1701176941 A bridge tunnel in Quebec another scenario for the 3rd connection

A bridge-tunnel in Quebec: another scenario for the 3rd connection? | All about the 3rd Quebec-Lévis connection

What if the best scenario for a new connection in the national capital was a bridge in Saint-Romuald, followed by a tunnel to Charest Boulevard in Quebec? This is the idea of ​​Bruno Massicotte, the engineer who carried out the first studies on the third link, and Daniel Toutant, responsible for the construction of the Highway 25 bridge that connects Laval to Montreal.

For months they searched for suitable sites to build the structure and then considered the type of infrastructure that could best serve the needs of the Capitale-Nationale after the third link project was abandoned and then revived by the Legault government was.

The sketches made indicate that the route begins at the Chemin des Îles in Lévis, in the Saint-Romuald sector. In your opinion, this is an ideal location, as the industrial orientation of this traffic artery does not entail any expropriation of living space.

In addition, Chemin des Îles is located at the intersection of Highway 20. It already has four lanes and has space for widening the interchange and establishing incentive parking.

The cable-stayed bridge, with a span of around 700 meters, would have six lanes, three in each direction. “Such a work, designed with aesthetic considerations, would become a trademark for the Capitale-Nationale region,” they wrote in an open letter. One of the routes could be used for local public transport.

Diagram of the planned route.

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A bridge-tunnel could connect Lévis with Quebec.

Photo: with kind permission

In their letter, the two engineers explain why the topography at this location is ideal: This is particularly because trucks could travel on the infrastructure, unlike the under-river tunnel, which the Legault government had abandoned because the gradient was too high for heavy goods steep was vehicles.

On the Quebec side, the bridge would become a tunnel dug into the rock all the way to Charest Boulevard. Mr Toutant and Mr Massicotte have not specified the exact location where the tunnel would start in their plans, but it would be realistic to assume it could be near Anse au Foulon.

A public transport station

Inside the tunnel, engineers are proposing to build stations on either side of the structure’s tracks. High-speed elevators would allow users to reach the surface in front of Saint-Charles-Garnier College on René-Lévesque Boulevard.

“This vertical connection would be located halfway between Parliament Hill and the Sainte-Foy employment center while also being close to Laval University, optimizing travel times for users,” their letter said.

Daniel Toutant highlights the effectiveness of such elevators around the world. The one he proposes should be around 60 meters high.

“Bus transport would do very well to connect us to the east-west connection,” he adds, at a time when the Caisse de dépôt etplacement du Québec is tasked with examining “a structuring project” for Quebec City.

Bridge diagram.

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The structure would be a cable-stayed bridge with a span of about 700 meters and would have six lanes, three in each direction.

Photo: with kind permission

For security reasons, a second link is required

“The main goal is to draw attention to safety,” continues Daniel Toutant. According to him and Bruno Massicotte, we should no longer talk about a third connection in Quebec, but about a second connection, since they do not consider the Quebec Bridge a suitable structure for traffic between the two banks.

Not only does the infrastructure not allow trucks to pass through, the lanes are also not numerous enough and are too narrow. “The old Quebec bridge is certainly not able to accommodate the additional traffic that would result from even a partial closure of the Pierre Laporte bridge, which is why we are talking about a second connection rather than a third. »

They write that a prolonged partial or total closure of the Pierre Laporte Bridge “would most likely endanger public safety and economic activity in Quebec.” […] We can no longer rule out a serious accident or natural disaster. In fact, the Quebec region lies in an active seismic zone with a high probability of major earthquakes. »

The Pierre Laporte Bridge and the structures located on the same axis were not designed according to these criteria and could therefore be seriously damaged in the event of a major earthquake, leaving the two banks without a functioning connection for emergency services. Adding to the seismic risk is the wear and tear of materials: steel structures can break from repeated traffic cycles, not to mention corrosion and other damage.

Bruno Massicotte, who is also a full professor in the Department of Civil, Geological and Mining Engineering at Polytechnique Montréal, claims that “severe earthquakes have already occurred in eastern Quebec and the recurrence period of these earthquakes is about 100 or 125 years. It is very likely that these earthquakes will occur again. What we don’t know is when. »

The argument of ridership was always used to justify the Third Link project in Quebec. However, according to Daniel Toutant, security is a factor that should have been taken into account beforehand. “We only have one viable connection,” he said, referring to the Pierre Laporte Bridge. “A connection that could prove disastrous if closed for a period of a week, a month or even a year,” he points out.

How long can we wait to build a new bridge in the state capital? “We must not hesitate too long,” pleads Mr. Massicotte. Such a project requires at least ten years of work. It will take ten years of study to ensure that it is generally well received, that the bridge is in the right place and meets needs, he replies.

The engineers conclude their open letter by saying: “This proposal appears to us to be both elegant, economically and technically realistic.” Apart from the choice of location, which must be the subject of detailed study, we have no doubt about the need to create a new one Building a bridge in the Quebec region. »