Bridge Demolition Details Emerge
Indiana and Kentucky transportation officials are releasing details for next week's planned demolition of the old Milton-Madison Bridge in Jefferson County. Destruction of the approximately 2,400-foot-long structure will occur in three stages and require closing the new bridge temporarily, creating a no-fly zone and cutting off traffic on the Ohio River. July 9, 2013
LOUISVILLE, Ken. - The main span of the old Milton-Madison Bridge is scheduled to be demolished on Wednesday, July 17, the first in a series of blasts to bring down the 2,427-foot-long steel structure. The blast will require the temporary closing of the adjacent new bridge that carries US 421 across the Ohio River between Milton, Ky., and Madison, Ind.
Weather permitting, the approximately 700-foot-long span over the main navigational channel is scheduled to be demolished next Wednesday morning. A 1,000-foot safety perimeter will require the adjacent new bridge to be temporarily closed for a few hours. An FAA no fly zone of 2,000 feet will also be in effect prior to and during the blast. More information will be provided in the coming days as to the specific timing of the blast and temporary bridge closure.
Once the safety perimeter is secured, sirens will sound at intervals prior to the blast. Local authorities will strictly enforce the perimeter, and any spectators entering that zone once cleared will postpone the demolition.
Noise and vibration levels caused by the blast are expected to be well below levels that would cause any type of damage to structures. Special measures and protective materials are being used during the blast to protect the original bridge piers, which are being strengthened and reused. Similar precautions will also be taken to protect the new bridge which sits 15 feet downstream from the old bridge. Traffic was switched from the old bridge to the new bridge last month.
Using many small explosive charges placed at critical locations on the bridge, subcontractor Advanced Explosives Demolition Inc. (AED) will detonate the charges in intervals to control the direction of fall. The blast itself is expected to last a few seconds. In the days leading up to the blast, AED will precut the truss in strategic locations to allow the bridge to drop straight down into the Ohio River.
In coordination with the U.S. Coast Guard, the Ohio River will be closed to traffic for 24 hours to allow for the demolition and retrieval of the truss bridge from the water. Pieces of the truss will be retrieved from the river, placed on barges, taken to the shore for further dismantling and eventually sold for scrap. Divers are on call to ensure all pieces are removed from the river.
The 1929 Milton-Madison Bridge will be demolished in a series of three blasts about seven days apart over the next few weeks. The public will be notified prior to each blast. Once the old truss is removed, work will begin on widening the original piers to accommodate the new 40-foot-wide bridge which is currently sitting on temporary piers. In the coming months, the new bridge will be slid into its permanent position on top of the original piers.
During the bridge closure, drivers can follow the signed truck detour to the nearest crossing, either 26 miles upstream at the Markland Locks and Dam Bridge or the Kennedy Bridge in Louisville, 46 miles downstream. Motorists detouring to I-65 should be aware that the Kennedy Bridge is also under construction, and check www.kyinbridges.com for traffic updates.
Walsh Construction Company's innovative multistep method of replacing the bridge avoided an expected year-long closure.
The Milton-Madison Bridge Project - a joint effort between the INDOT and the Kentucky Transportation Cabinet - has received numerous awards. It was named one of the top 10 bridge projects in the country by Roads and Bridges Magazine, received a 2012 Best of What's New Award from Popular Science magazine and received several state and national engineering awards for innovation. For more information, visit www.MiltonMadisonBridge.com or follow the project on Twitter.
Sources: The Indiana Department of Transportation, The Kentucky Transportation Cabinet