Construction to Completion (1943)
Construction commenced on 11 September 1941, and continued rapidly during the winter of 1941-42. Architects for the project had little or no lead time; sometimes construction actually outpaced planning. On 1 December 1941, when the president signed legislation transferring the military construction mission from the Quartermaster Corps to the Army Corps of Engineers, 4,000 men were laboring on the building in three shifts. One section was completed by the end of April 1942 and the first tenants moved in. The basic shell and roof were finished in one year, and the building was completed by 15 January 1943.
The Pentagon’s designers minimized or avoided using critical war materials whenever possible. They substituted concrete ramps for passenger elevators and used concrete drainpipes rather than metal. They eliminated bronze doors, copper ornaments, and metal toilet partitions, and avoided any unnecessary ornamentation.
The Pentagon was the largest office building in the country at that time covering 29 acres and housing 17.5 miles of corridors. Design and construction of such a building would normally have taken four years, but the Corps took only 16 months. At its peak the Pentagon housed nearly 33,000 workers.
The architects and Engineer officers who designed and constructed the Pentagon produced one of the most innovative and unique structures of the war era. With this massive yet efficient structure, the Corps not only resolved the problem of housing thousands of War Department employees during the war years, they also provided for future War Department needs.