Channeline’s innovative multi-segmental GRP lining technology provided a robust solution for complex large-diameter sewer rehabilitation in the US.
When it comes to relining some of the world’s largest and most geometrically complex underground infrastructure, Channeline continues to raise the bar with its bespoke, fully-structural glass-reinforced plastic (GRP) liners. A project in Detroit, Michigan, highlighted Channeline’s capacity to deliver custom-designed, large-diameter, and multi-segmental liners that meet the unique challenges of trenchless rehabilitation on a monumental scale.
In 2021, Channeline supplied GRP liners for a pilot rehabilitation project on the North Interceptor – East Arm (NI-EA) in Oakland-Macomb County, Detroit. The section of sewer in question, constructed in the 1970s, measured an enormous 17.5ft (5.3m) in diameter and had suffered significant structural deterioration due to corrosion from high hydrogen sulphide levels.
To meet the challenge, Channeline delivered a custom four-piece multi-segmental liner with a 16ft (4.9m) internal diameter and a wall thickness of 3.54 inches (9cm), designed to withstand severe loading using AWWA M45 Direct Bury methodology. The solution was also tailored to accommodate a six-degree curve in the alignment; a true demonstration of Channeline’s design flexibility.
Large-diameter pipes come with equally large logistical hurdles, particularly shipping.
To overcome this, Channeline developed a tongue-and-groove jointing system. This allows complex liners to be broken down into manageable, shippable segments without compromising strength or longevity.
The Detroit project showcases this perfectly. Thanks to nested transport configurations, Channeline was able to fit 4.5 liners per shipping container, an impressive feat for structures of this scale. This drastically reduced freight costs and simplified delivery for a liner system that was otherwise too large for conventional transport.
“Onsite, the multi-segmented units were quickly and securely bonded using Channeline’s proprietary structural adhesive, achieving the same integrity and 150-year service life as their monolithic counterparts,” Channeline Chief Operational Officer Tim Webb told Trenchless Australasia.
One of the key breakthroughs made possible by Channeline’s tongue-and-groove design is the ability to install structural liners through existing manholes or access shafts, entirely trenchlessly. This was critical in Detroit, where the construction footprint had to be kept under 150ft (45.7m).
Contractor Marra Services worked closely with Channeline’s design team to fine-tune the liner for ease of handling and placement, including solving the project’s most complex challenge: a tapered curve transition midline.
To move the liner 1500ft (457.2m) into place, engineering firm Kelley Engineering developed a self-propelled robotic pipe carrier capable of aligning and sealing each joint with precision. With this system in place, the team achieved an average installation rate of four liners per day.
A durable future with GRP
As well as the customisable qualities of Channeline GRP, the material also offers excellent durability thanks to its resistance to extreme temperatures, ultraviolet radiation, and chemical exposure.
On the Detroit project, a spray-in-place liner installed in 2017 had already shown signs of deterioration under harsh chemical conditions by 2021. This prompted a full replacement of an additional 110ft (33.5m) using Channeline.
“As far as we are aware, this is the largest fibreglass sewer liner ever built to date. This was a huge challenge for Channeline, but I was confident in my team and the Channeline product to get this done and exceed expectations,” Webb said.
Thanks to Channeline’s custom design and manufacture processes, large-diameters, non-circular profiles and complex curves are no problem for these liners.
For more information, visit channeline.com
This article was featured in the August edition of Trenchless Australasia.
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