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.

What was the primary cause of the World Trade Center Building 7 collapse according to NIST?

• Hurricane

• Earthquake

• Fire

• Explosives

What new type of collapse did NIST identify in their investigation?

• Earthquake-induced collapse

• Fire-induced progressive collapse

• Wind-induced collapse

• Flood-induced collapse

What did the NIST computer simulation reveal about the structural failure in Building 7?

• Heat from fires caused expansion of support beams

• The building was hit by a missile

• A gas leak caused the collapse

• The building was poorly constructed

What evidence did NIST find regarding the use of explosives in the collapse?

• Explosives were found in the debris

• Explosives were definitely used

• There was no evidence of explosives

• Explosives were used but not detected

What did the NIST team recommend to prevent future building collapses like that of WTC 7?

• Avoiding construction in urban areas

• Building shorter structures

• Stronger building codes and standards

• Use of more explosives