Age and the elements are taking a heavy toll on the 80-year-old Stillwater lift bridge, according to a new inspection report by the Minnesota Department of Transportation.
Transportation officials say the bridge is safe for the 17,900 vehicles that cross it daily, but because of deficiencies inspectors noted prior to Aug. 17, they have imposed additional weight restrictions and are making temporary repairs on the span.
According to the inspection report, four locations on the bridge showed signs of advanced corrosion and deterioration that were inadequate for the posted load of 40 tons for large trucks.
Inspectors discovered deterioration to steel beams, which unless repaired could cause the bridge to collapse.
Nancy Daubenberger, the department's bridge engineer, said the corrosion is serious enough that department decided to impose new vehicle weight and length limits. Weight limits will fall from 28 tons to 24 tons for single trucks and from 40 tons to 28 tons for semi-tractor trailers and trailer trucks.
"The temporary repairs we're doing here in the next week or so are to be able to make sure we have enough strength in some of these members to get us to the more comprehensive project next year," Daubenberger said.
The repairs, scheduled for next year, are designed to buy more time for the aging span. But many agree the bridge will have to be replaced.
The department plans a four-lane, freeway-style span about a mile down the river from Stillwater that could carry more traffic and relieve congestion.
MnDOT records show daily traffic volume across the Stillwater lift bridge has grown nearly tenfold from 1947. That year, 1,950 vehicles used the span.
Many of the people who use it today are commuters heading to homes in western Wisconsin communities including Somerset, about 10 miles from Stillwater. The town of about 2,300 residents is a destination for legions of tourists who tube down the Apple River, just a few steps from downtown.
Lots of new homes have sprouted on Somerset's outskirts with abundant green fields next to them ready for future development.
While plenty of new residents have moved in over the past decade businesses have been slow to follow because of the bridge congestion, Somerset Chamber of Commerce President Casey Brennan Goessl said.
"Even though the people are here, they're avoiding Somerset because of the bridge, absolutely," Goessl said.
Brennan Goessl and others view a new St. Croix River bridge as a development tool that will attract business and fuel the region's growth.
Opponents of the four-lane bridge, projected to cost $633 million, worry it will spawn development that degrades the small town feel and rural environment of the St. Croix valley.
They've proposed a smaller, three-lane bridge that would cost about $260 million — a proposal Gov. Mark Dayton has rejected.
"Why are we spending what's been estimated over $300 to $350 million dollars to subsidize development in western Wisconsin is very confusing at this point," said Sierra Club North Star chapter spokesman Jim Rickard, a St. Croix Valley resident.
Voices on all sides of the bridge issue have been using Congress' summer recess to talk with members about a new river crossing.
Bills in both the House and Senate would, if approved, pave the way for new bridge construction that could begin in 2014.
At the earliest, state transportation officials say the new span would open to traffic seven years from now.
In the meantime engineers say they will continue to repair the Stillwater lift bridge and keep it safe for drivers.