In collaboration with Harbourside Engineering Consultants, gbi was mandated to develop optimal deconstruction methods for the original Champlain Bridge, integrating environmental protection, material recovery, sustainable development, as well as research and innovation throughout the project.

Following an in-depth risk analysis of the various possible methodologies, the selected approach for dismantling the concrete sections of the bridge was primarily mechanical demolition using high-reach hydraulic excavators equipped with a shear or hammer. These excavators operated from temporary jetties for the portions near both shores, and from a catamaran barge for the spans located above the river.

The gbi team played an active role in implementing a catamaran barge, an immense floating platform, used to deconstruct the spans over the river. This platform, specially designed for dismantling the 30 spans between the Île-des-Sœurs jetty and the Seaway metal structure, was capable of lifting and moving an entire span of approximately 1,900 tonnes of concrete. It represented a significant challenge, both in its development and design, and in the monitoring of construction activities on-site. For the section above Route 132 in Brossard, a critical corridor for mobility in the Greater Montreal area, a full weekend (from Friday at 11 p.m. to Monday at 5 a.m.) was dedicated to dismantling four spans and three piers, representing approximately 12,000 tonnes of concrete removed.