Expert: AP article on imminent U.S. bridge collapses 'misleading' and alarmist
A former president of the American Society of Civil Engineers (ASCE) said that a recent AP article warning that thousands of U.S. bridges are on the verge of imminent collapse is an overly alarmist misreading of current data.
In an interview with Raw Story, engineer and bridge expert Andrew Hermann said that while many bridges in the country are reaching the putative end of their lifespans, the inspection system is rigorous enough that drivers, train passengers and pedestrians should not be afraid to trust the nation's bridge and highway system.
On Monday, AP Impact published an article entitled "Many U.S. Bridges Old, Risky and Run Down," in which the wire service said that in a study of 607,380 bridges in the country, 65,605 were listed as "structurally deficient" and 20,808 are considered "fracture critical." Of those bridges, 7,795 are both, which the AP said presents "a combination of red flags that experts say indicate significant disrepair and similar risk of collapse."
Herrmann, however, said that this is a misunderstanding of engineering terms.
"There's a little distortion in those facts," Herrmann said. "Yes, we have over 65,000 bridges that are structurally deficient and over 20,000 that are fracture critical, but fracture critical is really an engineering term" that means if one component of the bridge gave way, the whole bridge would collapse. He explained that brand new bridges can be considered fracture critical if they would fail with the removal of certain structures.
"But the misleading thing is that a bridge could be structurally deficient for a number of reasons way beyond the fracture critical," he said. "A bridge could be declared structurally deficient because of its deck, because of the piers that hold it up, because of the waterway. It could also be due to an analysis of the structure and the superstructure, but there's five categories, of which two would only apply to the fracture critical," meaning that the majority of the components holding the bridge together are perfectly functional.
"But," he said, "it's kind of misleading. It's sort of one plus one equals three and it's not really true...There's a very slim chance of them falling."
There are bridges in need of repair in the country, he said, and state and local governments are loath to part with the necessary monies, but on the whole, bridge inspectors are constantly working to make certain that the bridges are safe.
"The Department of Transportation inspects these bridges," said Herrmann. "There's a federal law that says that every bridge has to be inspected at least every two years. If engineers find things that are deficient in the bridge that cause concern, they inspect them more frequently. And if it's really a concern, they'll close the bridge."
Each year, the ASCE releases "report cards" on the health of U.S. infrastructure. The group also has issued a number of "Failure to Act" reports, in which scientists and engineers estimate the economic and social impact of doing nothing to shore up the country's infrastructure.
According to the latest Failure to Act report on bridges, Herrmann said, the agency found that investing $94 billion in bridges now will save the U.S. $900,000 by 2020 in lost productivity and other costs.
Sadly, he said, most politicians currently lack the political courage to take the necessary measures to raise money for bridge repair, such as gasoline taxes, toll charges for some highways and increased vehicle inspections. Also, rather than write highway funding bills in six year increments as had been done in the past, Congress now only authorizes funding for two years at a time.
"When you look at surface transportation infrastructure, it's not something you can do and plan for in just two years," he said. "You need that secure time frame to look forward so you can plan for the future."
The nation's infrastructure report cards, as well as the latest batch of Failure to Act reports can be read at ASCE.org.
[image from the 2007 I-35 bridge collapse in Minneapolis via miker / Shutterstock.com]