The Thomas F. Eagleton U.S. Courthouse in St. Louis, Mo., is an excellent example of the adaptability of architectural precast and the craftsmanship required to install it. The building façade was originally designed with 4” natural limestone. However, the General Service Agency (GSA) tightened the financials on the project and ruled in favor of precast concrete. Architectural precast concrete was specified to maintain the high level of finish and keep the project in budget and on schedule. Additionally, the decision to use a precast façade ensured the longevity of the façade offering a low-maintenance solution that preserves the building’s aesthetic appeal and performance.
The look of a conventional limestone façade was preserved through the variety of colors available in architectural precast concrete. The final color is striking in the sense that it changes depending on light. At times, it appears to have a hint of pink, while other times it resembles a warm red sunset.
To further mimic the feel of limestone, various textures were used: smooth, textured and rock-face. Using a single off-white mix design, the smooth panels received a light sandblast showing only the sand and cement matrix with no aggregates showing. Lightly roughened liner was used to give texture to the spandrel panels, and a 3/8"" x 3/8"" V-Rib liner embedded in the surface of vertical panels on the front and the back of the building provided the darker, textured finish. Rock-face panels were poured into rubber molds formed from rough-chipped limestone blocks giving 3 inches of relief. The bullnoses feature a split-stone finish which was created by molds crafted in the plant. The remainder of the project was formed with a bush-hammer rubber liner. There were many half-round column covers with the brush-blast finish with no liner. |