The project involves replacing the KY 152 Kennedy Mill Bridge over Herrington Lake, constructed in 1924 and spanning 800’ total. The bridge was part of a $7.5 million project to build the Dix Dam and create Herrington Lake in 1925. The Chicago Chimney Company constructed piers 2 and 3 as hollow concrete shafts before impounding the lake. Herrington Lake has the deepest waters in Kentucky, and two deep-water piers are approximately 190’ and 230’ tall. Shortly after impounding the lake, the 230’ pier on the Mercer side rose 30” and shifted 12” to the west. Several remediation projects over the years kept the bridge in service.
DLZ is conducting a Bridge Type Study that evaluated 17 bridge types to find the most economical structure and span arrangement. Also, DLZ was awarded the Final Design for the selected alternative. Stantec provided geotechnical investigations for the new bridge, cut slope in Garrard County, and retaining wall in Mercer County.
The final structural design replacing the existing structure is unique due to the depth of the lake. This challenge required a design solution that included the development of a substructure unit exceeding 250’-0” in total height with approximately 180’-0” being submerged underwater and an additional 35’-0” deep rock socked. After its completion, it will be the tallest pier submerged in water in the state. The superstructure also included two continuous 350’-0” long WSPC girder spans and a single 121’-5” PCI-beam span.
American Council of Engineering Companies (ACEC) Grand Award for Engineering Excellence
DLZ received a Grand Award for engineering excellence from the American Council of Engineering Companies (ACEC) of Kentucky for the KY 152 over Herrington Lake (Kennedy Mill Bridge) project in Mercer and Garrard Counties, Kentucky. ACEC’s Engineering Excellence is an annual design competition that recognizes engineering achievements that demonstrate the highest degree of merit and ingenuity.