Abitibi Canyon Generating Station Tailrace Rehabilitation

To support a major tailrace rehabilitation project at one of Ontario Power Generation’s marquee hydro facilities, Barclay designed, installed, and removed two independent cofferdams, including a modular 10 ft-high secondary cofferdam that isolated an entire 85 m-wide tailrace.

To ensure the highest standards of safety and structural integrity, the secondary cofferdam was fully engineered by a Professional Engineer using the Portadam concept as the basis for its design. The engineered system provided a safe, dry work environment, enabling comprehensive concrete repairs to all tailrace piers and gates.

Utilizing dive crews and PERI Multi-Flex formwork systems, Barclay constructed a water-retaining structure engineered to resist uplift and shear forces by using the weight of the retained water to stabilize the system. The secondary cofferdam was installed in a single day to meet the project’s demanding schedule.

The project also included unwatering more than 110 million gallons of water, providing scaffold access throughout the entire tailrace, removing deteriorated concrete, installing steel plate encapsulation, and placing new concrete to rehabilitate the tailrace piers and deck. All work was completed safely, ahead of schedule, and within budget.