From very tight deadlines to complex soil conditions, designing and building Montreal’s new Champlain Bridge has presented a number of interesting challenges for the project’s Environment & Geoscience team, which is entirely composed of SNC-Lavalin personnel.
As a member of the Signature on the Saint-Lawrence Group (SSL) consortium, SNC-Lavalin was awarded a contract for the design, construction, financing, operation, maintenance and rehabilitation of the new Champlain Bridge corridor. This project involves building a 3.4-kilometre cable-stayed bridge across the St. Lawrence River and a 470-metre bridge connecting Montreal to Nun’s Island, as well as reconstructing and widening a 4.5-kilometer portion of Highways 15 and 10.
When the project was officially awarded to SSL in April 2015, we were tasked with providing several key services to support the design and construction, and to manage related environmental concerns.
Laying the groundwork for a bridge built to last
The project involved building a variety of structures—like bridges, overpasses and retaining walls—on variable soil and rock materials, both on land and under the Saint-Lawrence river. We carried out geotechnical investigations to assess the general subsoil, rock and groundwater conditions prevailing at each foundation unit along the proposed bridge alignment. The geotechnical information was used to inform the design of the foundations, which include shallow footings placed directly on rock and deep foundations that include drilled shafts that penetrate the overburden till and are socketed into rock.
Compressible soils, in the form of an old landfill on the Montreal side and clay deposits on the opposite side, presented a challenge for the project’s highway designers, who anticipated the potential for significant settlement over the entire project life.
Ensuring quality control during construction
During the construction phase, our engineers and technicians carried out field and laboratory quality control testing of the soil, aggregates, concrete, asphalt, grout and other materials. We also performed quality assurance for the construction survey.
Protecting human and wildlife well-being
With the construction taking place in a densely populated area and across a major waterway, our Environment & Geoscience team designed and implemented a comprehensive Environmental Management System including control, management and monitoring measures to minimize environmental impacts. This includes daily monitoring of surface water quality, developing solutions to minimize generation of suspended sediments and preventing excess noise and dust generation at source. Our mandate also includes the management of contaminated soils with an effort to reuse as much as possible the excavated soils from marine and on land excavations and track all the soil movements.
We ensure compliance with all regulations and standards, and work with the project’s Communications team to maintain ongoing dialogue with neighboring communities. We obtained the certification ISO 14001 for the entire project in less than a year and we are targeting the Gold Award Envision Certification from the Institute for Sustainable Infrastructure (ISI).
Our specialists also designed and supervised the construction of three fish passages to enable lake sturgeon and other fish species to migrate through a jetty that was erected to facilitate bridge construction. These will be monitored annually during the migration period and complemented with a fish habitat rehabilitation program and a fish habitat compensation project once construction is complete.