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National Association of Realtors Building
Washington, D.C.
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First Washington, D.C. Building to Receive LEED™
Certification
 The
Washington, D.C. headquarters of the National Association of Realtors
was the first building within the District of Columbia to receive
certification from the U.S. Green Buildings Council’s LEED
rating program. Today it also houses the Portland Cement Association’s
Washington office. The 102,000-square-foot, 12-story structure achieved
this honor through a variety of innovative features, including an
efficient HVAC system and glass curtain wall that reduce energy
use by up to 30 percent, the elimination of CFC refrigerants, and
the use of a carbon dioxide monitoring system.
Achieving such an environmentally-sound structure was no easy feat,
particularly because the construction site, which had formerly housed
a gas station, was plagued by contaminated soil. In fact, more than
24 feet of soil had to be excavated and disposed of before construction
could begin. In addition, the geometry of the triangular site (located
three blocks from the Capitol at the intersection of a diagonal
street) called for an original approach to the building’s
design and construction.
 Concrete
provided the solution to many of these dilemmas. A concrete frame
allowed the building to be constructed within the restricted space.
Concrete floor slabs also provided the means to achieve the architect’s
vision for the structure’s curved-glass façade, a design
that necessitated minimal deflections. To minimize the effect of
concrete creep, the design incorporated post-tensioning, ensuring
that after the spans shortened and the creep caused the concrete
to deflect and uplift, long-term deflection was nonexistent. The
water/cement ratio of the 5,000-psi concrete also was restricted
in order to control creep. The concrete contained corrosion additives
to prevent damage to the reinforcing steel.
Some of the structure’s other design specifications also
presented challenges. The architect called for a minimal number
of columns, so post-tensioning was used in select areas in order
to create larger spans. The recessed edge of the slab at the second
floor required the design of intricate brackets behind the columns,
which enabled the design team to have the columns flying in front
of the supported second floor plate, almost as if the floor was
floating in the air behind them. The slab thickness is 14-inches
at the edge drops and 8-inches inside, while the columns are 24-inches
round.
 Construction
on the $46.5-million design-build project began in October 2002,
and the National Association of Realtors moved in to occupy five
of the building’s floors in May 2004. Since its completion,
the green structure has received several accolades—the Washington
Business Journal credited it with best architecture and best
financing, and it was a runner-up for best urban office project
and best sustainable growth project.
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Owner/Developer: National Association
of Realtors
Architect/Interior Architect:
Gund Partnership
Architect of Record: SMB Architects
-- Stephen M. Banigan
Structural Engineer: Fernandez &
Associates
Developer/Builder: Lawrence N. Brandt,
Inc.
Construction Manager: Carr America
Development
Concrete Contractor: Miller and Long
Post-Tension Supplier: Suncoast Post-Tension,
L.P.
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