Roane County, Tennessee

In early 2019, following a winter of heavy precipitation, Tennessee Department of Transportation (TDOT) personnel noticed cracks were occurring in an approximately 0.4-mile-long stretch of the westbound (WB) lanes of Interstate Highway 40 (I-40) along the south slope of Rockwood Mountain in Roane County, Tennessee. TDOT contracted with a geotechnical engineering consultant to perform a detailed geotechnical exploration and monitoring program. The consultant and TDOT developed a design (contract design) which would incorporate permanent tieback anchors with reaction blocks to stabilize the landslide. The contract design called for 1,714 (3-, 7- and 9-strand) anchors with each anchor bonded into bedrock below the slide surface. In the summer of 2020, TDOT awarded the construction contract for this project to Richard Goettle, Inc. Shortly thereafter, Goettle retained Burns Cooley Dennis, Inc. (BCD) to develop a Value Engineering (VE) design for the project.

The VE design used the same concept as the contract design, but used a smaller number of anchors than was called for in the contract design. The VE design reduced the number of anchors to 605 by using larger 12-strand anchors and longer bond lengths. The reduction in the number of permanent tieback anchors by greater than 275 percent was significant, allowing a greater spacing between the anchor and reducing the potential for the very long anchors to intersect. This reduction also minimized the overall project time for drilling through the boulder-strewn colluvium and residual soils to reach below the slide plane at depths reaching 200 ft. The on-site construction of stepped reaction blocks further improved construction efficiency and reduced construction-related traffic delays on I-40.

The VE design was accepted by TDOT in June 2021. Goettle achieved substantial project completion and installation of the tieback anchors in December 2022. The VE design significantly reduced the construction time, originally projected for the contract design in May 2024. The VE design provided slightly more load capacity than the contract design.

The project received special recognition for the following reasons:

  • The design incorporated relatively large 12-strand anchors, allowing for fewer anchors to be needed to achieve the desired factor of safety;
  • The required length of the anchors to reach stable bedrock below the shale surface and the boulders in the colluvial soils above the slide surface presented significant challenges;
  • The flexibility of the VE design and construction techniques allowed for adjustments to be made quickly without significant impacts to the project schedule or cost; and
  • The VE design allowed for the project to be completed 1.5 years prior to the originally projected completion date.

The stabilization of this section of I-40 is important to provide long-term stability to this important roadway in Tennessee. Because this stretch of I-40 crosses Rockwood Mountain, it is especially important, since closure of the interstate highway would require very time-consuming detours, affecting other portions of the Tennessee transportation infrastructure.

Project Details


May 2023


Richard Goettle, Inc.




ACEC-TN 2023 Grand Conceptor Award, Grand Award (Large Project Category), and ACEC National Recognition Award

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