Last week the greater Vancouver, B.C., area was hit with a mix of rain, snow, freezing rain and temperatures that hovered around freezing. The other thing motorists were hit with were chunks of falling ice, both from the brand-new $2.5-billion Port Mann Bridge, which opened Dec. 1, and the 20-plus-year-old Alex Fraser Bridge, just a handful of miles down the Fraser River from the Port Mann.
Around 100 insurance claims came in regarding falling ice or snow off the cables of the world’s widest cable-stay bridge, the Port Mann Bridge.
The public outcry was quick at first, as media reports pinpointed the Port Mann mishaps as design flaws, largely because the B.C. Ministry of Transportation closed the new bridge for over four hours and made a statement blaming contractor Kiewit-Flatiron for constructing a bridge with issues that needed immediate correction at the contractors’ expense.
B.C. transportation minister Mary Polak detailed in length how the taxpayers wouldn’t be responsible for the costs to fix the bridge and explained that the bridge contract clearly spelled out the need for a design that eliminated the risk of falling snow and ice, as happened on Thursday, Dec. 20.
For their part, the joint venture Kiewit-Flatiron released a statement to Vancouver media saying they will immediately look for a solution to the ice issue.
But when reports surfaced the next day that similar ice-falling events, albeit at a reduced rate, were also happening at the nearby Alex Fraser Bridge, which opened in 1986 and has never had work done to reduce ice-fall events, engineers started to question if last week’s weather mix was really a freak phenomenon that somehow contributed to an odd buildup of ice on the 288 cables at the Port Mann.
Granted, the design of the Alex Fraser is different from the Port Mann and the cables there don’t stretch over the roadway as at the new bridge, but the fact that no work has been done on the Alex Fraser to fix problems raises doubts about how—of if—work should be done on the Port Mann.
During a Thursday news conference, Polak was quick to point out that the government required a solution. When the Vancouver Sun asked her department what they planned to do about the Alex Fraser problem on Friday, Dec. 21, the question went unanswered.
Polak also says that the microclimate over the Fraser River in the location outside of Vancouver-area cities of New Westminster and Coquitlam, where the two bridges are located, raises the chances of continued ice events.
The Pacific Northwest, as a whole, must watch for ice buildup on bridges and the Tacoma Narrows Bridge in Washington State gets monitored for such occurrences. The last time that bridge was shut down for ice was in January 2011, before the ice started falling on cars, according to the Sun.
Was last week’s unfortunate string of accidents—two people were sent to the hospital, one with a broken arm, because of accidents related to falling ice—a freak weather event that can’t be mitigated or a bridge design flaw? And if changes are made to the Port Mann Bridge, what about the Alex Fraser Bridge?
Tim Newcomb is Engineering News-Record’s Pacific Northwest contributor. He has also written for TIME, Popular Mechanics, Popular Science and more. You can follow him on Twitter at @tdnewcomb or visit his website here.