Workers search for bodies in bridge debris

MINNEAPOLIS - Difficult conditions hampered the search for bodies still trapped beneath the twisted debris of a collapsed bridge Thursday, as finger-pointing began over a report two years ago that found the bridge was "structurally deficient."

The official death count from Wednesday evening’s collapse stood at four, but Police Chief Tim Dolan said more bodies were in the water. Hospital officials said 79 others were injured.

The victims were identified Thursday evening as Sherry Engebretsen, 60, of Shoreview; Julia Blackhawk, 32, of Savage; Patrick Holmes, 36, of Moundsview; and Artemio Trinidad-Mena, 29, of Minneapolis.

Authorities said eight were still missing, down from as many as 30 earlier, according to Reuters and local media reports. Many initially counted as missing turned up throughout the day.

"It's taken 24 hours, but I think we have a pretty accurate count," Hennepin County Sheriff Rich Stanek told the Minneapolis Star Tribune.

A strong current and low visibility hampered the search, and divers were pulled out of the water briefly Thursday afternoon so the water could be lowered, said Inspector Jeff Storms of the sheriff’s department.

“There are more than 10 vehicles in the river,” Fire Chief Jim Clack said, without saying if there were victims inside. The effort had shifted earlier in the day from rescue to recovery.

The eight-lane Interstate 35W bridge, a major Minneapolis artery, was in the midst of repairs when it buckled during the evening rush hour. Dozens of cars plummeted more than 60 feet into the Mississippi River, some falling on top of one of another. A school bus sat on the angled concrete.

The bridge is the state’s busiest, and carries approximately 141,000 vehicles per day.

Engineers wondered whether heavy traffic might have contributed to the collapse. Studies of the bridge have raised concern about cracks caused by metal fatigue.

"I think everybody is looking at fatigue right now, fatigue due to heavy traffic," said Kent Harries, an assistant professor of civil and environmental engineering in the University of Pittsburgh's School of Engineering. "This is an interstate bridge that sees a lot of truck traffic."

Problems found in 2005
Few high-traffic bridges in the United States scored worse than the Minneapolis bridge performed on its 2005 inspection, according to an analysis of federal records by MSNBC.com.

Only 4 percent of the high-traffic bridges in the nation scored lower than the I-35W bridge in Minneapolis, according to records in the National Bridge Inventory.

First, bridges are given what's called a "sufficiency rating." This measure includes some safety elements (such as structural integrity), but also weighs the bridge's size for its current traffic.

Taking into account many factors in a complex formula, the sufficiency rating ranges from 100 (the highest score) down to 0. A rating of 80 indicates that some rehabilitation may be needed. A score of 50 or less indicates that replacement may be in order.

The I-35W bridge in Minneapolis was given a score of 50.0 in the 2005 inspection.

Out of those 104,348 high-traffic bridges (those carrying at least 10,000 vehicles a day), 37,747 scored below 80, indicating some rehabilitation may be needed. That is 36 percent of the total.

But few bridges were rated below than the Minneapolis bridge. Out of those 104,348 high-traffic bridges, only 4,227, or 4 percent, scored below 50, or worse than the I-35W bridge.

The median sufficiency rating for bridges nationwide, including only those that carry 10,000 or more vehicles a day, is 85, according to MSNBC.com analysis of the National Bridge Inventory. Half the bridges score higher, and half lower, than 85.

On a second measure, the Minneapolis bridge was listed as "structurally deficient."

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.

A bridge is considered "functionally obsolete" if its design doesn't meet modern standards for the traffic it now carries (width, number of lanes), or if it is antiquated in important design elements such as clearances under the bridge, or alignment of the road as it approaches the bridge.

Nationally, one in four high-traffic bridges is in either -- or both -- of these categories.

The I-35W bridge in Minneapolis was rated as "structurally deficient" in a 2005 inspection, according to the National Bridge Inventory. Its deck was in "fair condition," the superstructure in "poor condition," and the substructure in "satisfactory condition."

Overall, the structural evaluation of the bridge was listed as "meets minimum tolerable limits to be left in place as is." The next lowest rating is "basically intolerable."

The cost of work needed on the bridge was estimated in 2005 at $3 million.

Records show that Minnesota officials were warned as early as 1990 that the was structurally deficient, yet they relied on a strategy of patchwork fixes and stepped-up inspections. The bridge got the rating from the federal government, who cited significant corrosion in its bearings. The bridge is one of 77,000 bridges in that category nationwide, 1,160 in Minnesota alone.

MSNBC

The designation means some portions of the bridge needed to be scheduled for repair or replacement. “It didn’t mean that the bridge is unsafe,” Transportation Secretary Mary Peters said.

This year’s inspection started in June and would have been finished in September after $2.4 million worth of maintenance on the deck, joints, guardrails and lights.

“We thought we had done all we could. Obviously something went terribly wrong,” state bridge engineer Dan Dorgan said.

Dorgan said the bearings could not have been repaired without jacking up the entire deck of the bridge. Because the bearings were not sliding, inspectors concluded the corrosion was not a major issue.

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