The Destruction of WTC7 on 9/11
For many years the destruction of World Trade Center Building 7 (WTC7), a 47-storey skyscraper that came down on the afternoon of 9/11 in a manner highly suggestive of a controlled demolition, was regarded as a mystery. This fact is well documented in David Ray Griffin’s book, “The Mysterious Collapse of World Trade Center 7” (Olive Branch Press, 2010). The building was not hit by a plane. While a government investigation of this event was in process, many independent researchers concluded that WTC7 had been brought down by explosives in a controlled demolition.
After a number of false starts, the official explanation of this event, developed by the National Institute of Standards and Technology (NIST), attributed the “collapse” to small office fires. These fires allegedly led to the thermal expansion of beams that moved a girder off its seat and to the structural failure of a key supporting column. This theory has been vigorously challenged by independent researchers, most recently by those affiliated with Architects & Engineers for 9/11 Truth. The discovery of a significant error, and the omission by NIST in its reports of key structural features of the building, recently led noted attorney, William F. Pepper to write a letter to Todd J. Zinser, Office of the Inspector General (OIG), U.S. Department of Commerce to seek resolution.
The conclusion by independent scientists and engineers that WTC7’s destruction was a controlled demolition is supported by a large amount of physical, eyewitness, and other evidence. Most notably, the sudden onset of collapse was followed by a period in which the building fell over 100 feet in free fall. This was shown by Scientists’ member David S. Chandler and presented during the public comment period, forcing the government scientists to back down on their claim that no physical laws were violated by their theory. For more information on WTC7 and controlled demolition, see Evidence for WTC7 Ignored or Unexplained By NIST on this site and the article Freefall and Building 7 on 9/11 by David Chandler.
NIST’s Theory for WTC7
NIST’s theory for WTC 7, as set forth in the NIST report NCSTAR 1-9, is that a critical girder (A2001) was moved off its seats by thermally expanding beams. This girder supported the 13th floor in the northeast corner of the building between exterior column 44 and corner core column 79. According to NIST, this girder failure led to the collapse of eight floors in the area supported by the girder down to the 5th floor, leaving column 79 laterally unsupported for nine stories. As a consequence column 79 buckled, leading to a collapse that progressed from north to south on the interior east side, followed by an east to west collapse of the interior and the subsequent buckling of the now laterally-unsupported exterior columns.
Recent Findings by Independent Researchers and Engineers
Researchers who examined NIST’s WTC7 theory had, for many years, no detailed information about the building or NIST’s computer model of the collapse mechanism. In 2011, however, a Freedom of Information Act (FOIA) request by Ronald H. Brookman, a structural engineer affiliated with Architects and Engineers for 9/11 Truth, resulted in the release by NIST of a large number of structural, erection, and shop fabrication drawings for the steel frame of the building. Independent examination of these drawings has led to the discovery of significant errors of fact and omission by NIST in its final report on WTC7. This work was carried out over a two year period by an international group of engineers and researchers affiliated with Architects and Engineers for 9/11 Truth. This group includes Ronald Brookman, David Cole, Tony Szamboti and others. See the article by Dennis P. McMahon, Esq for more information.
During the past two years, the following error and two omissions came to light. The NIST report:
- gave an incorrect value for the width of the seat for girder A2001 at column 79
- failed to mention stiffeners that provided support for girder A2001
- failed to mention lateral support beams which supported beam G3005 (connected to girder A2001) which allegedly buckled.
You can see here engineering drawings with the stiffener plates added as well as other views of girder A2001’s connection to column 79.
The locations of the preceding structural elements can be seen in figure 1 in William Pepper’s letter to Todd J. Zinser. Pepper states that the opinion of independent structural engineers is that, if included, the combined effect of this error and omissions by NIST is to “unambiguously” rule out NIST’s “probable collapse sequence.”
Attorney Pepper ends his letter by calling on Todd Zinser, OIG, to open an investigation into potential negligence and misconduct by the NIST investigators of WTC7, and raises the possibility of legal action should this request be rejected. At the same time, Pepper suggests that Zinser and NIST officials meet with a repesentative group of structural engineers who have studied the flaws in NIST’s analysis. Thusfar, the only response of the OIG has been to refer the matter back to NIST.
For those wishing to examine the recent WTC7 work in more detail, the following timeline provides links to documents that describe the research and actions over the past few years leading to Pepper’s letter.
Timeline of Recent WTC7 Research
November 2008: NIST NCSTAR 1-9, NIST’s final WTC7 report is released. The structural, erection, and shop fabrication drawings for the steel frame of the building were not publicly released.
Late 2011: FOIA requests are made by Ronald H. Brookman, S.E. for drawings and calculations for WTC7 by Cantor (FOIA 11-209 on 08/17/2011) and fabrication and erection drawings for WTC7 by Frankel Steel Ltd (FOIA 12-009 on 10/15/2011). These requests were filled on 09/20/2011 (drawings, but no calculations) and 11/23/2011 respectively.
Late 2011: Drawings are released. In early 2012, independent researchers find an error and omissions of structural features in the NIST report:
- seat length dimension for girder A2001 at column 79 is wrong – 12 inches NOT 11 inches
- stiffeners for critical girder A2001 omitted
- lateral support beams omitted for beam G3005 (connected to girder A2001) that allegedly buckled.
This error and the omissions, according to independent researchers and engineers, rule out NIST’s probable collapse sequence.
March 19, 2012: A FOIA request to NIST is made by structural engineer Ronald H. Brookman, S.E. about seat length and stiffeners for girder A2001 and lateral support beams for beam G3005. This request was not assigned a FOIA log number, and it was not processed through the NIST FOIA office due to the lack of written documentation available. Instead it was forwarded to the NIST Engineering Lab for a response.
June 27, 2012: A NIST Erratum corrects the seat length for girder A2001 at column 79 to 12 inches and gives a new lateral walk-off travel distance of 6.25 inches. NIST makes no mention of the omitted stiffeners and lateral support beams asked about in the March 19 letter.
On 06/27/2012 Brookman was informed by NIST (Therese McAllister, NIST WTC INvestigation Team) that, in response to his March 19, 2012 request, NIST had prepared two Frequently Asked Questions (FAQs). These can be found at Questions and Answers about the NIST WTC 7 Investigation and Updated Errata File. NIST pointed Brookman to its responses in answers 34 and 35 in the first of these FAQs, but failed to address Brookman’s questions 2, 4, 5, 6, 7, 9, and 10 from his March 19, 2012 letter.
October, 2012: A Discussion Paper by Ronald Brookman, published in the Journal of 9/11 Studies, discusses NIST’s analysis of the alleged structural failures leading to the collapse of WTC7. Brookman discusses the evidence for the existence of shear studs on girder A2001 that provided composite action with the concrete floor slab, the actual 12 inch length of the girder seat, and the existence of stiffeners omitted from NIST’s analysis. Brookman also filed a formal complaint with the American Society of Civil Engineers (ASCE) Committee on Professional Conduct (CPC). The ASCE refused to publish Brookman’s Discussion paper, and the CPC dismissed the complaint with no action on September 16, 2013
October 25, 2013: Michael Newman, a NIST public relations person, responds to inquiries made by David Cole on 26 July, 24 September, and 19 October, 2013:
- NIST admits that the stiffeners for girder A2001 were omitted but says they “did not need to be included.”
- NIST did not address the omission of lateral support beams for beam G3005.
In NIST’s final report, the number of figures that utilized Frankel drawing 9114 (showing the stiffeners) was actually seven, not five, as originally ascertained by David Cole from the draft report. According to NIST: “The web stiffeners shown at the end of the girder in Frankel drawing #9114 prevent web crippling. The structural analyses of WTC 7 did not show any web crippling failures. Therefore, the web crippling plates did not need to be included in the models/analyses.”
According to Ronald Brookman, S.E. (private communication), “… the reason given by Dr. Therese McAllister in NCSTAR 1-9 for the failure of girder A2001 at column 79 makes no sense considering the presence of bearing stiffeners welded to the flange and web and clearly shown on Frankel Steel drawing 9114.” “A loss of vertical support for the critical girder and its tributary floor area was assumed based on the pretense of a bottom-flange flexural failure even though the flange was stiffened to prevent such a failure.”
December 12, 2013: William Pepper writes a letter to Todd Zinser, OIG, US Dept of Commerce.
January 14, 2014: The OIG, US Dept of Commerce, responds to Pepper.