Pentagon (Pentagon)

• Pentagon, as its name suggests, is based on number 5: consists of 5 rings, 5 floors, and 1 middle yard with an area of ​​5 acres.

  Construction time : 1941 - 1943
• Location : Arlington, Virginia, USA

Considering the largest office building in the world with a total floor area of ​​616,518m ² (6.6 million square feet) and 28.15km on the Virginia coast of the Potomac River, on the other side is Washington, DC where Headquartered by the Ministry of Defense and the Ministry of Marine, Luo, US Air Force. The floor area is three times that of Empire State Building, while the US Capitol (Parliament House) is only one of five sides of the Pentagon. Despite its massive area, Pentagon is an effective research project : 10 spokes-like corridors connecting different parts of the building, can walk to any point within 7 minutes.

Designed and built by George Edwin Bergstrom in 1941 - 1943, the 5-faceted neoclassical building reminds us of the fortress structure diagram in the history of the building. However, Pentagonal station goes even further than previous works on the 5-sided visualization: the building structure consists of 5 5-sided shapes, not including the mezzanine and basement elevations, the main yard occupies an area of ​​5 acres. (2 ha). The distinctive five-sided cross-section is not only influenced by the fortress design but also because the original intended location has 5 sides. After the building is being constructed at another location at the same time, the 5-sided design still has a prominent feature.

Pentagon with Potoma river (Photo: inn-dc)

Built to unify 17 US War Ministries with one agency, Pentagon is a technical feat, construction is completed in just 16 months , Major General Brehon B. Sommervell, Head of Construction Department under the General Department of Post need, master the idea of ​​a massive building, and emphasize the basic diagram of the project, intended as a temporary citadel, to be built within 4 days. Construction begins immediately after the renovation is completed due to expansion

Pentagon is under construction, and completed in just 16 months.

land for construction - part of this plan is known as "Hell's Day" - because this area is a marsh, landfill and ruined buildings.

Once prepared, the engineer had to move 4.2 million cubic meters of soil and 41,492 concrete pillars to close the pile. The Potomac line is also a source of construction materials: 617,000 tons of sand and gravel were exploited, then processed into 332,000 m3 of concrete. As World War II approached, in the United States there was a shortage of structural steel supply, practically the size of using reinforced concrete as the main building material, along with Indiana limestone for the exterior facade. Accidentally when using concrete as the main construction material with enough steel to close a large warship.

Under the control of construction progress closely arranged, starting in August 1941 , many shifts with 13,000 workers working day and night, 7 days a week, more than 1,000 architects working in hangars fly nearby to draw construction drawings when the project is in progress. Employees can start working when completing a part of the building, more than 300 employees moved to work in the first part that was completed in August 1941, in December then 22,000 people. In order to facilitate the transportation to and from the massive construction, people built a 48km long access road. Pentagon also has its own police and firefighting force, as well as a separate water supply and drainage pipeline. In 1956, adding a helipad , today is a complex with its own terminal and taxi station as well as a subway stop.

Pentagonal view from above, despite its massive size,
but effective layout makes walking
any point within 7 minutes. (Photo: coe.uga)

Since 1993, Pentagon has conducted an entire embellishment project with a budget of $ 1.2 billion to be completed in 2006, the first embellishment since construction, not only to upgrade. communication and electromechanical equipment, but also additional office space.

18,581m2 (200,000 square feet) in a newly built mezzanine in the basement. In addition, for the first time the building is equipped with elevators, a total of 40 ladders, and replaces all 7748 windows. The embellishment team handled this work as well as the contractors building the Pentagon in the 1940s; once corrected a corner, only that it took 13 years to complete the embellishment compared to the first 16 months of construction.

But on September 11, 2001, the Pentagon became an unspeakable tragedy when a part of the western façade was destroyed by terrorists by driving a commercial passenger plane straight into the court. home, killing 189 people.

Actual data:

• Length of each facade: 280.72m
• Height: 23.56m
• Total length of corridors: 28.15km
• Total floor area: 616.518m ²
• Labor at peak: 13,000
• Construction cost: $ 49,600,000

The case destroyed the building on September 11, 2001
(Photo: assassinationscience)