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The Milton-Madison Bridge Project is a unique effort to replace the deteriorating US 421 Ohio River bridge between Milton, Ky., and Madison, Ind. The bridge is open to traffic.
Through the use of innovative design and construction methods, the bridge remains open during construction, with the exception of a few days. Using a method called “truss sliding,” a new 2,427-foot-long truss bridge will “slide” into place atop the existing piers, which are being strengthened and reused. The new bridge will open to traffic in 2013.
The fourth and final section of the old Milton-Madison Bridge was demolished on September 19, 2013. The other three sections of the 2,427-foot long bridge were demolished this summer using controlled explosives. The first explosive demolition took place on July 23, 2013 A second section was brought down on Aug 1. A 400-foot section was demolished on September 5 (video at right).
With the old truss gone, work begins now on widening the original piers which are being rehabilitated and reused. The final step comes later this year, when the new 2,427-foot-long bridge will be slid onto the renovated original piers. The bridge is expected to close for about a week while the slide and approach connections are completed.
Traffic switched from the old US 421 Milton-Madison Bridge to the new bridge in its temporary location on June 3, 2013. Drivers are accessing the new bridge – which is about 15 feet downstream of the old bridge – using the newly-constructed permanent approaches. The new span has a 15-ton weight limit and a 36-foot vehicle length restriction, meaning semis cannot use the bridge. The new bridge is 40 feet wide – twice as wide as the old bridge. It has two 12-foot lanes and eight-foot shoulders. A new sidewalk is also planned for the new span, but it is not expected to open until after the bridge slide.
The second “big lift” for the Milton-Madison Bridge Project was completed in September 2012. Time-lapse footage (at right) shows the 15-hour operation during which a 727-foot section of the new bridge was floated and lifted into place onto temporary piers. The span which weighs 2,067 tons, or 4.1 million pounds, was lifted to a height of 90 feet on Sept. 10, using special hydraulic jacks and bundled strands of steel cable.
The last step in the lift process involved the intricate placement of a massive beam under the new span. This beam will be used in 2013 when the entire truss bridge is slid from the temporary piers to the existing piers, which are being rehabbed and reused. The new bridge is expected to open to traffic in 2013.