Quebec will launch a multimillion-dollar lawsuit against three engineering firms that it now blames for the partial collapse of an expressway tunnel last July.
A report by two independent investigators has pinned the blame for the accident on “inappropriate” plans and specifications drawn up by a consortium composed of the engineering firms of SNC-Lavalin, Dessau and CIMA+, Quebec Transport Minister Pierre Moreau said at a news conference Friday (Feb. 3).
|Normally the scene of bumper-to-bumper traffic, the expressway was nearly deserted on the Sunday morning when the slab fell.|
The 25-ton, 48-foot-long slab of concrete detached from the ceiling and smashed onto the roadway of the Ville-Marie Expressway on a Sunday morning as construction workers were hydroblasting the surface of the wall that separated the westbound and eastbound lanes.
The concrete beam and light-shielding grids, known as paralumes, supported by the wall narrowly missed motorists and construction workers. The structures, made of concrete, metal and asbestos, had been installed to temper light in the tunnel.
100,000 Vehicles Daily
The expressway normally carries 100,000 vehicles daily but was nearly empty at the time of the accident.
After the collapse, Transport Quebec removed the remaining 134 grids from the tunnel after engineers found the shades and the beams that hold them to be in serious disrepair.
Similar structures were also removed from another tunnel in Montreal.
Transport officials initially blamed the maintenance workers for the collapse, but backed off from that assertion, pending Friday’s report.
And the report, indeed, found otherwise. The 40-page report was prepared by Dr. Marie-Josée Nollet, a civil engineer and professor of structures at École de Technologie Superieure of Montreal; and Dr. Jean-Philippe Charron, a civil engineering professor at Polytechnique Montréal.
‘A Mistake was Made’
The study revealed that the pressurized blasting of the downtown tunnel’s walls was poorly planned, Moreau said.
“The finding of the experts … is the fact that the conception of the work was improperly done,” Moreau said. “It is very clear that a mistake was made during the planning of the work and that it is at the root of the accident that occurred last July 31 – and those responsible will have to live with the consequences.”
|The independent report, by Dr. Marie-Josée Nollet and Dr. Jean-Philippe Charron, found that hydroblasting on the downtown tunnel’s walls was poorly planned.|
The report faults improper specifications provided to Laco Construction Inc., which performed the blasting. It concludes that the temporary structure put in place to support the ceiling while the work was being done was not strong enough to carry the weight.
Moreau did not say exactly how much the ministry would seek in damages, but suggested that it would be in the millions of dollars.
‘We’re Paying Them’
Asked if the Transport Ministry shared responsibility for the collapse, Moreau said no. The department has been criticized for not reviewing the plans made by the engineering group or supervising the work.
But Moreau said that to do so would be to duplicate the contractor’s work.
"It would mean for every plan we would ask an outside (firm) to draw up, we would have to redo the job," Moreau said. "We're paying them to do it."
The three firms are continuing to work on other contracts with the agency, and the Transport Department has no plans to issue sanctions for the collapse, Moreau said.
None of the firms has commented publicly on the report.
Earlier Concerns Noted
A day after the collapse, Transport Quebec released two inspection reports that had questioned the safety of the paralumes earlier.
“The current state of the concrete grid is worrisome,” said a 2008 SNC-Lavalin inspection report, the Montreal Gazette reported. “In the very short term, we recommend the damage be catalogued and that a structural analysis be conducted.”
The report was based on inspections carried out in February, April and May 2008, wrote Andy Riga, the newspaper’s transportation reporter.
According to Riga, the inspection report noted, among other things:
• “The concrete grids have delaminated surfaces and pieces of concrete could fall on lanes.”
• “Several sections of the walls supporting the grids include large areas of delaminated concrete.”
Wrote Riga: “It’s unclear if the ceiling damage was catalogued, if a structural analysis was conducted, or if the ceiling grid was ever repaired.”