September, 2019
A Structural Reevaluation of the Collapse of World Trade Center 7
Lead Researcher(s)
J. Leroy Hulsey, Ph.D., P.E., S.E.,
University of Alaska Fairbanks
Project Team
Feng Xiao, Associate Professor, Nanjing University of Science and Technology
Zhili Quan, Bridge Engineer, South Carolina Department of Transportation
Project Summary
This is a study of the collapse of the 47-story World Trade Center Building 7 (WTC7) at 5:20 P.M. on September 11, 2001.
The objective of the study was threefold: (1) Examine the structural response of WTC 7 to fire loads that may have occurred on September 11, 2001; (2) Rule out scenarios that could not have caused the observed collapse; and (3) Identify types of failures and their locations that may have caused the total collapse to occur as observed.
The UAF research team utilized three approaches for examining the structural response of WTC 7 to the conditions that may have occurred on September 11, 2001. First, we simulated the local structural response to fire loading that may have occurred below Floor 13, where most of the fires in WTC 7 are reported to have occurred. Second, we supplemented our own simulation by examining the collapse initiation hypothesis developed by the National Institute of Standards and Technology (NIST). Third, we simulated a number of scenarios within the overall structural system in order to determine what types of local failures and their locations may have caused the total collapse to occur as observed.
The principal conclusion of our study is that fire did not cause the collapse of WTC 7 on 9/11, contrary to the conclusions of NIST and private engineering firms that studied the collapse. The secondary conclusion of our study is that the collapse of WTC 7 was a global failure involving the near-simultaneous failure of every column in the building.
There will be a two-month public comment period from September 3 to November 15, 2019, with the final report to be released later this year. During this period, we welcome any and all members of the public to submit constructive comments intended to further the analyses and presentation of findings contained in the report. Designated reviewers external to UAF and Architects & Engineers for 9/11 Truth will also review the report during this period. Commenters are asked to send their comments in an attached PDF or Word document to publiccomment@AE911Truth.org.
http://ine.uaf.edu/wtc7
Full Report (draft): http://ine.uaf.edu/media/222439/uaf_wtc7_draft_report_09-03-2019.pdf
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