This contract was part of a work package to extend the subway from the Henri-Bourassa terminus in Montreal to the future Cartier station in Laval, by means of a tunnel underneath the Rivière-des-Prairies near the Viau Bridge.
Even though the layer of rock between the river bottom and the vault of the tunnel is of good quality, it was not considered thick enough to ensure a totally safe structure and had to be reinforced by an anchorage system.
Approximately 457 anchorages, 9 metre long steel bars placed with extreme precision into bored holes and injected with cement grout, were grouped into two sections near the riverbanks. All the work was performed from the river surface using barges, tugs, cranes and drills and was completed in under four months.