Tennessee's State Route 141 (SR 141) runs through the middle of the state. The nearly 70-mi. route connects multiple counties in the state, including Wilson and Trousdale. The Tennessee Department of Transportation (TDOT) is in the middle of two projects, 10 mi. apart, that they expect will improve traffic flow along the route in the counties noted above. The Trousdale County project, known as the State Route 10 to Cedar Bluff Road project, involves complex construction that has challenged the construction team.
Long Time Coming
Both construction projects have been in development for more than 20 years. In fact, TDOT has many projects in development. Projects only move to the next phase of development and ultimately construction when everything, including funding, is in place.
The projects moved forward in 2023, a momentous year in Tennessee transportation, with the passage of the state's Transportation Modernization Act.
TDOT photo
From the TMA press release, it "… will create a new strategy and invest $3.3 billion to accommodate Tennessee's record growth, address traffic congestion and meet transportation needs across rural and urban communities."
The press release adds, "The plan will give the Tennessee Department of Transportation (TDOT) the resources needed to solve the state's current and future mobility challenges…"
Bypass Hartsville
The objective of the State Route 10 to Cedar Bluff Road project is to have SR 141 bypass Hartsville. Hartsville has approximately 12,000 residents and is the county seat of Trousdale. Currently, SR 141 goes through downtown Hartsville. The area is generally very walkable, is lined with small businesses and the streets cannot be widened.
SR 141, which is one lane in each direction in this corridor, has an ADT of just more than 4,500 — four percent is truck traffic. TDOT and area residents agree that they don't want the traffic going through the city.
"The new alignment bypasses the city of Hartsville and can be widened to two lanes as we have enough right of way should we deem it necessary in the future," TDOT resident engineer of District 37, Sarah Fugate told Construction Equipment Guide. Fugate is part of the oversight team for both SR 141 projects.
TDOT photo
The new alignment will speed up the traffic flow as the new stretch won't have traffic signals or stop signs. Note that the old alignment will remain in use, but it won't serve as a key route to travel to nearby Macon County.
The new 4.3-mi. alignment is entirely through open fields. It requires the team, led by Tennessee-based Jones Brothers, which regularly works with TDOT, to complete 1.3 million cu. yds. of grading.
What will be done with the dirt?
"We'll use the soil that includes hard rock for the new alignment," Fugate said. "The contractor arranges for the remainder of the waste to be deposited in a nearby location."
Cumberland River Crossing
The new alignment of SR 141 also will cross the Cumberland River. The windy river runs nearly 700 mi. through Kentucky and Tennessee, including Trousdale County.
Note that the old alignment also crossed the Cumberland River.
"The current bridge is far away from the new alignment, so it's not usable as part of the new alignment," Fugate said. It will remain in place.
Therefore, the team is building a new 1,710-ft.-long beam bridge with steel girders in three of the spans and prestressed concrete bulb-tee beams in the other five spans.
Fugate said the bridge is one of the longest bridges TDOT has ever built. For comparison, the project requires a second bridge. The bridge will enable traffic to cross over SR 25, and it's just 197 ft. long.
The one-third-of-a-mile-long bridge will have eight spans upon completion, including one 450-ft.-long spanning the river.
TDOT photo
One of the piers is in the river. The team built cofferdams to remove the water and reach the bottom of the river. The design team designed the pier to withstand barge impact, as they're prevalent on the river.
The river pier has proven to be a significant challenge for the team.
"We've run into geotechnical challenges as the contractor discovered some voids in the rock," Fugate said.
The design called for the team to build into the rock, but the rock discovered so far is not stable.
"We may have to dig out up to 20 feet more to reach rock that can support the foundation," Fugate said. "We're considering other options including drilling like micropiles but are currently doing more Geotech investigation to confirm how significant the voids are."
Environmental issues are another challenge the team has been dealing with.
"There are a few stream relocations on this job, and construction is impacting several of them," Fugate said. "When we impact streams, we either have to pay credits to the environmental agencies or improve the streams."
How can the streams be improved? The team can add features to the streams to make them feel more natural. Options include:
• Make the streams more curvy.
• Vary the bottom of the stream.
• Put trees in the banks of the stream for wildlife to live and hide.
• Install rocks in the stream bed.
"Stream designers specialize in this work, and they came up with a very specific plan," Fugate said.
Environmental agencies review the plans to ensure they meet their standards before giving final approval.
Time, Money
The original budget for the project is $99 million. Fugate expects the project to exceed the budget due to geotechnical issues.
TDOT photo
"Our initial estimate is it will cost an extra $3 million if we move forward with the micropile option," Fugate said.
The rest of the project is going as planned, so there are no other major budget issues.
"There are few utilities in the area, and no active traffic helps the contractor boost productivity," Fugate said.
The state government is providing 100 percent of the construction funding. The federal government kicked in money for preconstruction work, including design and right-of-way acquisition.
Construction began in December 2023 and is scheduled to conclude in July 2027. The conclusion date also is in question because of the geotechnical issue.
"We anticipate the contractor will request extra time due to the extra work related to the geotechnical issues," Fugate said.
The extension length has yet to be determined, though it's expected to be measured in months, not years.
"The contractor is working hard to minimize the added time as they are working on the bridge in other capacities while the geotechnical issues are being addressed," Fugate said.
When the project is completed (and the second SR 141), drivers on the corridor will experience improved traffic flow. Travelers will enjoy a more reliable journey through middle Tennessee. Finally, Hartsville's downtown area will see a reduction in traffic. CEG
