GREEN BAY, Wis. (AP) -- The sag in the Green Bay bridge used by thousands of cars a day is likely due to corrosion in pilings that buckled underneath a support pier, Wisconsin Department of Transportation officials said Thursday.
The Leo Frigo Memorial Bridge over the Fox River has been closed since early Sept. 25, when a deep dip developed in the pavement. Officials quickly determined that a support pier under that part of the bridge had sunk about 2 feet, but they weren't sure why.
The agency's investigation determined 100-foot-long pilings under the pier had corroded, probably from water and the soil composition in that area and organic matter.
Lesser corrosion was found on the piers near the one that sank, though most of the 51 piers were in good shape, officials said at a news conference.
"This does not indicate the rest of the bridge is in danger of collapse," said Tom Buchholz, the DOT project manager for the bridge investigation. "These foundations, these piles, have huge safety factors on them so if one pile fails there are 39 others to support the bridge."
DOT spokesman Kim Rudat said now that the cause has been identified, attention would shift to planning repairs.
Officials advised people to allow extra travel time to get to Sunday's game between the Green Bay Packers and Detroit Lions. The Leo Frigo bridge typically carries 31,000 cars on game days, about 3,000 more than on non-game Sundays. Cars are being rerouted from Interstate 43 to other roads and bridges.
"We're all on the same page. We all have the same mission: We want to get to the game safely and on time," traffic engineer Randy Asman said.
The 33-year-old bridge stretches 8,000 feet and is the second longest in Wisconsin.