Sustainable/LEED

Midtown Center/Fannie Mae HQ

SK&A provided structural engineering services for a new headquarters building for the Federal National Mortgage Association (FNMA), commonly known as Fannie Mae.  The new 875,000 sf Midtown Center office complex is comprised of two 14-story towers, East and West.  The structure features 45,000 sf of retail space, multiple three-story atria, three levels of below-grade parking, as well as a fitness center, rooftop terrace, and private alley.  The project also includes a 15,000 sf public courtyard surrounded by the buildings on three sides and is activated by ground floor retail.

A unique and distinct design feature within the complex are its three interconnecting “tunnel” bridges which span more than 110 feet across the site’s courtyard, connecting the east and west towers at levels 9 through 14.  The bridges feature interior walkways (inside of the bridges) and exterior walkways (on top of the bridges, open to the air).  The bridges were typically designed as “king-post” trusses utilizing heavy W36 section for top chord, eight-inch square tube steel section for bottom chord, and two (2) three-inch diameter high-strength tension rods by “Macalloy” as diagonal members connecting to an eight-inch square tube section vertical steel post, at the center of the bridge.

The three-story, below-grade parking deck uses conventionally reinforced concrete flat slab construction.  The courtyard slab and private alley above the top garage level is designed for landscape and fire truck loads.  The office level structural framing consists of eight-inch, post-tensioned concrete slab with eight-inch-thick drop panels over columns.  This efficient framing system allowed sufficient plenum space for the installation of MEP systems within the ceiling as well as the curtainwall anchors.  The project will pursue LEED Gold certification.  

View photos from a 2017 Site Visit.

Ron Brown College Preparatory High School

SK&A provided structural engineering services for the renovation of an existing school building into a modernized facility for a new all-male high school, particularly for young men of color.  Originally constructed in 1966, the building was shuttered due to decreased enrollment in 2013.  The project is located in northeast DC on a site adjacent to a community center/library.  The project was implemented over two phases. 

Phase 1 included the modernization of the building’s main entrance, which is centrally located and connects the structure via two wings—an academic wing and a multi-purpose wing.  Additional modifications included: a new main office and administrative suite; a new, expanded library/media center; a cafeteria/multi-purpose room, music room, lab spaces and classrooms.  Phase 2 of the project entailed renovations on the second and third floors, including the gymnasium and auditorium. 

Structural work included introduction of new rooftop mechanical equipment and screen enclosures, new entrance vestibules and lobby, removal of a portion of the second floor to create the two-story media center, and extensive crawl space repairs to address significant deterioration.

Murch Elementary School

SK&A provided structural engineering services for the modernization and expansion of the historic two-story Murch Elementary School building, originally built in 1929.  The renovated building and new addition is approximately 100,000 sf and serves a student body of 700 students.

The school’s renovations include updated classrooms, “pull-out” instruction spaces, a full-size gymnasium with stage, media center with “maker space,” laptop laboratory and small group instruction spaces, an administrative/welcome center, an art and kiln room, cafeteria, and a parking garage.  The building is expected to achieve LEED for Schools Gold certification.  

The project’s superstructure primarily consists of structural steel framing in combination with a limited area of cast-in-place concrete construction. Structural steel framing within the project includes composite steel, open web joists, and long-span roof construction.  The project’s concrete construction is limited to the floor framing above the garage and plaza.  The existing buildings were analyzed to support new mechanical equipment and provide large openings in the existing bearing walls at the connection between the old and new building.
 

Bancroft Elementary School Modernization

The old Bancroft campus consisted of five adjoining buildings totaling 94,000 sf.  Originally constructed in 1923, numerous modifications were made to the base structure: three buildings were added in 1932, 1961 and 1973, along with an addition constructed in 1938.  Due to the site’s topography, the buildings adjoined at various misaligned levels.  

Integrating ideas from a completed feasibility study (which SK&A also contributed to), the modernization of the campus included the demolition of two of the existing buildings as well as the previous expansion.  A new unifying building addition was constructed, knitting together the remaining historic structures with the new facility and providing a simplified circulation pattern within the reconnected campus.  

The completed project features multiple courtyards; a new multi-purpose “Curiosity Center” media area; and new outdoor playing fields.  The project’s superstructure primarily consists of structural steel framing in combination with a limited area of cast-in-place concrete construction.  Structural steel framing includes composite steel, open web joists and long-span roof construction.  Concrete construction is limited to the floor framing above the garage and plaza.

The existing buildings to remain were analyzed to support new mechanical equipment and provide large openings in the existing bearing walls at the connection between the old and new building. The modernized school will serve over 550 students and is LEED for Schools Gold certified.  
 

DC Water Headquarters

SK&A provided structural engineering services for the design of DC Water’s new headquarters.  The stylistic, modern facility is located on 2.75 acres, adjacent to the waterfront mixed-use development, The Yards, and the Washington National’s baseball stadium.  

The new building is a six-story, 150,000 gsf steel-frame structure with a fluid form. The building footprint was carefully shaped to develop a unique, site-specific solar response and consists of full-height curtainwall on the south, east, and west sides to take advantage of the scenic views, and gradually shifts to punched windows on the less scenic north side of the building.  The structure consists of a framed concrete slab-at-grade with six levels (five office levels and an accessible roof terrace) of composite steel construction.

The exterior facades feature a glass and aluminum curtain wall system on the south facade, and a “variegated green rainscreen panel system” on the north and west facades.  The building was constructed around and above the existing “O” Street Pumping Station, which maintained full operations throughout construction.  Foundations for the structure consists of below grade transfer elements and deep foundations.  As part of the landscape design, an exterior boardwalk and metal grating structure was implemented over existing tidal gates.

New mechanical equipment support and an enclosure were added on top of the existing pump station building.  New openings in the exterior walls at the ground floor  of the pump station facility provide a visual connection to the pump room from the new lobby.

Additional project features include an entry court, interactive exhibit space, and a boardwalk along the south facade.  The mechanical systems uses the pump station wastewater for heat recovery and rainwater from the rooftop will be collected in a cistern to use for toilet flushing.

Atlantic Plumbing, 8th and V Streets, NW

The former Atlantic Plumbing site, located along 8th and V Streets near Florida Avenue, NW, includes three separate parcels A, B and C.  SK&A provided structural engineering services for the development of Parcels A and B which include two new, luxury, urban high-design residential buildings with ground-level retail spaces and underground parking for 190 cars.  Parcel C, which is currently under design, includes a nine-story hotel and a 10-story residential building connected together by a bridge spanning W Street, NW.  

The first building at 2112 8th Street, NW (Parcel A) is a 10-story, cast-in-place concrete building with 339 units and two levels of below-grade parking.  Building amenities include a rooftop pool, bar, kitchenettes, movie screening area, vegetable garden plots, a business center, communal lounge area with theater, a fitness center, and bicycle storage rooms.  To give the building an edgy, industrial look, the exterior exo-skeleton frame of the building is comprised of Corten weathering steel.  The design and detail of the steel frame exo-skeleton is designed to resist both lateral and thermal loads.

2030 8th Street, NW (Parcel B) includes a second building with six stories and 71 condominium units.  This smaller building is a cast-in-place concrete structure with one level of below-grade parking.  The building features 10’ ceilings, rooftop terraces, a business center, as well as fitness and bicycle storage rooms.

In addition to traditional retail, the project includes 1,500 sf of artist studios occupied by the Washington Project for the Arts as well as a 10,000 sf Landmark movie theater.

L’Enfant Plaza East & West Retail Renovations

Located in Washington, DC’s southwest quadrant across from the National Mall and Smithsonian Museums, L’Enfant Plaza is a massive mixed-use, commercial complex of multiple mid-century buildings originally constructed in the 1960’s.  The complex features office/commercial and governmental buildings, a hotel, an underground shopping mall and parking, as well as a major subway station.  The overall complex has been undergoing an extensive renovation and redesign, including the redevelopment of the retail mall as well as the existing L’Enfant Plaza hotel and an office building.  A new 600,000 sf office building will also be constructed in the center of the plaza. 

The retail renovation projects included modernization of the existing underground retail mall, the development of a new glass atrium providing access to the underground retail corridor, and structural strengthening at the promenade and plaza levels to accommodate the future nine-story office building.  The strengthening work for the office building was conducted concurrently with the retail renovation to allow retail operations to continue uninterrupted during construction.

For the strengthening portion of the project, a cost-effective demolition concept was devised involving almost no re-shoring of the existing slab.  New concrete framing was constructed over an existing auditorium occupied by the National Transportation Safety Board (NTSB).  To construct the framing, SK&A assisted the contractor in developing a steel formwork system using new and existing columns for support.  A grid of compression beams was also designed to support the plaza layout and future office building concept.  

The large glass atrium portion of the project is composed of a series of steel moment frames.  Slip-critical bolts at the column-to-beam connection were used to accommodate the contractor’s preference for steel erection.  Additionally, the east stair spans between the promenade and plaza levels, with no posts beneath the landings.

The East and West portions of the renovation were designed and constructed as two separate projects.  The West project received an SEA-MW award in the $15-40 Million Renovation category in February 2015. 

600 Massachusetts Avenue, NW

Located adjacent to the Washington Convention Center and close to Chinatown, SK&A recently completed structural design services for this new 12-story, concrete-framed Class “A” commercial office building.  Currently under construction, the structure includes 401,000 gsf of above-grade space, plus an additional 44,000 gsf of space on a below-grade concourse.  Parking is provided on three below-grade levels and totals approximately 132,500 gsf.  The project also required the relocation and restoration of two historic townhouses as additional office space. 

The building’s exterior facade incorporates natural stone, brick, and metal paneling along the glass curtain wall system.  Perimeter columns are spaced 30 feet apart for maximum openness and space.  Additional features include a light-filled lobby with stone flooring, wood and stone walls, and a water feature; floor plates with slab-to-slab heights of at least 11 feet; private balconies on five floors; and a rooftop terrace with an outdoor conference area.

Liberty Center Office Building (675 Randolph Street)

This 13-story, 353,000 sf Class "A" office building is occupied by the Federal Government’s Defense Advanced Research Projects Agency (DARPA) in Arlington, VA.  The building is located within the larger Liberty Center complex, which is a 5.35-acre, mixed-use development with two office buildings, a residential tower with retail, and structured below-grade parking.  The development is certified at the Gold level under the LEED-ND (Neighborhood Development) pilot program.

Designed to meet the Department of Defense minimum Anti-Terrorism Force Protection (ATFP) standards, the building has an 82-foot secured perimeter and is surrounded by a sizeable lawn separating it from the surrounding buildings within the complex.

Southern Regional TechRec Complex

Located in Prince George’s County, MD, the Southern Regional TechRec Complex is a state-of-the-art, multigenerational community facility providing a broad range of recreational and technology resources.  The facility’s features include: a double court gymnasium with suspended running track, a large multi-purpose room, fitness rooms, a climbing wall, classrooms, group exercise areas, a kitchen, a professional recording studio, a dance studio, soccer and multi-purpose fields, and parking spaces for 200 cars.  The building also includes a vegetative green roof, cafe and lounge areas, computer and science labs, and an open viewing gallery.

The highlight of the facility’s façade is an expansive multi-colored glass curtain wall system, running the length of the building.  Additional design elements include perforated metal paneling within the exterior façade and a curving steel stairway leading to the mezzanine viewing area.  The building’s design has received multiple awards, including “Public Building of the Year” from the American Institute of Architects’s (AIA)/Maryland, a “Gold Award for Architectural Excellence” from AIA/Potomac Valley and a “Detail Award in Architecture” from AIA/DC.

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