The Washington Avenue Bridge redesign project on the Green Line in Minneapolis has been recognized for engineering excellence by the American Council of Engineering Companies of Minnesota.
The project involved a redesigned bridge over the Mississippi River to accommodate light-rail trains. The council presented the 2013 Engineering Excellence Grand Award to the Metropolitan Council and AECOM for retrofitting the bridge for the Green Line, which is 89 percent complete and scheduled to open in mid-2014, Metropolitan Council officials said in a prepared statement.
Built in 1965, the double-deck bridge is less than a mile downriver from the Interstate 35W bridge that collapsed in August 2007. A couple of months before the disaster, the Metropolitan Council awarded the Washington Avenue Bridge retrofit contract to AECOM. After the I-35 bridge collapse, the Washington Avenue project took on heightened importance, council officials said.
Like the bridge that collapsed, the Washington Avenue Bridge was "fracture critical," meaning that its structure lacked redundancy to prevent a collapse should a single structural member fail, they said.
"The project criteria itself was a challenge: provide for an additional 75 years of service life and meet current design specifications for the new and existing structural members," AECOM officials said.
The bridge rehabilitation included the construction of four new truss girders interlaced among the steel framing of the existing structure.
The Green Line, also known as the Central Corridor Light-Rail Transit Project, will link downtown St. Paul and downtown Minneapolis along Washington and University avenues via the state Capitol and the University of Minnesota.
AECOM also is working on the Southwest Light-Rail Transit Project, also known as the Green Line extension.
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