Overlooking the Missouri River in Jefferson City, Mo., the Christopher S. Bond Courthouse showcases the beauty and durability that precast concrete can bring to a project. The 118,000 ft 2 (11,000 m 2 ) facility features thin granite and limestone cast into a solid-panel precast concrete facade.
The granite and limestone pieces used in this structure are just 3 to 6.6 in. (75 to 170 mm) thick, and up to 8 × 10 ft (2.4 × 3.0 m) in overall size, weighing up to 1400 lb (635 kg) each. The precaster developed a special dual vacuum suction cup system to move the pieces during the production process. The thin stone was cast into larger pieces of precast concrete that are up to 10 × 40 ft (3 × 12 m) in overall size.
By plant casting the granite and limestone pieces into the precast concrete, the team was able to accelerate the project schedule, allowing the work to finish much more quickly. They also significantly simplified the design, which allowed them to cut $3,500,000 from the budget while still including multiple shapes, curves, column wraps, and other intricate detailing. The final design included sills and other protruding elements that required panels to be built up as much as 2 ft (600 mm) in the form.
The use of precast concrete also reduced the number of trades on-site, and helped it divert 80% of construction waste materials from landfills, both of which contribute to the project's LEED certification goals.