Structural Digest

Looking At The Structures That Define Us

The Age of Disrepair: What Do We Do With All These Bridges?

The issue of ageing infrastructure has become a serious concern in countries throughout the world. Bridges built in the past century have begun to crumble causing serious  injuries, and in some cases death. In 2007, a bridge in Minnesota collapsed, killing 13 and injuring 145 people (I-35W Bridge Collapse) .Below is a video of the bridges collapse:

As a result, an investigation was conducted by the Federal Government of the United States to determine the cause of the collapse. In addition, the National Transit Safety Board was created to help improve the state of infrastructure and prevent future collapses. However, it seems that this issue has not been eradicated. During a speech in Galesburg, Illinois, President Obama stated, “We’ve got more than 100,000 bridges that are old enough to qualify for Medicare” (The Hill Report). According to a report released by Transportation for America, “11% of all bridges in the US are structurally deficient”. Considering that Americans make 260 million trips across bridges each day, this is a major issue (T4 America Report).

North of the border, Canadians are facing similar problems. A report released by Statistics Canada in 2007 stated that, “The average age of bridges went from 21.3 years in 1985 to 24.5 years in 2007, an increase of 3.2 years” (StatsCan Report). The province of Ontario has the third oldest bridge infrastructure in Canada (after Quebec and Nova Scotia) and its ailing bridge infrastructure has received a high degree of media attention. In Toronto, the capital of Ontario, the Gardiner Expressway has been identified as in need of serious repairs. The Gardiner is a major artery in Toronto’s downtown core, and a number of plans have been proposed to help rehabilitate it’s ageing bridges. However, the cost is quite steep. A current estimate puts the cost of repairing the bridge at $505 million (Globe and Mail Report).

Delamination on Gardiner Bridge Piers. Photo Credit: CBC News

It is well known that repairing older bridges drastically reduce maintenance costs. As a result, many engineers are starting to develop creative solutions to help restore these bridges. Innovation, unfortunately, comes with a price tag. As cities face more funding cuts, engineers are forced to use cheaper, less effective techniques to restore bridges. Professor Paul Gauvreau of the University of Toronto states, “When engineers are repeatedly requested to implement yesterday’s solutions – that is, not to innovate – engineering becomes a mere commodity that can be bought and sold at the lowest price” (Globe and Mail Report). As is often the case, these low-cost repairs are not very effective, and can lead to higher repair bills in the future.

A number of solutions have been proposed in the last few years that could potentially save cities millions of dollars on their repair bills. Some of these solutions include increasing the frequency of inspections, providing better drainage to current bridge decks, using domes to protect the bridge from rain and snow, and installing steel mesh beneath the bridges to catch any falling concrete (National Post Report).

Inspection of the Underside of a Bridge Deck in Missouri. Photo Credit: Missouri Department of Transportation

These solutions, however, are not always practical. More research needs to be done to find cost-effective repair techniques. Researchers all across the world are investing time and funding to help develop better, more efficient procedures for rehabilitating old bridges. As this research progresses, it will be interesting to see which solutions are adopted by the industry. In the meantime, cities will continue to pursue a ‘band-aid’ response to bridge deficiencies, leading to a higher potential for future accidents.

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2 comments on “The Age of Disrepair: What Do We Do With All These Bridges?

  1. ramigmansour
    August 7, 2013

    Travel Leisure has composed a list of the twenty most dangerous bridges in the US:

    http://www.travelandleisure.com/articles/americas-most-dangerous-bridges

  2. Pingback: A Revolution in Bridge Repair | Structural Digest

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