MnDOT delivers first project using CMGC method

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By BRIAN JOHNSON
BridgeTower Media Newswires

MINNEAPOLIS – The Minnesota Department of Transportation this week wrapped up work on the first project it has delivered using the construction manager-general contractor system: the $145.9 million Winona Bridge rehabilitation and construction project.

The city of Winona and MnDOT held a dedication ceremony on Monday to mark the reopening of the historic Warren through-truss bridge after an extensive rehabilitation that touched on everything from the deck to the gusset plates.

The project was MnDOT’s first to be delivered by the construction manager-general contractor method, which requires a contractor – Ames Construction in this case — to bid against an independent cost estimator on individual work packages. On its website, Ames said the CMGC method “engages a construction manager during the design process” and “allows new bridge construction to begin while still finalizing design.”

“CMGC is not for every project, but … it gives us another tool to look at the project and figure out what the best method is,” said Mike Dougherty, a MnDOT spokesman.

The work on the Winona bridge began in the fall of 2016, shortly after a new concrete box-girder bridge opened just upriver from the vintage 1940s-era span.  The crossings carry Highway 43 over the Mississippi River in Winona. When the historic bridge reopens, travelers will leave the southeast Minnesota city on that span and enter on the new bridge, according to MnDOT.

Dougherty said the rehab will make the bridge last 50 years longer.

Repairing the bridge was no small feat. Among other things, the project called for the rehabilitation of the through truss, the removal and replacement of the deck, and the removal of approach spans and sidewalks.

The finishing touches include sand blasting, priming, painting and landscaping. Some of the site work around the bridge will continue this summer after the bridge reopens to motorists, according to MnDOT.

The project team drilled down to the nuts and bolts of the structure. As part of the work, crews removed nearly 35,000 rivets and replaced them with high-strength bolts. Put another way, they had to nearly pull the bridge apart while also making sure it stayed intact, Dougherty said.

“They had a lot of analysis and calculations of what could be removed and replaced while still maintaining the bridge upright,” Dougherty said.

Winona Mayor Mark Peterson said the reopening of the bridge will mark a “historic day” for the city.

“We have added a new bridge in 2016 and now the historic bridge has been rehabilitated to ensure we can rely on it into the future and maintain one of our city’s signature symbols,” Peterson said in a statement.