In just over a year, motorists passing through Chattanooga on interstates 75 or 24 will start seeing orange barrels at the infamous traffic-snagging interchange at the Tennessee-Georgia state line known as the "Split."
State officials have issued a request for letters of interest from firms seeking to land a design-build contract for the long-awaited revamp of the interstate area, notorious for traffic backups and crashes for the past three decades. The project cost is estimated at $65 million, according to the IMPROVE Act list signed into law in April by Gov. Bill Haslam, who visited the interchange project site in June.
"Design-build" is a project delivery method that combines in a single contract all or some parts of the design and construction phases, including design, right-of-way acquisition, regulatory permit approvals, utility relocation and construction.
"The winning design-build team will take care of all aspects of the project," said Jennifer Flynn, spokeswoman for the Tennessee Department of Transportation. "We should have the design-build team on board by the end of the year."
April 27, 2018: Anticipated release of request for qualifications
July 27, 2018: Anticipated release of final request for proposals
Oct. 19, 2018: Anticipated public price proposal opening set for 9 a.m.
Oct. 26, 2018: Anticipated award of design-building contract, or rejection of all
Nov. 2, 2018: Anticipated issuance of initial notice to proceed
Source: Tennessee Department of Transportation
The team's goal will be to design, modify and reconstruct the interchange from the Georgia line to East Brainerd Road on I-75 and from the starting end of I-24 to Belvoir Avenue, according to the request for letters of interest. The winning firm also will be responsible for any necessary right-of-way acquisition.
New bridges will replace the old ones over I-24 at Spring Creek, McBrien and Moore roads. Bridges in the project area that pass over obstacles will be replaced, according to project documents.
The new bridges will be built to allow the future addition of lanes on I-24, Flynn said.
A major feature in the updated interchange "reconfigures I-24 ramps to enter and exit I-75 from the right side, shifts the interchange to the west and modifies the welcome center area traffic circulation," documents state.
"The project is expected to use 'flyover ramp' designs to allow traffic traveling in different directions to pass at varying levels," Flynn said.
A smaller local example of a flyover ramp is the connection from I-75 North to Highway 153, where two lanes exit the interstate to the right, go up and over all lanes of I-75 and connect with two lanes merging from the right off of I-75 South, Flynn said.
The design-build concept allows the winning firm to determine how all those goals are accomplished, officials said. The primary purposes of the project are to relieve current and future traffic congestion, reduce the high crash rate and improve the existing interchange's outdated design.
One standing design element is an on-ramp that will extend from Ringgold Road in East Ridge in front of Bass Pro Shops and behind the Hamilton County Welcome Center as it merges onto I-75 North. Welcome center traffic also will use that ramp, according to initial drawings. TDOT's drawing do not contain any elements of redesign of the interchange, just the current footprint of the existing interchange.
Flynn said another bridge replacement project could be done on I-24 at Germantown Road simultaneously on a separate contract. Germantown Road passes under I-24 with on-ramps and off-ramps that connect to North Terrace and South Terrace.
"It will be done using an accelerated construction process called Construction Manager/General Contractor," Flynn said.
That process "is a contracting method that involves a contractor in the design and construction phases of the project," she said. "The intent is to form a partnership with TDOT, the designer and the contractor."
Documents state that project has an anticipated completion date of Aug. 31, 2019. TDOT has not set an estimated completion date for the interchange project. Flynn said the projects will be coordinated if construction on them overlaps.
She said the Belvoir Avenue bridge over I-24 will remain as is for the time being.
"TDOT inspects bridges every two years and they are evaluated," Flynn said. "If the need arises in the future, this bridge will be addressed then."
Meanwhile, proposal packages from firms interested in the interchange project must be submitted by Nov. 17.
The IMPROVE Act — Improving Manufacturing, Public Roads, and Opportunities for a Vibrant Economy — cuts sales taxes on food, phases out the Hall income tax over the next five years, and makes changes to the state's franchise and excise tax while raising gas and diesel taxes by six cents and 10 cents, respectively, over a three-year period. It also imposes several fees, including a $5 increase on annual car registrations.
The act will bring in an estimated $350 million for the state's dedicated highway fund, as well as funding for local governments' road and bridge needs all over Tennessee, including major projects in Hamilton County such as the I-24/I-75 interchange.
Contact staff writer Ben Benton at email@example.com or 423-757-6569. Follow him on Twitter @BenBenton or at www.facebook.com/benbenton1 on Facebook.