Location: Marshall and Trigg Counties, Kentucky
The two bridges carrying U.S. 68/KY 80 over Kentucky Lake and Lake Barkley connect to the Land Between the Lakes (LBL) National Recreation Area, a 170,000-acre public recreation area that is managed by the U.S. Forest Service. The replacement of the bridges is associated with a larger effort to widen and improve approximately 20 miles of U.S. 68/KY 80 from the U.S. 68/KY 80 split in Aurora at Kenlake State Resort Park in Marshall County to the western terminus of the Cadiz bypass in Trigg County to a four-lane highway. U.S. 68 is the only east-west roadway through the recreation area and the only crossing of the lakes in Kentucky. Studies and inspection reports determined that both bridges are functionally obsolete, are very narrow, and have continuing maintenance issues.
Michael Baker International has been providing engineering services for the replacement of the bridges since 2007. Michael Baker’s services include project management, a bridge-type study, surveys and mapping, roadway alignments, pavement design, drainage design, maintenance-of-traffic plans, cost and quantity estimates, right-of-way plans, permit coordination, utility coordination, agency and stakeholder coordination, public involvement, environmental compliance support, and preliminary and final design.
Michael Baker worked with a citizens' advisory committee and used a three-round public involvement process to identify aesthetic preferences for the new bridges that would meet the engineering, environmental, and budget requirements of the project, which is located in a highly critical seismic zone. Michael Baker developed three-dimensional models of alternative bridge types to create renderings by superimposing models onto photos and displayed the renderings at the public meetings. Michael Baker continues to maintain a project website (www.lakebridges.com) to keep the public informed as the project progresses.
The selected bridge type for both bridges is a basket handle, tied-arch design. The new 550-foot-long, four-lane bridges will feature 11-foot-wide lanes, four-foot-wide shoulders, and 10-foot-wide shared pedestrian and bicycle path, with a 60-foot minimum vertical clearance. The shared-use paths will connect with the pedestrian and bicycle paths in the LBL and the adjacent KenLake State Resort Park and include underpasses so that pedestrians and cyclists will be able to follow the trails without having to cross four lanes of traffic on U.S. 68. The existing bridges will be removed following completion of the new structures. Environmental permitting and agency coordination requirements have presented challenges throughout the course of the project, as different agencies have jurisdiction over different depths of the lakes. The Tennessee Valley Authority, which created the lakes by impounding the rivers, has been actively involved with the project. The park has a 700-acre habitat restoration preserve for elk and bison. The project has required extensive coordination with the U.S. Fish and Wildlife Service, Kentucky Division of Fish and Wildlife, and the Kentucky Parks Department, in addition to the U.S. Forest Service.