Construction of the Woodruff Arts Center in the heart of Atlanta's art district started with self consolidating concrete (SCC) to create a smooth, void-free surface on 1400 linear feet of wall that ranged from 9 inches to 4 feet thick and from 16 to 35 feet high. The acceptance criteria for the concrete allowed no more than five defects or bugholes within any square foot, and those were limited to the size of a dime. And no rubbing or patching was permitted.
The walls were to be built first, but reveals had to be engineered to align with other elements of the project. The vertical reveals had to match vertical joints in the siding and handrails above, sidewalk below, and window mullions within. The horizontal reveal also had to line up with the finished floor elevations on different levels, and the thickness of the wall had to line up with brick pavers in the second floor courtyard.
Because so much rested on getting it right the first time, the finish and construction methods were determined through a series of four mock-ups. In the end, the Agilia concrete supplied by LaFarge North America was a straight cement mix. Although that created a high heat of hydration, it was chosen as the preferred issue to overcome rather than the color variations introduced by fly ash and slag. New MDO plyform was used for the formwork. To further avoid surface imperfections, the contractor attached the reveals by screwing them on from the outside to prevent the screws from being seen once the forms were removed. Using a heavy coil tie with setback cones handled the form pressure. Once the project was complete, setback plugs were installed instead of patching.