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Minneapolis Bridge Collapse Will Have Nationwide Fallout

Aug. 2, 2007

Story Contact:  Kevin Carlson, 573-882-3346,

COLUMBIA, Mo. — The collapse of the Interstate 35W bridge in downtown Minneapolis on Wednesday evening brought the structural safety of the nation's aging overpasses into tragic focus. University of Missouri-Columbia civil engineer Glenn Washer believes the catastrophe is a watershed event in the bridge industry that may spur states to revise how they prioritize the funding of bridge inspection and repair.

“There are almost 600,000 bridges in this country, with an average age of 42 years,” said Washer, assistant professor in MU's Department of Civil and Environmental Engineering. “With that many aging bridges, accidents can happen. The only way to completely eliminate the risk is to not drive on bridges. There is a massive effort by State Departments of Transportation to inspect, monitor and maintain bridges, but implementing some of the new technology and getting the work done is a significant challenge.”

The last major bridge collapse happened 40 years ago. On Dec. 15, 1967, the Silver Bridge in Pleasant Point, W.Va., buckled into the Ohio River, claiming 46 lives. Bridges were not inspected before that point, and the unfortunate event spurred states to implement monitoring efforts to thwart future disasters. The fallout from the Minneapolis collapse could trigger similar action.

“There is incredible technology out there to help monitor and diagnose problems, and we continue to develop new technologies to keep up with the infrastructure of bridges,” Washer said. “This will bring new focus to that, as well as remind the public that we use and count on bridges every day.”

Nearly 13 percent of the nation's bridges were classified as “structurally deficient,” meaning they are deteriorating, as of 2004, according to the latest report issued by the Federal Highway Administration (FHWA). Another 13 percent were classified as “functionally obsolete,” meaning they are structurally sound but no longer meet transportation standards and demands. In Missouri, 31 percent of the state's bridges are either structurally deficient or functionally obsolete, according to the November 2006 issue of Better Roads magazine, which is geared toward the governmental highway and bridge construction industry.

Earlier this year, Washer received $109,500 from the National Academy of Sciences to develop a system that can continuously monitor piers — the primary support systems of a bridge — and warn of structural weaknesses. Upon completion of a prototype, the New York Department of Transportation will select a bridge to conduct a six-month test of the system. He also has recently received a $240,000 grant from the Missouri Department of Transportation to develop infrared imaging technologies to detect defects in concrete bridges.

Prior to joining the faculty at MU, Washer was the Federal Highway Administration's leading technical expert for the inspection and nondestructive evaluation (NDE) of highway bridges. While with the FHWA, Washer led a national study of the reliability of visual inspection methods, the primary methods used to assess the condition and safety of the nation's bridges.