A sensor placed on the Old Ledbetter Bridge Friday by Kentucky Transportation Cabinet engineers and inspectors detected additional movement in west approach spans on the Old Ledbetter Bridge this weekend.
Engineers and geologists were hopeful dryer weather over the last few days would allow the bluff to stabilize, but over the weekend the sensor sent an alert indicating additional earth movement at the site. The additional 1/2 inch over the weekend adds to 2.25 inches of total vertical and horizontal movement last week.
On April 30th, transportation officials received word two approach span sections on the McCracken Side of the bridge had dropped about 2 feet. 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.
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 continue to monitor the bluff for additional soil movement. 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 old structure is the threat to river traffic. The main river navigation span has been deemed safe for boats passing under it.
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. 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.
Transportation officials continue to urge the public to avoid areas beneath the bridge approach spans on the McCracken County side of the river and areas of the bluff that show 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.