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Heifer International Headquarters
Little Rock, Arkansas
Date Completed: 01/2006
Architect: Polk Stanley Rowland Curzon Porter Architects
Developer/Owner: Heifer Project International

Heifer wanted a design that reflected the “concentric rings of influence” symbol for its new headquarters in Little Rock, Arkansas.  This symbol represents the goal of providing an animal for a family in a community and allowing that to be a “drop of water” generating ripples that flow to others.  Therefore the building’s gentle curve emanates from the overall four-phase master plan, conceived as a series of concentric rings expanding outward from a central commons that represents the impact point of a gift.

The four-story, semi-circular, office building, framed with steel plate shear walls, was constructed on one the largest Brownfield recoveries in the state. Roof framing consists of a wood roof deck spanning sleepers on top of steel beams spanning steel girders that in turn span steel tree columns. The tree columns consist of round pipe columns that continue from the floors below, cantilevering approximately 8 ft above the fourth floor, with steel pipe members creating the branches supporting the roof framing.  The roof is inverted to provide a “valley” in the middle of the building to collect and recycle rainwater. Extended steel beams at the roof edge are capped with galvanized steel grates to extend the sun protection and lighten the edge in a crown-like fashion.  Floor framing consists of a minimum of 2½ in. of normal weight concrete on top of composite steel deck spanning between wide flange steel beams that span wide-flange steel girders and round steel columns.  Lateral stability for the building is provided by the floor deck acting as a diaphragm, spanning between steel plate shear walls from the foundation to the fourth floor.  Lateral loads at the roof are resisted by the roof deck acting as a diaphragm spanning the tree columns, which cantilever above the fourth floor. The columns transfer lateral loads at the roof to the fourth floor diaphragm. The design employed extensive cantilevered floor elements to minimize the number of columns and provide a feeling of openness.  The building presented several challenges to the design team, one of which was working with round columns. The project team initially considered round cast-in-place concrete columns and a steel floor framing system, but eliminated this option due to concerns with tolerances for the concrete and connecting the steel to the concrete. It then considered round precast concrete columns, but ultimately decided on large round steel pipe columns in order to satisfy the architect’s desire for round columns, as well as to ease connection of the steel framing to the columns.

The semi-circular shape of the building was another challenge, as it complicated the layout of the steel system and expansion joint; the building is more than 440 ft long, so an expansion joint was added near the center of the building. Due to building irregularities, each half of the building was analyzed for lateral loads using static and dynamic methods.

Since the structural steel system was exposed in the majority of the facility, it required closer coordination with the architectural, mechanical, and electrical details including details at windows and tree columns and up-lighting in tree columns. In addition, a raised floor system was used on most of the building to run utilities and wiring.  Because Heifer seeks attainable agricultural solutions within the parameters of each project’s region, the building had to reflect this methodology as well. As such, one of the major goals for the building was to use locally sourced materials that would exceed LEED requirements for distance to site and recycled content. Steel was fabricated at a facility just three blocks from the site, and the aluminum curtain wall and skin, making up over 90% of the exterior, was fabricated directly across the street at a major glazing company. In all, 97% of the project’s materials were recycled.  (Taken from 2007 IDEAS2 awards page in May 2007 Issue of Modern Steel Construction.)



    
   
   
   
   
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