On a 95-degree day this summer, New York City’s Third Avenue Bridge, connecting the Bronx and Manhattan, got stuck in the open position for hours. As heat and flooding scorched and scoured the Midwest, a steel railroad bridge connecting Iowa with South Dakota collapsed under surging waters. In Lewiston, Maine, a bridge closed after the pavement buckled from fluctuating temperatures.
America’s bridges, a quarter of which were built before 1960, were already in need of repair. But now, extreme heat and increased flooding linked to climate change are accelerating the disintegration of the nation’s bridges, engineers say, essentially causing them to age prematurely.
The result is a quiet but growing threat to the safe movement of people and goods around the country, and another example of how climate change is reshaping daily life in ways Americans may not realize.
“We have a bridge crisis that is specifically tied to extreme weather events,” said Paul Chinowsky, a professor of civil engineering at the University of Colorado Boulder who researches the effects of climate change on infrastructure. “These are not things that would happen under normal climate circumstances. These are not things that we’ve ever seen at this rate.”
Bridges designed and built decades ago with materials not intended to withstand sharp temperature swings are now rapidly swelling and contracting, leaving them weakened.
“It’s getting so hot that the pieces that hold the concrete and steel, those bridges can literally fall apart like Tinkertoys,” Dr. Chinowsky said.
As temperatures reached the hottest in recorded history this year, much of the nation’s infrastructure, from highways to runways, has suffered. But bridges face particular risks.
“With bridges, you’re working with infrastructure that may have been planned, designed and built decades ago,” Pete Buttigieg, the transportation secretary, said in an interview. “It’s one of the forms of infrastructure that takes the longest to update or refresh. And yet we’re seeing those vulnerabilities everywhere across the country.”
A study in the journal PLOS ONE found that extreme temperatures resulting from climate change could cause one in four steel bridges in the United States to collapse by 2050. By 2040, failures caused by extreme heat could require widespread bridge repairs and closures, the researchers found.
Another study found that exposure to new levels of extreme heat is causing the pavement on American bridges to buckle. Meanwhile, heavy precipitation linked to climate change is increasing the phenomenon of “bridge scour,” the erosion of soil sediment around bridge foundations that is the leading cause of bridge failure in the United States, studies show.
Troubled bridges are already starting to affect supply chains and the cost of goods. In 2022, a 30-foot section of bridge on the California-Arizona border of Interstate 10, along a major trucking route from Phoenix to the port of Los Angeles, was swept away during record rainfall. That washout followed a 2015 collapse of another Interstate 10 span, the Tex Wash Bridge, during what was described at the time as a 1,000-year flood. Each closure added an estimated $2.5 million per day to trucking costs because of delays and additional fuel, according to the American Transportation Research Institute. Such bridge closures are projected to increase significantly across the country over the coming decade, engineers said.
“With a lot of these bridge closures, trucks have to reroute far more than normal. It adds anywhere from 15 to 100 miles per trip, when a trucking trip typically costs about $91 per hour,” said Dan Murray, senior vice president of the American Transportation Research Institute. “And it becomes very inflationary. We’re buying the same goods and the unexpected costs get passed on to consumers.”
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Impact of climate change on the integrity of the superstructure of deteriorated U.S. bridges:
Bridges in America are aging and deteriorating, causing substantial financial strain on federal resources and tax payers’ money. Of the various deterioration issues in bridges, one of the most common and costly is malfunctioning of expansion joints, connecting two bridge spans, due to accumulation of debris and dirt in the joint. Although expansion joints are small components of bridges’ superstructure, their malfunction can result in major structural problems and when coupled with thermal stresses, the demand on the structural elements could be further amplified. Intuitively, these additional demands are expected to even worsen if one considers potential future temperature rise due to climate change. Indeed, it has been speculated that climate change is likely to have negative effect on bridges worldwide. However, to date there has been no serious attempts to quantify this effect on a larger spatial scale with no studies pertaining to the integrity of the main load carrying girders. In this study, we attempt to quantify the effect of clogged joints and climate change on failure of the superstructure of a class of steel bridges around the U.S. We surprisingly find that potentially most of the main load carrying girders, in the analyzed bridges, could reach their ultimate capacity when subjected to service load and future climate changes. We further discover that out of nine U.S. regions, the most vulnerable bridges, in a descending order, are those located in the Northern Rockies & Plains, Northwest and Upper Midwest. Ultimately, this study proposes an approach to establish a priority order of bridge maintenance and repair to manage limited funding among a vast inventory in an era of climate change.