During the last two years, engineers have gathered information about material below the Kentucky Lake floor to aid in design of a new bridge. In recent weeks, a drilling rig has been at the bridge site to gather geotechnical information at specific locations where piers will be built to support the main arch span for the new bridge. In 2011, geotechnical information was obtained to aid in the design of the widened causeways and bridge approach spans.

Mike McGregor, Project Development Engineer for KYTC District 1 and Project Manager for the Lake Bridges Project, said each boring usually takes several days to complete.

“The drilling crew is providing critical information that will help with the design of the piers for the main span of the new bridge,” McGregor said. “Every few feet we take a sample of rock beneath the lake bed to provide a profile of sub-surface conditions.  That gives bridge designers soil and rock density and strength information that is critical in the design and construction of a pier support system.”

Last week a group of design engineers working on the Lake Bridges Project made a site visit to check on progress. Now that drilling work is complete and the samples analyzed, engineers will have detailed information needed to design and  construct that part of the bridge support structure below the lake bed.

Darrin Beckett, a KYTC engineer who is supervising the drilling, said placement of the drilling rig over specific pier sites required close coordination with the District 1 Lighting Crew, U.S. Coast Guard, U.S. Army Corps of Engineers, and the river towing industry.

“Due to placement of the drilling rig in the main channel span, we have worked closely with the Coast Guard to accommodate river traffic,” Beckett said. “The bridge design team has had ongoing conversations with the river industry to phase eventual construction of the new bridge so as to minimize shifts in river traffic at the site.”

The Motor Vessel GAIL ANN, which was on station with the drilling rig, maintained a radio watch 24 hours a day to assist vessels with passing instructions.

The Lake Bridges Project includes planning for construction of new bridges to carry U.S. 68 and KY 80 across Kentucky Lake and Lake Barkley at the western and eastern entrances to the Land Between The Lakes National Recreation Area in western Kentucky.

The first sign of actual construction on the Kentucky Lake Bridge is expected by early 2013 with the letting of an advance project.  This will include the widening of causeways on both ends of the Kentucky Lake bridge and the construction of an approach  bridge to cross a lagoon at the west end of the causeway on the Marshall County side of the new structure.  Construction of these approaches will provide contractors access to the lake for construction of the main crossing in the future.

Work on a replacement crossing for the Eggners Ferry Bridge has a tentative start date in 2014 with a start date on the new Lake Barkley Bridge to follow a year or two later.  Work on each of the new basket handle tied-arch bridges is expected to take about four years to complete.

For more information on the Lake Bridges Project go to www.lakebridges.com.