Sustainable/LEED

Situated on “The Hill,” Fairfax County’s highest elevation, and in walking distance to the Greensboro Metro station on the Silver Line of the Washington area’s subway system, The Boro is a new, mixed-use, transit-oriented, urban-style community within Tysons, VA.  Totaling 4.25 million square feet on 18.1 acres, the development integrates a mix of residential, office, retail, and entertainment buildings along with 4.23 acres of community green spaces.   

SK&A provided structural engineering services for a two-level upscale, luxury movie theater, and a new 20-story class “A” office tower.  The Showplace Icon theater (94,800 sf) includes 14 state-of-the-art screens and upscale dining options.  The Boro Tower (345,000 sf) includes ground level retail (8,260 sf) and five levels of below grade parking for 1,200 spaces.  The building also features a glass curtain wall and up to 10-foot ceiling heights.    

SK&A provided structural engineering services for the modernization of the existing 50,734 sf facility and introduction of new 54,000 sf additions, which include new classrooms, gymnasium, and rooftop turf field to improve the school’s current operations.   

The superstructure for the new additions consists of structural steel framing with composite steel beams, open web joists and long-span roof construction.   Steel framed full story trusses support the elevated walkway bridge between the new and existing buildings on the west side of the existing school.   Indoor common spaces were created by enclosing existing courtyard spaces between existing buildings with new steel framed roofs, supported by the existing building bearing walls. 

Situated on the waterfront, this five-story office building provides breathtaking views of the Potomac River.  Cantilevering out over 35 feet, Parcel 10 also known as the DCX Office Building, has been compared to a floating jewel box extending to the Potomac River.  Even more striking, the structural profile at the ends of the cantilevered floors is only eight inches thick.

The challenge to the team was simple: create a light, floating five-story office building with 35-foot cantilevers.  SK&A worked closely with the architect early on for studies that would be acceptable to the architectural program.  While numerous concepts with steel and concrete were done, at the end it was determined that a two-way post-tensioned high strength concrete (7,000 psi) slab with drop panels provided both the thin structural profile and long cantilevers, which the architect envisioned.  To achieve a thin profile at the ends of the perimeter, the drop panels were tapered in thickness.  A 5’-0” perimeter of a “no drop panel zone” was created to allow the thin profile at the exterior of the building, while also allowing the glass façade to extend up from floor to floor without the use of spandrel glass.  

Situated on the edge of the Potomac River, the Wharf Parcel 8 also known as the Tides Apartments and Pendry Hotel, pushed the boundary of sloped buildings.  With 13 stories of hotel on the west side and 13 stories of residential units on the east side, the U-shaped building creates unobstructed views of the Potomac River for both functions.  This was imperative to the architectural design of the building. 

Located directly over the underground METRO green line tunnels, the new foundations needed to adhere to the strict requirements of the Washington Metropolitan Area Transit Authority for building overtop of an existing operational tunnel.  A hybrid system of a mat foundation and spread footings were used to help reduce the surcharge on the tunnel below as well as create an economically efficient design for the foundations.  Noise and vibration from the tunnel below were also a concern.  An isolation pad under the mat foundation, spread footings, and columns were used to mitigate any noise and vibration from the tunnel below that would propagate through the first several floors of the building. 

SK&A provided structural engineering services for a new 200,000 sf, four-story, innovative high school facility that aims to inspire academic and civic excellence within the student body of 800 students.  A new learning commons area is centrally positioned within the facility’s four-story atrium and will host interactive and collaborative activities.  The new school is constructed on the Shaw Elementary School site, which was demolished and replaced by the new structure.  The site also incorporates public recreational facilities, including a skate park, dog park, and basketball courts.

The project features indoor and outdoor classroom spaces, rooftop terraces, an outdoor plaza, a new outdoor athletic field, and a new gymnasium, which cantilevers over the floor below.  Long span roof trusses cross the length of the two-story gymnasium’s perimeter.  The columns and braced frames offset vertically from the perimeter frame through to the recessed cafeteria floor below.  The building is aiming for LEED BD+C Schools - Gold certification with a goal to be Net Zero Energy ready.

SK&A provided structural engineering services for the American Physical Therapy Association’s (APTA) new headquarters building located in Alexandria’s Potomac Yard neighborhood.  The seven-story, 85,000 sf building features and atrium with floating stairwell, meeting space, roof terrace, fitness center, café, and a public plaza.  The building is expected to achieve LEED Silver certification with sustainable design features, which incorporate spaces that save energy and water, generate less waste, and support human health.

The ground floor and below grade parking levels are conventionally reinforced concrete with drop panels supported by concrete columns.  A landscaped public plaza at on the ground floor is located over the garage.  It includes planters up to 4’-6” deep and has been designed to support firetruck loading.  Above grade, the slabs are post-tensioned concrete with 44-foot maximum spans.  The roof terrace at the 7th floor includes planters and paved public gathering spaces.    

Part of a 3.3 million sf mixed-use development situated along Washington DC’s Southwest Waterfront, The Wharf Parcel 3A also known as 800 Maine, is an 11-story, 233,000 sf Class “A” office building.  The office building is constructed atop a shared two-level underground garage occupying the entire project site.  The superstructure and underground garage are concrete-frame with conventionally reinforced floor slabs, reinforced concrete columns (typically 30-ft. apart), concrete shear walls, and select post-tensioned concrete components.

The building is also located in a section of the site where WMATA’s Yellow Line metro tunnel and air intake shaft conflict with the western side of the building’s columns and foundations.  To bridge over the existing WMATA structures, a solution was executed using underground concrete transfer girders over the tunnel and a two-story elevated steel truss between levels 2 to 4, which spans 90 feet. 

The SK&A team’s structural ingenuity and close collaboration with the owner, architect, and design builder ultimately delivered a visually appealing and structurally sound building, with WMATA’s structures intact and operational during construction.

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.

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.

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.