Hurricane Helene created a massive washout under Route 321 near Butler, Tennessee, closing a key regional highway that connects communities throughout Johnson County to schools, hospitals, and jobs. The damage required an immediate response from the Tennessee Department of Transportation (TDOT), which in turn called on Producer Member, Permatile Concrete Products Company, to supply an engineered replacement structure capable of meeting the emergency recovery schedule.
The plans called for a 408-foot double run of 120-inch special design reinforced concrete pipe. With the pipe designed to sit under 47 feet of cover, the immense structural loads would be far beyond any standard highway specification. At this burial depth, the vertical pressure alone creates enormous demands before accounting for traffic loads from a state highway.
Each pipe section was engineered by Permatile Concrete Products in-house Professional Engineers to handle the extreme burial depth. Special design shop drawings and calculations were required for this specific application, going beyond standard specifications to meet the unique performance demands. TDOT's decision for this material was crucial, as reinforced concrete pipe is sustainable, resilient and reliable and has a long and successful history in such deep burial projects. Critically, Permatile's ability to produce the highly specialized pipe sections off-site was the key to keeping the entire recovery on its aggressive schedule.
This precast approach eliminated potential on-site casting delays and allowed site contractors to move forward with installation. Permatile was able to move from initial engineering to the final delivery of all 408 feet of specialized pipe in less than 90 days. The project demonstrated how off-site manufacturing of custom-engineered precast components can meet the demands of emergency infrastructure recovery.
This section of Highway 83 benefitted from a total reconstruction. Slopes were flattened and curves were straightened to make travel much safer for the public. All reinforced concrete pipe and precast concrete box culvert crossings were upsized to improve drainage as well.
The project was completed on October 14, 2019. A major benefit of using precast box culverts included the quick installation, which reduced any chance of delays occurring as can happen with cast-in-place in the wet spring and summer seasons. The use of precast also greatly shortened the time needed for the open window of excavation.
Location: Route 321 - Butler, Tennessee
Date Completed: 2025
Project Owner: Tennessee Department of Transportation
Contractor: Bakers Construction Services
Designer: TDOT/Permatile Concrete Products Company