For 85 years, motorists have driven over the Ocoee River on the now aging U.S. 64 bridge, but later this year, a new $12.6 million signature bridge will replace the existing structure in Polk County, Tennessee.

The project “will improve the safety and operations of the facility, update the bridge to current standards and allow for future expansion,” says Joe Deering, Tennessee Department of Transportation (TDOT) Region 2 Director.

The original 546-foot, 13-span bridge was built in 1937, with one lane in each direction and 1-foot-wide shoulders. The bridge has surpassed the average lifespan for its type and is showing signs of structural and functional deterioration.

U.S. Route 64 is classified as a Rural Principle Arterial Route. It is part of a larger corridor that runs 394 miles across southern Tennessee and connects communities from Interstate 75 to U.S. 68. It also serves as a gateway into the Ocoee River Gorge, with one side in the Cherokee National Forest in the Appalachian Mountains.

The bridge is part of the Appalachian Development Highway System (ADHS), and the work must comply with ADHS standards, which include having the capability of handling 50 mph traffic and the ability to expand the road to four lanes to meet future needs, Deering says. Appalachian Resource Commission provided funds for the replacement bridge. A 2019 study projected traffic to be about 5,790 vehicles daily in 2022.

“This corridor is a major route for the Ocoee River rafting community,” Deering says.

TDOT has been using the design-build project delivery method to combine all or some portions of the design and construction phases of a project, including design, regulatory permit approvals, utility relocation and construction into a single contract. This process saves money and expedites project delivery.

The department has used the design-build delivery method on larger and urban Interstate projects, with high annual average traffic counts and decided to try it on a smaller, rural project. TDOT has dedicated teams for managing alternative delivery projects, such as this one.

Contractor Charles Blalock and Sons of Sevierville, Tennessee, received the contract with design partner Volkert of Mobile, Alabama.

This is Blalock’s first design-build project reports Wes Hawley, Project Manager for Blalock.

“We are interested in everything TDOT is doing, and we wanted to learn the process,” Hawley says. “Overall, it has been a good experience for us.”

“Having a good design partner, like Volkert, has been helpful,” Hawley says. “It helps us work through plans as they occur.”

Blalock, founded in 1963, employs more than 700 people and has completed numerous large transportation projects and commercial site preparations throughout the Southeast. The company primarily works in TDOT’s Districts 1 and 2.

Crews broke ground in September 2020, and expect to complete the bridge project this summer.

Crews are building the 700-foot-long, three-span, steel I-beam girder bridge to the north of the existing structure. The new bridge will have two 12-foot travel lanes, a third center lane for future use and two 10-foot shoulders. It can be widened in the future into a four-lane bridge.

At its peak, the new alignment is 12-foot higher than the original bridge to meet ADHS requirements. Blalock can only construct above the river in certain seasons, and has to protect river traffic. There also are work restrictions related to snail darters and bird nesting seasons.

Driven pile foundations and piers support the new structure.

“The original plans called for a drilled shaft foundation, but once we did our geotechnical exploration discovered that wasn’t best,” Hawley says. “The quality of rock along the Ocoee River bank did not lend itself to drilled shafts.”

He explains that the area was full of voids, which when trying to fill the shafts could result in “massive overages when pumping concrete.”

Blalock is building the bridge from both sides of the river. Crews began setting span one on the west side of the river, then placed span two on the east side and a third arched span in the middle. The lifts took place in fall 2021. The company used a local survey company to ensure everything came together as planned. Blalock also used GPS equipment for grading.

The company is using 300-ton crawler cranes on each side of the water to lift the steel beams. The water was too shallow to allow a barge set up, Hawley explains.

Aesthetic elements include the arched, weathered steel beams; the Ocoee River emblem on the piers facing the river; rock finishes; decorative pillars with the Ocoee symbol; bridge rails and accent lighting. The features will be viewable from the road and from the river.

Blalock and Volkert took the department’s renderings and incorporated those elements into the final design to ensure TDOT obtained all of the aesthetic details it desired.

“The bridge and the lighting will be great,” Hawley says.

The project also includes improving intersections with Hildabrand Road to the west and Welcome Valley Road to the east to accommodate the new bridge. Work on those approaches started first, and they will be wide enough for future expansion. ADHS informed TDOT that the new alignment cannot exceed a 6 percent grade.

Since the bridge is being built on new alignment, it reduces traffic issues. The contractor is not allowed to close the road, even during the tie-ins.

Once the new bridge opens to traffic, crews will remove the aging structure and build a maintenance road on the old approaches.

“On this project, I am proud of how our design-build team of Blalock and Volkert, TDOT and our owner’s representative Gresham Smith [of Chattanooga, Tennessee], all worked together to make the project a success,” Deering concludes. “The aesthetics of this bridge make this a gateway into the Ocoee River Gorge.”