The Wisconsin Department of Transportation has shut down an on-ramp to Interstate 43 in Milwaukee because of a design flaw.
The closed structure is the southbound I-43 ramp from Wisconsin Avenue in the Marquette Interchange. According to WisDOT, crews discovered cracks in one of the columns supporting the structure during a routine inspection Monday.
Peg Schmitt, director of public affairs at the Wisconsin Department of Transportation, said the standard inspection Monday revealed hairline cracks in the ramp’s infrastructure.
“These are what we refer to as shear cracks that run in a diagonal direction — almost as if you put your fists side by side and move them up and down from each other, that’s shear force,” said Beth Cannestra, director of the Wisconsin Department of Transportation Bureau of Structures. “It’s more of a slippage-type force.
“When you see that kind of force, it’s often because something isn’t able to handle the load it supports.”
Cannestra said similar investigations have found cracks much more open than the ones found on the I-43 ramp, and as a result she said those findings did not warrant an immediate ramp shutdown. It did, however, spur her office to look into the cause.
“With rough calculations, we determined there was an error in design, so we notified the consultant (HNTB Corp.) and asked they look at their calculations,” Cannestra said. “Once we got the loading information, we decided to take action out of regard for public safety.”
Such routine inspections are conducted every two years, she said, and this marked the first time the Marquette Interchange was reviewed since August 2008 — shortly after construction on the project was completed.
“It was our heads up, and that’s why we do inspections,” she said. “If there’s any possibility of any sort of problem, we’re going to take action. We don’t risk the safety of the public.”
Despite the anticipated boost in holiday traffic, Schmitt said the Marquette Interchange was unlikely to see a dramatic increase from the 15,000 vehicles that use the ramp daily. The Marquette University student body is expected to be among those most affected by the abrupt closure.
“We’ve always had a good working relationship with the Wisconsin Department of Transportation, and they made us aware of the announcement before it even occurred,” said Andy Brodzeller, Marquette University media relations specialist. “The DOT has already adjusted alternate routes for anyone to use, whether it’s for our own campus body or the general public.”
The design firm, HNTB Corp., of Kansas City, Mo., will fix the problem at no cost to taxpayers, according to WisDOT. However, it is unclear how long the repairs will take or how much they will cost. Cannestra said the ramp will be closed through the holiday weekend.
Cannestra said she is confident WisDOT will continue its long-standing working relationship with HNTB, and she did not believe emergency inspections will be necessary on additional state projects done by the company.
“They’ve really been a good team player with this,” Cannestra said. “They’ve been on board since the problem has been identified and accepted responsibility for their work. They’ve acknowledged it’s a design error, and they recognize they’re responsible for the repair.”
HNTB officials did not immediately return calls for comment.
As a result of the ramp closure, WisDOT is advising motorists to take 11th Street south to Tory Hill Road/Michigan Avenue. Turn left onto Tory Hill Road/Michigan Avenue and continue east on Michigan Avenue to North 2nd Street. Turn right onto North 2nd Street to the I-43 southbound/I-94 eastbound entrance ramp.
The Associated Press contributed to this report.