Why is Montreal’s Champlain Bridge, built within living memory, already on its last legs?

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A modern bridge is expected to last more than a century. Yet barely five decades after it opened for operation in 1962, Montreal’s Champlain Bridge is entering its twilight years. Despite engineers’ ongoing efforts to buttress damaged girders using high-tech carbon-fibre panels and even a 75-ton “superbeam,” the most-trafficked bridge in the country continues to deteriorate. In 2011, a Structural Health Assessment study concluded that nobody truly knows how corroded the bridge’s concrete innards have become, and darkly warned that the loss of even a single edge-girder “could result in the progressive collapse of the span.” A replacement bridge, to be designed by Danish architect Poul Ove Jensen, is slated for completion in 2018, with a projected cost to Canadian taxpayers of between $3- and $5-billion.

Who’s the culprit? As discussed below, the Champlain Bridge suffers from several important design flaws. Yet the historical figure who truly doomed the Champlain Bridge wasn’t the architect, the supervising engineer or the concrete provider. More likely, it was the guy who drove the winter salt truck. Year after year, tons upon tons of the stuff, mixed with rain and melted snow, created a corrosive brew that spilled over the bridge’s parapets onto the outer girders, and seeped through the expansion joints and deck onto the supporting piers below.

“They told me that they’d never salt the bridge,” says Hugh Pratley, 87, who designed the Champlain Bridge in the mid-1950s. “But it was a hollow promise. They left the snow clearing to the province. And the plows and trucks that cleared and salted the adjoining highways, they just kept rolling onto the bridge.” By the 1980s, engineers realized how much damage was being done, and a new drainage system was installed. But by that time, the damage was irreversible. The bridge had been constructed with no formal drainage system.

At this point in the narrative, it is worth pausing to linger on the life and times of  a living legend of North American bridge design and engineering: His memories from the period when the Champlain Bridge was being conceived go a long way toward explaining how $2-million worth of penny-pinching in the 1950s has left a multi-billion-dollar infrastructure bill on the table for the taxpayers of 2014.