconstruction conference was conducted in late April 2022, but the commencement of construction was delayed until the end of October 2022, due to long delivery times for pipes, valves, fittings, and other materials. The rehabilitation of the Northwoods, Turkey Creek, and Noisette FMs is complete. The Ingleside rehabilitation should be completed by the end of 2024. This case study focuses on the interesting, unique challenges met during the project.

As urban infrastructure ages, the rehabilitation of stormwater pipes becomes a critical concern to ensure the efficiency and reliability of aging municipal drainage systems. This paper presents an overview of two stormwater pipe rehabilitation projects conducted for the City of Fort Worth as part of the city’s storm drain improvement program. The projects encompassed an in-depth comparison of different trenchless rehabilitation techniques, considering factors such as cost-effectiveness, environmental impact, constructability, and schedule. Most importantly, the improvement looked at the overall effectiveness of extending the service life of stormwater mains and laterals and continuing to provide adequate service during storm events. After thorough evaluation, two types of trenchless methods for rehabilitation were recommended: Cured-in-Place Pipe (CIPP) and Spray Applied Pipe Lining (SAPL) using geopolymer concrete. The projects’ findings emphasize the advantages of utilizing CIPP and SAPL with geopolymer concrete for enhancing stormwater system longevity and performance.

The focus of this presentation is to highlight why detailed data collection is important during condition assessment and the need for continued coordination between the design engineer and condition assessment engineer to mitigate unexpected changes during the rehabilitation design process. The San Jose-Santa Clara Regional Wastewater Facility is now finishing Phase 2 of its Yard Piping Improvements Project, which included rehabilitating an 84-in. pipeline 5 years after its condition assessment and the changed pipeline conditions encountered. This paper presents an overview of the condition assessment approach and findings, rehabilitation design package preparation, including assumed construction allowances, a recount of how construction proceeded, and lessons learned from the City of San Jose’s perspective to save time and money during construction. Key takeaways: (1) Benefits of condition assessment for preparing rehabilitation design packages; (2) considerations during pipeline rehabilitation construction; and (3) lessons learned from Owner’s perspective.

It is customary practice for water agencies to use sensors in the sewer collection system to track flows and levels in pipes and manholes, allowing them to operate the system more efficiently by understanding changes in capacity in real time. Utilities can use other types of sensors to track water quality, providing a more comprehensive picture and allowing the facility manager to understand organic loads before they reach the plant, minimize plant upsets, and allow for more proactive operation. However, sensors can also monitor corrosive discharges into the sewer system that have the potential to damage pipes, manholes, structures, and pump stations. The City of Memphis implemented real-time industrial discharge monitoring, resulting in a decrease of almost 80% in the minutes of noncompliance in the first few months. Use of real-time remote monitoring equipment can enhance the resilience and performance of wastewater utilities.

The City of Frisco, Texas, has a population of over 220,000 over a 69.1-square mile area. The City’s Stewart Creek interceptor collects wastewater from a 25-square mile sewershed. Phase 4 of the Stewart Creek North Interceptor (SCNI) consists of approximately 15,440 linear feet of existing 10-in. to 24-in. wastewater main roughly parallel to a tributary of Stewart Creek, constructed beginning in 1991 of primarily PVC and vitrified clay pipes. A condition assessment identified various defects throughout the Phase 4 limits, and the City’s Master Plan indicated that the interceptor within Phase 4 is predominantly undersized for build-out conditions. The City contracted with Halff to provide study and design for replacement of Phase 4 of the SCNI. The engineer performed a pre-design sizing and alignment study. The recommended alignment primarily followed the existing alignment, with realignments in some areas to improve constructability and maintenance accessibility and to reduce public impacts. The final design and construction ultimately included 14,870 linear feet of 12-in. to 36-in. replacement interceptor. This paper will discuss this critical project and the various challenges faced throughout design and construction. The project included several challenges. Though not uncommon among similar projects, the project involves bored highway, major roadway, and railroad crossings, multiple creek crossings, coordination with various utilities, and generally narrow construction corridors in several locations. Challenges more unique to this project include construction through land formerly part of a battery recycling plant on which soil contamination has been identified, construction through multiple neighborhood open space areas, and coordination with multiple developers which owned undeveloped land through which the alignment crosses. The coordination with developers resulted in multiple alignment changes late in design due to the developers’ requests during easement acquisition negotiations to better facilitate upcoming developments. Due to the timeline required to obtain easements from 20 private properties, the project was split into two construction packages. Phase 4A, including construction of 9,010 linear feet of 15-in. to 36-in. pipeline, bid in February 2023 and was awarded for a construction contract amount of approximately $8.65 million. Phase 4B, including construction of 5,860 linear feet of 12-in. to 15-in. pipeline, bid in December 2023 and was awarded for a construction contract amount of approximately $4.81 million. Both phases were bid with a base of PVC pipe and lined concrete manholes, with fiberglass pipe for sections of the interceptor 18 in. and larger and polymer concrete manholes as bid alternates. The City elected to incorporate the bid alternates into the construction. The same contractor was awarded both Phase 4A and Phase 4B, and both phases are currently under construction.

Delaware DOT (DelDOT) completed their first large scale geopolymer mortar pipe rehabilitation project in February 2022. The geopolymer liner design assumed that the existing pipes were fully deteriorated and utilized the distributed beam over partial ring design method (distributed beam for short) requiring an unreinforced geopolymer mortar liner ranging from 2.4 to 3.2 in. thick on arch structures up to ~17′ wide. This created a structurally independent, corrosion-resistant, new pipe inside the old pipe structure. This paper discusses the trenchless options considered, why DelDOT selected geopolymer mortar, what is a geopolymer, liner design methodology, H&H hydraulic analysis, and construction including internal/external bypass, cold weather construction QAQC, and lessons learned. It provides perspectives from the owner, design consultant, contractor, and material manufacturer.

Owned and managed by the Regional Municipality of York, the Aurora Magnetic-Flow-Meter Bypass (AMB) stands as a subterranean, permanent sanitary bypass sewer situated at the southeastern intersection of Bloomington Road and Yonge Street within the confines of the Town of Richmond Hill. This vital infrastructure facilitates the essential upkeep and maintenance of the Magmeter, as and when needed. Recent assessments of the AMB have revealed a state of deterioration that demands urgent intervention to avert potential failure. In response, a comprehensive rehabilitation plan for the AMB has been conceptualized by Jacobs. This comprehensive plan encompasses the structural lining of a 43-m section of a sanitary sewer with a diameter of 1,050 mm, in addition to the rehabilitation of nine distinctively configured chambers. These chambers connected with the AMB include a pentagonal chamber and an L-shaped chamber. The latter is composed of three individual chambers seamlessly interconnected, yet distinctly separated by flow control components, such as sluice gates and stop logs. The intricate nature of this project is compounded by the presence of compact maintenance openings and the inclusion of a drop structure. The distinctive design of these chambers presented a formidable challenge during both the design and construction phases. Each chamber necessitated a tailor-made solution to address its unique characteristics and requirements. Of particular note is the fact that the existing flow control elements had ceased to perform their intended functions, thereby elevating the project’s complexity. A notable facet of the rehabilitation strategy was its conceptualization to be executed without resorting to the establishment of an above-ground temporary bypass system.

Cured-in-place pipe (CIPP) lining is a widely adopted method for infrastructure renewal, offering advantages, such as rapid installation and cost-effectiveness. However, concerns regarding the environmental impacts of volatile organic compound (VOC) emissions during the installation process have raised concerns over the CIPP method. The literature review conducted with this research indicated the need for stringent monitoring and management practices to mitigate adverse effects, emphasizing the importance of comprehensive evaluation protocols. This paper presents initial results from a case study focusing on VOC emissions, specifically investigating non-styrene polyester resins and water curing. The methodology involved air sampling using various equipments, including photoionization detectors (PID), summa canisters, passive worker sampler sorbent tubes, and method 18 cartridges, to capture emissions from CIPP activities. The preliminary findings indicate that non-styrene polyester resins do not exceed exposure limits set out by OSHA and the EPA. Future phases of this project will explore different resins and curing methods, with findings to be published in subsequent papers.

Use of non-circular geometry pipe enabled the Dallas Water Utilities (DWU) to overcome the challenges and constraints associated with creating a new larger capacity bypass pipeline through the City of Dallas Glendale Park (Park). In response to a pipe failure in Park, DWU was confronted with having to construct an approximately 2,800 linear foot (LF) bypass alignment to its 54-in. diameter Five Mile Creek Interceptor sewer (Interceptor). Future capacity needs equated to a 72-in. diameter pipeline at the same slope. A traditional circular pipe design approach could not be applied as approximately 41% of the chosen alignment path for a 72-in. diameter pipe would provide less than 1 ft of cover and in one location, the pipe would be above grade. Subsequent analysis of potentially splitting the flow into two smaller parallel circular pipes was not able to identify a combination of parallel configurations that would meet the flow capacity requirements. With this project as a case study, this presentation will examine the novel sewer design and construction of direct-bury non-circular pipe geometries. Utility owners will learn key factors to consider when selecting non-circular pipe geometries, including the benefits, challenges, and limitations. The presenters will also discuss the production aspects and construction handling and quality control methods used for the first direct-bury application of US manufactured non-circular glass fiber reinforced polymer (GFRP) pipe and bifurcation wyes in new wastewater pipeline construction in Texas.

Public utility owners have a responsibility to ensure that buried utilities are properly maintained so as to extend the useful life of that utility. The degree of difficulty to care for the asset grows when the asset needing care is buried deeper than all others. Accessing deep lines puts surrounding utilities at risk. Tightened rights-of-way, and an increased population of buried utilities, can create significant impediments just to get to the underground worksite. Owners must be clear in the pre-bid phase to ensure that any and all methodologies to be used do no damage to adjacent structures/installations. On the other hand, contractors that would bid on deep utility work distinguish themselves through efficient means and methods. If an owner was to exclude certain technologies, the bidding contractors must be aware of those restrictions, and have an alternative access plan to be successful. Meanwhile, the underground construction world continues has seen marked increases in fatalities, primarily due to inadequate protective system application. The owner must protect the asset, and the contractor must protect the employee. Preservation of existing utilities is important, but cannot outweigh the safety of workers accessing those deep utilities.

Metro Vancouver is responsible for the conveyance and treatment of wastewater for the Greater Vancouver area which is home to approximately 2.5 million residents. Sections of the wastewater conveyance system are reaching the end of their design life or have experienced accelerated degradation due to corrosive conditions. One such sewer is the New Westminster Interceptor (NWI) Columbia Section, which is a 1.6 km concrete sewer ranging from 1,067- to 1,524-mm diameter. Metro Vancouver has performed temporary repairs along the Columbia Section over the past 20 years. Jacobs was retained as the design engineer to develop a long-term solution and provided construction engineering services for trenchless rehabilitation of the NWI Columbia Section by sliplining the existing concrete pipe with new fiber-reinforced polymer (FRP) pipe. This paper provides an overview of the project and presents a case study of the challenges as they relate to the Owner, Engineer, and various stakeholders.

In Burnaby, BC, there was a need to refurbish over 200 m of a DN 150 refinery wastewater main. Installing a new carbon steel pipe was not practical because of the expected high corrosion levels; HDPE or PVC materials were not considered suitable alternatives due to potential issues related to thermal expansion. Flexible Fabric Reinforced Pipe (FFRP) systems present significant advantages as they operate independently from the host pipe and can navigate multiple bends while accommodating high-pressure ratings. Simultaneously, they offer a high level of stability thanks to a reinforcement layer made of aramid. These attributes, combined with a small construction footprint and short rehabilitation times, made FFRP the ideal technology for this rehabilitation project. This paper will outline the technical characteristics of the FFRP and describe the installation process along with its associated requirements. The paper then concludes with a report on the rehabilitation of a refinery wastewater main.

The Western Bays of Long Island New York were once a productive fishing area. Much of the excess nitrogen in the Bay is attributed to wastewater treatment facilities that discharge directly into the Bays. In an effort to improve the marsh’s ecosystem, the New York State Department of Environmental Conservation (NYSDEC) and Nassau County Department of Public Works entered into a unique partnership to implement a Design–Build project that would remove up to 90% of the nitrogen loading in an already compromised area. Up to 75 million gallons per day (MGD) of wet and dry weather flow needed to be diverted from the Bay Park Sewage Treatment Plant (BPSTP) to the Cedar Creek Water Pollution Control Plant (CCWPCP) to be discharged via the existing ocean outfall at that site. This Bay Park Conveyance Project would require the construction of a 12.4-mi long force main from the South Shore Water Reclamation Facility to the existing Cedar Creek Water Pollution Control Plant (WPCP) outfall. The plan was to utilize 7.3 mi of an existing abandoned 72″ steel lock-bar pipe. This aqueduct would require full rehabilitation of the existing pipeline. The preliminary design for the 72″ pipeline was to rehabilitate the pipe by sliplining with Fiberglass Reinforced Polymer Mortar (FRPM) pipe or Steel pipe. Carbon Fiber Reinforced Polymer (CFRP) lining would be considered, but on very limited sections of pipeline due to installation cost and efficiency. The design criteria developed provided the basis for the system design, including appropriate standards, Mandatory Requirement for performance and/or materials, and product specifications. This paper will review this project in detail from cradle to grave covering aspects from the background with initial design parameters and to the process of final design and construction completion. Included in this presentation will also be lessons learned throughout the design and construction process.

The Lakewood Interceptor Tunnel in Lakewood, Ohio (pop. >50,000), was originally constructed from 1918 to 1945 by tunnelling methods largely through rock strata at depths varying from 20 ft to 94 ft. It carries over 77% of the wastewater flow for the city of Lakewood (city) and is over 20,000 ft long. The egg-shaped pipe is 56.5-in. high by 42.5-in. wide and was predominately constructed with clay tile segmental block pipe with localized areas constructed with conventional brick. It is being rehabilitated using segmental Glass Reinforced Plastic (GRP) composite pipe sliplined with a fully grouted annulus. The structural design of the liner utilized the ASCE MOP 145 (2021)—Design of Close-Fit Liners for The Rehabilitation of Gravity Pipe. In 2021, the city noticed an increase in the frequency of localized collapses of the tunnel roof. This initiated a condition assessment (CA) program of the entire interceptor to evaluate options to rehabilitate the tunnel to eliminate further collapses and provide the entire interceptor with a new design life. The CA program utilized a multi-sensor platform equipped with high-definition CCTV, time-of-flight LIDAR profiling above the flowline, and SONAR profiling below the flowline to quantify condition both visually and dimensionally. The inspections revealed severe mortar loss in brick sections, movement and instability of the sewer walls, and localized loss of the crown of the tunnel in many areas. The rock strata prevented migration of the collapse to the surface, but overall, the assessment indicated that large sections of the tunnel were in a state of incipient failure that warranted widespread structural rehabilitation. The depth of the tunnel, its proximity to residences and apartment complexes, and the large flow volume created many challenges for rehabilitation. Based on a review of a wide array of rehabilitation techniques, the use of segmental GRP composites was selected due to its ability to be matched to a wide array of subtle cross section changes, overall constructability given the unique site conditions, ability to be installed without bypassing sewer flows, and life cycle cost considerations. Type testing criteria were developed to facilitate design of the lining based on 100-year life objectives and the construction phase includes a verification process to confirm that all core design objectives can be confirmed as being met in the construction phase. The project was bid in January 2023 and awarded for $25.4 million. This paper provides a detailed overview of the assessment and design process and an update on construction progress and challenges.

The Red River which serves as the border between Minnesota and North Dakota has a history of flooding, causing billion dollars in damage. The US Army Corps of Engineers (USACE), along with other federal/state/local resources, embarked on a fast-tracked project to mitigate future flood damage—“Fargo Moorhead Area Diversion Project.” The critical purpose of this project is re-routing flow around the Fargo/Moorhead area via the construction of 30-mi channel that ranges from 200- to 300-ft wide. Before the channel was to be constructed, there were 107 utilities identified that conflicted with the channel. The majority of these utilities (gas, communication, electric, and water) were re-routed under the proposed diversion channel alignment via horizontal directional drilling. Combining some utilities and adding a few new ones—it was determined that 36 drills were required. This paper is a review of the process and installation of the relocated utilities.

Trenchless technologies are an innovative, cost-effective method to restore our aging infrastructure. Each trenchless method has a different technical envelope and tolerates differing site constraints to be installed properly. These site constraints include pipe bends, topography, valves, and other connections to the pipeline. Given these features, each trenchless technology will require varying levels of civil support to complete the project. Despite the innovation that trenchless solutions bring to pipeline projects, there is still a level of risk from what can be discovered in the field based on the accuracy of as-built information, current GIS data, and other historical records. Many times, these “differing site conditions” can be mitigated using the chosen trenchless technology’s adaptability for field changes, but sometimes, there is a more drastic change needed. In these cases, pivoting to a different, yet innovative and cost-effective trenchless solution, is a better fit for the project goals.

The Tarrant Regional Water District (TRWD) and the City of Dallas Water Utilities (DWU) are in process of developing a 350 MGD water transmission system known as the Integrated Pipeline Project (IPL). Considering various project conditions, a set of particularly risky tunnels was combined into the PL19TUN project—a component project of the overall IPL. To mitigate against these risks, the Owner’s Project Team (OPT) developed a unique procurement strategy consisting of prequalification, collaborative workshops, and a competitive sealed proposal (CSP) process which resulted in a refined project scope and the selection by best value ranking of a qualified contractor to construct the project. This paper will discuss project conditions, constructability reviews, the collaborative CSP procurement, and risk management for this interesting project.

Are you afraid of floating or collapsing the carrier pipe during tunnel grouting? What about tunnel and pipe failure resulting in a road or railroad settling, not to mention water, or even worse wastewater, shooting out of the ground onto a road or into a river? These are just some of the dangers of improper grouting of tunnels, proving that tunnel grouting can be just as risky as tunnel excavation itself. If too much grout at too high of pressure is introduced while grouting the annular space between the tunnel liner and carrier pipe, the grout can exceed the allowable strength of the carrier pipe and cause it to collapse. If too little grout is introduced or at too little pressure, the grout will not completely fill the annular space to protect the tunnel after the tunnel liner corrodes. Once the grout begins to harden, chiseling out the grout and carrier pipe may be the only solution, so it is important to get tunnel grouting right the first try. The design team needs to develop specifications to set the Contractor up for success by specifying acceptable grout mixes, densities, pressures, and number of lifts. The specifications should also include methods for preventing the pipe from deflecting or floating and require an overall tunnel grouting work plan. Large diameter pipes likely require multiple lifts and blocking, hold-down jacks, and/or filling the pipe with water to prevent floatation. Contractors need to select and test mix designs for grout, perform calculations for the theoretical volume of grout, and develop a plan for injecting the grout to fill all voids in the annulus. For contact grouting, the Contractor must plan for the installation of grout ports in the primary tunnel liner when the grout is to be injected depending on the type of primary tunnel liner. For backfill grouting, grout may need to be injected at multiple locations along the tunnel to fill all voids and evenly distribute the grout. Planning the backfill grouting operation is crucial, because removing a bad grout job can damage the primary tunnel liner and carrier pipe as well as cost significant time and money. Based on recent experience with water and sewer line projects across Texas, we have developed some best practices when performing tunnel grouting. This paper will discuss those best practices, specification language, example calculations, and tips during submittal review to avoid the costly consequences of improper grouting which will benefit Owners, Engineers, and Contractors.

Toronto Water’s Ashbridges Bay Treatment Plant Outfall (ABTPO) project will be the largest wastewater treatment plant effluent outfall in Canada. This paper discusses contract administration challenges encountered throughout the ABTPO construction phase. Project-specific construction management approaches, issues, and lessons learned are explored, including quality, schedule, risk and claims management, as well as the application of a Dispute Review Board (DRB). Owner and Consultant perspectives discuss how claims were successfully resolved for ABTPO. Contract administration insights for major disputes are presented, including a stuck bucket during shaft secant pile installation, three separate Differing Site Conditions (DSC) events involving unexpected adverse ground conditions with water inflows at greater than 400 lpm during Tunnel Boring Machine (TBM) tunnelling, and off-shore work claims involving riser installation DSC and marine weather conditions (e.g., adverse wind and waves). Lessons learned from successfully resolving these claims are also presented.

The Saunderson PRV project is a multi-year project to upgrade water supply for the Lower Townsite (LTS) neighbourhood in Fort McMurray, Alberta. The project includes the construction of a new PRV chamber, extension of the existing primary high pressure water supply line, and the installation of a new supply line from the existing LTS Reservoir in the Abasand Heights neighborhood to the new PRV chamber by horizontal directional drilling (HDD). The focus of this paper is on the design and installation of the 445 m long and 914 mm diameter HDPE DR9 directionally drilled supply line crossing of Highway 63 from the LTS to the Abasand Heights plateau, a topographic elevation difference of approximately 65 m between entry and exit. Project complexities resulting from the elevation difference between drill entry and exit included risk of flush-backs during reaming passes, overbreak pipe support for pullback, buoyancy control requirements during pullback, and annular space grouting post-installation.

The Project involved rehabilitating three 72-in. tunnels, with unique condition and accessibility challenges, under a compressed design and construction schedule of less than 1 year with three 10-day shutdowns to work in the tunnels. The project team, comprised of Michels Trenchless Inc. and Stantec, implemented innovative solutions to address these challenges. Geopolymer lining and fiberglass reinforced pipe (FRP) were selected to restore the tunnels’ integrity and extend their lifespan by 75+ years. The team installed approximately 3,600 ft of the geopolymer liner in the Lilac and Red Mountain Tunnels during two 10-day shutdowns. For the more deteriorated Oat Hill Tunnel, 63-in. FRP sliplining was used. The project team set a new record for the largest diameter and fastest installation of FRP sliplining, completing 3,600 linear feet around the clock in just 3 days. The project achieved timeline milestones, completing the rehabilitation within the three planned shutdowns of 10 days each.

Over a century ago, seven 16-in. wrought iron watermains known as the Kearny Multiples (Multiples) were installed across the Passaic River transferring water from Passaic Valley Water Commission’s (PVWC) Little Falls Water Treatment Plant to PVWC’s North Arlington system and the Commission’s wholesale customers, Lyndhurst, and Harrison. The water mains, which sat atop the Passaic River riverbed, were subject to the river’s tide levels and currents. Throughout the years, failures began to occur and by 2023 only two active crossings remained which significantly reduced the hydraulic capacity to the PVWC customers east of the river. In May 2023, PVWC engaged with J. Fletcher Creamer & Son, Inc., and Rädlinger Primus Line, Inc., to structurally rehabilitate the remaining two active pipe crossings and rehabilitate two decommissioned pipe crossings. This presentation will cover the overall history of the project, the unique liner solution and construction methods, and the coordination that took place both within PVWC and with our neighboring utilities.

The Diablo Water District (District) is located in the eastern portion of the San Francisco Bay Area in Northern California. This part of Contra Costa County has experienced several recent periods of rapid growth; however, when the United States economy began to enter a recession in 2008, one of the larger developments within the District’s sphere of influence and future service area, the Delta Coves development, decided to postpone construction of its planned 494 single family houses after spending over 2 years performing site grading and installation of underground utilities. This resulted in over 50,000 ft (15,240 m) of installed 8-in. (200 mm) to 16-in. (400 mm) PVC water mains, plus related distribution infrastructure, being abandoned in-place without any prior inspection or acceptance by the District. In 2014, the developer became interested in completing the development. This paper describes the process and methods used by the District to understand, repair, and eventually assume ownership of these assets, including various methods of inspection, analysis of PVC pipe, and the use of ice pigging prior to final disinfection and testing for acceptance.

In January 2023, MWCo detected a leak on a 48-in. PCCP within a 4.38-mi long transmission main that conveys potable water from MWCo’s 60 MGD CJO WTP to their distribution system. The leak was detected within an existing easement adjacent to a major highway in the Township of Edison, NJ. In order to assess the cause and extent of this leak, MWCo shutdown the pipeline for an emergency repair and used this as an opportunity to perform a more detailed condition assessment of a portion of this transmission main. This opportunistic inspection consisted of a visual, sounding, and electromagnetic inspection of approximately 5,500 LF of the pipeline to evaluate distress and recommend pipes for repair. Based on these results and recommendations, MWCo elected to repair approximately 1,655 LF of the pipeline using CFRP. This paper presents the importance of the efficient application of specialty inspection, analysis, design of repairs, and implementation of these repairs. This proactive, comprehensive condition assessment and repair approach prevented possible catastrophic failure and should prevent future leaks and maintain the reliability of this transmission main for years to come.

A large municipality in Texas tackled the challenge of rehabilitating corroded underground potable water infrastructure at risk of failure. The 24-in. cast iron pipes had several areas where they had shifted from alignment. The project involved innovative solutions to address these complexities, including applying the spray-in-place pipe (SIPP) method using 100% solids, and high build epoxy. This technology, widely used in Europe but relatively new in the United States, involves high-pressure spraying of durable materials to coat the interior of pipes, even those with multiple bends. The owner conducted a thorough technology feasibility evaluation, selecting an experienced national contractor for the epoxy application. This paper emphasizes the challenges faced and presents the successful use of SIPP for rehabilitation, providing a valuable case study for utilities dealing with similar issues.

This paper focuses on the rehabilitation of steel stormwater discharge pipelines from a levee sump pump station. Irving Flood Control District Section III (IFCD-3) maintains 5.5 mi of waterways in Irving, Texas. The station’s six welded steel pipelines, constructed in 1979, exhibit significant corrosion, requiring repair or replacement. IFCD-3 contracted with Halff to develop a rehabilitation plan, exploring options like conventional replacement or internal rehabilitation using carbon fiber reinforced polymer (CFRP). The recommendation to apply internal CFRP rehabilitation considered factors, such as shutdown needs, internal pressure capacity, corrosion rate, and costs. Since CFRP involves manual application, the pipelines will be rehabilitated in two segments with access points for man-entry and ventilation. Competitive sealed bidding ensued with two contractors submitting bids. The recommended solution aims to maintain the integrity of the pipelines, supporting IFCD-3 in its regional flood protection efforts.

The City of Wichita’s Botanica Gardens faces a critical infrastructure challenge involving a 48-in. diameter pipe that extends 700 ft across its property. The aging pipe now requires significant rehabilitation or replacement to ensure structural integrity and sanitary service. While about 65% of the pipe was previously addressed through a combination of complete cast iron (CI) pipe replacement and slip-lining, the remaining 35% posed complex challenges. Two sections could not be slip-lined due to layout defects, and CI replacement would entail major service disruptions and expenses. To assess the suitability of Manufactured In-place Composite Pipe (MICP) technology, SippTech, LLC, conducted a thorough series of evaluations. These included creating an above-ground replica model to mimic the projects pipe deflections, evaluating the operational challenges faced by applicator robots navigating deflections, and ensuring compliance with Class IV structural pipe standards defined by AWWA. With most traditional rehabilitation methods falling short, the choice came down to complete CI pipe replacement or adopting MICP technology. To gain municipal approval for the project, a 224-ft MICP pipe installation within a replica model at the SippTech facility becomes a crucial step. This demonstration will help secure the necessary support from city authorities.