Zoë Coull is a professional engineer and the CEO of Ice Dragon Corrosion Inc.
Canada’s infrastructure system is inextricably linked to Canada’s economic and social prosperity, but governments don’t always see the value of maintaining it. While they do inject funding into infrastructure, it tends to go toward building new shiny assets rather than keeping our existing ones, some of which date back hundreds of years, from failing in the face of age and exposure to Canada’s harsh environments. Political ribbon-cutting opportunities for routine maintenance, after all, don’t make good news stories.
But short-term thinking around infrastructure often results in leaving repairs until they’re critically needed, at which point they can become extensive and expensive, giving rise to that reliable Canadian joke: There are two seasons, winter and construction.
The liberal use of de-icing salts is used to improve winter safety on roads and bridges across the country, but salt corrodes reinforcing steel, causing concrete to crack and potentially fall off. Corrosion alone costs the global economy more than $3-trillion across industries every year, according to the National Association of Corrosion Engineers.
Deferring repairs leads to urgent and disruptive projects such as the work under way on the Don Valley Parkway, the sole north-south expressway into Toronto, which will close multiple lanes of traffic over the summer and likely beyond. And such a reactive approach can also lead governments to opt for the cheapest immediate option, which doesn’t maximize risk avoidance, performance and the cost over the life of the asset.
The good news is that, on average, we can save a full 15 per cent to 35 per cent of these costs over the life cycle of our assets just by adopting technology and processes that already exist and have been taken up much more readily outside Canada. It will require significant investment and strategic policy to ensure we do not fall behind in global competitiveness, and this long-term thinking must cascade down to a boots-on-the-ground design level, so we have technical solutions and pro-active management programs that ensure our infrastructure is safe, reliable and cost-effective. But as the Morandi bridge collapse in Italy and the Flint water crisis in Michigan tell us, failure to do so not only jeopardizes the economy – it can end in disaster.
London offers a good example of the benefits of this long-term thinking. In the early 2000s, a section of the elevated M4 bypass, which circles West London, required extensive repair due to de-icing salt. The two-lane M4 carries around 90,000 vehicles a day, and runs over a busy three-lane secondary highway. Extensive repair through traditional methods for the supporting concrete structures under the elevated roadway came in at a cost of $8-million each. This replacement program would also have required an unhappy nine-kilometre detour of all traffic; West London would have come to a standstill.
So the project team decided to use a technology called cathodic protection, a technique that was pioneered in North America and has been used in concrete for the past four decades. It involves protecting the embedded steel using a very low current from an external power supply; the power needed to protect a soccer field-sized area of reinforced concrete for the promised 50-year life span is similar to the power required to light a few 100-watt light bulbs.
By using this technology, the road closings were less restrictive and more lanes stayed open. The repair was completed in a shorter time frame, and it was safer, quieter and cleaner. Importantly, it cost only $500,000 per pier – a massive savings over the traditional repair route. The cathodic protection system, too, was designed to protect the bridge for more than five decades; in comparison, traditional patch repairs, which knock out the loose concrete and reinstate it, may only last a few years.
The installed cathodic protection system also has embedded monitoring devices, which allow remote download of real-time condition data. This technology has been evolving for decades for use in highway infrastructure, and allows asset owners to check on the structure’s health from the comfort of their desks – as if the bridge is wearing a Fitbit.
As our municipalities look to make their infrastructure-management programs more effective, we need to look for tech opportunities that move us toward truly sustainable infrastructure. We need to take advantage of lessons that have already been learned to create better value for current taxpayers and future generations alike.
Corrosion and continuing maintenance might not be sexy. But we can’t afford to ignore it.
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