A sensor placed on the Old Ledbetter Bridge by Kentucky Transportation Cabinet engineers and inspectors detected additional movement in west approach spans on the Old Ledbetter Bridge this weekend.
On April 30, transportation officials received word two approach span sections on the McCracken Side of the bridge had dropped about 2 feet. The Old Ledbetter Bridge has been closed and awaiting demolition since traffic moved to the New US 60 Tennessee River Bridge on July 31, 2013.
After getting a call from a resident on April 30th, inspectors found a land slip along the bluff below the bridge had moved two of the land-based piers supporting the west approach spans. Since that initial investigation, inspectors have regularly checked the aging structure for additional signs of movement. On Friday, the Kentucky Transportation Center installed sensor and a video camera to monitor the slumping approach spans.
Over the weekend the sensor sent an alert indicating additional earth movement at the site. The additional 1/2 inch of movement means the approach spans have showed 2.75 inches of both vertical and horizontal movement in the last week, indicating the shifting hillside is continuing to move the land-based approach piers.
Engineers and geologists were hopeful dryer weather over the last few days would allow the bluff to stabilize.
While an earlier assessment indicated a collapse of the approach spans is not likely to impact the main truss over the river navigation channel, engineers and geologists have continued to closely monitor the bluff for additional soil movement
Transportation officials continue to urge the public to avoid areas beneath the bridge approach spans on the McCracken County side of the river and stay away from areas of the bluff that show signs of land movement.
Technicians plan to place solar powered navigation lights on the main truss spans and piers in case power to the existing lights should be cut by an additional drop in the approach spans.
On Thursday the Transportation Cabinet signed a $5.6 million agreement for expedited demolition of the old bridge with Kay & Kay/Hayden Bridge Joint Venture, the group that constructed the New US 60 Tennessee River Bridge.
Transportation officials have continued to be in regular communication with the U.S. Coast Guard and McCracken County Emergency Management about the ailing approach spans and the land slippage along the bluff.
McCracken County Emergency Management Director Jerome Mansfield continues to remind residents with homes overlooking the river along off Camel Back Road to report anything unusual that might indicate additional movement of land along the bluff.
Highway traffic was moved off the Old Ledbetter Bridge last July when the New Ledbetter Bridge opened to traffic, so the main concern about the stability of the old structure is the potential threat to river traffic. The main river navigation span has been carefully checked and deemed safe for boats passing under it.
Geologists from the Kentucky Geological Survey have visited the site twice to map and monitor the land slippage. On Thursday, engineers found an old concrete stairway they had used to access areas below the bridge the day of their original investigation had been moved down the bluff by the landslide and could no longer be used.
With the recent fatal landslide in Washington State, a sinkhole that developed under the National Corvette Museum in Bowling Green, KY, and several smaller sinkholes and landslides around the region, Emergency Management officials want residents of the bluff near the Old Ledbetter Bridge to remain alert for any additional signs of land movement.
The Old Ledbetter Bridge opened to traffic in 1931. It was restricted to a 3-ton load limit in January 2012 while the new bridge was under construction just upstream. KYTC officials expedited construction of the new bridge and it opened to traffic on July 31, 2013, eleven months ahead of schedule.
