900 16th Street
Washington, DC
Douglas W. Watson
Construction Management Option
Project Sponsor: James G. Davis Construction Corporation
The zoning requirements of the 900 16th project fall under the classification of C-3-C which permits the right of development for a major business to a maximum lot occupancy of 100% and a maximum height of 90 feet.
Building Statistics: Part 1
Architecture
Location: Washington, DC
Main Building Occupant: Miller & Chevalier
Primary Occupancy Type: Office Building Type B
Gross SF Area: 201,481 SF
Above Grade Levels: 9
Total Levels: 12
Dates of Construction: February 3rd, 2015 - March 2016
Delivery Method: Negotiated CM at Risk
Contracted GMP Value: $38,000,000
Current Contract Value: $42,000,000
General Information
Project Team
Owner: Information is withheld a per the owners request
General Contractor: James G. Davis Construction Corporation
Architect of Record: Cooper Carry
Design Architect: Robert A.M. Stern Architects, LLP
Facade Design: Buro Happold Consulting Engineers
Structural Engineer: Thornton-Tamasetti
MEP Engineer: Dewberry
Civil Engineer: Wiles Mensch Corporation – DC
Architectural Design:
The architectural design consists of a single 9 story tower with 3 subgrade levels of parking. In total this structure encompasses roughly 200,000 SF. The first parking level, sublevel 1, is home to the main pump room and switch gear. Entrance is permitted to the building on the Lobby level. The 2nd to the 8th floors follow a typical open office space layout with the central core and elevator lobby located on the West side. The penthouse on the 9th floor is set back from the rest of the floors below to allow for a rooftop terrace. Main architectural features are an aluminum storefront curtain wall with a statuary bronze finish, to match the historic buildings nearby, and a 3 dimensional structural curtain wall that extends from the lobby to the 5th floor.
Architectural Function:
900 16th Street consists of mostly open office space with the main tenant being the law firm of Miller & Chevalier, who will occupy the 4th to the Penthouse (9th Floor). The main amenities that this building features include 3 sublevels of parking, a 1,500 SF fitness center, and a view of the Washington Monument. The rendering below captures the view that can be seen from the penthouse of 900 16th Street. The Third Church of Christ Scientist, which had initial existed on the site, was relocated to the North portion of the new building (highlighted below in green). It will occupy the space in that area from the lobby to the third floor.
Image Courtesy of Google Maps
Image Courtesy of Robert A.M. Stern Architects, LLP
Image Courtesy of Robert A.M. Stern Architects, LLP
Image Courtesy of Cooper Cary
Image Courtesy of Cooper Cary
Code Requirements
- IBC 2006 with DCMR 12 D.C. Construction Code Supplement (2008)
- International Fire Code 2006 with amendments 2007 & 2010
- International Plumbing Code 2006 with amendments 2007-2011
- International Mechanical Code 2006 with amendments 2007, 2008, 2010 & 2011
- National Electric Code 2005 with amendments 2009
- International Fuel Gas Code 2006 with amendments 2007-2010
- International Energy Conservation Code 2006 with amendments 2009 & 2011
- DC Law 8-36 District of Columbia Environmental Policy Act 1989
- DCMR Title 11 – Zoning Regulations Green Building Act of 2006
Zoning Requirements
Located only a two blocks from the Lafayette Square and the White House, 900 16th Street is located within the historic district of Sixteenth Street (represented by the red dot in the image to the right). Washington DC's Historic Preservation Office (HPO) provides historic preservation guidelines of which designers must follow for new construction projects. Keys to designing a building in this district include:
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Match materials of nearby structures or using like materials
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Respect to heights of adjacent buildings
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Construct similar landscapes around the structure
Historical Requirements
Building Enclosure
Façade:
The façade is comprised of a mixture of curtainwalls and various stone cladding that have been cast into precast concrete panels. As seen in the detail 3A below embed plates are in both the floor slabs and precast panels. A welded connection using steel angle holds the panels in place. The street level of the building consists of an aluminum store front with a statuary bronze finish, all of which is accented with a granite base and marble cladding. Above the retail levels the main façade changes to limestone with marble inlays surrounding aluminum punch window units. Aluminum curtain walls are at both the North East and South East corners of the building.
Roofing:
The roofing system is made up of 3 main systems: a green roof, hot-fluid applied roofing, and thermoplastic polyolefin roofing. Asphalt based hot fluid applied membrane is the main method of water proofing used. The green roof systems is comprised of a root barrier, Styrofoam insulation, Gardendrain GR15 drainage composite, Systemfilter filter fabric, and finally between 1 and 8 inches of growth medium. (Reference details below for discriptions of roofing systems)
Sustainablitiy
[This building was design to receive a LEED Gold rating]
The designers truly maximized the amount of green roof area while giving the building occupants and owner exactly what they wanted. Nearly the entire roof above the penthouse will be a green roof system. Two separate green roof areas are located on the penthouse terrace. Access and egress points to the terrace push occupants around the green areas and allow for the flow of foot traffic to be uninhibited. Many of the other LEED points that are being sought after involve waste management of construction materials, using materials with recycled content and utilizing regional suppliers and manufacturers to provide building materials.
Image Courtesy of Cooper Cary
Image Courtesy of Cooper Cary
Image Courtesy of Cooper Cary
Image Courtesy of DC Office of Planning
Image Courtesy of Cooper Cary
Building Statistics: Part 2
Click HERE to jump directly to Part II
Construction of 900 16th Street began with the demolition of two existing structures on the site. The church, located in the South West, and the church’s monitor building, is located at the north most portion of the site. Following the abatement of hazardous materials in the structures, the demolition of each structure began. The monitor building was demolished using a Brokk and a crane with suspended safety netting to protect the site. By utilizing an excavator with a jackhammer attachment, the neighboring church was destroyed. The sidewalks on both 16th Street and I Street were removed as a part of the demolition phase. They will be replaced upon completion of the core and shell structure.
After completion of the demolition phase, the excavation for the three levels of subgrade parking and foundations began. Due to the proximity of the metro line to the South of the site, all piles were required to be drilled and set permanently with a slurry material. As the excavation continued downward the slurry material was chipped away from the piles so that they could receive the wooden lagging. Due to the various site surroundings, three types of support of excavation were used on this project. As previously stated, just South of the site, 10 feet to be exact, is an active metro tunnel of the DC metro system. The South and West portions of the excavation used a system consisting of walers with I-beam rakers and cement heel blocks. Initially, the plan was to use underpinning on the North portion of the excavation. However, due to poor existing condition drawings, a system of bracket piles had to be utilized. Tiebacks were used on the East wall of the excavation. The parking substructure began upon completion of the excavation and foundations. At various stages of the pours, two methods of concrete placement were used; crane and bucket and a pump truck. Upon reaching the superstructure the pours fell into 3 sequences per level. These sequences moved North to South and from the start of framing took between 13 and 24 calendar days to complete.
Construction
Structure
The main structural element of this building is cast-in place concrete. A mixed system of 2-way slabs with drop panels, post-tensioned slabs with drop panels, and shear walls are used in the structure. The utilization of drop panels allow for maximum floor to floor height by reducing the punching shear at each column. Foundations used for 900 16th Street include 15 KSI bearing capacity spread footings and a 5” thick slab on grade. Four shear walls run from the foundation to the top of the structure. Two 12” thick shear walls, denoted SW1 and SW2, are located just to the South West of the elevators. Shear walls SW3 and SW4 are both 16” thick and are located on the North and South sides of the central elevator bank. All subgrade parking levels and the ground level are comprised of Two-way slab systems with drop panels, varying between 9” slabs with 10” drop panels and 10” slabs with 5” drop panels. Levels two through eight utilize post-tensioned slabs. All slabs throughout these levels are 7” thick with 8” drop panels. Unlike most typical post-tension slabs, these slabs were tensioned once the concrete reached a compressive strength of 3000 psi. The typical drop panel throughout the entire structure is 10’ by 10’. The ninth floor is comprised of PT slabs but the slab dimensions vary between a 12”thick with 6” drop panels and a 9” thick slab with 8” drop panels.
Structure
Lighting
Note: The lighting fixtures are not a part of the core and shell scope of work, therefore will not be included in this thesis project.
The main utility enters the structure from the south of the structure and runs through a concrete encased duct bank to the main electrical room located on the first parking level. The incoming 277/480V utility energizes the two 2000A, 3 phase, 4 wire switchboards located in the main electrical room. Each switchgear energizes a separate bus duct, which supplies power to the rest of the levels. One bus duct gives power to the first through the fourth levels, while the second bus duct supplies levels five through nine. Separate from the two main switchboards is a third specifically designated for the retail area on the first floor. This piece of equipment is sized at 3 phase, 4 wire, 800A operating at 277/480V.
Electrical
Note: The main major mechanical system components are included in the scope of the base building contract but the distribution systems on each floor will be installed at a later date by the interiors contractor.
The main system used to provide cooling and heat to the structure is through a chilled water system with a central plant. Two main water chilling units, WCU-1 and WCU-2, are located on the P1 level and have cooling capacities of 172 tons and 150 Tons respectively. Accompanying the two chillers are two cooling towers that are located behind a mechanical screen wall in the Northwest corner of the 9th floor. Each cooling tower has a capacity of 500 GPM for a total capacity of 1000 GPM. Cooling and heating is provided to each of the nine levels of the superstructure by air handling units located on each level. The sizes of the nine AHU’s vary between 4,500 CFM, 7,000 CFM, 8,000 CFM, and 11,500 CFM. Ventilation at the three-subgrade parking levels is provided by a system of supply fans, several circulation fans, and exhaust fans.
Mechanical
Fire Protection
The primary fire suppression system in the building is a dry-pipe system. The main pump room is located on the first parking level.
Transportation
Transportation to the various floors of 900 16th Street is provided mainly through the central elevator core that is located on the West side of the floor area. Each of these four elevators runs from the lowest subgrade level, P3, to the ninth floor. There is a secondary elevator located within the footprint of the church. This secondary elevator services the building from level P2 to level 2.