Austin Football Club is the first professional sports team in Austin, Texas, and the Major League Soccer team needed a home befitting its status. The designers of the new stadium wanted the structure to provide an open-air space that would also shield fans from the hot Texas sun and frequent rains so it could be used year round.
And it had to be erected quickly. The entire project timeline was just 18 months, making precast concrete the obvious choice.
“Precast concrete was selected due to the short timeline in order to erect the bowl fast and dry in the spaces below,” says Jeff Nixon, managing director of Walter P Moore. “Precast concrete also is a better product when it comes to durability for a seating bowl structure.”
The design features a 20,500-seat, open-air stadium with a large roof canopy that covers the entire seating area. Both structural and architectural precast concrete were used in the project to deliver the desired aesthetics, says Paul Elrod, director of project management for Heldenfels Enterprises. “Precast concrete also contributed significantly to the LEED certification process and overall cost savings.”
For the structural precast concrete, a 75-year life-cycle mixture consisting of Type III cement, Class F fly ash, dolomite aggregate, and a corrosion-inhibitor admixture was used. This combination was important to deliver a resilient structure that could stand up to the elements. “The precast concrete gives it a nice clean look especially when sitting on steel,” Nixon says.
For the architectural panels, the design team used in-house custom-made formliners to create variations in the stair tower locations. The inserted boards were sandblasted before casting bed installation to achieve a uniform wood-grain appearance. The designers also used building information modeling (BIM) software throughout the design process to enable the very compressed project timeline.
To accommodate the owner’s desire for double stadia seating risers that offer a “seamless look over the vomitory walls,” Elrod’s team cut a 6 ft notch out of the structural stems. “It was difficult to produce, but we accomplished it by making custom blockouts, and using a special lifting device to place them,” Elrod says.
Sequencing the precast concrete with the steel erector was the largest challenge, as the stadium has a steel canopy over three of the sections, Elrod explains. The canopies prevented crane access to set the precast concrete, so it was critical for his team to tightly coordinate their work on a daily basis throughout erection to ensure no project delays. “BIM allowed for needed changes to support other subcontractors, which resulted in additional time savings on the project,” he says.
The other primary challenge was simultaneous steel and precast concrete erection. Only minimal lay-down area was available, so trucks had to deliver precast concrete pieces daily and retrieve empty trailers on a constant, rotating basis. To accommodate these constraints and accelerate construction, precast concrete erection took place during the second shift, using the day-shift steel erector’s crane.
The result is a welcoming, open space that will serve Texas soccer fans for decades to come. “We think this is one of the most beautiful and unique soccer stadiums in the country,” Elrod says.