General Building Data
Building name: Army National Guard(ArNG) Readiness Center Addition
Location and site: 111 S. George Mason Dr. Arlington, VA. The site includes the existing Readiness center and this particular building is to be an expansion.
Building Occupant Name: Army National Guard
Function: Joint Headquarters Administrative Building. Offices
Size (total square feet): 251,000 square feet
Number of stories: 5 stories above grade with 3 stories below grade
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Dates of construction: December 2008- March 2011
Actual cost information: Direct Costs- $86 million Indirect Costs- $9.5 million
Total- approx $100 million
Project delivery method: Design-Bid-Build with Lump Sum. General Contractor holds lump sum contracts with subcontractors.
Architecture
Design and Functional components:The ArNG Readiness Center addition will function as an administrative headquarters in conjunction with the existing complex on site. The main purpose of the addition is to expand on the current facilities and account for future growth. There are a total of 8 floors, 3 below grade and 5 above. The stories below grade are the largest of the building(in footprint) and they house open office spaces, fitness facilities, an auditorium, and Joint Operations Center to name a few. An interesting note is the use of sound proofing measures for security purposes in more sensitive areas of the building. As for the 5 stories above grade, they are encased in a triangular tower. These areas will be used for general office space, conference rooms, as well as a library. Where the tower emerges from the lower levels creates a plaza area for multiple uses. This area itself is doubles as a green roof. As mentioned before, this building is an addition to the current facilities on site and will be connected with a bridge span. The most unique architectural feature(aesthetic only) is the large steel tricorn perched atop the southern point of the tower. An interesting piece which was added as a bid option and really adds character to the building.
Because of the nature of the building(Readiness Center) there are several security features that must be incorporated such as standoff distances, blast walls, berms, and internal reinforcing.
Major national model code/s:
• International Building Code 2006 (IBC)
• Unified Facilities Criteria
• National Fire Protection Agency Codes (NFPA)
• PAM 200-1, 415-15,420-7
• Military Planning 1190
Zoning: Arlington Country's District S3-A is the location of the site. This allows for public buildings, service buildings, public parks, and recreation areas.
Historical requirements: Not applicable
Building Enclosure:Pictures to be provided
Building façades- The main façade of the ArNG Readiness Center addition is surrounding the triangular tower area. This is comprised of a glazed aluminum curtain wall system and a combination of batter/ribbed precast concrete panels. The panels for the curtain wall are constructed from aluminum and glass. Specific glass types are currently being researched and will be provided soon. The wall components as a whole were designed to act as a single system to meet Department of Defense Building standards.
Roofing- There is two very different roofing systems specified on this project. One covers the tower area and the other encloses the lower plaza level. The tower roofing is comprised of a structural concrete slab covered with a vapor barrier, sloped rigid insulation, and a single-ply waterproofing membrane with a ballast topping.
The plaza level(green roof) system is comprised of a structural concrete slab with a topping of concrete slopped for drainage. Included is a rubberized membrane containing a clay filler, flashing membrane, polyester fabric reinforcing, fiberglass root barrier, drainage retention mat, filter fabric and a specified soil for planting.
Sustainability Features: The most prominent sustainable feature is found in the plaza space. The intensive green roof is not only an aesthetic feature but an environmental one as well. As far as materials use(glass/roofing types) there is a potential for added sustainable components and LEED points. At this point the building is expected to reach LEED silver but more research is being conducted to confirm those reports.
Construction
Ground was broken for the ArNG Readiness Center Addition on December 1, 2008 with a scheduled completion date of March 1, 2011. The specified general contractor is Tompkins Builders, a subsidiary of Turner Construction Company, with a design-bid-build contract. Tompkins then holds lump sum contracts with subcontractors on the site. There are two areas of the project, the new parking garage and the main addition. These are being built simultaneously causing substantial coordination between Tompkins and its subcontracts. Due to the constraints of the site, such coordination must be planned out in advanced to ease alleviate congestion issues. As is common on many recent projects, building information modeling is being used for nearly all systems being placed in the building. These include the mechanical, plumbing, electrical, and structural systems in the building allowing for easier coordination between these different areas.
Electrical/Lighting
The existing site and the ArNG Readiness Center Addition are supplied by the Dominion Power Company. The power enters the site at 35.4 kV which is then stepped down by a switchgear. From here it enters the building by way of 2 main feeders each at 15 kV. Once inside the building, the feeders connect to substations where the power is stepped down to a 480/277V, 3 phase, 4 wire system which is distributed throughout the remainder of the building. The lighting systems however are fed by 208/120, 3 phase, 4 wire panel boards.
These panel boards will handle either fluorescent lamps at 277V or incandescent lamps at 120V. To control such equipment there will be automatic controls in place for much of the building. This excludes the open office areas which will have programmable lighting fixtures in place. As for smaller offices around the Operations Center, some will have occupant controls and dimming capabilities.
Emergency power is supplied by two 1500 kW diesel-powered generators located in the penthouse level. This emergency power is connected to the substations on the second story. This connection is made by a large conduit riser which runs down the seven stories and cuts east-west to the room housing the substation.
Mechanical Systems
The ArNG building houses a hydronic HVAC system consisting of a heating and chilled water 4 pipe system. This water is distributed to air handling units (AHU) on each floor which attach into variable air volume (VAV) terminals. There are a total of 17 AHU with one specified per tower level. The 3 underground levels hold the majority of the units and they range anywhere from 500 cfm to 4250 cfm. Typical size for the 5 tower levels is 1550 cfm. To distribute appropriate ventilation to different spaces, fan coil units (FCU) are used in conjunction with the VAV terminals. These AHU's and VAV's are supplied by 100% outdoor air. To monitor the temperature in each space and control the FCU's as well as regulate individual units, a building automation system (BAS) is utilized. On the roof there is a mechanical penthouse which houses energy recovery units and backup generators.
There are two 400 ton centrifugal water‐cooled chillers specified in conjunction with two cooling towers.
Structural Systems
The ArNG Addition's structural system is mainly cast-in-place concrete. There is however an exception in which structural steel is utilized for the southern stairwell in the tower. A lateral bracing system using the floor and roof systems provides support for the walls.
Bay sizes are fairly typical, ranging from 20'x25' to 20'x30' using a 2 way flat plate system. The concrete columns have a typical size of 1'-10"x1'-10" with (8)#8 reinforcing bars including #3 horizontal ties at 12" on center.
As for the structural steel system for the above mentioned stairwell, it consist of rectangular beams as well as round composite columns. These beams range from HSS12x8x.625 to HSS14x4x.625 while the columns are HSS8.625x.322 or HSS11.25x.500.
A mat slab is specified for the foundation system. This system works by combining various layers of cornet and stone to obtain the desired compressive strength. The layers specified for this particular system are as follows: 6" of crushed stone base, 2" concrete mud mat, 3'-7" reinforced mat foundation, 2'-9" of aggregate, and a 12" concrete slab-on-grade housing #5 bars at 18" on center.
Fire Protection System
Service water is available by means of two existing hydrants on site. The flow rate provided by the two hydrants is 1520 gallons per minute (GPM). The ArNG building itself was design for two hazard conditions: light hazard (requires 0.10 GPM over 3000 sq. ft.) and ordinary hazard (requires 0.20 GPM over 3000 sq. ft.). The building as a whole is mainly sprinkled with an automatic wet-pipe system, including concealed sprinklers with risers in the stairwells. For areas which are sensitive to water damage, such as the server room, an FM 200 system is used. This system uses a colorless, non-toxic gas which is housed in two 300 gallon cylinders. This system is extremely efficient and can extinguish a fire within 10 seconds of detection.
Fire ratings for the building vary depending on use. All elevator cores and stairwells have a two hour fire rating. Other important areas such as corridors, mechanical/electrical rooms, and telecomm rooms have a one hour rating.
As for fire detection, the ArNG building contains digital, addressable fire-alarm system. This type of system utilizes heat detectors, duet smoke detectors, automatic alarm operations and sprinkler water flow, along with manual stations.
Transportation
The ArNG building contains three stairwells, two of which service every floor. The rest of the stairwells service only the three underground levels (1P,2P, 3P). The most important and aesthetic stairwell is the number 2 stair. This set of stairs is located in the center of the plaza level and it extends to the upper most tower levels. The stairwell itself is encased in glass and can clearly be seen extending along the southern tip of the triangular tower. This stairwell is also topped off by the steel tricorn which gives the building a lot of its character.
Aside from stairs, the ArNG building will contain two elevator pits which will hold six machine room less (MRL) elevators. Three of these elevators (cars 4,5,6) will be strictly for service purposes. The other three (cars 1,2,3) will be for passenger use. These elevators will service every floor with car 5 allowing access to the mechanical penthouse. The elevator specifications are as follows: elevators run at 350 feet per minute, passenger car dimensions are 6'-8" x 5'-5", service car dimensions are 5'-8" x 7'-10 1/2".
Telecommunication
The ArNG building is being utilized for Joint Headquarters Administrative purposes. As a result this building will provide support to the National Guard in all 50 states/territories. This requires not only multiple communication capabilities but facilitates the need for a secure network. To accomplish this task, the building has been equipped with at least two IT/Telecomm rooms per floor. To simplify coordination between duct work, piping, and electrical conduit; 100% access flooring is provided in all IT/Telecomm rooms, conference rooms, and open office spaces. This removes the electrical conduit outside of the cramped ceiling space. All of the telecomm systems will be installed via means of floor boxes in the access flooring system.
Special/Security Systems
The nature of the ArNG building, a readiness center, requires advanced security systems. One such system is the use of intrusion detection. Certain areas of the building are more sensitive than others, so this system can detect intrusions on the building envelope as well as other protected areas. Also provided is card key access, annunciators, surge protection for sensitive equipment, and pull boxes.
Another security measure which needs to be incorporated is the blast requirements of the building. This has gracefully been included into many of the façade materials. The use of blast rated glass and precast panels for lower tower levels as well as a berm placed all around the base of the building and up to the plaza level have become aesthetic pieces while serving their intended purpose of protection.