Since I-35W, state has more eyes and sharper focus on bridges

Published 7:52 am Tuesday, August 1, 2017

By Brian Bakst

MPR News/90.1 FM

Built in 1961 and carrying some 23,000 cars a day, the Blatnik Bridge in Duluth has experienced ample wear and tear.

Email newsletter signup

Last year, nearly two dozen of Blatnik’s connector plates and a pivotal floor beam were repaired or replaced after a 2014 inspection revealed cracks that had only been temporarily fixed. The plate work was part of a $2.8 million refurbishment, with more work planned on the steel truss bridge in the years to come.

“If anything is discovered that poses imminent danger to the public, the bridge would be closed immediately for repair,” the Minnesota Department of Transportation assured in an update.

Annual inspection reports for the state’s second-longest bridge read like a diary of defects — some minor, some more concerning — that makes Blatnik a fixture on the state’s fix-up list. It’s among a shrinking roster of “fracture-critical” bridges in the state, which are those built without redundancies that could make them susceptible to collapse if a key component fails.

These bridges generated public unease in the wake of the Interstate 35W bridge disaster in Minneapolis, which killed 13 and injured 145, when that fracture-critical bridge broke apart during rush hour on Aug. 1, 2007. In the years since, MnDOT has worked to rebuild the state’s most vulnerable bridges, and to rebuild confidence that it is keeping close tabs on bridge health.

Ed Lutgen, the inspection program manager at MnDOT, said the I-35W tragedy stuck with him and others in the department. That’s evident by the orange hardhat that he wears in the field, bearing decals with a 35W logo.

“Every August I remember the day and the memories come back to me,” said Lutgen, who was on scene after the collapse as investigators searched for the cause. “I look at that every day, and as I’m out doing some of these inspections to make sure the lessons learned from that event can really be carried forward to that next generation of engineers and inspectors.”

Chris Ramberg, an inspection coordinator, was among those hired after the collapse.

“The inspection program was well-delivered to the guys coming in,” he said. “They did a nice job passing on their knowledge of what went on to us guys who started after it.”

On a rainy morning a couple weeks back, Ramberg and veteran inspector Brad Dumbeck were lined up for inspections of a series of overpass bridges along Highway 610 in Brooklyn Park.

Traffic whizzed by at 65 mph when Dumbeck exited the truck parked with flashing lights atop the cab.

He was dressed top to bottom in reflective yellow and lugged lots of gear — on a belt, in his pockets and draped across his neck. He had gauges for measuring cracks, markers to label problem spots, a digital camera and a clipboard for documenting various components, two flashlights and a pair of binoculars to see into each nook and cranny.

Dumbeck started with a rolling wheel — picture a unicycle without the seat — that he used to measure the length and width of the bridge and its components. That was to make sure it matches design specifications.

“Without that, I’d be dragging the tape measure out a lot,” he said. “It helps.”

He ran his hand along hairline cracks in a concrete abutment. It means there are moisture issues, but none that are alarming to him. A bit later, Dumbeck paused to jot down notes, but he was still taking stock of things.

“Right now, I’m listening to the top of the deck,” he explained. “As a car goes over, I’m listening to what the joints are telling me.”

It’s tedious work involving sight, sound and feel.