Work to begin lifting the sagging portions of the Leo Frigo Memorial Bridge on I-43 in Green Bay, Wisconsin is scheduled to begin Tuesday. According to the Green Bay Press Gazette, Zenith Tech Inc. is working on the repairs. It will be a BIG lift, indeed…..
Raising the troubled Leo Frigo Memorial Bridge back into place will be a task equivalent to hoisting an entire fleet of 747s into the air.
Experts have calculated that the sagging section of Green Bay’s distressed bridge weighs more than 3 million pounds, or about 1,600 tons.
Zenith Tech crews are expected to spend several days using hydraulic jacks to boost the Leo Frigo back into position — a process that will go slow, by design.
Starting with the northbound lanes, Zenith Tech will insert 10 hydraulic jacks beneath the bridge deck and operate them all simultaneously to raise the platform. Each jack will be exerting enough pressure to support 183,000 pounds, although Dreher said their capacity is 50 percent greater than that — just in case it is needed.
Dreher said the jacks will be calibrated carefully to operate in perfect unison, so there is no risk of the bridge deck leaning one way or the other as it is elevated.
“You can’t just go in there and start jacking away,” he said. “It definitely takes some coordination and good communication.
A very challenging and interesting repair project. Kudos to the Wisconsin DOT and all involved in getting the repairs done quickly.
Scot Becker, director of the Bureau of Structures and the state’s bridge engineer, said the fix will consist of installing four concrete shafts beneath five affected piers to take over support from corroded underground steel structures, called pilings. Then, the bridge itself will be jacked up 2 feet, and concrete and steel will be poured to keep the bridge in position.
The bridge, which spans the Fox River in Green Bay, has been closed since late September, after pilings became corroded and buckled under one of the piers, causing a 400-foot-long section of the bridge to sink 2 feet. Since then, it has drooped another half inch, and the state is monitoring the bridge for further movement.
An investigation concentrating mainly in the area from Quincy St. to the Fox River found that soil surrounding the pier contained industrial byproducts over wetlands, which caused the corrosion.
Corrosion of steel pilings below a support pier on the Leo Frigo Memorial Bridge in Green Bay caused Pier 22 to buckle last week, creating a long, deep dip in the bridge deck and forcing the bridge’s indefinite closure.
The 100-foot-long pilings under the pier were degraded from a combination of water and the composition of soil surrounding the bridge support, Wisconsin Department of Transportation officials said Thursday.
It appears that the suspect piers are in an area of fill, the composition of which may be contributing to the corrosion of the piles:
The investigation is focused on the area from the Fox River east to North Quincy Street on the east side of the bridge, where fill materials like foundry sand and organic materials are part of the soil profile.
“We’ve encountered all kinds of different things,” Buchholz said about soil samples in that area.
In addition to investigating the cause of the settlement of the pier, the bridge has been inspected by the Wisconsin DOT and is not in danger of collapse. As a precaution, the bridge remains closed during the investigation.
While several of the DBA staff were at the DFI 38th Annual Conference on Deep Foundations last week, we received texts and calls from colleagues wondering if we had been called about the apparent foundation failure at the Leo Frigo Memorial Bridge in Green Bay, Wisconsin. As of now, DBA has not been asked to be involved with the evaluation. The Wisconsin DOT is currently investigating. Our friend, Randy Post over at Geoprac.net has a post on the event, including a CNN video report that also recounts some other more dramatic bridge failures that were NOT due to foundation failures.
This bridge was built in 1980 and the “failure” is limited to a single pier that has subsided or settled a couple of feet in a rather sudden manner.