NIST Video: Why the Building (WTC7) Fell

The video discusses the collapse of the World Trade Center Building 7 on September 11th, attributed to fire-induced progressive collapse, a phenomenon identified by the National Institute of Standards and Technology (NIST). The collapse was modeled using complex computer simulations, showing that heat from fires caused structural failures. NIST found no evidence of explosives, as no loud sounds were detected. The building's design met codes at the time, but the event highlighted the need for stronger building codes and reevaluation of fire performance in structures with long-span floors.

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