Paralumes, as the structures are known in French, are currently used in just three locations in Quebec, all in the Montreal area, Transport Quebec spokesman Real Gregoire confirmed: Over sections of the downtown Ville Marie Tunnel, including the Viger section where part of the paralume collapsed on July 31; in the tunnel sections of Highway 13 between Highways 20 and 40 on the West Island; and on either side of the Louis-Hippolyte Lafontaine Tunnel linking Highway 25 from Montreal’s east end with the South Shore.
One of the longest stretches of paralumes is the one on Highway 13. That road was slated for “demolition of the paralumes and lighting improvement” in a Transport Quebec document in May called “Sites with potential for road safety improvements, 2011-2112.” The project status was listed as “in preparation.”
Gregoire on Monday could not say why the roof of the Dorval Tunnel — as the covered section of Highway 13 is called — needs to be demolished or provide details about other paralumes, saying “we are overloaded with media requests.”
Normand Tetreault, president of Soconex and a civil engineer with 33 years experience who specializes in concrete structure repairs, said there is no reason to believe drivers in the Dorval Tunnel are in any immediate danger, despite the fact Transport Quebec wants to demolish the louvered ceiling.
That is, he added, unless workers start drilling the walls near the support beams that hold the paralumes up — which is what took place the morning of the collapse in the Ville Marie. “There’s no reason to think (the paralumes) will start dancing and jumping on the roadway unless similar factors are present,” Tetreault said.
But he wondered what Transport Quebec is planning to replace them with. The paralumes “cover a large section of that tunnel. They would need to replace them with something.”
Tetreault explained that the Dorval Tunnel paralumes prevent drivers from being distracted by low-flying airplanes coming in for landings at the adjacent Trudeau airport. “That’s the east-west landing strip and it’s very busy.”
As for the older Louis-Hippolyte Lafontaine Tunnel, the paralumes there do not appear to be made of the same materials used in the Ville Marie and Dorval tunnels, Tetreault said. They are also shaped differently. “There may be concrete and asbestos mixed, which would make it lighter,” he said. The Ville Marie paralumes are also made of a variety of materials depending on the section, he noted.