Surprise! Donohue Bridge repairs cost more than expected

The twin-span Donohue Bridge wasn’t constructed the way its blueprints said it was, engineers have discovered. Journal Photo

Troy Shantz

Construction workers repairing the Donohue Bridge have run into a problem, so the $4.5 million budgeted for the latest round of repairs just won’t be enough, city staff say.

Engineers have found that reinforced steel connections shown on the original blueprints don’t exist in the twin spans connecting Sarnia with the Chemical Valley.

Though it’s still safe to drive on the 260-metre-long bridge, the discovery complicates the plan to jack up and support its ends while new bearing pads are installed and girder ends repaired.

“A lot of times when we’re doing projects you’re relying on information that you have… that everything is where it should be,” said acting city engineer Mike Berkvens.

“But a lot of times it’s not always that accurate or things change. It happens more often than we care to admit.”

So it’s back to the drawing board for the engineering firm of Amec Foster Wheeler, which is figuring out a work-around.

“It is going to cost us extra money,” Berkvens confirmed.

“At this time we don’t know a set amount, how much it will be in the future, but it definitely isn’t going to be the easy way that we thought it was going to be.”

Council had already earmarked $4.5 million and in May approved $1.7 million for the latest round of repairs.

Sarnia’s long-troubled ‘Bridge of Sighs’ was built in 1969 and has undergone major repair work in 1982, 1983, 2009, 2010, 2013, 2014 and again this year, with more reconstruction planned.

In fact, it has taken longer and cost more per-metre to repair the Donohue Bridge than it did to build the Blue Water Bridge to Michigan.

But fixing it is still cheaper than replacing it, city staff say. Building a new bridge could cost $32 million, not counting removal and design work.

“Most bridges are 10 metres long and they’re fairly simple. This structure has two train tracks under it (and) it’s quite elevated,” Berkvens said.

“To do it all in one year would be millions of dollars … we’re fortunate that we can do sections at different times.”

Currently, traffic on the bridge is restricted to one northbound and one southbound lane. Two-lane traffic in both directions could be restored temporarily next month once the current phase of reconstruction is complete.

But, Berkvens said, it is essential to the life of the Donohue Bridge that the repair work continues into 2018 and again in 2019.