Two laboratories will test the bolts that failed to hold together the Nipigon River Bridge Sunday.
The National Research Council in Ottawa and the Surface Science Western research facility at the University of Western Ontario will perform stress tests to determine their limits.
The bolts holding the girder to the bearing on an expansion joint broke on the cable-stayed bridge’s north side Sunday afternoon, closing the TransCanada Highway for 17 hours.
Engineers re-opened one lane of the highway Monday by weighing the bridge down with 110 concrete blocks in the westbound lane, weighing 2,721 kilograms each.
The interim solution begs questions over the bridge’s safety, as it was opened to traffic only 42 days earlier.
“I think it’s literally going to be testing the stresses, the strain, at what pressure would the bolts break. That’s why they’re going to actually try to break the bolts themselves,” said Thunder Bay-Superior North MPP Michael Gravelle.
“The big questions are, what caused this to happen? How could this happen? That’s we need the expertise of these two extremely reputable facilities to do that.
“When we determine what caused it, hopefully that will lead to how do we make sure this won’t happen again? How can we provide a guarantee of safety on the bridge so we can open it to two-lane traffic?”
Testing will determine a number of physical, mechanical and chemical properties of the bolts, as well as consideration of whether temperature fluctuations may have played a role in their failure.
Gravelle said an update will be available next week as to whether the testing will determine the cause of the bolts’ failure.
The province expects construction on the mirror half of the completed cable-stayed section of the Nipigon River Bridge is expected to be completed in 2017. The project is valued at $106-million.
