When Transport Québec closed one of two Montreal-bound lanes on the Mercier Bridge last week because a fissure was detected in a steel beam, it spawned monster congestion that left some South Shore commuters fuming in traffic for as long as two hours.

It also probably provoked some nightmarish flashbacks for anyone who lived through the summer of 2011. That’s when the entirety of the eastbound span toward Montreal was closed for four months for emergency repairs to reinforce corroded gusset plates — a low point in a continuing saga of the aging Mercier that didn’t end there. Far from it.

Fortunately, emergency repairs for the latest problem took place over the weekend, and the span is reported to be back to normal for Monday morning rush hour. (Fingers crossed.)

But how long before something else breaks and this happens all over again?

A look through The Gazette’s archives shows the Mercier has been in rough shape for at least two decades and undergoing some sort of remediation by either the Quebec or federal government since 2008. It has never really stopped since. Hundreds of millions have been spent on a bridge that is nearing the end of its lifespan.

But there are no concrete plans to replace this critical piece of infrastructure, which is used by 75,000 vehicles a day, including 12,000 trucks.

Joint ownership by two levels of government and its route through the Mohawk community of Kahnawake may........

© Montreal Gazette