The Milton-Madison Bridge Project is expected to mark another major milestone next week when a second massive section of the new bridge is lifted into place. The 727-ft preassembled section of steel truss will be hoisted onto temporary piers, another in a series of steps to replace the U.S. 421 bridge, connecting Milton, Ky., and Madison, Ind.
The existing bridge remains open during the lift, currently scheduled to begin at noon on Sept. 10, weather permitting. The span, which was preassembled on barges in Milton, will be floated into position and lifted using strand jacking.
Special hydraulic jacks and bundled strands of steel cable will lift the 2,067-ton span to a height of 90-95 ft onto temporary piers 4 and 5, immediately north of the first section that was lifted in June.
Because the span lift takes place in the main navigational channel, the river will be closed to commercial traffic for approximately 24 hours. The U.S. Coast Guard will determine when the river can safely reopen. Recreational boaters will also be prohibited from using the area near the lift during this time. A “no wake” zone will be established 1,000 ft upstream and downstream of the bridge, and boats must stay back 500 ft on either side of the bridge. For the safety of the boaters and the workers, this restricted area will be enforced. Once the span reaches its full height, a “sliding girder” will be placed under the truss, supported by the temporary pier and a concrete pedestal on the existing piers. This massive beam will be used next spring when the completed 2,426-ft bridge slides from its temporary position onto the permanent piers, which are being rehabilitated and strengthened.
The new bridge is currently scheduled to open to traffic in spring 2013.
The Milton-Madison Bridge Project is a joint effort between the Indiana Department of Transportation and the Kentucky Transportation Cabinet. For more information, visit http://www.miltonmadisonbridge.com.