Collapses of the World Trade Center Tower – Assignment Example

The paper "Collapses of the World Trade Center Tower" is a worthy example of an assignment on engineering and construction. National Institute of Standards and Technology (NIST) spent three years to investigate the reasons for the collapse of the twin towers of the world trade center (WTC) in New York City. After the extensive hard work, they presented the report. The report disagrees to any planned demolition or controlled collapse. The reasons for collapse explained in their report are interconnected to each other. The huge destruction of the twin towers ultimately resulting in the global collapse took place on September 11, 2001. A Boeing 767 aircraft collided into each of the twin towers. This aircraft was about 20 percent bigger than 707. NIST during their investigation formulated some theories to reach the actual reasons for the collapse. Their basic and the major theory is the fire theory for fall of the twin towers. (NIST, 2005) According to this theory, the reasons declared for the collapse are as follows; 1- Support columns damaged, 2- Dispersion of jet fuel on multiple floors, 3- Compression of the air in front of the building, 4- A huge weight of the molten aluminum alloys of the craft fell on the building, 5- A large number of thermites. Damaging of support columns- Impact of the planes of a huge size and a tremendously fast speed caused a remarkable destruction. The steel used in the construction of the exterior columns was comparatively of a lighter quality, so the support columns were damaged severely. Further, the fire coating on the floors was extricated. Dispersed jet fuel- The jet fuel from the craft dispersed thoroughly on the building. The jet fuel ignited fires on multiple floors. A heavy smoke and an immense heat were produced that deformed the major structures of the building. Compression of the air-The falling mass of the towers blocked the air ahead of them. This blockage produced a piston-like action in which the smoke and the debris was being forced out of the windows when the lower stories were falling. Molten aluminum alloys- This molten material was basically a mixture of powdered aluminum matter and iron oxide which fell down from the aircraft. It burnt at an extremely high temperature of the fire. The towers distorted completely from top to bottom leaving only the fragments of their steel frames and aluminum shields. (NIST, 2005)