On September 11, 2001, World Trade Center 1 and 2 were hit approximately 15 minutes separately by a Boeing aircraft. Apparently, house 1 was struck at 8:48 a.m. by an American Airliner whereas WTC 2 was knocked at 9:00 a.m. by United Airlines craft. NIST alleges that WTC 2 buckled at 9:59 a.m. prior to the falling of WTC 1 at 10:28 a.m ( Goodrich, 2002).
Founded on its detailed examination, NIST resolved that the WTC building fell due to the impact of the planes disengaged and destroyed support pillars, dislocated fireproofing lining covering the steel base binds as well as steel pillars, and broadly distributed jet fuel over numerous floors. Then, the subsequent enormous quantity of jet-fuel burned numerous floor fires reaching temperatures as huge as 1,0000C ominously weakened the columns and floors with extricated fireproofing until floors drooped and caved on the perimeter pillars ( Corbett & Brannigan, 2015). This resulted in an inward caving of the perimeter pillars and catastrophe of the south wing of WTC 1 as well as the other wing of WTC 2, prompting the downfall of each of the towers. NIST claims the debris triggered structural mutilation to the southwest area of the edifice splitting seven exterior pillars but this organizational damage did not lead to the collapse.
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Apparently, the fires instigated by the debris and not the structural destruction that resulted from the effects led to the building's downfall after the fires expanded and spread to the northeast section after several hours. NIST further asserts that the debris effect caused no harm to the spray applied fire resistive material that was used to the steel pillars, girders, as well as beams apart from the instant vicinity of the destroyed pillars ( Corbett & Brannigan, 2015). The debris effect damage did play a subordinate role in the final stages of the falling pattern, where the outer portico buckled at the lower bases where the effect damage was situated.
References
Corbett, G. P., & Brannigan, F. L. (2015). Brannigan’s building construction for the fire service (5th ed.). Burlington, MA: Jones & Bartlett.
Goodrich, J. N. (2002). September 11, 2001 attack on America: a record of the immediate impacts and reactions in the USA travel and tourism industry. Tourism Management , 23 (6), 573-580.
