Project of the Year – Rehabilitation
39-in. Water Transmission Main Rehabilitation Using Swagelining
By Sharon M. Bueno Oct 18, 2014
The Gulf Coast Water Authority (GCWA) and the City of League City, Texas, were faced with the need to rehabilitate 6,800 ft of a 39-in. PCCP water transmission main along a relatively narrow section of roadway.
The decision to complete the rehabilitation of this main — which provides an interconnect between the City of Houston and Galveston County — using Swagelining allowed planners to keep the same hydraulic model/capacity, as well as giving the pipe a full structural overhaul that extended the life expectancy to at least 100 years.
According to project officials, the Calder Road project also resulted in a few firsts in North America: 1) it is the largest diameter, high-pressure, full structural pressure pipeline rehabilitation project completed and 2) no other trenchless method has ever completed a project requiring a fully structural solution at an operating pressure of 125 psi.
Pretty impressive results and that is why this project was selected the 2014 Trenchless Technology Project of the Year for Rehabilitation.
“The project certainly represents the largest diameter pipe rehabilitated in North America utilizing the Swagelining technology,” says Tom Hayes, vice president of Murphy Pipeline Contractors (MPC), the contractor for this project and one of the leading contractors in North America that specializes in the Swagelining process. MPC owns the North American licensing rights from U.K.-based Swagelining Ltd.
Swagelining technology uses a high-density polyethylene (HDPE) liner with an outside diameter larger than the inside diameter of the existing pipe to be renewed. The liner is pulled through a single reduction die before entering the host pipe, temporarily reducing the liner’s diameter and allowing insertion. Once insertion is completed, the liner reverts to its original size, expanding until it is stopped by the inside diameter of the pipe and giving it a “tight fit lining” rehabilitation. Due to the tight fit, thin-walled HDPE liners and semi-structural HDPE pipe can be installed.
In the case of the 39-in. PCCP, the existing pipe required a fully structural rehabilitation. The use of Swagelining allowed MPC to install a fully structural HDPE PE4710 DR 17 pipe with a working pressure rating of 125 psi.
What Was NeededGulf Coast Water Authority (GCWA) provides water for industry, agriculture and municipalities in Brazoria, Fort Bend, and Galveston counties. This includes more than 185,000 customers in Galveston County alone. Located southeast of Houston, the City of League City is a city on the upswing, with its population nearly doubling since 2000 to more than 83,500, according 2010 census figures.
The 39-in. PCCP water transmission main on Calder Road — owned by GCWA and operated by the City of League City — feeds a water plant supplying water to the western quadrant of the City. The transmission main, originally constructed in 1971 to supply surface water to the City of Galveston, interconnects between GCWA’s Thomas S. Mackey Water Treatment Plant and the City of Houston’s Southeast Water Treatment Plant. The 39-in. main had been experiencing a variety of issues in recent years, including breaks and leaking joints and was in serious need of rehabilitation.
Given the age of the 39-in. PCCP and the operating history of this water transmission main, GCWA and the City knew they needed a fully structural solution to the problem. The main’s capacity also needed to remain the same or be increased to allow for future expanded use.
“Water is becoming scarce [in this area of the country]. The drought in 2011 really opened a lot of people’s eyes,” says James Vanderwater, district engineer with Gulf Coast Water Authority. “We have found that the Brazos River may not be as reliable as we thought it was for a raw water source. This water line provides a critical interconnect between the City of Houston and Galveston County and we believe it was important to maintain as much capacity as possible. The City of League City told us what their future plans were for the water line and there wouldn’t be much left for an interconnect if we sliplined it.”
He further notes that League City needed the capacity at the Calder Road water plant to remain, at minimum, at 25 mgd and any of the proposed options would have to meet that requirement. However, using Swagelining, flow capacity is closer to 38 mgd, leaving 12 to 13 mgd for future added capacity needs, Vanderwater says.
Sounds simple enough but other issues had to be factored into whatever means GCWA and the City elected to use for the project, which also included replacement of twin intake pipes off the 39-in. main, increasing their size from 10 in. to 24 in. in diameter. A bigger concern had nothing to do with the pipes but the location of the work.
In addition to the rehab work to the main, the 6,800-ft section on Calder Road where the work would take place was scheduled for surface improvements and widening; the rehabilitation project needed to be done before that work began. “It was such a small footprint to work in. There was no space to work. [Calder Road] is a two-lane side road that is a feeder road for the community. The road was 22 ft wide and we had an easement area where the pipe laid that was 10 ft wide,” MPC president Andy Mayer explains. “We were only permitted to shut down half of the road.”
The tight space made it challenging to where and how MPC would stage the pipe, weld the pipe, where to dig the insertion pits and where to pull the pipe into place to minimize the disruption to the community.
During the design phase, several trenchless methods were considered and the final bids came down to sliplining vs. a compressive tight-fit HDPE liner installed using Swagelining — both methods that would have solved the rehabilitation issue. But Swagelining proved to be the method that GCWA believed would provide the best overall solution.
“The design criteria required a fully structural rehabilitation solution capable of 125 psi operating pressure,” says Mayer, adding that “Installing the tight compressive fit HDPE liner by Swagelining increased the final ID of the pipe 4.45 in. over the base bid with sliplining.”
MPC would install 39.37-in. DR 17 4710 HDPE pipe (supplied by ISCO) using the Swagelining process. The 2.32-in. wall thickness pipe was pulled through a single reduction die and installed in four installations, ranging from 1,250 to 2,100 ft in length. Each installation also required the liner to be pulled through multiple bends. The long pull lengths aided crews as they allowed for long-fused sections of the HDPE to be installed and eliminating the potential for future leaks. For each pull, 50-ft lengths of pipe were butt-fused using a rolling McElroy 1648 machine. MPC used a HammerHead HB175 static pulling rig for two of the installations and a TT Technologies Grundoburst 1250G pulling rig for the other two. A HammerHead winch was used to pull the pigs and scraping devices to clean the pipe prior to the rehab work.
Hayes notes that the use of the DR 17 HDPE represents a pipe that is not dependent on the host pipe for any structural enhancement. The same pipe was used in making all the end connections installed via direct bury. Any other trenchless process would have needed to transition to either PVC or ductile iron pipe to make the connections and require special end connectors to seal the annulus, he explains.
“The end connections were installed by fusing the lined HDPE pipe directly to the 1,000-mm DR 17 HDPE using a manufactured flange adapter,” Hayes says. “This completely eliminates the need for special end connectors, as well as eliminating mechanical joints that are sources for potential leaks.”
The north end of the project was extended by about 300 ft to an existing 36-in. diameter butterfly valve; the south end required a flanged reducer, butterfly valve and blow off. Thrust restraints were needed at both ends of the project to protect the existing pipe from potentially blowing out from the pressure during construction. During construction, the existing water plant was kept connected to the City of Houston water supply or the GCWA water supply through a 12-in. diameter bypass set up aboveground.
The MPC crews worked closely with the community to minimize the disruption during construction, keeping residents informed each step of the way. “Most people when they are kept informed are understanding,” Mayer says, noting the City “did a great job prior to the project of informing its residents.”
Swagelining FactorSwagelining is an emerging trenchless technology in North America, already having had success in Europe. The technology lends itself to medium- to large-diameter pressurized mains, both water and sewer force mains.
In an article for Trenchless Technology (November 2012), MPC vice president and educational director Todd Grafenauer wrote about Swagelining and its potential for the trenchless market: Just as the industry has seen various trenchless technologies come to the forefront to rehab smaller diameter pipelines, Swagelining technology is emerging as a leading candidate to renew and replace mid- to large-diameter water transmission and sewer force mains. Developed more than 30 years ago by British Gas and United Utilities (then known as North West Water) to address the problem of failing pipeline systems that were buried and entangled with other utilities throughout urban and rural areas, the principle of Swagelining was developed. It is considered by the pipeline industry as the benchmark in polymer lining technology for its ability to deliver cost-effective lining solutions in every environment. With an extensive list of work across the globe, the technology has been proven in many extreme projects spanning three decades onshore and subsea. Projects have been completed for water, sewer force main, mining, hydrocarbons, chemicals, bulk products and gas distribution.
“The value that client is receiving with Swagelining over [in this case] sliplining is that the client is maximizing their final ID and that is where Swagelining is starting to see a great value to some of these pipeline projects,” Grafenauer says. “The owner has the ability specify a thin walled liner, a semi-structural liner or in this instance a fully structural solution.”
The Calder Road project is an important project for the Swagelining technology, showing just what it can do for municipalities. “We feel we found a solution for aging large diameter infrastructure and each time we successfully deliver a project is testament to the technology and the product we are using,” Mayer says.
Sharon M. Bueno is managing editor for Trenchless Technology.
Project of the Year – New Installation
New Jersey-New York Expansion Project
By Sharon M. Bueno Oct 18, 2014
Everything about the New Jersey-New York Expansion Project is massive and complex. From the initial design to the re-design to the amount of equipment assembled to the actual pipeline installation, this project had the makings of an once-in-a-lifetime horizontal directional drilling (HDD) project.
And for the owner, engineers and contractor, it sure was.
The project is an expansion of Spectra Energy’s Texas Eastern Transmission and Algonguin Gas Transmission pipeline systems to deliver new, critically needed natural gas supplies to the New Jersey and New York areas, including Manhattan — the first high-pressure natural gas pipeline in New York City in four decades. The project utilized HDD on 40 percent of the installation (or eight of the 20 miles), allowing construction beneath waterways, highways and streets without impeding traffic and provided an additional layer of safety, given the depth of the pipe.
A critical portion of the project involved the completion of nine incredible HDD crossings that were in diameters of 30 in. (six crossings) and 42 in. (three crossings) and ranged in length from 1,707 to 8,100 ft. Some crossings averaged one to two months to complete while another (Kill Van Kull) required eight months to finish. Use of the pilot hole intersect method was required on seven of the crossings due to their enormous length and locations. The Direct Pipe method was also used to install large diameter casing.
The project involved the assembling of a massive amount of equipment including the use of ten 1.2 million-lb drilling rigs (at times used simultaneously on multiple crossings), more than 30 drill motors and 20 steering tools (INROCK), with more than 55,000 ft of drill pipe deployed. Ground conditions consisted of some serious rock, including several layers of bedrock in some of the crossings, as well as diabase, sandstone and siltstone.
From conception to completion, the project took more than five years before gas flowed and involved the sweat and efforts of everyone involved. The project is compelling, complicated and, most importantly, complete. And it has been selected as the 2014 Trenchless Technology Project of the Year for New Installation.
“[This] project was critically needed infrastructure to address the energy demand, growth, deliver cost-savings and economic value and to address the environmental imperatives of that region,” says Tina Faraca, vice president of U.S. engineering and construction for Spectra Energy. “Our project provided enough safe, reliable energy to heat the equivalent of more than an additional 2 million homes a day. It effectively doubled the amount of natural gas flowing into Manhattan.”
“This project is a significant achievement in the history of Michels and the HDD industry,” says Tim McGuire, vice president of directional crossings at Michels Corp., HDD contractor for the project. “It was extremely challenging trying to figure out how to drill many of the crossings the likes of which have never been attempted before anywhere in the industry when you consider the combined lengths, diameter, conditions and tolerances that had to be traversed let alone the backdrop for each of the worksites was among some of the most densely populated real estate in the world.”
Ted Foltz has been involved in the HDD industry since 1992 and with Michels since 2003. He served as the onsite project manager and he described the project this way: “I’ve been involved with projects with more drills on it and done in a shorter time. We did one that had 33 drills on it and were done in five months. But this one had rock and some of the [bores] were very long and most had multiple horizontal curves. Some had four or five curves. This was definitely an once-in-a-lifetime project for me.”
Planning and Planning Again“You look at the project and say 20 miles, how hard can that be?” Faraca says. “But constructing the pipeline in and around New York City posed significant challenges.”
For a project of this size and magnitude, coordination and thorough planning are crucial to getting it off the ground. Hours of meetings were commonplace and backup plans and design strategies were a given. Planning for the unexpected was also needed (such as when Hurricane Sandy landed in New Jersey and New York in the middle of construction in October 2012).
Michels began working on the project two years before actual drilling would begin in July 2012. The Michels team, working with Spectra Energy and HDD engineering firm J.D. Hair, put together the feasibility assessment, constructability planning and site investigation. Purchase of advance tooling and equipment took place nearly a year ahead of construction to ensure availability of resources throughout.
The use of HDD was vital to Spectra Energy’s ability to obtain construction permits for the project; however, the technical degree of difficulty for most of the crossings would place the actual construction of these among some of the most challenging ever taken, McGuire says. All nine crossings had to be drilled in one of the most congested and densely populated urban areas of the world, with eight of them drilled through a mix of fill material and glacial till overburden, and around a vast array of utilities, then completed through sedimentary, metamorphic and igneous rock — sometimes all within the same crossing. These nine crossings would be considered monumental by any HDD industry standard, according to McGuire.
Design and logistics of the crossings were critical. McGuire describes the situation this way: “Early on, we had to find the best available HDD setup areas in proximity to the preferred pipeline alignment at the desired HDD crossing locations within extremely congested and populated areas. We needed to find sufficient space to stage our drilling equipment at both ends of the crossings. We also needed to verify that the links and geometric alignments of the proposed crossings were within the realm of HDD feasibility.”
He adds that “We also determined [early on] that many of the crossings were going to be broaching the upper limits of what had been achieved thus far in HDD construction, with one undoubtedly laid out in record territory for a 30-in. crossing in North America at just over 8,000 ft.”
Spectra Energy embarked on an extensive geotechnical study of the underground alignments and drilling conditions, which revealed a diverse range of near surface till soils containing cobbles and boulders and soft river sediments, as well as an abundance of existing utilities in the vicinity of the crossings. Several of the crossing routes required additional geotechnical study and the Hudson River crossing (30-in. ID with a length of 5,378 ft) necessitated multiple, significant realignments and studies before a path above the bedrock could be found that allowed the crossing to proceed.
The diverse nature of the overburden, including some contaminated soils and man-made debris in proximity to existing utilities and structures required a large diameter (48- to 60-in.) surface casing installation program before the crossings could begin. Michels used every combination of casing installation method it developed over the years to install the casings. For the 18th Street crossing (30-in. ID with a length of 4,861 ft), the Direct Pipe method with a Herrenknecht 48-in. tunneling machine was used to install the surface casing.
“In addition, the only available easements required many of the [crossings] to be routed and designed with several horizontal turns, often through solid rock and extremely tight tolerances to avoid missing the critical alignment corners,” McGuire says. As an example, he notes that the 18th Street crossing had to follow the actual roadway alignment as it was completed through solid bedrock with a 24-degree ‘S’ curve out to the marine landing point at the platform in the Hudson River.
And then there was Hurricane Sandy, the largest Atlantic hurricane on record that would arrive in New York City under a full moon when the tides were already 20 percent higher, resulting in a storm surge that was 4 ft higher than ever recorded on the Hudson. The storm forced crews to evacuate and secure equipment/personnel from the structure platform and several other drilling locations, halting construction. The storm’s impact interrupted work for 10 days.
Project officials also had to manage other constraints throughout, such as noise emission, which required extensive sound mitigation measures including walls, tent-type structures and specialized silenced construction equipment techniques such as a Direct Pipe casing installation and a specially built ‘silenced’ drilling rig. For the Hudson River and 18th Street crossings, a marine subcontractor was called on to support the design and construction of a 2.3 million-lb structure platform in the river to handle the drilling setup.
Spectra Energy is no stranger to employing HDD to install its pipelines but this project proved to be a new level of pipeline design and technology. “This was by far the most exciting and most complex project to date,” Faraca says. “We applaud Michels for this well-deserved acknowledgement by Trenchless Technology.”
“I credit Spectra Energy on this project. They took a bold initiative in taking on this project,” McGuire says. “We were enormously successful but only through careful planning and attention to detail and commitment to safety, the environment and the community. Michels was proud to be a part their construction team and believe the HDD work completed on this project will serve as a milestone for years to come of what can be achieved with this construction method.”
Sharon M. Bueno is managing editor for Trenchless Technology.