Video: Milton-Madison Bridge Truss Slide

The Milton-Madison Bridge spanning the Ohio River and connecting Milton, Kentucky and Madison, Indiana made history last Thursday, as it became the longest bridge in North America to be slid laterally into place. Workers spent many hours on Thursday sliding the half-mile-long bridge into place from temporary piers adjacent to the permanent piers. The 30 million pound span was pushed 55 feet using steel cables and eight computerized hydraulic jacks.

The Milton-Madison Bridge opened in 1929 and serves approximately 10,000 cars per day. The bridge has since become functionally obsolete and structurally deficient. The Indiana and Kentucky Departments of Transportation could not decide on a location for a new bridge in 1995, so they spent $10 million fixing the existing bridge instead. The new $131 million bridge will be 2,428 feet long and have two 12 foot wide lanes. According to the project’s website, “After a year of environmental studies and input from community, state and federal agencies, KYTC and INDOT determined that a method called “superstructure replacement” offered the fastest and most cost-effective way to build a safe new bridge, while having the least impact on the historic towns and the natural environment. Superstructure replacement involves building a new steel truss atop the existing piers, which will be brought up to modern standards.”  Walsh construction originally planned on closing the existing bridge for only 10 days during construction of the new bridge piers rather than the anticipated year-long closing, but a steel bearing dislodged while prepping the bridge to be moved. This caused a month-long delay to the project and closed down the existing span.

The embedded time-lapse video shows the bridge being moved 16 feet by the “truss sliding” method.