|
Progress on the new $103 million Milton-Madison Bridge project is sliding steadily forward—if, occasionally, in sideways fashion.
The novel project is being built in the same footprint as the existing 85-year-old bridge, using design and construction methods called "superstructure replacement" and "truss sliding."
Construction Innovation
With superstructure replacement, the existing piers are widened, strengthened and then reused.
 |
|
Images, video: www.miltonmadisonbridge.com |
|
Crews jacked a corner of the bridge over the weekend to replace a slipped bearing.
|
With truss sliding, as the name suggests, the new superstructure is built on steel piers adjacent to the existing bridge. Then, using computer-controlled hydraulic jacks, the new superstructure is pulled across steel beams into place on top of the renovated existing piers. The downstream piers are then removed.
While the truss slide method has been used occasionally, Madison-Milton Bridge project officials says this is the longest such project ever undertaken in the U.S. The new Milton-Madison main truss is 2,428 feet long and 40 feet wide.
Project officials say the design-build innovations will cut years from the project schedule and reduce the overall cost by 20 percent. Indeed, the new bridge is already open to traffic on temporary piers.
The Little Slide
Last week, general contractor Walsh Construction successfully slid a 100-foot concrete approach into place on the massive structure, which will connect Milton, KY, with Madison, IN, over the Ohio River.
|
|
|
Time-lapse video reduces the two-hour sliding installation of a 100-foot concrete approach to one minute.
|
The approximately two-hour project on March 13, reduced to about one minute via time-lapse video, was a critical precursor to sliding the bridge's nearly half-mile steel truss into place—possibly as soon as next week, authorities say.
The main truss slide will use the same equipment and process as the approach slide over the Kentucky riverbank.
Bearing Project
The concrete approach slide followed a project to replace a five-foot-square steel truss bearing that dislodged March 11 as crews were installing sliding harnesses on the bridge.
The concrete slide was completed, but crews began a 15-hour jacking process on Friday afternoon (March 21) to raise the bridge's southeast corner nearly one foot to slide the bearing back into place.
 |
|
A five-foot-square steel bearing was replaced last weekend after it dislodged while crews were installing harnesses for the upcoming truss slide.
|
By 6 a.m. Saturday (March 22), the jacks were removed and the bridge load was back on its bearings.
“The jacking process went as expected,” said Dav Kessinger, project manager for Kentucky Transportation Cabinet, which is overseeing the project with the Indiana Department of Transportation. “With this work completed, the focus is now on preparations for sliding the main truss.”
The Big Slide
The steel truss will be moved 55 feet onto the permanent piers, closing the bridge for one week. The bridge will remain closed while crews pour concrete, install expansion joints, stripe pavement and complete the connection of the bridge to the permanent approaches.
 |
 |
|
Four jacks, each able to lift 250 tons, were used to raise the southeast corner of the bridge March 22—a process that "went as expected,” said Dav Kessinger (right), project manager for Kentucky Transportation Cabinet.
|
In all, project officials expect to be able to limit the bridge closure to just 10 days of the project—a fraction of the year-long closure originally anticipated.
Construction updates, including a live web cam, are available on the project site.
|
