A long-awaited construction project on Interstate 75 intended to greatly improve traffic flow through a fast-growing area of eastern Tennessee is finally underway, with completion anticipated by Nov. 15, 2015.
The $12.8 million project includes replacement of an antiquated, two-lane bridge and realignment of all four ramps at exit 20 on Interstate 75 in Bradley County, Tenn. The project area is about 30 mi. north of Chattanooga, Tenn., and near the southern edge of the city of Cleveland, Tenn.
The contract for the project, which also includes grading, drainage, paving and widening of roadway that leads to the interchange, was awarded to Simpson Construction Company of Cleveland in May, 2013. Construction began on July 1.
"This project is desperately needed," said Jennifer Flynn, a community relations officer with the Tennessee Department of Transportation (TDOT). "Local people have been asking for it for a long time. The existing two-lane bridge over I-75 at that exit was constructed when the area was more rural. Now, that part of eastern Tennessee is developing rapidly, and traffic routinely backs up because the bridge can’t handle it."
Flynn said that another TDOT project currently under development should help improve the traffic situation. This involves building a new interchange on APD40, which is the bypass around Cleveland and the roadway that leads to the exit 20 interchange, and the addition of an auxiliary lane on each side of APD40 between the two interchanges. In addition, the city of Cleveland is in the process of improving several local roads that will eventually connect with the new interchange.
David Denham, vice president and project manager of Simpson Construction Company, agreed with Flynn’s assessment of the need to reconstruct exit 20.
"The intersection and the bridge are outdated and in dire need of replacement," Denham said. "The exit is the first one you get to in Cleveland as you are heading north from Chattanooga, and it’s the exit that puts you onto the bypass around the city. Traffic backs up across the bridge and also on the interstate. The alignment of the ramps is such that trucks can’t handle them. Sometimes the trucks get hung up and traffic can’t get by."
TDOT estimates 21,000 vehicles cross the 32-ft. (9.8 m) wide span every day. This traffic includes a steady stream of trucks traveling to and from a nearby industrial park off ADP40. The bridge was built in 1970.
Denham said the project was proceeding on schedule, with work continuing five days a week, from 6 p.m. to about 6 a.m. He said that although winter weather had slowed the project somewhat, good headway was made during the fall and he was looking forward to better weather in the spring.
The project is being completed in four broad phases. During the first phase, according to Denham, a two-lane section of the new bridge is being constructed adjacent to the existing bridge. Once that is complete, work will begin on reconstructing the northbound exit ramp from I-75 and the northbound entrance ramp onto I-75, on the east side of the interstate.
Once the new northbound ramps are complete, traffic will be put on them and onto the new section of the bridge, and the old northbound ramps and the old bridge will be torn down. The next phase of the project will see construction of the final three lanes of the new bridge and the two ramps on the southbound, west side of the interstate. When complete, the new bridge will be 97 ft. (29.6 m) wide with two lanes in either direction and a fifth lane, which will be used for turning by traffic traveling in both directions, in the center.
Denham said that two of the new concrete ramps would require 20 ft. (6.1 m) high retaining walls that do not currently exist, and that the project will include some minor utility work, new intersection lighting, new traffic signal lighting and relocation of a water line and a telecommunication line.
The project will require 65,000 cu. yds. (49,696.1 cu m) of road and drainage excavation, 111,000 cu. yds. (84,101 cu m) of borrow material and a total of 11,000 sq. ft. (1,021.9 sq m) of retaining walls for the two ramps. One of the retaining walls will be pile and beam construction, while the other will be constructed from a cement modular segmental unit.
A number of subcontractors will have crews working on the site along with Simpson. The subcontractors and the approximate amount of their contracts include Steve Williams Construction LLC of Cleveland, for grading ($1 million); Talley Construction Co. Inc. of Rossville, Ga., for asphalt paving ($1.7 million); Interstate Concrete Construction LLC of Cleveland, for cement paving ($1.5 million); Greenstar LLC of Cleveland, which will lay the new drainage pipes ($450,000); Long Foundation Drilling Co. of Hermitage, Tenn., for shaft drilling, ($335,000); NABCO Electric of Chattanooga, which will construct the traffic signals and telecommunication lines ($728,000); and Service Electric Company of Chattanooga, which will be responsible for the overhead electrical work ($166,000).
Denham said many different types of equipment, made by a number of different manufacturers, will be used over the course of the project. They include the Link-Belt HC-268, a 250-ton (226.8 t) lattice boom truck crane; the Link-Belt HC-238A, a 140-ton (127 t) wire rope truck crane; a Miller Formless Co M-8800 Bi-directional slipform barrier wall and paver; and the Komatsu hydraulic excavator PC300 LC.
He said that grading subcontractor, Steve Williams Construction, was able to contract with a private individual with property adjacent to the construction site, so the company will be able to use scrapers and off-road trucks to move the borrow it needs to the work area. The company owns and uses Caterpillar equipment.
Denham said that as work continues on the site for the next 18 months or so, area traffic will get much worse before it gets better.
"When this project is complete, the traffic will be wonderful," Denham said. "But until then, traffic will be terrible for everyone. We’re going to have lane reductions, temporary traffic realignments, detours, narrow turns and portable concrete traffic barriers everywhere."
Even so, Denham said he does not expect many complaints.
"This was a terribly outdated bridge, and everyone has known its replacement was coming," Denham said. "Everyone knows the bridge is outdated, and everyone wants it to be replaced."
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