CONSTRUCTION
A 600-foot, 1,700-ton section of the new Milton-Madison Bridge is rising above the shoreline in Milton, Ky. The span is part of the new US 421 bridge over the Ohio River connecting Milton, Ky., and Madison, Ind.
Workers are currently preassembling the new truss bridge on barges just west of the existing bridge. Once complete, the span will be floated a short distance upstream. Special jacks will lift the entire section into place onto temporary towers, which are being built immediately downstream of the existing bridge. A second 727-foot section of span will be built and “lifted” in a similar manner. The remainder of the truss will be erected on top of the temporary towers using cranes.
At one point, there will be two bridges sitting side-by-side. Traffic will be moved from the old bridge to the new bridge on the temporary towers. Eventually, the old superstructure – the upper steel section – will be severed from the piers using controlled explosives. The pieces will be removed from the river bottom with cranes within about 24 hours. The final step comes in 2013 when Walsh Construction Company ‘slides’ the new bridge from the temporary towers onto the existing piers, which have been strengthened.”
The “design-build” method is used to save time by overlapping the design phase and construction phase of a project. While the process moves at a faster pace, it does not compromise quality and safety. Inspectors are monitoring every step of construction.
Watch the construction process
Tentative Project Schedule
