Now blooming out of the downtown Atlanta soil is an iconic-looking structure, progressive and forward-looking in terms of its design and technology, and one intended to serve as an international symbol for the state of Georgia and the city of Atlanta. These initial cues came straight from Arthur Blank, Owner of AMB Sports & Entertainment – the parent company of the Atlanta Falcons and Atlanta United.
Bill Johnson, SVP and Design Principal at HOK Sports + Recreation + Entertainment, remembers these seeds of his imaginative design.
“When we came in with this concept in the interview process, the Falcons were either going to love it, or they were going to hate it,” says Johnson. “It wasn’t going to be in the middle. We swung for the fences so to speak. And it fulfilled a lot of [Arthur Blank’s] preconceptions about what he wanted the project to be.”
Out of the initial ideation came a thesis that the energy of football and soccer is focused in the center, resulting in the iconic oculus roof, reminiscent of the Roman Pantheon. Also inspired by the Falcons logo and team colors, Johnson created the mesmerizing exterior geometry of the building.
Combining the oculus with the falcon’s wing inspirations, Johnson next created a first-of-its-kind retractable roof design – a grand departure from the simple single-panel or bi-parting-panel designs typically enclosing sports and entertainment venues.
Oculus and Operable Roof
First conceived as a circular opening, the roof geometry was simple. Eight congruent segments with congruent movement would easily come together to close the roof. But after stadium designs were refined, the circle stretched to an oval, introducing complicating variables. Now the pieces vary in shape and size, and move slightly faster or slower over distances slightly longer or shorter than one another.
“When we came in with this concept in the interview process, the Falcons were either going to love it, or they were going to hate it. It wasn’t going to be in the middle. We swung for the fences so to speak." – Bill Johnson, SVP and Design Principal at HOK Sports + Recreation + Entertainment
A significant milestone was achieved in December when Mercedes-Benz Stadium’s signature element was decentered. Shoring towers were taken down, and 36 million pounds of fixed-roof steel dropped 22 inches as planned, settled, and supported itself.
“That’s a celebration for everybody because that means things can start getting demobilized and moved out of the bowl, opening up real estate so they can finish the lower level bowl,” says Mac McCoy, SVP and Director of Project Management at HOK Sports + Recreation + Entertainment.
With the workspace now clear of the shoring towers, the components of the operable roof portion, known as “petals” (like the petals of a flower), are now being assembled on the floor. Once installed, the eight triangular-shaped pieces will open and close in approximately ten seconds.
The 18,000 tons of 70-foot-tall fixed-roof steel trusses supporting the operable roof and overall structural loads also abut what will be the world’s largest scoreboard and create its unique shape. Mercedes-Benz Stadium partnered with Daktronics to create 60,000 square feet (58 feet high by 1,100 lineal feet) of LED board, dubbed the halo board, that lines the circumference of the building’s signature oculus just beneath the roofline.
“When we went to all this trouble to create an opening in the center and energy in the center and a roof moving away from the center, the last thing we wanted to do was plug it up with a traditional board,” says Johnson.
Window to the City
The skin of the building is made up of multiple systems of metal panel, glazing, and the world’s largest installation of single-membrane ethylene tetrafluoroethylene (ETFE).
ETFE is a sturdy, lightweight plastic that sheds dirt and provides transparency in lieu of glass. Designers can insert a frit (a series of dots) on the material to protect patrons from the sun. At Mercedes-Benz Stadium, the ETFE on the south and west sides of the building has a 70% to 80% opacity.
As fans move about the building, the frit dissolves. On the north and east sides, the ETFE is clear and 16-stories tall, producing “the window to the city”.
The window to the city provides exceptional views out to the Atlanta skyline from downtown to midtown all the way to Buckhead. And looking in from all those locations, Atlantans view the next icon of their city.