To engineer the replacement of five corrugated metal culverts with a 1,800 m diameter, located under the Dufferin-Montmorency highway in Quebec City, the MTQ hired the experts at Excavations Lafontaine, who paired up with the precast concrete division at Béton Provincial to complete this sensitive portion of the project.
Rusted and weakened over time, the metal culverts needed to be replaced with reinforced concrete culverts, extending their useful life to at least 75 years. Overall, the new commissioned structures needed to be 56.1 metres long, 6.0 metres wide and 4.5 metres high, with walls 500 mm thick: colossal structures, with pieces weighing nearly 36 tons each! No matter how advanced a technology gets, it is still often at nature’s mercy. Built along the inter-tidal zone of the Saint Lawrence River, this infrastructure overlooks a rich ecosystem of flora and fauna that depend on the changing tides.
Excavations Lafontaine and Béton Provincial had to use their experience and expertise to contend with the rhythm and characteristics of the Saint Lawrence tides. Pieces were placed upstream to downstream for some of the work, and some components had to be modified so that installation could be carried out in several phases. The precast concrete pieces had to be delivered to the worksite with extreme precision so that installation could take place within timelines determined by the tides.
