Lessons learned from Minnesota bridge collapse

| 11/18/2008

Federal officials are calling for the bridge inspection process to change following the release of an NTSB report that cited design flaws and inadequate load capacity as contributing to the collapse of the I-35 bridge in Minneapolis in August 2007.

The collapse killed 13 people and injured 145 during the evening rush hour on Aug. 1, 2007.

The National Transportation Safety Board issued its final report on Friday, Nov. 14, declaring that a design flaw during previous modifications plus the weight and placement of construction equipment created the perfect storm that led to the collapse of the Interstate 35 span.

“We believe this thorough investigation should put to rest any speculation as to the root cause of this terrible accident and provide a roadmap for improvements to prevent future tragedies,” NTSB Acting Chairman Mark V. Rosenker stated in the board’s report.

U.S. Rep. James Oberstar, D-MN, who chairs the House Transportation and Infrastructure Committee, said the future of bridge inspections must change to prevent future tragedies.

“Inspectors will now have to go back to the design of the bridge itself, to review the engineering documents,” Oberstar stated.

“They can no longer assume that the bridge was properly designed.”

NTSB officials said the inadequate design of the bridge’s gusset plates, while the responsibility of the designing firm, were not detected by state or federal transportation officials in previous reviews of the 40-year-old I-35W bridge.

Oberstar said there are 740 bridges of similar age and design in the U.S.

Oberstar filed a bill in the House of Representatives following the bridge collapse, calling for the federal government to spend $1 billion and revise the way structurally deficient bridges are prioritized for repair or replacement.

The bill, HR3999, passed the House overwhelmingly but was stalled on the Senate floor prior to the recent federal election.

Congress and the Barack Obama administration will have the task of addressing the nation’s aging highway and bridge infrastructure as committees, including Oberstar’s, set out to write the next large-scale transportation due in Congress in 2009.

In the meantime, current U.S. Transportation Secretary Mary Peters directed the Federal Highway Administration to revise its training materials and inspection procedures and to work with the states to improve the design process.

“All of us in the business of transportation safety have an absolute responsibility to ensure that the right lessons and the right conclusions are drawn from this terrible incident,” Peters stated.

– By David Tanner, staff writer