The co-winners of the 2011 Precast/Prestressed Concrete Institute’s (PCI) Design Awards for the Stadiums/Arenas/Sports Facilities category showcase how skilled, creative precasting crews can mimic natural stone. Both projects, Target Field (home of the Minnesota Twins) and the Indiana University Stadium's north end zone addition, demonstrate stone-like effects by use of form liners or by actually casting in odd-size limestone blocks.
Various thicknesses of honed and quarry creek rock-faced stone were cast into the precast concrete wall system for Target Field. However, casting in odd-size limestone blocks with non-uniform surfaces and thickness (varying by up to 2 in.) presented a major challenge. Solution: The limestone blocks were placed face down in the precast form with 3/4-in. joints, and stainless steel ties were used to anchor the blocks to the precast. A bond breaker prevented concrete from entering the joints and allowed thermal expansion of the dissimilar materials.
The stadium design also included a gradation in stone color from darker stone at the base to lighter at the top. Furthermore, the structure consisted of a multi-level waffle slab floor system with concrete columns at random locations.
For the Indiana University Stadium addition, precast concrete form liners were used to impart a split-faced limestone-like texture to emulate giant blocks of quarry limestone. The form liners were created by taking impressions from limestone blocks. Bands of smooth-faced precast were integrated with the textured areas to help articulate the look of individual stone blocks. The corners of the towers feature panels poured with an invisible cold formed joint at the outside corner, allowing significant depth to each leg and further creating the illusion of large stone blocks to coordinate with the collegiate gothic limestone architecture of the academic campus. Cast into the architectural panels is a one-story tall IU university logo. Moreover, the university’s name is also cast into the panels with an incised font.