Provencher_Roy has recently completed the Darwin Bridges on Nuns’ Island in Montréal which was built with recyclable and sustainable materials including locally sourced recycled glass.
Almost 60 years old, the Darwin Bridges has endured the ravages of time and erosion. The tightening of the sidewalks was beginning to cause discomfort for pedestrians, bicycles, and strollers and the passage underneath the bridges was starting to accumulate puddles of water amidst limited visibility.
As a result, Ville de Montréal called upon Provencher_Roy to reconstruct this infrastructure, while simultaneously bringing the design up to code.
“In the 1960s, urbanization of the Island was originally inspired by the new residential suburbs cropping up in the United States. As a result, neighbourhoods in ‘grape’ configurations were linked to urban vehicular routes. But alongside these enduring routes are numerous pedestrian pathways, which are separated from the roads and connect residential zones to community parks, like Parc de West-Vancouver,” said Jacques Rousseau, project manager.
The Darwin Bridges serves as the meeting place at the crossroads of a Nuns’ Island urban boulevard and pedestrian and cycling path.
“The concept was always there, but the design and construction standards of the time favoured the automobile, with corrugated galvanized iron guardrails to prevent vehicles from falling. For this project, we were therefore working in a paradoxical 1960s context, on an innovative urban project to improve the user experience, while also contending with the formal urban treatments required for road transportation,” said Jacques. “Our intention therefore reconciles these two rudimentary propositions in the development of a solution that at once enhances the architectural language and fulfills safety regulations.”
According to Jacques, “the Ville was won over by the idea to create curved arch-like formwork,” following the curvature of the road to express a unique language.
This decision eliminated iron guardrails and integrated a security clearance of more than four metres. The result was an avant-garde design that conveys a sense of movement and spans the full 37-metre bridges.
The central median strip between the two bridges was opened up and dug out. Beginning at the highway, two curved arches slope down towards the cycling path, defining the pedestrian crossing area and unveiling an opportunity for landscape design. This presents itself through the placement of retaining walls between the bridges, creating tiered green terraces, reminiscent of the nearby Parc de West-Vancouver.
The outward-facing sides of the bridges are embellished with hollowed half-circles and flower stems, giving the impression of a low-relief of stylized flowers. When evening arrives, the pathway is illuminated with warm tones from sustainable LED lighting. This inviting transformation of the area, coupled with the incorporation of safety lighting fixtures beneath the bridges, promotes a sense of security among users and prevents tunnel sensations.
The novelty of this bridge construction lies in the chosen materials. The bridges were built with cast-in-place concrete, made up of 10 per cent finely ground recycled glass. In collaboration with the Université de Sherbrooke and Ville de Montréal, the project builds upon 17 years of research on the integration of ground glass into civic infrastructures.
This 100 per cent Québécois patented GGP invention was added as a ternary binder, which enables the project to make an environmental impact by reducing greenhouse gas emissions by 40 tonnes, the equivalent of driving 200,000 kilometres in a vehicle.
The GGP used replaced the cement typically used, constituting 40,000 kilograms of locally recycled glass and representing 70,000 wine bottles.
The architectural team also developed the whitest GGP possible for the bridges, characterized by a less raw colour than traditional aggregates. Due to the addition of stainless steel bars to reinforce the lifespan of the bridges, it is also more solid and estimated at over 125 years, compared to 75 years for a typical concrete structure.
The design is currently a candidate for ENVISION environmental certification, the urban infrastructure equivalent of LEED.
Location: Montréal / Ile des Sœurs, Québec, Canada
Project’s name: Ponts Darwin
Client: Ville de Montréal
Surface Area: 37m
Structure: SNC-Lavalin (durabilité du béton)
Entrepreneur: Tisseur Inc
Certification: Candidat à la certification Envision