Federal Center South

Seattle, Washington

  • Services Civil Engineering, Structural Engineering
  • Market(s) Government, Mass Timber, Office
  • Sustainability LEED Platinum
  • Awards Outstanding Project Award, New Buildings $30M-$100M, National Council of Structural Engineers Associations (NCSEA), 2015
    Excellence in Structural Engineering Award, National Council of Structural Engineers Associations(NCSEA), 2015
    Honor Award, Commercial Office Building of the Year, Wood Works, 2014
    Best of the Year - Green, Interior Design Magazine, 2013
    Best Project - Government/Public Buildings, ENR Best Projects, 2013
    Office Development of the Year - Public, NAIOP Night of the Stars, 2013
    Green Washington Award Winner: Special Recognition for Cutting-Edge Buildings, Seattle Business Magazine, 2013
    Special Mention, Sustainability Honorable Mention, Northern Pacific Chapter IIDA, 2013


Square Feet


Acre Campus


Of the site's areas through water quality treatment facilities
  • Owner U.S. General Services Administration
  • Architect ZGF Architects
  • Contractor Sellen Construction
  • Collaborators SiteWorkshop
    Lane Coburn & Associates LLC
    Sequoyah Electric
    The Greenbusch Group
  • Team Seattle, WA
Federal Center South

KPFF provided structural and civil engineering services for this design/build office building that serves as the headquarters for the US Army Corps of Engineers in the Puget Sound region. The 206,000 SF building is located in the Federal Center South campus along the Duwamish River in South Seattle. The project is part of the High Performance Green Building design program, and attained LEED platinum certification from the U.S. Green Building Council. It has naturally lit spaces and an energy-efficient HVAC system with under-floor air distribution.

All design work was designed in conformance with Anti-Terrorism/Force protection standards.

The building structure consists of a combination of steel and heavy timber framing. The heavy timber is reclaimed from a warehouse building that previously occupied the site. The building also contains a structural steel diagrid at the perimeter, which carries building loads and serves as the progressive collapse resisting system. The building is supported on steel pipe pile foundations.

Civil Sustainable Goals

One of the primary goals for the Federal Center South project was for the drainage design to mimic natural drainage systems to the greatest extent possible, while achieving required water quality and quantity controls. This drainage goal required an integrated approach, heavily influencing the site plan and grading design.

The initial focus of the design was to minimize impervious surfaces by limiting the amount of parking areas and drive aisles, converting normally hardscaped fire lanes into permeable surfaces, and eliminating curbs which channelize flows. The site design leverages the naturally permeable soils on the site, encouraging sheet flow and infiltration through the landscape, while still providing surface feature reservoirs to collect and treat excess runoff.

The design uses surface features and topography to route excess runoff around the site, while limiting the use of traditional conveyance system of curbs, catch basins, and below-grade piping. Due to the relatively flat nature of the site, the design makes use of the collection ponds and associated weirs to convey large overflow runoff events to the site’s natural discharge location, the Duwamish River. The small section of traditional conveyance is located at the downstream ends of the new drainage design, where the site discharges to the Duwamish River through existing piped outfalls. These systems are only used in large overflow events.

Key elements of the design include:

  • Increasing the perviousness of the 8.8-acre site from essentially 0% to 66%
  • Retaining the 95th Percentile Rainfall event and mimicking natural drainage patterns, per EISA Section 438, via infiltration, evapotranspiration, and reuse.
  • Sending approximately 99% of the site’s areas through water quality treatment facilities, which include 1,170-lf filter strips, a bioswale, and approximately 39,000 SF of rain gardens and bio-retention facilities.

Additional Awards:

  • Top 10 LEED Projects of 2013, Interiors & Sources
  • Design Annual Winner, Environmental Graphics, Communication Arts
  • National Design-Build Award, Design-Build Institute of America
  • Society for Environmental Graphic Design
  • Craftsmanship Award, Puget Sound Chapter Construction Specifications Institute
  • Washington Civic Design Awards, AIA
  • Construction Award-Public building $50 million-$100 million, AGC
  • Construction Management Project Achievement Award Winner, Vertical Project, CMAA
  • AIA COTE Top 10 Green Projects, AIA Committee on the Environment
  • Special Mention, Architizer A+ Awards (Office Building Low Rise), Architizer
  • Best in State, Silver Award, 2013 Engineering Excellence Awards, ACEC Washington
  • 2012 Honor Award-First Place for High-Performance Buildings, Beyond Green High-Performance Building Award, National Institute of Building Sciences, Sustainable Buildings Industry Council
  • Honorable Mention, What Makes It Green?, AIA Seattle Chapter
  • Best in Category for Design IN Mass, Northern Pacific Chapter IIDA, 2013

Learn more about the project here.

Federal Center South

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