The new Champlain Bridge spanning 3.4 km over the St. Lawrence River between Montreal and Brossard, Quebec, is being constructed alongside the current aging Champlain Bridge. The concrete-and-steel bridge is being built with an expected lifespan of 125 years. All work is being done under the auspices of the joint venture group Signature on the Saint Lawrence.
The footings and foundation columns of the new bridge were prefabricated on the west jetty (one of the three jetties built to serve as the primary construction worksites). Each of the 900-ton foundations that have been placed in the water consists of a pair of 11-ft x 11-ft or 11-ft x 9-ft concrete footings that weigh 609 tons, or about the weight of 11 Bombardier CS300 jet airliners. The footings are connected to angled foundation columns. A W-shaped pier cap that will support the bridge span is balanced atop the two columns.
A floating foundation installer (FFI) was used to pick up the foundation assembly from the jetty and position it over a pre-excavated spot designated by GPS coordinates to ensure accurate placement. Once the exact location was reached, the FFI began lowering the foundation into place on the bedrock of the river.
Because the bedrock is not always level, three hydraulic jacks were permanently attached to the bottom of each foundation. Once the foundation was in its final position, divers scoured the area beneath the footing with pressure hoses; then the hydraulic jacks were used to adjust the foundations to the correct angle that was critical to placement of the pier caps. Finally, concrete was poured around the footings to anchor them in place.
To form a permanent support for the correctly angled foundations, once the foundation columns reached above the water line, the workers pumped Epojet LV, a moisture tolerant ultra-low-viscosity injection resin, in the hoses and gear boxes of the hydraulic jacks after displacing the hydraulic fluids with pressurized air.
MAPEI’s Epojet LV did indeed fill the space “between a rock and a hard place.”