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Site C concrete foundation program completed

1.68 million cubic metres placed to support powerhouse, spillways, and dam abutment
Aerial view of the Site C dam construction site with the approach channel pictured on the left, December 2021.

BC Hydro says it has reached a major milestone at Site C with the completion of the dam’s roller compacted concrete program.

In a project update this week, BC Hydro said 1.68 million cubic metres of roller compacted concrete has been placed since 2017 in three large buttresses, or foundations, that support the powerhouse, spillways, and the dam abutment.

The powerhouse buttress was completed in 2018, the upper spillway buttress in fall 2019, and the dam and core buttress in October 2021, according to BC Hydro.

“Combined, the buttresses measure approximately 800 metres long and up to 70 metres wide and will ensure the stability of the dam structures, including in the unlikely event of a major earthquake,” BC Hydro said.

The concrete was manufactured on-site and transported by trucks to the buttresses. Of the concrete placed, 650,000 cubic metres was placed for the powerhouse buttress, 650,000 cubic metres for the spillway buttress, and 450,000 cubic metres for the dam and core buttress.

Rendering of the Site C buttresses.

BC Hydro says the Site C buttresses form the second-largest concrete structure in B.C. after its Revelstoke Dam, and is the largest roller-compacted concrete dam structure in Canada. The total volume of the Site C buttress is six times the volume of concrete used to build the Burj Khalifa in Dubai, the tallest building in the world, according to BC Hydro.

"Roller-compacted concrete has many properties similar to conventional concrete, but is constructed with a placement method that makes it well suited for large-scale dam construction," the company said.

There were 4,633 workers employed on the dam in October. As of Dec. 14, there were 1,377 workers in camp, including 10 in isolation due to COVID-19. There are two active cases amongst the workforce, with five others isolating at home.

Email Managing Editor Matt Preprost at

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