The comments contained below reflect solely the personal and professional opinions of the authors of this text and should in no way be interpreted as the position of their respective employers.
A security problem
The question of a new road connection between Lévis and Quebec arises not only in terms of traffic volumes: issues of public safety and the need to support economic activity not only in Greater Quebec, but also in Saguenay-Lac-Saint-Jean and the USA North Shore, which is often overlooked in discussions on this topic, is, in our opinion, the most important. Since Eastern Quebec only has one high-capacity highway connection, a partial or complete closure of the Pierre Laporte Bridge would most likely jeopardize public safety and economic activity in Quebec. The Pierre Laporte Bridge and the structures on the north and south banks have already passed the 50-year mark (1970) and must undergo extensive renovation and rehabilitation work, which will certainly lead to road closures. We cannot 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 Canadian Bridge Design Code designates so-called “essential1” structures when they are essential to the integrity of regional transportation and to the economy or security of the region. These structures are designed to remain fully functional even in the event of a large earthquake. Since these design requirements are new, the Pierre Laporte Bridge and the structures lying in the same axis were not designed according to these criteria and could therefore be seriously damaged in the event of a major earthquake, rendering the two banks inoperable 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 that reduces the reliability of the structures over time. 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 speak of a “second connection” rather than a “third connection” speak.
A choice dictated by topography
When planning a structure to cross a watercourse, it is often the topography of the banks that dictates the type of infrastructure chosen. For example, the banks of the St. Lawrence River along the axis of Highway 20 (Louis-Hippolyte-La Fontaine Bridge-Tunnel) are horizontal on both sides. If we had decided to build a bridge there, the approaches would have had to be extended over a very long distance to meet the clearance required by the sea route and maintain acceptable gradients for trucks. Therefore, the choice of a tunnel for the Quebec project was perplexing for us, as the Trans-Canada Highway (A-20) at the chosen location is 65 meters above the river level and therefore required the construction of a very long tunnel to sink so low, that the structure can fit under the riverbed. This is the opposite of the conditions that prevailed at the Louis-Hippolyte-La Fontaine bridge-tunnel.
A modern bridge
A clear height for navigation on the river of about 60 meters and an average level of the A-20 on the west side of Lévis of about 45 meters result in an average gradient of less than 0.5% between the axis of the A-20 and the highest point of the bridge in the middle of the river (4 km). This topography, which was favorable for the construction of a bridge, therefore encouraged us to advance our thinking and explore locations suitable for the construction of the structure. We have therefore selected the Chemin des Îles axis as a possible route to briefly assess its feasibility, advantages and disadvantages. The crossing at this point is 2700 meters long and requires a clear span of 700 meters, well below modern cable-stayed structures which have a clear span of more than 1000 meters. Such a work, designed from an aesthetic point of view, would become the trademark of the Capitale-Nationale region.
Langqi Bridge (Fuzhou in China), 680 m clear span. Free photo
The advantages that such a route brings include, for the south side: a motorway junction to the right of the A-20 and the Chemin des Îles, which already exists (with the necessary space for eventual widening), the possibility of incentive parking within to introduce transfer ramps (without expropriation), a Chemin des Îles, which already has four lanes and is mainly home to industrial residents. At the northern end of the Chemin des Îles, pillars could be placed 100 to 150 meters apart on the agricultural land below, which would have no greater impact on the farm than electricity pylons.
The recommended structure would connect to Champlain Boulevard and continue its route in a tunnel dug into the rock that would connect to Highway 440 (Charest Boulevard). All trucks exiting Champlain Boulevard must strictly exit west, while those transporting hazardous materials must absolutely exit there. Stations (for buses or other public transport) would be dug on both sides of the tunnel tracks on the right side of the east-west public transport axis (Boulevard René-Lévesque opposite the Saint-Charles-Garnier College) and would be connected by high-speed elevators. 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. This six-lane structure (three in each direction) would of course also include lanes reserved for public transportation and carpooling.
A vision of the future
The abandonment of the Quebec-Lévis tunnel project opens the door to a consideration that should focus on the essential issue of public and economic security, considering that there is only one viable highway connection between Quebec and Lévis. We hardly dare to imagine a situation in which traffic between the two banks of the Quebec region would be disrupted for weeks, even months or years. This proposal seems to us to be both elegant, economically and technically realistic. Apart from the choice of location, which must be the subject of in-depth study, we have no doubt about the need to build a new bridge in the Quebec region.
Footnote:1 In Montreal, the Olivier-Charbonneau (A-25) and Samuel-De Champlain bridges were designed as “essential bridges” and would therefore be the only passable routes for emergency vehicles in the event of a disaster.
Daniel Toutant is an engineer who recently came out of retirement to oversee the construction of a new terminal at Saint-Hubert Airport. He was responsible for the Highway 25 bridge project (Olivier Charbonneau Bridge).
Bruno Massicotte is a full professor in the Department of Civil, Geological and Mining Engineering at Polytechnique Montréal. In 2015, he conducted a pre-feasibility study for the Ministry of Transportation for a road link east of Quebec.
