Touts New State-of-the-Art Safety Design Used on the Marquette Interchange

Governor Jim Doyle today announced the Wisconsin Department of Transportation (WisDOT) will complete inspections of the 15 deck truss bridges in the state within the next two weeks.  A 16^th deck truss bridge located in Burnett County has been removed and is currently being rebuilt.  The Governor also directed WisDOT to take the added step of installing sensors on the 15 bridges to provide 24-hour monitoring to test the structures.  Following the Minnesota tragedy, Governor Doyle directed WisDOT to review safety data for all of the 13,654 bridges in the state.  

The Marquette Interchange includes new state-of-the-art design that will make the bridges the safest in the country.  The interchange incorporates eight steel box girder bridges that are the first bridges of their kind to be considered non-fracture critical by the Federal Highway Administration, which means that the bridges would not collapse even with the complete failure of one of the two steel box girders.

“People in Wisconsin should have confidence that our bridges are safe,” said Governor Doyle. “While we must learn the cause of the Minnesota tragedy, I want the state to take extra measures immediately to ensure our bridges are sound.  In Wisconsin we are using the best, newest technology available on our roads and bridges to ensure the safety of people in Wisconsin.  The Marquette Interchange stands as a model for all of the country.”   

The Governor touted the improved “high performance” steel that was used in the fabrication of the steel box girders as an extra measure of safety in the design of the Marquette Interchange. This design approach and the use of high performance steel will be the normal way to build steel box girders in Wisconsin on future projects.

WisDOT plans to mount “accelerometers” on Wisconsin’s 15 deck truss bridges to check for any unusual movement.  The instruments will directly feed information back to WisDOT via wireless technology as to how the bridges are performing. Any unexpected movements would be investigated immediately.

Deck Truss bridges are similar in design to the I-35 West bridge in Minnesota that collapsed last week.  The state no longer builds deck truss bridges on the state system as they have been replaced with more modern designs.  On a deck truss bridge, the superstructure typically consists of two parallel trusses that are the main load-carrying members of the bridge and the roadway is placed on top of the main members. 

A list of the inspection schedule for the 15 deck truss bridges is below.

Deck truss bridges in Wisconsin – Inspection Schedule

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