A Structural Reevaluation of the Collapse of World Trade Center 7

Project Info

Lead Researcher(s)

Project Team

  • Feng Xiao, Associate Professor, Nanjing University of Science and Technology
  • Zhili Quan, Bridge Engineer, South Carolina Department of Transportation

Project Dates

May 1, 2015 - December 31, 2019

Funding

Architects & Engineers for 9/11 Truth
Project Budget: $316,153

Final Report

Download Final Report

A Structural Reevaluation of the Collapse of World Trade Center 7 (March 2020)

Simulations and Videos

Figure 4.16
Hypothetical Failure of Columns 76 to 81

Figure 4.17a
Near-Simultaneous Failure of All Columns, Perspective 1

Figure 4.17a
Video of WTC 7 Collapse, Perspective 1

 

Figure 4.17b
Near-Simultaneous Failure of All Columns, Perspective 2

 

Figure 4.17b
Video of WTC 7 Collapse, Perspective 2

Draft Report

A Structural Reevaluation of the Collapse of World Trade Center 7 (September 2019)

Public Comments (September to November 2019)

Open Data

All input data, results data, and simulations that were used or generated during this study can be downloaded as a ZIP file:

Download UAF WTC 7 Files (zip | 256 GB)
Please be advised that the size of this ZIP file is 256 GB and that, after unzipping the file, the size of the folder containing all of the files is 632 GB. Therefore, downloading the ZIP file and unzipping it will require approximately 900 GB of storage space.

Presentations

A Structural Reevaluation of the Collapse of World Trade Center 7 presentation by Dr. Leroy Hulsey on September 3, 2019 at the University of Alaska Fairbanks.

Collapse of World Trade Center Building 7 presentation by Dr. Leroy Hulsey on September 6, 2017 at the University of Alaska Fairbanks.

Progress Reports

WTC7 Progress Report (September 2017)

WTC7 Progress Statement (March 27, 2018)

Project Summary

This is a study of the collapse of World Trade Center Building 7 (WTC 7) — a 47-story building that suffered a total collapse at 5:20 PM on September 11, 2001, following the horrible events of that morning. 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.

Download Final Report