You could almost believe the crew boring holes in the ground this month along Interstate 24 near the infamous interchange with Interstate 75 known as the split was planting orange barrel seeds.
The first work toward phase 2 of the I-24/I-75 interchange reconstruction project got underway March 21 as a three-person team began drilling to extract soil samples along I-24 and North Terrace Road to provide technical information for contractors when the design-build project is released for bids that could be awarded by the end of the year, according to the Tennessee Department of Transportation.
Brentwood, Tennessee-based GeoEngineers geotechnical engineer Emily Reed said she and a crew from Chattanooga-based Tri-State Drilling started core drilling for soil samples March 21 as part of the phase 2 of the interchange project.
"We're putting together information for bidders so they can have an accurate depiction of soil conditions," Reed said.
The bedrock along the stretch differs between deep and shallow depending on where the sample is taken, she said. It's important information for contractors to know when they consider the amount of work involved in preparing the soil.
Over the past few days, the crew has worked its way from North Terrace onto South Terrace. The shoulder on I-24 East and the left lane on South Terrace will be temporarily closed for the work, according to TDOT.
But orange barrel seeds?
"No, they're seeds of progress," Reed retorted quickly with a laugh as she stood behind a work truck on North Terrace recently.
Reed said the initial work has been unhampered by weather.
"It has gone well so far," she said, noting there was considerably more sampling needed along the other side of I-24 on South Terrace, then the sampling work will move to the east side of the interchange.
"We'll have the other section to do on I-75 on both sides," Reed said.
In the coming weeks, the crew will move to I-75 on east side of the interchange, where the outside interstate lanes will be closed periodically for samples to be taken there, Reed said.
TDOT officials say contractor information related to phase 2 bids is coming soon.
The state has a short list of four "design-build" teams to submit proposals on phase 2, TDOT spokesperson Beth Emmons said Wednesday in an email.
"The department is also in the process of completing the 'request for proposal' and functional plans, which will provide design and construction parameters for the design-build teams," Emmons said. "These documents will be provided to the design-build teams later this spring."
The four design-build teams include contractor Archer Western Construction with design consultant STV Inc.; contractor C.W. Matthews Contracting Company with design consultant Barge Design Solutions; contractor Superior Construction Company Southeast with design consultant WSP USA; and contractor Wright Brothers Construction Company Inc. with design consultant RK&K, according to TDOT records. TDOT selects the most qualified teams based on how they score on qualification parameters, according to project information.
"The design-build teams will submit their proposals and bid this fall, and the project should be awarded to the winning bidder by the end of the calendar year," Emmons said. She said no cost estimates are available because the the state is seeking bids.
TDOT Region 2 Director Joe Deering said state engineers developed the conceptual plans of I-75/ I-24 phase 2, but because this project is a design-build project, the bid-winning design-build team on the project will be responsible for the final detailed plans.
"The project limits are between I-24 at Spring Street to Germantown Road and I-75 south of the CSX Railroad to East Brainerd Road," Deering said in an email.
"The project will include additional travel lanes along I-75 and I-24 and reconfiguring of the on- and off-ramps along I-24 to improve the operational efficiency," he said. "This project will also include new bridges on I-24 at Moore and McBrien roads and I-75 over the CSX Railroad.
"We plan to release the request for proposals to the design-build teams in May 2022 and award the project in late 2022," he said.
Phase 1 of the $133.5 million Split project was finished in August 2021, and replacement projects for bridges over I-24 at Spring Creek Road and Belvoir Avenue are complete, as well as I-24's bridges over Germantown Road. The Spring Creek Road bridge replacement project was part of the $133.5 million phase 1 of the Split project while the bridges at Belvoir and Germantown were part of a separate $32.9 million contract. The footprint of all the new bridges allows for the additional new lanes, officials said.
Meanwhile, the connector ramps from I-75 North and South to I-24 West continue to bottleneck despite completion of phase 1 of the interchange portion of the project, but that's because the new lanes have nowhere to go until the phase 2 is completed, according to TDOT.
TDOT's proposed conceptual plan documents describe the basics, though details are subject to change.
From the Split at I-24 going toward Nashville under the Spring Creek Road bridges and a new McBrien Road bridge, I-24 West will be five lanes wide in both directions. Then westbound drivers will see a new two-lane exit for Moore Road and a reduction of I-24 to four lanes. The current on-ramp from Moore Road to I-24 West will be closed to allow room for an off-ramp from I-24 West onto North Terrace, and a new on-ramp for I-24 West will go where the existing off-ramp is now, proposed plans show.
Heading east on I-24 toward the Split from Missionary Ridge the highway will remain three-lanes wide until it passes under the Belvoir Avenue bridge, and a fourth lane begins as I-24 East approaches and passes under a new Moore Road bridge. An existing on-ramp from South Terrace to I-24 East will become a fifth lane going under the new McBrien Road bridge, proposed plans show. Eastbound off- and on-ramps along South Terrace will be reconfigured similar to those on the westbound side.
Proposed plans also call for modifications on North Terrace and South Terrace to accommodate the new design, according to documents.
According to TDOT histories, Tennessee was known as a detour state in the 1920s due to the inability to cross Monteagle Mountain, about 30 miles west of Chattanooga. Although a road was built across the mountain in 1923, it wasn't until I-24 was built over the mountain from 1962 to 1968 that travel became safe for motorists.
Over the decades since, state and local officials on several occasions sought a fix for the ongoing traffic problems at the interchange and its arteries along I-24, according to Times Free Press archives.
The design of I-24 where it passed through the East Ridge and Brainerd areas drew fire in the mid-1960s when community leaders marched on City Hall to protest plans that excluded on-ramps and off-ramps, according to archives.