The Pentagon
The Pentagon serves as the headquarters of the United States Department of Defense. As one of the world's largest office buildings, it has a floor space of 3,705,793 square feet, or three times that of the Empire State Buiding in New York. The Pentagon houses a daily working population of approximately 24,000 employees, both military and civilian.

The Pentagon Reservation is located in southeastern Arlington County, Virginia, and is situated between a large man-made lagoon (the Pentagon Lagoon, formed during construction) and the southeastern corner of Arlington National Cemetery. The northeastern and eastern facades have unobstructed vistas of the Monumental Core of the Nation?s Capital across the Potomac River. The Pentagon?s relatively low profile also permits clear vistas of Washington from the highlands of Arlington National Cemetery.

The Pentagon Complex is composed of 200 acres of lawn as well of 16 parking lots, which hold approximately 8,770 cars. Despite 17.5 miles of corridors it takes only seven minutes to walk between any two points in the building. It houses more than 4,200 clocks, 691 water fountains, 284 rest rooms, one dining room, 2 cafeterias, 6 snack bars and one outdoor snack bar. Restaurant service is outsourced under contract to a civilian operation.

Over 200,000 telephone calls are made daily through phones connected by 100,000 miles of telephone cable while the Defense Post Office handles about 1,200,000 pieces of mail monthly. Various libraries are located throughout the building with the Army Library alone providing 300,000 publications and 1,700 periodicals in various languages.

The Pentagon building is composed of five concentric pentagonal rings connected by ten radial corridors. Each of its outer walls is 921.6 feet long. The building covers 29 acres, the largest ground area of any office building in the world. A five-acre pentagonal courtyard is located in the building?s center. The building and its central courtyard cover 34 acres. There are 17.5 miles of corridors in the building. The structure is three times the size of the Empire State Building and 50 percent larger than Chicago?s Merchandise Mart. The building rests on 41,492 concrete piles, the combined length of which would stretch 200 miles. The five concentric pentagonal rings are separated by interior courts which serve as light wells. This design feature increases the number of windows allowing natural light. Each ring has five stories. The Mall and River sides of the building have a Basement area which includes a partial Mezzanine. The innermost and outermost rings have sloping slate roofs, while the other three rings have flat, built-up roofs. The rings are connected at each floor level by a series of ten radial corridors extending from the ?A? ring (innermost) to the ?E? ring (outermost).

The building was constructed in the early years of World War II in the space of only 16 months, and was completed on January 15, 1943 at a cost of roughly $83 million. Its construction managed the consolidation of 17 buildings belonging to the War Department, and required 5.5 million cubic yards of earth, 41,492 concrete piles, as well the dredging of 680,000 tons of sand and gravel into 435,000 cubic yards of concrete.

During the first half of 1941 the War Department found it increasingly difficult to provide space for the headquarters staff of an expanding army. In May, the Public Buildings Administration proposed erecting temporary structures for various agencies on the outskirts of the city. In July 1941, 24,000 personnel were scattered among 17 buildings in Washington, D.C., with others in Fort Myer and Alexandria, Virginia. By the beginning of 1942, the number of personnel was expected to reach 30,000. The President, therefore, asked Congress for authority to construct additional buildings within or near the District of Columbia. The War Department?s Chief of Construction, Brigadier General Brehon B. Somervell, had a better idea, a scheme to house the entire War Department under one roof. He talked to General Moore, Deputy Chief of Staff, and to U.S. Representative Woodrum (D-Virginia) about his idea.

At a Thursday, July 17, 1941, hearing on construction projects before the House Subcommittee on Appropriations, the Chairman, Mr. Woodrum of Virginia, suggested to Brigadier General Eugene Reybold and Brigadier General Somervell that the War Department find an overall solution to its space problem rather than the partial solution proposed by the Public Buildings Administration. Somervell directed Architect G. Edwin Bergstrom to place on his desk, by 9 o?clock Monday morning, basic plans and architectural perspectives for an office building to house 40,000 people. Five days later, on Tuesday, July 22, 1941, Reybold and Somervell presented the plan to the Subcommittee. The plan was approved by the House on July 28, 1941, and by the Senate on August 14, 1941. On August 25, 1941, President Roosevelt signed the bill appropriating funds for construction. However, because of considerable controversy over the proposed location at the foot of Arlington National Cemetery, he reserved the right to pick the site. The following day, the President directed that the construction site be moved south to the Pentagon?s present location.

The Pentagon?s unusual five-sided configuration was dictated by the site originally proposed (adjacent to Memorial Drive, about three-fourths of a mile north of where the building was actually constructed). An early plan called for a square structure with one corner cut off to accommodate an existing road. This resulted in a skewed Pentagon shape. Serious objections were raised to locating the building on open land directly between Arlington Cemetery and Washington?s Monumental Core, and discussions ensued regarding selection of a building site resulting in less visual and physical impact from the project. During the debate on the site, the project?s chief architects, George Edwin Bergstrom and David J. Witmer, continued to refine the design. The final design retained the five sides, in the form of a true pentagon, which gave rise to the building?s name. That shape resulted in the most efficient use of available space. The concept of using several concentric rings to contain the space evolved during further refinement of design. Preliminary design and drafting took just 34 days. A project of this magnitude and urgency demanded the rapid assembly of an unprecedented design and production effort.

Construction began on September 11, 1941, and was completed on January 15, 1943. At one stage of construction, 15,000 people were employed on the job working three shifts, 24 hours a day. At night, they worked under floodlights. Construction took just 16 months, a remarkable feat of engineering and management.

The exterior walls of the concentric rings and the interior courtyard are exposed concrete. They appear to have a wood-grain texture because they were poured into wooden forms made of 8-inch boards. A gap was left between boards enabling concrete to ooze and form a slight ridge. From a distance this gives an appearance of limestone. Clockwise from its northern point, the Pentagon?s five facades are the Mall Terrace Entrance facade, the River Terrace Entrance facade, the Concourse Entrance (or Metro Station) facade, the South Parking Entrance facade, and the Heliport facade. The outer facades of the Pentagon are simple, with a minimum of ornamental embellishment. Although the ornamentation style is classical in origin, it has been greatly simplified. The outer walls are limestone, as a direct result of a restriction by President Roosevelt that there be no marble in the building.

The shortages of materials required for war production raised many design and construction problems. The use of reinforced concrete in lieu of formed steel for the building made possible a saving of 43,000 tons of steel, more than enough to build a battleship. The use of concrete ramps rather than elevators further reduced steel requirements. Drainage pipes were concrete; ducts were fiber, interior doors were wood. An unusual wall design - concrete spandrells carried to window sill level - eliminated many miles of through-wall copper flashing. When Somervell was asked to make still more drastic reductions, he agreed to ?striptease? the entire structure. Bronze doors, copper ornamentation, and metal partitions in rest rooms were among the first to go. The stripping process continued throughout construction.

The Pentagon?s original interior space layout has been modified over the years. Walkways and service corridors have been closed and converted to office and storage space. Original office areas that were large open spaces have been chopped up and enclosed with full height partitions that make the building functionally inefficient. This adversely affects heating, ventilating, and air conditioning system controls and distribution.

Before the Renovation Program began, none of the original major building systems had ever been replaced nor had they been significantly upgraded. The widespread use of computers and modern technology has overwhelmed the capacity of deteriorated building systems. Electrical, plumbing, heating, ventilation, and air conditioning (HVAC) systems need to be replaced and modernized to accommodate added loads and to provide efficiency and flexiblity. The electrical system was designed for a manual office and does not support the demands of today?s high-tech office environment. The current Pentagon information and telecommunications infrastructure is an accumulation of systems and networks, which have been installed, in a piecemeal fashion, since 1943. There are multiple deficiencies specific to the information management and telecommunications posture of the Pentagon. These include outdated and overworked communications systems, an enormous number of single user-oriented and user-unique data systems, inadequate wiring systems, obsolete and congested wire closets, risers, cable pathways, and protected distributed systems, poor quality grounding systems, and limited wiring system access due to asbestos hazards.

The Defense Authorization Act of Fiscal Year 1991 transferred control of the Pentagon Reservation from the Administrator of General Services to the Secretary of Defense. Under the same Act, Congress established the Pentagon Reservation Maintenance Revolving Fund for the expressed intent of renovating the Pentagon. The renovation work involves the demolition and removal of all partitions, ceilings, floor finishes, mechanical, electrical, plumbing, fire protection, and communications systems. The basic structural system, as well as the stairwells and their enclosing walls, will remain. All electrical, mechanical, and plumbing systems will be replaced and a modernized telecommunication back-bone infrastructure will be installed.

Early in the planning process, it was determined that the most efficient way to renovate the Pentagon while keeping the building operational for its 25,000 tenants was to relocate one fifth of the building?s personnel from their current location in the Pentagon into temporary offices, or swing space, in and around the building. Over 910,000 square feet (45 floors) of external swing space has been renovated in office buildings in nearby Rosslyn and Crystal City, Virginia.

The improvements include the new South Terrace Pedestrian Bridges, which will connect South Parking to Corridors 2 and 3. The South Terrace structure consists of two bridges accommodating pedestrian traffic entering the Pentagon at the second floor at Corridors 2 and 3. This work incorporates some of the security improvements by re-routing public access to the second floor and improves safety by separating pedestrians from the vehicular traffic on the very busy Rotary Road in South Parking.

The design of Wedge 1 began in January 1994, and the last revisions were completed in FY 1999. Construction activity began in January 1998, with a ?wall bashing? ceremony in February 1998, to symbolically signify the start of the above-ground work activity. The first tenants began to move into renovated office space in Wedge 1 in February 2001. Wedges 2 through 5 (all five floors) are currently being planned as a single acquisition, with phased construction. The approved acquisition strategy will utilize a design-build project delivery method with performance based criteria. The objective is to realize cost savings with one prime design-build team through the benefits of a true partnering environment by minimizing the learning curve on each wedge. On September 14, 2001, the Wedges 2-5 project (contract MDA947-01-C-2001) was awarded to Hensel Phelps Construction Company,

The Remote Delivery Facility (RDF) is a new 250,000-square foot shipping and receiving facility adjoining the Pentagon. The RDF significantly improves the physical security of the Pentagon by providing a secure consolidated location for receiving and screening thousands of items shipped to the building each day. Before construction of the RDF could begin, the Mall Extension parking lot was demolished. By storing the excavated soil at sites around the Pentagon Reservation for later use instead of disposing of it off site, the Program saved over $1 million. Demolition was completed in June 1999. The landscaping of the roof of the facility to create a park-like atmosphere. This will enhance the view for the tenants who work on the E-ring of the Mall Terrace and create an alternate location for some of the ceremonial activities that take place on the River Terrace.

There are large ceremonial terraces in front of the Pentagon?s Mall and River Entrances. The River Entrance terrace extends 900 feet to the Pentagon Lagoon bounded by a ceremonial landing dock and two monumental stairways. The maximum width of the River Terrace is 450 feet. The terrace in front of the Mall Entrance is smaller, measuring 600 feet by 125 feet.

The South Terrace Project includes two pedestrian bridges over Rotary Drive, renovation of the loading dock, and connection to the 2nd Floor of the Pentagon at Corridors 2 and 3. The main purpose of the project is to provide separation of vehicular and pedestrian access while easing traffic congestion along Rotary Drive. The first of two bridges was completed in December 1999. The second bridge, and connecting bus stop wall, was completed in February 2001.

The Metro Entrance Facility project was directed by Congress in the FY2000 Department of Defense Appropriations Act in response to recent security assessments that identified the need to improve the physical security of the Pentagon. These initiatives involve relocating the current bus station and removing the existing direct entry into the Pentagon from the Metrorail station. The Pentagon Metro Station is the most highly trafficked Metro stop in Northern Virginia with over 34,000 riders daily. The Metro Entrance Facility project will improve the security of the Pentagon's Metro Entrance by reorganizing Pentagon arrival, access and circulation areas to create a safer environment. In order to improve the security of the Pentagon Metro Entrance, the Pentagon Renovation Program will remove the escalators and elevators connected to the Pentagon from the Metrorail platform and relocate all vehicle traffic away from the building. A new building will be constructed adjacent to the face of the Pentagon to allow for the screening of visitors prior to entering the Pentagon. This new building will house the Pentagon tour and badge offices. To organize Pentagon arrival, a more controllable ingress/egress procedure will be established for employees, visitors and public transportation users. Inside the Pentagon, all pedestrian traffic will be elevated to the second floor. Design and construction of the new bus facility began in Spring 2001. The bus facility wasoperational in November 2001. The new entrance building adjacent to the Pentagon will be completed in Fall 2002.

The Physical Fitness and Readiness Facility (PFRF) will replace the existing 55-year old Pentagon Athletic Facility with a larger, modern facility that meets membership fitness and readiness needs based on current usage patterns and anticipated incremental growth. The 130,000-square-foot facility will be located at basement level underneath and adjacent to the Pentagon?s Mall Terrace.

The Pentagon Lagoon was created during construction of the building as a result of dredging sand and gravel for concrete, and to obtain fill for landscaping. The lagoon is also the location of the water intake for the Pentagon?s Heating & Refrigeration Plant. The Roaches Run Waterfowl Sanctuary lagoon, created during construction of the George Washington Parkway in the early 1930?s, is used for the Heating & Refrigeration Plant?s water discharge outfall.

The Pentagon Reservation has been altered over the years. A heliport was added; Shirley Highway (now I-395), a limited access Interstate Highway and interchange, infringed on the Pentagon site on the south side; a major Metro station and transfer point was added, and under-building bus and taxi tunnels were converted to offices.

The Pentagon site originally contained three cloverleaf interchanges that were among the earliest such structures constructed in the United States. These freeway-scale interchanges were necessary to handle traffic associated with the large number of people working in the building.

For newcomers to the Washington area, the first problem encountered is getting around. The Pentagon is actually located in Arlington, Virginia, across the Potomac River from Washington, DC, and at the convergence of several major roadways. Careful planning and attention to directional signs is a MUST for the newcomer. Generally, approach to the Pentagon will be on the Henry G. Shirley Memorial Highway (Interstate 395).

Inprocessing personnel should park only in designated visitors' parking areas. Parking in other than the visitors lots is reserved for parking permits and is strictly enforced. In the assignment of spaces, preference is given to carpools, although some parking permits are available for unusual working hours or special situations.

Admittance to the Pentagon building is by escort or building pass. An Armed Forces identification card can be used on week days during normal duty hours only. Visitors without a building pass are screened by electronic detectors.

An airliner crashed into the Pentagon Tuesday 11 September 2001 in an apparent terrorist attack. If there is any building that symbolizes American national security, it is the Pentagon -- the massive, five-sided office complex that is the headquarters of the U-S Defense Department. But that symbol was severely tarnished when an airliner commandeered by terrorists slammed into the building -- cutting a path of destruction through a portion of the five-story structure.

Some 24-thousand people work in the Pentagon. Initial reports soon after the terrorist attack said a hijacked American Airlines jet ploughed into the military complex that was under construction. The Pentagon, the White House, and most other government buildings were evacuated, sending thousands of scared federal workers into Washington streets. The capital was in virtual gridlock, with people jamming the roads and police sirens wailing.

The headquarters of the US Defense Department was open for business Tuesday morning but it was anything but business as usual. Thousands of workers returned to the Pentagon. But many found their offices were still considered unsafe. Some have been redirected to other defense department sites in the area while others are sharing space with Pentagon staffers whose offices are open.

Close to half of the famous five-sided structure was cordoned off and fires were still burning. Officials said there were two different fires: one located in the roof of this World War Two era structure. The other involved jet fuel from the airliner that slammed into the building. Some of the specialists brought in to join the hundreds of firefighters on duty are from airport fire units.