A not-so-standard precast concrete barrier is helping keep cars and fans safe for Nashville’s first IndyCar race.
By Matt Werner
Nashville is known for its honky tonks, live music and partygoers dancing the night away downtown. Come August, the sounds of country music will be overtaken by the roar of engines as IndyCar makes its first trip to the Nashville streets for the Music City Grand Prix.
Cars will race through the streets and over the iconic Korean Veterans Memorial Bridge, marking the first time a race course will pass over a body of water. Creating a 2.17-mile track in the heart of a city is no easy endeavor, but precast concrete is taking center stage as officials hope to create Music City’s next big event.
Ingredients for a good show
Discussions about having an IndyCar race in Nashville had been ongoing for years, but coming up with a track design that worked for the racing series, city and local businesses proved difficult.
Eventually, an idea was pitched – having the cars race across the bridge.
“It creates a fantastic visual for the people here and those watching at home,” Music City GP President Christian Parker said. “So we designed the track with that in mind. It also elongated the track quite a bit to where we didn’t have to interfere with downtown businesses.”
The actual track design came from Tony Cotman with NZRConsulting, who has designed tracks around the world. The key to any track design is making sure the racing is great but also that spectators are entertained and have great visuals, too.
“When we’re designing any track, those are the basic fundamentals,” Cotman said. “Then we start thinking, ‘This would be nice,’ or in this case, ‘Wouldn’t it be cool to use the bridge?’ and getting those pieces to be plausible.
“In this situation, it just so happened that the bridge would play a major part. When you see that bridge, you’ll know exactly where you are.”
The business side
Early on, Music City GP officials engaged with Dr. Heather Brown, a former professor in the School of Concrete and Construction Management at nearby Middle Tennessee State University. She served as a resource on all things concrete, helping officials understand what would be needed and what was possible with concrete.
With top speeds expected to be around 195 mph, several upgrades are being made to the streets that will become the race circuit. Ensuring a proper racing surface is key. Having a precast concrete barrier along the entire track is equally important to prevent cars from running off the track and to protect spectators from possible debris.
While highway barrier is a standard product among many precast concrete producers, what’s being used for the Music City GP is anything but. Should a car get loose coming out of a turn or lock wheels with another, the barrier will help absorb and dispense the energy.
“When you look at the barrier from the outside, it probably just looks like a slab of concrete sitting there,” Cotman said. “On the inside, that’s the business side. That’s where all the components and cage link together.”
In tandem with Brown and wanting to keep things local, Music City GP officials engaged with local precasters to manufacture the barrier. NPCA Member Jarrett Concrete Products in nearby Ashland City, Tenn., took on the challenge.
Each barrier measures approximately 12 feet long, 40 inches tall and 22 inches wide at the base. Each piece also weighs a whopping 9,500 pounds.
“They’re pretty robust and have linking systems in it unlike any barrier we’ve seen before,” said Frank Bowen, Jarrett’s business development manager. “The reinforcing design is just as impressive as the piece itself.”
The linking system is made by a company in Europe that specializes in avalanche fall protection for cliffside roads. Each connector is welded to ASTM A706 No. 5 rebar, which runs continuous throughout the entire length of the barrier. The reinforcement design also includes a welded wire cage connected to No. 4 rebar.
Despite the number of connections, the team at Jarrett picked things up quickly.
“We don’t regularly manufacture barriers here, so this was a new, custom project for us, all-in-all,” Bowen said. “It has a pretty detailed reinforcing design, but it’s a relatively simple shape to make.”
The other key item was proportioning the mix design so it would have a 5,000-psi compressive strength and have a minimum unit weight of 140 pounds per cubic foot. Coming up with the design was an opportunity for Brown and her students to get their hands dirty and learn more about concrete.
“The whole project came at a good time to incorporate it into our senior research class,” Brown said. “They could think about what the concrete was being used for, and having an introduction into precast is priceless from a learning standpoint for them.”
Students were able to test, sample and even mix concrete to see the different ways to satisfy the specifications. They also learned how temperature impacts concrete since Jarrett would be producing pieces in winter and spring months.
What they came up with was two different designs, one that included Class C fly ash and one that included Class F fly ash. With inconsistent supplies of fly ash in some areas, Brown and the students wanted to give Jarrett options.
“The whole idea was just to see what they could do,” Brown said. “It showed students what it takes to develop a mix, so they have a better understanding about what goes into concrete, the quality control, testing and everything.”
Planning at a high level
With only a few months to manufacture nearly 2,000 segments, planning was key for the Jarrett team. Bowen developed a Gantt chart for the project schedule that outlined when they would order components, when forms would arrive and how many pieces would be produced each day.
“I am absolutely reliant on my Gantt chart,” Bowen said. “I set that up from the very beginning, and look at it every single day. Without having that Gantt chart, we would have been lost, absolutely lost.”
Jarrett added a crane and more production space to keep up with producing 10-15 barriers per day. The company needed to reorganize and make space in the storage yard to accommodate all the barriers.
“By doing that, we can hold about 600 pieces at a time,” Bowen said. “At that point, we have to ship them to the storage site by the track. We’re just trying to fill it up and ship them out, fill it up, ship them out.”
Cotman noted how well everything has gone from green to checkered flag.
“They have produced a really high-quality barrier,” he said.
Parker paid a visit to the plant and came away impressed with everything as well.
“Being in the plant, you get a newfound appreciation for the sophistication and science and math that really goes into concrete,” he said. “Jarrett’s done a tremendous job at not only maximizing their facility but their employees too.
“It’s such a sophisticated operation, and watching it in action is pretty impressive.”
Production, planning and teamwork all were key. Now, officials hope to make the Music City GP the next great race on the IndyCar calendar.
“I think the racing should be great, and the location for fans is going to be killer,” Cotman said. “Everyone seems to really like Nashville, so it has all the makings to be dynamite. We’ll find out in August.”
Matt Werner is a former NPCA communications manager.