Physical collapse is happening now
On Tuesday afternoon, President Biden announced federal funding will rebuild the Francis Scott Key Bridge, which more than 30,000 cars use daily.
“In terms of where you go from here, you’ve got a bridge that’s failed, and probably more likely, you want to rebuild it. So what are your options?” Schofer says.
“Going forward, you’ve got some really interesting design options that could either make the likelihood of this kind of event very small or eliminated entirely, and I think probably that’s what they’ll do with a new design.”
But many other key structures across the country aren’t getting the same attention.
“There are cautionary tales all over,” says Maria Lehman, president of the American Society of Civil Engineeers (ASCE) and vice chair of the Biden administration’s National Infrastructure Advisory Council. “Every county in the country has a list of bridges that, if they had money, they would replace tomorrow.”
The 617,000 bridges in the U.S. include not just those spanning mighty rivers but also every highway overpass and minor link across a stream—and close to one tenth of them are significantly compromised. “If you have to think in terms of catastrophe, we’re already there,” says Amlan Mukherjee, the director of sustainability focusing on infrastructure at WAP Sustainability Consulting.
In 2007, the collapse of an I-35W bridge in Minnesota killed 13 people and injured 145. More recently, a six-lane bridge over the Mississippi was closed for three months in 2021, disrupting interstate travel and shipping because an inspector missed a significant crack. Americans drive 178 million trips on structurally deficient bridges each day, according to the 2021 report from the ASCE.
Yet the U.S. spends only 1.5 to 2.5 percent of its GDP on infrastructure, proportionately less than half of what the European Union spends, Lehman says. This long-term lack of funding has run out the clock on many solutions. Many U.S. bridges were built to last 30 to 50 years, but nearly half are at least half a century old. The average age of U.S. levees is also 50; dams average 57.
The future of U.S. infrastructure
Mukherjee is optimistic about the use of new technology to solve some of the country’s infrastructure issues, though adoption has been slow. Drones can provide human inspectors with up-close views of areas they can’t reach themselves and reduce chance of human error; a drone on an unrelated project captured footage of the Mississippi bridge crack two years before its discovery.
Bilal Ayyub, a professor of civil and environmental engineering at the University of Maryland, College Park, has also worked with North American freight railroads to find weak links using computer modeling. This can comb through thousands of stations to “identify exactly which point if it fails will have the biggest impact,” he says.