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On the Toughness of the Pentagon Structure



Paul K. Mlakar, D O. Dusenberry, J R. Harris, G A. Haynes, Long Phan, M A. Sozen


On 11 September 2001, the reinforced concrete structure of the Pentagon Building was able to resist, without collapse, the impact of a large commercial airliner despite the total loss of 26 columns and severe damage to 15 columns at the ground level. The ensuing fire and related fire-fighting activities led to collapse of a portion of the building approximately one half-hour after the impact. In this paper, the reasons for the demonstrated toughness of the reinforced concrete structure are examined and attributed to use of spiral columns, effective splicing of reinforcing bars, strong girders, and short span lengths.
Journal of Performance of Constructed Facilities
19 No 3


Mlakar, P. , Dusenberry, D. , Harris, J. , Haynes, G. , Phan, L. and Sozen, M. (2005), On the Toughness of the Pentagon Structure, Journal of Performance of Constructed Facilities (Accessed June 21, 2024)


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Created July 31, 2005, Updated October 12, 2021