Best Justice and Correctional Structure
U.S. Federal Courthouse
Nineteen federal agencies share the new 413,000 ft2 (38,400 m2) U.S. Courthouse in Jackson, Miss., requiring an organized layout of courtrooms, offices, and public spaces in two offset volumes angled to suit a site that includes an adjacent stream bed. With a need to meet a variety of federal security standards while providing an impressive aesthetic design, designers clad the exterior with two-story precast concrete architectural panels that also helped reduce costs.
The designers faced a site with less-than-ideal clay soil in addition to strict government requirements for resistance to progressive collapse and blast. They also knew that the owners wanted a strong image that projected security and authority. As a result, the exterior envelope accounted for more than 40% of the budget.
The efficiencies created by using architectural precast concrete panels in nontraditional ways helped keep the construction budget at just over $350/ft2 ($3,700/m2). The two-story, post-tensioned E-shaped panels were erected vertically rather than creating a more traditional one-story, long spandrel and vertical wall panel around windows. The saw-toothed patterned surfaces as well as the projecting sills, along with deep recesses for the windows, were built into the wall panels at the plant, facilitating erection.
“The articulation of the exterior surface was a key reason we selected this project,” says Tom Brock, a member of the buildings awards jury. “The precast with a shiplap detail was very attractive. It created a shadowline that took what was otherwise a very monolithic surface and allowed it to change during the course of the day. It was a very attractive use of precast.”
Designers also used precast concrete to achieve a variety of curving, rounded geometric shapes. The building has no 90-degree corners, with obtuse and acute corners creating 10 angles at which the panels had to connect. Casting these pieces monolithically allowed precast concrete to do the job that otherwise would have required several materials to create the same look. The shiplap design was created with considerable planning to provide the needed patterning, which varied between panels.
The large, all-in-one panels also reduced joints, reducing long-term maintenance. Casting the components in a controlled environment also enhanced the overall quality and tolerances of the pieces produced. This was especially important in providing uniformity for the sustainable integral color.
“This project had a lot of requirements for blast resistance, but it also had to be a public space,” says Wanda Lau, a member of the buildings awards jury. “Sometimes those objectives can interfere with each other. By using precast concrete, this project incorporated a level of design into a public building that makes it much more of a civic space.”
Location: Jackson, Miss.
Owner: United States General Services Administration, Atlanta, Ga.
Architect: H3 Hardy Collaboration Architecture, New York, N.Y., www.h3hc.com
Engineer: Walter P. Moore, Houston, Tex.
Contractor: W.G. Yates Construction, Jackson, Miss.
Precaster: Gate Precast Co, Monroeville, Ala., www.gateprecast.com
Precast specialty engineer: DC Engineering P.C., Ashland, Va.
Project size: 413,000 ft2 (38,400 m2)
Project cost: $136.1 million