Province still looking for answers in bridge failure

The province’s transportation ministry continues its review of the causes of the recent failure of the Nipigon Bridge in northwestern Ontario, an investigation of significant concern to PEO.

The newly completed, cable-stayed bridge had to be closed to traffic January 10 after part of the bridge deck separated from the road surface during a mid-winter storm. The bridge was partially opened to traffic days later after the ministry completed emergency repairs.

It was later determined that bolts on part of the new bridge’s supporting structure snapped off and allowed the deck to rise about 60 cm above the road surface.

The Ontario Ministry of Transportation (MTO) has since sent the broken bolts to two independent labs to determine the exact cause of the failure.

A temporary repair was reviewed by an independent engineering firm and found to be appropriate.

Annamarie Piscopo, an official with MTO’s northwestern region office, said April 1 that testing of the bolts continues at the two labs and work is ongoing to determine the cause of the failure. “Once a cause has been determined, the information will be made public,” she said.

Two of the new bridge’s four lanes were opened to traffic in late February. And the ministry will now go forward with the next stage of construction as it is confident the recent issues will not reoccur.

The next phase of work includes demolition of the old bridge, which is expected to take approximately six weeks, weather permitting. Work will then shift to construction of the second half of the new bridge, and to construction of the third tower for the remainder of the year.

MTO says the recent problems with the bridge were not related to the tower design.

As reported (Engineering Dimensions, March/April 2016, p. 16), PEO is monitoring the ministry’s investigation into the Nipigon Bridge failure with PEO staff, including the registrar, liaising regularly with the ministry as it conducts its investigation, to determine where engineering may have been a factor in the failure. The information received is being assessed from PEO’s standpoint as a regulator.

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