TORONTO—Hundreds of support beams used in the construction of one of Canada’s largest infrastructure projects will be replaced after an expert panel questioned their safety and durability.
Windsor Essex Mobility Group (WEMG), which is responsible for the $1.4-billion Windsor parkway, said 508 of the 562 concrete girders identified by the panel will be replaced, which will delay the project.
The Windsor parkway is part of a refurbished border crossing between Windsor, Ont. and Detroit, Mich.
The panel found that tack welding was used in assembling the girders, which violates federal code. It also makes steel brittle and susceptible to early corrosion, it said.
The consortium said it will replace 500 girders made in Ontario by Freyssinet Canada Ltd. at no cost to the province. They include 288 girders that were installed and 212 that were made but not installed.
Eight girders made by Prestressed Systems Inc. and installed on the North Talbot Road bridge will also be replaced, it said.
The overpass was shut down Aug. 29 when concerns arose over the safety of the support beams.
The consortium said the decision is “unrelated” to the use of tack welding in the assembly of the girders, saying it’s been used for years.
It’s replacing the Freyssinet girders because new information came to light during recent inspections and testing of some of the girders, WEMG said.
“I don’t agree with a lot of the stuff that’s in the report itself,” said Michael Hatchell, WEMG’s technical director.
“We’ve made the decision we’ve made, we think it’s the best for the province to move forward.”
Transportation Minister Glen Murray said he’s pleased that WEMG “has decided to do the right thing and take responsibility for the actions of its subcontractor.”
Last month, Murray said the government wouldn’t replace the Freyssinet girders, even though the panel couldn’t confirm that they were safe. Instead, he said the government would monitor them to see if they show signs of cracking or corrosion and fix them if necessary.
The panel revealed in its second report that 62 of Prestressed’s support beams don’t meet federal code either.
They include the eight girders that are to be replaced and another 54 that were used in constructing a tunnel.
Not only was tack welding used in the 62 Prestressed girders, but the concrete strength was reduced, which “made matters worse,” the report said.
Since the tunnel isn’t used for heavy traffic, the 54 girders’ “structural deficiency is therefore relatively insignificant,” the report said. But durability is still an issue because tack welding makes them vulnerable to accelerated corrosion.
Hatchell said the company isn’t concerned about corrosion and is working with the government and conducting inspections.
Infrastructure Ontario was aware that there was a problem with the girders last December, months after the company in charge of the project knew that they were made using tack welding, the report said.
WEMG, whose engineers warned against tack welding, approved its use by both Freyssinet and Prestressed, it said. WEMG didn’t tell the government or the expert panel about it until the end of August.
“We did allow it to happen, but again, I have no concerns about tack welds themselves and what’s there,” Hatchell said.
The panel said some of the Freyssinet girders were manufactured before the Ontario plant obtained certification from the Canadian Standards Association, which was responsible for quality control. Most were installed in two tunnels.
Infrastructure Ontario and the Ministry of Transportation discovered that tack welding was used during a meeting with WEMG and Freyssinet in December 2012. Murray says he wasn’t aware of the problem until May.
The Liberals stopped the installation in July, but critics say they should have acted months earlier.