Located in the new wing of the vibrant Aventura Mall, the new two-story retail store provides a visual anchor to the mall, drawing patrons into the shopping experience.
The owner originally chose precast concrete for aesthetic reasons; however, the choice also helped solve problems related to the constrained site and tight schedule. The greatest innovation on this project was the collaboration among the architect, engineers, precast concrete producer, and contractors to ensure every piece of the project met the owner’s goals from design through construction.
“No one trade was left standing alone to resolve conflicts or design goals,” says Bruce Bartscher, vice president of operations for Gate Precast. “Every member of the team worked together and explored every option before final decisions were made.”
The store consists of a large, open, tree-filled atrium, an amphitheater, and a stone feature wall capped by an undulating roof made of precast concrete beams and vaults. The roof, which takes inspiration from Miami’s art deco roots, consists of 80-ft precast concrete beams that span 60 ft clear between columns. The beams are joined by concrete arches that contain building systems and lighting, and are clad with acoustic fabric on the underside. The support columns are also clad with precast concrete sections, and the entire assembly has been grouted to create a seamless integrated whole.
The precast concrete used at Aventura is integral to the structure; it ties together columns and creates the roof and lateral shear diaphragm through the use of steel column caps precast into the beam ends, which are integrated with the facade glazing and mullion systems. This project required extremely tight tolerances and offered little room for installation attachments and adjustments. The team addressed this challenge with a lightweight precast concrete design that improved maneuverability and workability. “In all, 77 column cover sections were installed, with half rounds cast to fit perfectly together on either side of the glazing,” Bartscher says.
To achieve the project schedule, the precast concrete producer had to achieve exceptional quality control to ensure that the various shapes, sizes, and weights of the different precast concrete pieces were efficiently produced. To accommodate variations in curing and cooling times, the precast concrete producer's team tested multiple aggregate patterns and grouting methods and created multiple mock-ups to test how the curing would evolve. They used that information to adjust batch mixtures to align with the goals for the finish and to avoid alligator cracking.
To avoid installation surprises, the construction team used mock-ups and test beams to conduct practice runs with the rigging sequence at the precast concrete producer's plant, which made the actual installation run smoothly.
The beams were precast in three sections and post-tensioned before they were shipped. Once the beams were cast, delivery had to meet strict transportation requirements, which included a police escort, daytime delivery, and avoidance of all highways for the 250-mile journey. The beams were delivered one per day for eight days and lifted into place with an 800-ton crane. Once the beams were set, infilling between the beams with the vaults made for a seamless assembly.
The careful planning and collaborative problem-solving resulted in a beautiful structure that feels light and airy, with soaring glass windows that invite passersby to come in. The owner loves the elegant simplicity of the design, and appreciates how the designers were able to achieve a beautiful, resilient, and energy-efficient solution that met all of their needs.