closed072708

I-35E reopened after part of bridge falls

Marlin Levison, Star Tribune

MnDOT officials inspect the Marlyland Avenue bridge overpass where the birdge material fell onto a vehicle being driven on Interstate 35E Saturday afternoon.

Pieces hit two vehicles, but no one was hurt. Traffic was jammed.

By PATRICK KENNEDY, Star Tribune

Last update: July 27, 2008 - 9:22 PM

Chunks of concrete crashed down from the Maryland Avenue overpass onto Interstate 35E Saturday, shutting down the busy freeway for several hours and causing a big traffic jam. The freeway is open today.

Concrete pieces struck two vehicles, one on the hood and the other on the windshield, but no one was hurt, said Kent Barnard, a spokesman for the Minnesota Department of Transportation.

A section, about 6 feet by 9 feet and 1 inch thick, fell from the bottom of the overpass in several pieces and covered the northbound lanes of I-35E with powdery debris.

The State Patrol closed the freeway in both directions shortly after the incident at 4:45 p.m. Traffic was rerouted onto exit ramps to get around the overpass.

Traffic on Maryland Avenue was also rerouted, but a MnDOT supervisor who visually inspected the bridge shortly after the incident cleared traffic to go over Maryland.

A bridge assessment team was dispatched to the site to investigate and determine if the bridge was safe, Barnard said.

Next week, inspectors will conduct a broader examination.

"We must take all precautions to keep the public safe," he said. "This is not totally unheard of for something like this to happen."

Minnesota State Patrol Lt. Rochelle Schrofer who was on scene described the incident as a "delamination" of the roadway: The underside of the roadway fell. It wasn't known what caused the pieces to fall.

A lift truck inspected sections that pass over both the northbound and southbound lanes.

By mid-evening, inspectors were cleaning the northbound side of the bridge.

"They actually go in there with a jackhammer device and knock down debris to the roadbed then sweep it up," Schrofer said. Work was continuing on the northbound side before moving over to the southbound side, where she said inspectors planned to clear more debris.

According to MnDOT's Statewide Bridge Inspections database, the Maryland Avenue overpass is bridge #6513. It was built in 1958, remodeled in 1973, and last inspected on Aug. 15, 2007.

It was given a sufficiency rating of 77 out of a 100 and was considered "structurally deficient." Generally bridge inspectors say a bridge with a rating below 80 means it needs rehabilitation while ratings of 50 or less may indicate the bridge needs to be replaced.

The bridge inspection report indicated the concrete deck underside had experienced some delamination in the past, but the areas had been repaired.

"It's not a terrible rating but it's partially rated that way because of the deck," Barnard said.

Patrick Kennedy • 612-673-7926 Staff writers Tim Harlow and Glenn Howatt contributed to this report.

Continue to next page