I-35 bridge was rated among the nation's worst

Bill Dedman Investigative reporter • Profile • E-mail

Only 4 percent of the nation's high-traffic bridges scored worse during inspections than the steel-deck truss bridge in Minneapolis that collapsed into the Mississippi River on Wednesday, according to an analysis of federal records by MSNBC.com.

The Minneapolis bridge was not alone in being flawed. More than 70,000 bridges across the country are rated as "structurally deficient," like the span that collapsed in Minneapolis, according to federal statistics.

To see a list of deficient or obsolete bridges in each state, click here.

It is unclear how many of the spans pose actual safety risks. Federal officials alerted the states late Thursday to immediately inspect all bridges similar to the Mississippi River span that collapsed.

Minneapolis and beyond
According to the MSNBC.com analysis of federal inspection records, the bridge that collapsed Wednesday was near the bottom of the ratings systems.

The I-35W bridge was given a low "sufficiency rating," which varies from the best score of 100 down to 0. Its score was only 50. A score below 80 indicates that some rehabilitation may be needed, while a score of 50 or less shows that replacement may be in order. This measure includes safety elements (such as structural integrity), but also factors in elements such as the bridge's size for its current traffic.

Nationwide, few high-traffic bridges rated below below the Minneapolis bridge. Out of the 104,348 heavily used structures, only 4,227, or 4 percent, scored below 50, or worse than the I-35W bridge. MSNBC.com used minimum daily traffic of 10,000 vehicles to indicate that a bridge gets significant daily use.

On a separate measure, while the I-35W bridge was rated structurally deficient in 2005, it was deemed to have met "minimum tolerable limits to be left in place as it is," according to the federal National Bridge Inventory database of inspection records.

The next lowest rating is "basically intolerable."

A bridge is rated as structurally deficient if it gets a rating of "poor" or worse on any of its three main components: deck, superstructure, and substructure, or if its overall structural evaluation is "intolerable." There are other criteria, but these are the main ones.

The Minneapolis bridge's deck, or driving surface, was rated in "fair condition." The superstructure was in "poor condition," and the substructure in "satisfactory condition."

If one limits the picture to just the 104,348 bridges that carry at least 10,000 vehicles a day, then 6,960 bridges are rated as structurally deficient, and 20,494 are functionally obsolete, indicating they weren't designed to meet modern standards or their current traffic levels.

The cost of immediate work needed to the bridge was about $3 million in 2005, according to federal database.

'Anomaly'
Meanwhile, the head of the National Transportation Safety Board said people shouldn’t fret about general bridge safety across the country.

“I don’t believe that they should be worried at all,” NTSB Chairman Mark Rosenker said on Friday from the scene of the collapse in Minneapolis.

“Rules that have been put into place as a result of a recommendation that we made some 30 years ago have improved the conditions and the standards that in fact these things are being inspected on,” Rosenker said.

“But with that said, as a result of this catastrophic disaster, we’re going to be looking at the rules and finding out in fact if they should be tightened, made more stringent," he said.

Rosenker said it’s too early to know if the accident could have been avoided.

“They are built not to fall down. This is an anomaly and we’re going to try to find out why this is an anomaly and prevent that anomaly from ever happening again” he said in an appearance on ABC’s “Good Morning America."

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