Chilling Tower
Imagine this: a 50,000-pound chiller tower teetering dangerously toward the Tar River. As wild as that sounds, it was the exact predicament that sparked this critical project at the Rocky Mount power plant, home to Chico’s Mexican Restaurant. In 2024, Tropical Storm Debby unleashed chaos, transforming what began as a stabilization effort into a high-stakes rescue mission.
Appian Engineers had already established plans to stabilize the riverbank behind the power plant due to severe distress in the existing sheet metal piling bulkhead. However, Tropical Storm Debby, which made landfall from August 8th to August 9th, dumped nearly six inches of water into the Tar River tributary drainage basin. The waters rose relentlessly until August 14th, creating a fissure in the riverbank just behind the chiller tower pad. The slope instability threatened a total collapse of the bulkhead and riverbank.
Hired by Appian Engineers, Ram Jack from Durham, NC, installed post-construction helical piers and tie-backs to stabilize the structure. However, they did not anticipate the urgent danger as floodwaters receded, causing the pad to shift dramatically and a surface fracture to widen to more than 10 inches within 24 hours. The job quickly escalated from stabilization to a full-scale rescue operation.
Enter SE&M and Edwards Crane, who worked swiftly to secure and relocate the chiller tower to stable ground. This is when Barnhill was called in to perform clearing, grubbing, and demolition to prepare a new area for the chiller. Bridgeview Contractors followed with the construction of a reinforced concrete tower pad and a new latticed steel chiller tower. By the end of August, the tower was safely moved to higher ground and operational, restoring much-needed air conditioning to the power plant.
But the challenges didn’t stop there. During the move, the electrical and water to the chiller was shut off, but the pipe system continued leaking, further saturating the subgrade and destabilizing the riverbank. The kitchen at the back of Chico’s Mexican Restaurant sat dangerously close to the riverbank, shifting the team’s focus to preventing its collapse. The owner asked Appian Engineers to develop solutions for bulkhead stabilization or replacement.
Initially, building another retention pile-panel wall was suggested, but the cost was prohibitive. Barnhill and Appian collaborated to devise a more practical solution: using Class 2 river rip rap, filled in with Class B rip rap to lock it in place.
“Once we got everything cleared, we cut out dirt and began putting in fabric and plating it with Class B rip rap,” explained Jeremy Whitehurst, Barnhill Project Manager on this job, and now Vice President of the Rocky Mount Division.
The job presented another unique challenge—the discovery of a Neuse River Riverdog habitat (an aquatic salamander) right in the work zone. Designated as a critical area by the US Fish & Wildlife Service, the crew had to wait for federal permits and order a turbidity curtain to protect the habitat. The curtain, sourced from Tampa, Florida, was delayed due to another hurricane. Despite the setback, by October 24, 2024, Barnhill and Bridgeview installed a 10-foot-tall, 200-foot-long turbidity curtain, safeguarding the riverdog habitat. Job complete!
“This job was a tight one for sure,” recalled William Downing, Equipment Operator. “The dirt was so slippery, I had to keep spinning in place to avoid falling into the river.” With limited space to work, precision was critical.
“Overall, the job went smoothly, especially considering everything we were up against,” said Charlie Palmer, Pipe Foreman. “We had to get in the water with life jackets and use a boat to place the turbidity curtain—that’s not something we do every day.”
Despite the complex challenges, the team delivered under budget and within a two-week timeframe, utilizing 638 tons of Class 2 rip rap and 154 tons of Class B rip rap. Kudos to Charlie Palmer and his crew for their meticulous work and determination.
This project was a testament to the power of teamwork, resilience, and expertise. Facing nature’s fury, environmental obstacles, and tight timelines, Barnhill and all partners involved rose to the occasion—saving the chiller tower, stabilizing the riverbank, and restoring critical operations at the Rocky Mount power plant.