Falling concrete highlights risk of bigger collapse

Falling concrete highlights risk of bigger collapse
Retaining wall on opposite side of Donegani overpass visibly decaying

By Robert Frank

“A chunk of concrete falling from an overpass can be dangerous, even if it’s only baseball-sized,” affirmed Mayor Bill McMurchie, after part of a Pointe Claire overpass fell onto Donegani Avenue, July 6.

Though no one was injured, the incident brought to light obvious signs of deterioration in the load-bearing wall on the opposite side of the overpass, adjacent to CN Rail’s transcontinental main line.

“Ownership of the bridge was forcibly transferred from the province to the city as part of the so-called Ryan Reforms of 1990,” Mayor McMurchie told The Suburban during an interview at the bridge site, where he consulted with city engineering officials after personally inspecting the damage.

He explained that the Ryan Reforms were an initiative by then-Municipal Affairs Minister Claude Ryan to transfer to municipal taxpayers expenses that had hitherto been paid for by the province.

As a result, many small towns throughout Quebec can no longer afford the eye-watering cost of replacing major infrastructure.

Fortunately for Pointe Claire taxpayers, the roadway over Donegani—which also carries heavy traffic along St. John Boulevard over the CN Rail and CP Rail transcontinental main lines—is supported by strong steel I-beams. Those have proved more durable than the reinforced concrete structures that have been implicated in infamous bridge collapses throughout the province.

Only the sidewalk beside the roadway and the two load-bearing walls at either end of the bridge are supported by stressed concrete. Since pedestrians weigh much less than cars and trucks, they cause much less wear and tear on the sidewalk, which city contractors easily repaired immediately after the July 6 incident. Public safety officials reopened Donegani by suppertime that day.

Casual observers of the retaining wall on the south side, though, can easily see rusting reinforcing rods, which the dissolving concrete has left completely exposed to the elements. If corrosion weakens those rods sufficiently, it could weaken the entire structure and increase the risk of a catastrophic collapse.

CN Rail spokeswoman Julie Sénecal told The Suburban that the railway is always careful to assess safety risks that could pose a hazard to the more than 40 freight and passenger trains that pass underneath the bridge on a typical day.

“CN is in communication with all the owners of structures that are not under the responsibility of CN in order to ensure safety of our employees and operations.”

MTQ spokeswoman Caroline Larose said that two other deteriorating bridges in Sainte Anne de Bellevue were transferred to the town, right after the province built Highway 40 in 1965. The town has been trying to find an affordable replacement since they were deemed unsafe and closed on March 29, 2011.

Visibly deteriorating: A crumbling south wall supports the Donegani overpass, which serves as a retaining wall for highway 20 bridge berms.
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