The Plymouth Avenue Bridge over the Mississippi River in Minneapolis won't reopen until October, almost exactly two years since corrosion of its cables forced its closure to all but cyclists and pedestrians.

Although the $6 million repair project has been funded for almost a year, the city engineer's office just signed off on it this week. Assuming construction begins in July, the bridge should open around mid-October, according to Jack Yuzna, a city engineer. But it will open with just two of its four lanes; all lanes are expected to be open when repairs are completed in 2013.

The October opening is three months later than projected by the city last summer. The repairs involve breaking out concrete around the corroded cables, replacing the cables and then pouring new concrete. The cables stretch the length of the bridge and hold together the box girders.

Engineers didn't want to start the project in the fall, only to stop when the weather grew too cold for concrete work. Then plans to use city crews for some of the concrete demolition changed when the city realized that there would be delays to take bids on specialized equipment and material for the job. So it now plans to seek bids from contractors, Yuzna said.

The closing of the Plymouth bridge in 2010 and the Lowry Avenue Bridge in 2008 have driven up traffic on the Broadway bridge that lies between them. Traffic rose by one-third on the Broadway bridge to a daily average of more than 25,000 cars between 2005, when both bridges were still open, and 2009. Hennepin County plans to open a new Lowry Bridge in August.

When it opened in 1983, the Plymouth Avenue bridge was the first in Minnesota to feature a post-tensioned box girder design. Construction began last month on the city's $14 million Van White Memorial Bridge, also a post-tensioned box girder bridge. The bridge will carry cars, pedestrians and bikers over railroad tracks and Bassett Creek, a long-planned connection between Dunwoody Boulevard and redeveloped areas of the North Side.

Steve Brandt • 612-673-4438