No-Dig North 2023 Canadian project of the Year Rehabilitation: York-Peel Feedermain Emergency Repair
The Regional Municipality of York, situated between Toronto and Lake Simcoe in Southern Ontario, is no stranger to incorporating trenchless technologies into its scheduled work and emergency repairs.
York Region has found that trenchless technology’s benefits are many including managing environmental constraints, minimizing traffic flow impacts, reducing surface disruptions and the maneuverability around existing underground utilities.
So, it should come as no surprise that when it was found that the York-Peel Feedermain, a critical feedermain for the Region was leaking in two locations and needed immediate attention, that trenchless was the go-to solution.
The innovation and speed of the repair, as well as the collaboration between owner, engineers and contractors were among the reasons the York-Peel Feedermain Emergency Repair earned honors as the No-Dig North 2023 Canadian Project of the Year Rehabilitation.
York Region is a two-tier municipality with a population of more than 1.2 million residents and 55,600 businesses. York Region provides bulk water to its nine local cities and towns and collects, moves, treats and discharges wastewater from local systems. York Region owns and operates 300 km of trunk sewers and pressurized systems, including sewage forcemains and watermains across 1,700 sq km.
The Region has a long-standing Linear Infrastructure Asset Management program, which proactively identifies and manages risks for all watermains, sanitary and storm sewers. “The purpose of the program is to monitor and evaluate York Region’s linear assets’ condition and performance throughout their life cycle,” Tom Millis, senior project manager, Capital Planning and Delivery for Public Works at York Region. “This identifies system deficiencies and determines timely, cost-effective maintenance and rehabilitation measures.”
Based on the importance of the feedermain, the Region inspects it every two years. It was during a routine leak detection inspection via SmartBall technology in September 2022, that the Region first detected a leak along the main. Upon further investigation, the Region discovered that portions of the feedermain were leaking at two locations along the Humber and East Humber rivers.
The York-Peel Feedermain is a 25-km long, 1,800-mm, prestressed concrete cylinder pipe (PCCP) transmission main installed in 2005 to convey water from Peel Region to York Region. It provides approximately 30 per cent of the drinking water for the York Region water system, so the repair solution could not be put off.
Both leaks were located in the City of Vaughan and within the Toronto Region Conservation Authority (TRCA) regulated area. The first leak was detected at the Humber River near the intersection of Rutherford Road and Highway 27. This leak was more severe, with an estimated leak rate of 30-litres per second and located beneath the Humber River and close to the Rutherford Road bridge crossing. The second location was near the East Humber River at Rutherford Road and Pine Valley Road.
“The location and significance of the leak found in October, required the transmission main to be temporarily taken out of service. While this was possible during the winter months, the spring peak water demand would require the main to be back in service to maintain the water supply,” says Kevin Bainbridge, C.E.T., vice president of Robinson Consultants. “As a result, the Region needed to make repairs in an expedited manner.”
To achieve this, the Region quickly retained Robinson Consultants in partnership with TYLin in October to provide engineering support including repair approach, retaining a qualified contractor and field services during the repair. From November to January the design team worked to select the right repair method and retain a contractor to complete the work. All work needed to be complete by April. Project funding came from asset management reserves through York Region’s 10-year capital plan.
Selecting a Trenchless Solution
“York Region’s goal was to find a solution that had minimal disruption to the surrounding natural environment, could be done in an expedited schedule and fit the operational and environmental constraints and complexities of the area,” says Millisf
When looking at York Region’s history of trenchless rehabilitation measures, it has used sprayed-in-place pipe (SIPP), sliplining and CIPP. Specifically, it has used geopolymer spray liner (for SIPP), centrifugally cast fiberglass-reinforced polymer mortar pipe (HOBAS) for sliplining and multiple incarnations of CIPP liner.
However, for this project, TYLin and Robinson Consultants looked at several options available and determined that a new (to York Region) rehab approach was needed. The design team selected carbon fibre reinforced polymer (CFRP) as the preferred option.
“In considering a few different rehabilitation methods, it was determined that CFRP was the only method which could deliver the repair in the time frame required,” says Bainbridge.
He notes that the decision was made based on a review of technologies of transmission mains similar in size, operating pressure and geometry. They also looked for a product that could be installed in a difficult to access location.
In selecting CFRP the design team was looking for a solution that would not only repair the present leaks but also one that would prevent future disruption, as well as reinforce the pipe. Though a long-available method of trenchless repair, Bainbridge notes that experienced contractors and consultants familiar with CFRP repairs are few in Ontario.
Winning the project was Memme Infrastructure Contractors, of Caledon, Ontario, in partnership with Pullman Services which used a CFRP product from Structural Technologies.
“The use of CFRP was new to York Region; however, the features of this trenchless technology provided the best solution to protect the critical infrastructure through challenging areas and meet the tight timeframe,” says Millis. “Completing this repair within a tight timeframe was critical to minimizing any additional stress on York Region’s existing water supply system.”
Installing CFRP involves the hand application of multiple layers of carbon fibre fabric that is coated with an epoxy resin. By using this technique, the structural performance of the pipe is improved by increasing its load-bearing capacity, stiffness and durability. Because CFRP is applied in sheet form it can be installed through both horizontal and vertical bends.
However, before crews could install the CFRP, the leaks needed to be stopped and the host pipe cleaned to achieve a proper bond between the pipe and rehabilitation material. For the former, Pullman Services removed the existing grout from the steel barrel, injected polyurethane and installed a Weko-Seal gasket. On the cleaning side, the pipe was pressure washed to ensure the concrete was free of surface debris.
Approximately 7 km of pipeline was isolated for the project because there was limited access to the leaking sections. The water – approximately 18,000,000 L – was drained, neutralized and pumped to energy dissipation pools. All told, crews rehabilitated 370 m of the feedermain with CFRP. At peak crews were applying 61 m per day at a thickness of two liners.
“The entire repair was very well executed, with no significant challenges; however, it is important to retain a project team (owner, consultant(s) and contractor(s)) who are skilled and experienced at the components of work they are taking on,” says Bainbridge. “Given the nature of the needed repair and the size of the York-Peel transmission main, this project established the significant abilities of the trenchless technology industry to deliver solutions to address even the most challenging projects.”
As an added safety measure and to increase the durability of the feedermain, all joints were sand blasted and glass fibre reinforced polymer (GFRP) panels were applied before the CFRP layers. The York-Peel Feedermain was recommissioned in April 2023 as planned.
The Emergency Repair Timeline
- September 2022: Leak detection inspection was conducted and leak identified.
- October 2022: Follow-up isolation and pressure testing; confirmed the leak locations and size.
- November 2022: The feedermain was taken offline, draining started, internal pipe inspection conducted and repair design was completed.
- December 2022: Repair contractor mobilized
- March 2023: Carbon fibre-reinforced polymers were installed and joint repairs completed.
- April 2023: The feedermain was commissioned and back in service.
Collaboration Is Key
“The success of these types of projects are heavily reliant on the assembled project team. In this case, a diverse team who each brought a particularly needed experience,” says Bainbridge.
Because of the many jurisdictions in the repair area, constant communication and collaboration was key. Millis notes that this meant constant contact not only with the City of Vaughan, but also Peel Region, the City of Toronto, conservation authorities and the Ministry of the Environment, Conservation and Parks as the work progressed.
“Construction notices and updates were hand-delivered or mailed to residents, businesses, local cities and towns and interested persons that were in proximity to the work and areas impacted. Static signage and portable message boards were used to notify motorists and transit users about the work area and traffic impacts,” says Millis. “Information about the work was posted on york.ca and shared with local cities and towns for visibility. Regular social media updates informed residents, stakeholders and interested persons about the work and impacts. Additional communication and signage were required for closure of a park trail, which was close to one of the leak sites.”
While not a normal project for the Region, Millis notes that based on this experience, York Region will continue to be an innovator when looking at the use of trenchless technologies to improve its underground infrastructure systems.
“York Region continues exploring innovative and alternative construction technologies and contracting methods,” he says. “Large scale repairs like this often require a design-build approach with input from all interested persons to collaboratively plan the execution and mitigate issues to meet tight timelines.”
Project Owner: Regional Municipality of York
Engineers: TYLin International Canada Inc. and Robinson Consultants Inc.
Contractors: Memme Infrastructure Contractors, Pullman and Simpson Gumpertz & Heger (SGH)
Supplier: Structural Technologies Inc.
Value of Trenchless Project: $15,449,065.91