September 9, 2010

DAN O’REILLY

The 6.1-metre-long pipe sections weigh anywhere from 22,500 to 25,000 kilograms.

FOCUS | Sewer and Watermain

Peel Region feedermain project faces host of challenges

DAN O’REILLY

correspondent

Even though approximately 50 per cent of the route is along the Highway 410 right-of-way corridor, allowing for easy machine access, the eight-kilometre Beckett Sproule Feedermain now being installed in Ontario’s Peel Region has a host of challenges.

Six tunnels under heavily travelled highways and one creek are required to extend the concrete pressure pipe from the Hanlan transfer pumping station at Britannia and Tomken roads in Mississauga north to the Beckett Sproule Reservoir just west of Highway 410 and north of Steeles Avenue in Brampton.

The tunnels will be under Highway 410, Highway 407, Steeles Avenue, Derry Road, Courtneypark Drive and the Etobicoke Creek.

Newmarket-based Technicore Underground Inc. has completed the Derry Road tunnel and is currently doing the preparatory work for Courtneypark Drive and Highway 407.

It is also the tunnel contractor for the Etobicoke Creek section, says Peel Region project manager Matthew Bennett. Tenders for the Highway 410 and Steeles tunnels will be issued shortly, he says.

At 450 metres long and 22 metres deep, the Highway 410 tunnel will be the longest.

But it was the wet flowing sand under Steeles Avenue, pinpointed during the initial geotechnical studies, that could have been the most problematic.

Not only would the tunnel require a watertight liner, the tunnelling could cause earth movement or even sinkholes and potentially damage existing sewers in the area, Bennett said.

Concerned about the magnitude of those potential problems, the region asked its consultant, MMM Group, to conduct more tests. Additional bore hole drilling concluded that, if the tunnel was lowered, it would be in rock, says Bennett.

Apart from the detailed design, numerous private property easements had to be secured before construction started.

The feedermain is one of a series of interconnecting facilities needed to meet water demands for planned new development in northwest Brampton and infill growth in Mississauga, as well as well as fulfilling Peel’s obligations to supply surplus water from the Lakeview Water Treatment Plant to York Region under a service agreement between the two regions, he says.

Under construction since the fall of 2008 and scheduled for completion in the summer of 2011, the project has been divided into nine separate contracts.

There are also two consultants. The MMM Group was retained to carry out the detailed design of the north section in Brampton, while AECOM was responsible for designing the southern Mississauga portion.

The region “felt it best to divide the project into phases to get the best competitive prices and workable schedule. It wasn’t considered feasible to have one big project,” Bennett said.

The general contractors are Stouffville-based Pachino Construction Co. Ltd and Vaughan-based TACC Construction Ltd.

At this point, TACC is installing approximately 50 metres of the concrete pressure pipe a day in the Courtneypark Drive area, says project supervisor Robert Tement.

While the open-cut excavation is fairly straightforward, the 6.1-metre-long pipe sections weigh anywhere from 22,500 to 25,000 kilograms, and that’s why the 10-person crew is using a 100-ton Link-Belt crane and a 140-ton CAT 5110 excavator, says Tement.

“We (TACC) believe it is the largest excavator in use in the Ontario sewer and watermain industry.”

While Hanson Brick was the supplier for one contract, the pipe for the other phases is being manufactured and delivered by Barrie-based Munro Concrete Products Ltd.

“By the completion of the project, Munro will have supplied over 2,000 pieces,” said marketing director Theresa Erskine.

Munro’s engineers used the consultant’s drawings showing the pipe line and valve chambers to determine the exact pipe requirements, number of sections, elevations, angles and restrain joints to produce the final layout for the pipe and fittings, she says.

All pipe pieces have a unique serial number allowing information about the manufacturing, quality assurance tests and raw materials to be tracked, Erskine said.

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