Greenwood bridge will be closed 5-6 months during 2023 replacement project

Engineers working on the planned 2023 replacement of the Clark County G bridge over the Black River in Greenwood are anticipating the crossing will be completely closed for 5-6 months once work begins. If the summer construction season includes lots of rain and high water, that timeline could be even longer.

Speaking at a May 18 public informational meeting at Clark Electric Cooperative’s meeting room, Kevin Hagen of AECOM, a Stevens Point firm hired to work with the county on the replacement project, said the 2023 work will be a complete replacement project, all the way down to the concrete abutments that are secured into the Black River bedrock. Expected to cost nearly $3 million, the new bridge will be longer and wider, and will not have an overhead truss structure as does the one built in 1938 that has connected Greenwood to the west for more than eight decades.

The county has certainly gotten its money’s worth with the old bridge, Hagen said. The bridge was built 83 years ago and has undergone one major rehabilitation job since -- a concrete deck resurfacing in 1996 -- and had surpassed its expected life span.

“The typical service life of a bridge is 50 to 75 years,” Hagen said.

A 2020 inspection showed the bridge’s sub-deck trusses are showing significant signs of wear and deterioration. Further compromising the bridge is its overhead structure, which, at 13.5 feet in height, is subject to strikes by tall trucks or farm equipment. That has bent multiple beams on the structure, which, in turn, decreases its strength.

“That’s been hit several times over the years,” Hagen said. “Every time the bridge is hit it causes concern over

CONTRIBUTED IMAGE the capacity. Those hits certainly can do some damage.”

Hagen said the Wisconsin Department of Transportation did make a determination that the County G bridge is too old and dysfunctional for renovation. To widen the deck beyond its narrow 24-foot width would have required major structural upgrades, Hagen said, making a renovation too costly.

“On this particular bridge, rehabilitation is not feasible,” Hagen said. “This bridge is both structurally deficient and functionally obsolete.”

The new bridge under design will be wider and longer. It will still have 11-foot traffic lanes, but there will be four feet of shoulder space on either side. Now there is less than a foot, which makes it “uncomfortable” for pedestrians or bicyclists.

“It’s pretty narrow,” Hagen said.

The new bridge could also be widened further to add a lane for snowmobile and ATV traffic. Clark County has applied for funding through the state recreational vehicle registration fund, and if money is available, there is time to design the new span with the extra width.

“We don’t know what the results of that funding will be,” Hagen said.

Without the extra lane, the new bridge is being designed with a 32-foot width.

It will also be a foot higher in elevation. The extra elevation is needed to accommodate hydraulic loads during times of high water, and that will mean the bridge will also be lengthened a bit.

The new bridge will have two concrete abutments placed in the river. There is just one abutment now, in the bridge’s center.

Hagen said the exact project timeline is still uncertain, but plans are going forward for a 2023 construction season project. The official detour will take traffic south to the Black River bridge on County Road OO. The project will begin with removal of the old structure, and there will be no time during work when the any traffic will be able to pass.

“Five to six months is what we’re estimating right now,” Hagen said.

Because the river depth is too shallow during low water times, crews will not be able to use a barge as a work base. Instead, gravel approaches will be built from both sides to bring in equipment.

State transportation funds will cover 80 percent of the total project, with Clark County on the hook for the rest because the bridge is on a county road.

“It’s a pretty good deal for the county,” Hagen said.

“On this particular bridge, rehabilitation is not feasible. This bridge is both structurally deficient and functionally obsolete.” -- AECON engineer Kevin Hagen