Solution found for Port Mann Bridge ice bombs problem

Dec 19 2017, 6:55 am

Two weeks ago, I covered in-depth the public reaction to the new Port Mann Bridge’s ice and snow build-up problems. I argued that such problems for brand new machinery, buildings, and infrastructure were very prone to initial problems, but these problems were also often quickly resolved regardless of whether it were caused by engineering issues or initial maintenance error. As expected and promised, engineers have now found a solution to prevent ice and snow build-up on the suspension cables of the Port Mann Bridge.

The private contractors responsible for designing and building the bridge have found a 3-pronged fix to the conditions that led to the December 19, 2012 ice bombs incident. The first and primary part of the solution involves the installation of a custom-designed cable sweeper on the overhead suspension cables of the bridge. The newly designed sweeper is outfitted with brushes and scrapers (like snow ploughs) that will move along the bridge suspension cable lengths to prevent snow and ice from accumulating and falling onto the bridge road deck.

A rendering of the custom-designed cable sweeper for the Port Mann Bridge. (Image credit: BC Ministry of Transportation and Infrastructure)

The custom-designed cable sweepers will move on wheels to ensure the sweeper glides down the suspension cables smoothly, effectively, and quickly (moving at speeds of 61-metres/200-feet per minute). These sweepers will be installed on 152 of the 288 bridge suspension cables and are currently being manufactured for installation and testing next week. The sweepers will move up and down the suspension cables, making two clearing passes for each deployment, by using hydraulically operated winches installed on the bridge towers. The sweeper snow and ice removal system will be deployed by bridge maintenance workers as soon as snow begins to fall.

The Port Mann Bridge is getting a new system to keep its suspension cables clear of ice and snow. It is a custom-designed cable sweeper and this video below shows how it will work:

The second part of the fix involves giving the bridge suspension cables an additional hydrophobic coating which will reduce the adhesion of water and ice to the cable surfaces. At this time, four different hydrophobic solutions are being tested in a laboratory that replicates severe weather conditions, particularly the severe winter weather conditions that created the ice and snow build-up in December 2012. Pending successful laboratory testing, the new hydrophobic coating will be applied to the bridge’s suspension cables this summer when the weather is warm and dry.

Finally, the third part of the solution is a preventative measure in addition to the other two solutions described above. A de-icing solution could be applied to the Port Mann Bridge’s suspension cables prior to a forecasted snowstorm. This precautionary method is similar to the de-icing spray procedures that aircrafts receive during snowfall to prevent ice build-up. The de-icing solution is non-corrosive and environmentally friendly.

The construction contractor, Kiewit-Flatiron, is responsible for fixing such problems at no cost to the provincial government. This is part of the contractor’s guarantee should problems be found within a certain period of time following official construction completion. Taxpayers are not on the hook for the cost to fix these issues with the Port Mann Bridge nor is the bridge the “lemon” and fiasco that many had too quickly judged it as. After all, problems with the bridge have so far only arisen during severe winter weather and effective solutions have been quickly found to address these woes in such winter conditions.

Road and public transit infrastructure are no stranger to operational issues during winter weather (and neither is your personal car). For instance, we can also recall the issues SkyTrain has had with snowfall, notably the Canada Line’s incident on November 26, 2010.

Written and researched by Kenneth Chan, a Columnist at Vancity Buzz. Follow Kenneth on Twitter: @kjmagine

Featured image credit: PhotoDG

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