Federal Center South Building 1202
Designer: ZGF Architects
Client: U.S. Army Corps of Engineers
“With plenty of daylight, this interior environment embraces the culture of rivers. Incredibly progressive for a government building, this space offers a sense of community for the employees.” -Jury
For decades, the U.S. Army Corps of Engineers (USACE) either sweltered or froze, depending on the season, in a 1932 Albert Kahn-designed former Ford Motor Company plant on a Superfund site south of downtown Seattle. The factory’s windows were inoperable, limiting fresh air, and daylight did not penetrate far into the 100,000-square-foot floor plates. Six-foot-tall office partitions reinforced departmental separation and made collaboration difficult for the civilian and military workforce.
The 2009 American Recovery and Reinvestment Act provided funding for a new USACE Northwest headquarters and an opportunity to showcase one of the Corps’ key missions: restoring and sustaining the environment. Built on a site adjacent to the previous one on the Duwamish Waterway, the new headquarters is in the top one percent of energy-efficient office buildings in the United States, and fosters community and a collective identity among staff. The building is the result of an innovative design/build partnership between ZGF Architects and Sellen Construction. “Our goal was to create an esprit de corps for the Corps,” says Allyn Stellmacher, the ZGF partner in charge of the project.
ZGF took a cue from the twists and turns of the nearby Duwamish Waterway and designed the open office space in an oxbow shape around a central atrium. The U-shaped form of the 209,000-square-foot building delivers daylight into the narrow, 60-foot-wide floorplates, providing natural light to more than 90 percent of the interiors. Key to the building’s success is an ultra-efficient envelope that balances a high level of insulation without inhibiting transmission of daylight, allowing the innovative mechanical system to perform at optimal capacity.
The sleek, stainless-steel skin conceals a surprisingly rough-hewn interior. Recovery Act funding required the reuse of timber from a demolished warehouse on the site, and ZGF ingeniously incorporated it to give the atrium an appealing weathered character. Inside, a bed of rock and slate meanders across the atrium floor to resemble a river. Building upon biophilic design principles to evoke a positive response to nature, the designers incorporated timber columns that line the banks like trees, and water that gurgles through channels cut into boulders. The water features are fed by a rainwater reuse system that captures water from the roof and stores it in a 25,000-gallon cistern. An estimated 430,000 gallons of rainwater will be harvested annually, providing a 79-percent reduction in potable water use for toilets and irrigation.
Sky bridges and stairs crisscross the atrium to connect open office space on upper levels at multiple points. By grouping conference areas in the commons, the designers were able to keep full-height walls to a minimum in the office areas, and the low, 50-inch-tall workstation partitions allow visual access within and between departments. “Based on feedback from the Corps, the design has definitely improved collaboration between groups,” says General Services Administration (GSA) project manager Rick Thomas. “People can now walk across the sky bridges to connect, or talk to their colleagues over the lower partitions.”
An underfloor air distribution system for ventilation and cooling delivers 100 percent filtered air from outside, and the natural process of convection exhausts air through the atrium to a high-efficiency heat recovery system. The building is one of the first in the region to use structural piles for geothermal heating and cooling, as well as a phase change thermal storage tank. The tank and a ground loop provide back-up heating or cooling to meet demands during peak seasonal loads.
“The Corps’ mission is integrated throughout the building, which reflects a dedication to restore and sustain the environment,” Thomas says. At certain times of the day, members of the Corps can watch river otters playing in the waterfront site’s restored wetlands. With a light touch on the surrounding environment and well-executed interiors, this office is a sustainable, uplifting upgrade for the Corps employees.