Residential

161 Peachtree Center

Previously constructed as a seven-story cast in place parking garage, the new vertical expansion of 161 Peachtree Center in Atlanta, GA included two new parking levels and 18 floors of residential units.  Originally designed in 2001 for a future 12-story office building, the new developer acquired the current building with the intent of revising the future office tower into a residential building.  The main issue is an existing office structural frame layout was not conducive to a modern residential building.  

Tower only columns were introduced to reduce the span and minimize the slab thickness to eight inches max.  This allowed for shorter floor to floor heights and reduced the weight and height of the structure.  Since tower only columns could not extend below to foundations due to the existing parking garage drive aisle and parking layout, large 8’-0” deep bonded post-tensioned transfer girders were introduced at the interstitial 14th floor.  Similarly to the tower only columns, the tower only shear walls could not extend below into the existing parking garage.  The shear walls had to stop at the 14th floor transfer level, which created a vertical irregularity within the lateral system.  Nine-foot-tall bonded post-tensioned transfer girders were used to transfer the shear wall gravity and lateral loads to the surrounding columns and diaphragm.  

The Wharf Parcel 8

Situated on the edge of the Potomac River, the Wharf Parcel 8 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. 

Skyline Towers Roof Replacement and Penthouse Renovations

The Skyline Towers residential apartment building complex features two (2) twenty-six story cast-in-place concrete structures each with penthouse amenity spaces.  An initial roof condition assessment, which included roof cuts of the main roof and penthouse amenity roofs, revealed that the original roof membrane had failed and was concealed by a global application of single ply modified bitumen membrane.  Due to a lack of original drawings, Ground Penetrating Radar (GPR) scanning and exploratory demolition of the South Tower’s main roof slab was done, to model and analyze the structural capacity of the slab to support the new proposed roof terrace loads. Following the roof condition assessment and structural analysis, the roof areas were prioritized for replacement and the South Tower main roof and penthouse amenity roofs were selected to be replaced ahead of other renovations planned for the apartment buildings.

The penthouse amenity roof replacement scopes were designed, bid, and executed by a qualified local roofing contractor with the work completed in phases while the building remained occupied, and the amenity spaces were under renovation.  Each amenity space roof assembly was removed and replaced with a multiple ply modified bitumen roof assembly.  New air barrier, rigid insulation, coverboard, liquid-applied flashings, and sheet metal flashings were installed. Isolated concrete repairs were also completed throughout the penthouse screen wall enclosure. Structural analysis and strengthening of the existing roof joists were also completed for the installation of new rooftop equipment units for the penthouse HVAC improvements.  

Edgemont at Bethesda Metro Green Roof Replacement

SK&A’s Repair and Restoration Division performed a detailed survey and evaluation of the roof areas for the apartment building located at 4903 Edgemoor Lane in Bethesda, MD.  As part of the survey, the original architectural and structural drawings were reviewed as well as maintenance reports for the building.  The roof areas were then visually inspected in order to evaluate the condition of the single-ply PVC membrane assembly and to observe the condition of the flashings, terminations, and overall quality of the roofing construction.  

The building roof, which was original to the building, was recommended for complete removal and replacement with a new two-ply SBS modified bitumen membrane adhered to the concrete roof slab in an inverted roof membrane assembly (IRMA) configuration.  The new roof assembly design also incorporated fleece reinforced PMMA liquid flashings and increased insulation to meet new energy code requirements.  As part satisfying Montgomery County’s “green space” requirements, the roof replacement was designed and detailed as a green roof assembly.  

Ingleside at Rock Creek

SK&A provided structural engineering services for the addition of new buildings and the renovation of an existing facility at the 14-acre Ingleside Retirement Community Campus in Washington, DC.  Located adjacent to Rock Creek Park at 3050 Military Road, NW, the non-profit retirement community’s current site was originally established in 1960.  The new changes to the site consist of:  

  • A new independent living facility (120,000 sf) with 90 units, a new assisted living facility (50,000 sf) with 15 residences, and structured parking (60,000 gsf).  The two residential buildings will connect to each other as well as existing buildings at the site.
  • A new skilled nursing and memory support facility (100,000 gsf), plus structured parking below (44,000 gsf).
  • A new independent living commons, renovation of the existing commons, as well as overall sitework (15,000 gsf).  The new commons or “Center for Healthy Living” will contain multiple amenity spaces, including a salon/day spa, classrooms and art studios, cafe, yoga and aerobics studio, technology center, meditation room, and fitness center.  

The Silva, 1630 Columbia Road, NW

SK&A provided structural engineering services for the Silva, a new 10-story, residential building in the Adams Morgan neighborhood of northwest DC.  The building features 172 luxury apartment units and amenities such as a rooftop pool, café/lounge, courtyard with fire pits, fitness center, and pet spa.  Below grade are two levels for parking along with bike storage and electric vehicle charging stations.  The building also provides an internal connection to the existing Scottish Rite Temple building. 

The Silva is a multi-story concrete frame structure.  The slabs are post-tensioned at upper levels and conventionally reinforced slabs at ground and underground floors.  Lateral resisting system consists of concrete shear walls in combination with moment frames.

The Foundry, 200 Stovall Street

Built in the 1970’s, 200 Stovall was your typical 13-story, cast-in-place, conventionally reinforced, office building with a bland metal panel exterior skin and an interior forest of columns spaced 20’-0” on center.  Succumbed by the lackluster office market, the building was converted into a high-class residential tower (810,000 sf), fitting 525 residential units and 236 parking spaces with minimal demolition, foundation work, or column removal.

Using structural steel, an additional four floors were added to the existing concrete-framed building.  The vertical addition increased the lateral load on the existing concrete moment framed structure.  Vertical concrete shear walls and steel moment framed were post-installed at the lower floors to resist these additional lateral loads.  New openings in the second, third, and fourth floors were required for a new parking ramp.  To reduce weight, structural steel was used for the framing of these elements.  To modernize the exterior, the existing office-style metal panel façade was removed and replaced with a precast concrete panelized system with thin-set brick. 

West Half Street

Situated directly across from the new Washington Nationals Stadium, West Half Street is a 13-story residential building featuring a modern, high-end, canti-levered design with gradually alternating and descending outdoor terraces.  The building includes 465 apartments in studio, one- and two-bedroom layouts, 61,000 sf of retail on two floors, and multiple amenities such as a rooftop pool, penthouse lounge areas/clubrooms, and a central courtyard.  The aboveground structure sits atop a three-story underground garage with 329 parking spaces.  

The building was designed to be the crown jewel of the surrounding development area providing residents with unobstructed views of the baseball stadium and surrounding Navy Yard waterfront neighborhood.  SK&A worked with the architect to design a building that continuously rotated and twisted which allowed for these views.  To support the large cantilevers from the building face, Y-branch columns with tie-beams were utilized.  Strategically placed concrete shear walls resist the building’s natural tendency to twist and rotate under its own self-weight.  The Y-branch columns were also designed to support the ends of the ever-increasing cantilevers.

The completed design culminated into a graceful, functional, and exceptional residential structure that adds to the diverse architectural fabric of the Navy Yard waterfront neighborhood.  The building’s new residents will enjoy prime views of game-day action with personalized experiences of the surrounding ballpark atmosphere.   

 

Woodbury Park, 2220 Fairfax Drive

Two nine-story residential buildings with underground parking.  One building contains 108 rental units, and the other building has 99 condominium units.  There is a canopy structure between the two buildings at street-level, serving a common drop-off area.  Structured parking is provided for 303 cars in three underground levels.  Gross floor area of residential construction is 270,900 sf including lobby-level office, community and retail space.  Gross floor area of parking is approximately 121,500 sf.

SK&A provided structural design services as well as testing and inspection services for the condominium building. The superstructure for the building consists of conventionally reinforced, cast-in-place concrete, with masonry brick veneer.

Palisades of Towson

An 18-story, luxury apartment building, The Palisades of Towson features studio, one and two-bedroom units as well as multiple amenities, such as a heated rooftop pool with sundeck, outdoor fireplace with seating area and state-of-the-art fitness center. The high-rise building also includes two levels of parking below grade. 

The building’s substructure and superstructure consist of cast-in-place concrete footings and walls with conventionally reinforced slabs in the garage, and post-tensioned slabs in the tower.

SK&A provided structural design services and a variety of structural inspection and testing services, including inspections of reinforcing steel, post-tensioned steel, formwork, shoring and reshoring, and concrete placement as well as concrete laboratory testing and monitoring of concrete quality.

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