The Tennessee Department of Transportation has awarded the contract for the I-75/I-24 interchange modification design-build project. The low bid of $132,644,398.00 was submitted by C.W. Matthews Contracting Co., Inc. The winning design-build proposal will complete design and construction of this project in less than three years, officials said.
“By using the design-build contracting method for this complex project, we were able to explore every available option to deliver it in the most timely and cost-efficient way,” Assistant Chief Engineer/Region 2 Director Joe Deering said. “The process resulted in several innovative concepts, and the winning proposal will save two years of expected construction time.”
Design-build is a project delivery method that combines all or some portions of the design and construction phases of a project into a single contract. TDOT is using the design-build concept on some of its larger projects to expedite project delivery and streamline design processes.
Over the next several months, the design-builder for the I-75/I-24 interchange modification project will complete the design of the project and acquire necessary permits. In the spring of 2019, the design-builder will begin geotechnical improvements to the project area with construction expected to begin in the late fall of 2019. Once construction begins, every effort will be made to minimize impacts to drivers, officials said.
The I-75/I-24 interchange modification project was one of 962 critical transportation projects included in the 2017 IMPROVE Act legislation.
Officials said, "The planned improvements to the interchange at Interstate 75 and Interstate 24 in Hamilton County will consist of modification and reconstruction between the Georgia state line and west of the East Brainerd Road interchange on I-75 and between Spring Creek Road and the I-75/I-24 interchange on I-24.
"The improvements will increase the safety, efficiency, and operation of the interstate, while providing congestion relief and addressing the deficiencies of the existing interchange.
"The existing I-75/I-24 interchange is a heavily traveled corridor that serves Tennessee and Georgia. Both I-75 and I-24 provide a direct connection to downtown Chattanooga, Lookout Mountain, and other area attractions, while I-24 also serves as a direct link between I-75 and I-59.
"Continued growth and increased traffic volumes along the I-75 and I-24 corridors have increased concerns for the safety of the interchange. A review of the project area revealed ramp geometry, merging distances, and Welcome Center access as operational deficiencies.
"Interchange modifications are necessary to increase capacity, correct merge points, and enhance ramp function. The planned design will improve the safety and operation of the interchange, while providing a facility that meets traffic demands.
"The existing project area is along the I-75 and I-24 corridors located southeast of Chattanooga in Hamilton County. The project extends from Spring Creek Road over I-24 to approximately one mile west of the I-75 interchange to East Brainerd Road. The total roadway length is 2.7 miles.
"Within the project area, I-24 is primarily a six-lane, controlled-access facility, separated by a concrete barrier wall with a right-of-way width of approximately 500 feet. I-75 is primarily an eight-lane, controlled-access facility, separated by a concrete barrier wall with a variable right-of-way width of approximately 300 to 600 feet.
"The planned design consists of widening the existing roads and ramps, increasing ramp radii, reconfiguring I-24 ramps to enter and exit I-75 from the right side, shifting the interchange to the west, and modifying the Welcome Center area traffic circulation.
"The project will also include new bridges for Spring Creek Road over I-24, as well as interstate bridges. Retaining walls will be required along interstate ramps and between I-75 and the Welcome Center area."