Quiz for "Global Failure: A Structural Reevaluation of the Collapse of World Trade Center 7"

Take this short quiz to test your understanding of the material and verify that you completed the presentation.

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1. Your Information:

Name:

Email address:

City, State:

Engineer, Architect, or Other?

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2. Prior to 9/11/01 how many steel-framed high-rise buildings have suffered complete collapse due to fire?

a. Zero

b. 2

c. 8

d. 15

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3. According to the 2008 report by the National Institute of Standards and Technology (NIST), World Trade Center Building 7 collapsed primarily due to:

a. Diesel fuel fires from the diesel generators on the 5th floor.

b. Structural damage caused by debris from the collapse of WTC 1.

c. Normal offices ignited by debris from the collapse of WTC 1.

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4. The series of structural failures that NIST found to be the most likely cause of the collapse involved:

a. The thermal expansion of fire-protected, long-span floor beams.

b. The lateral movement and walk-off of the building’s largest girder, which was later proven to be connected to the concrete floor slab above it with 30 shear studs.

c. A complete failure of the internal structural steel system in less than 20 seconds, triggered by the failure of a single column.

d. A complete collapse of the building’s exterior shell in less than 7 seconds.

e. All of the above.

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5. Following the release of its draft report, NIST was confronted with the fact that WTC 7 experienced full free-fall acceleration, and it was forced to acknowledge this fact in its final report issued in November 2008. For approximately how long and over what distance (in terms of stories) was WTC 7 in absolute free fall?

a. There was no period of free fall. Fire cannot cause a building to collapse that quickly.

b. For less than one second over a distance of one story, i.e., a fairly insignificant duration.

c. For about 2.25 to 2.5 seconds, over a distance of eight stories, i.e., one-third of its 7-second fall.

d. For 7 seconds over a distance of 47 stories, i.e., the whole way down.

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6. True or False: NIST included in its final report a detailed examination of the sulfidated steel from WTC 7 that was documented in Appendix C of the FEMA report - which The New York Times had called “perhaps the deepest mystery uncovered in the investigation.”

True. NIST included a detailed examination and a plausible explanation for the sulfidation of steel from WTC 7.

False. NIST did not follow up on the analysis documented in Appendix C of the FEMA report.

(This concludes the quiz. The following questions are optional.)

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7. Optional: Do you believe that a new investigation into the collapse of World Trade Center Building 7 is warranted?

Yes

Other (please specify)

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8. Optional: Would you like to receive our occasional email news bulletins?

Yes!

No, thank you.

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