|Fraud Exposed in NIST WTC 7 Reports – Part 2 of 5|
|Written by Chris Sarns|
|Monday, 10 June 2013 05:01|
Editor’s note: To this day, most people, including many architects and engineers, are not aware that a third skyscraper, World Trade Center Building 7, mysteriously collapsed along with the World Trade Center Twin Towers on September 11, 2001. The official report on this building’s collapse by the National Institute of Standards and Technology (NIST) has been challenged by many reputable and credentialed technical professionals. The NIST analysis has not undergone the rigors of scientific peer review – the typical pathway for validating significant scientific theories. Chris Sarns’ research appears in Dr. David Ray Griffin’s book titled
The destruction of this skyscraper on September 11 was truly unprecedented in the history of high-rise buildings. More than 1,900 architects and engineers at AE911Truth are demanding a new investigation.
Chris Sarns has also been deeply involved in the work of AE911Truth, where he provides his expertise on WTC 7.
Part 1 of Chris Sarns’ report, regarding the burned-out fire in WTC7, is available here.
Quotes from the NIST WTC7 report are shown in "brown"
NIST used numerous unscientific methods and fraudulent inputs to get the key girder to fail in its computer simulation..
NIST arbitrarily added 10% to the temperature results of its fire dynamics simulation (FDS).
"Case A used the temperature data as obtained from the FDS simulation. Case B increased the Case A gas temperatures by 10 percent." NCSTAR 1A p. 32 [pdf p. 74]
“…only the fire-induced damage produced by Case B temperatures was carried forward as the initial condition for the building collapse analysis.” NCSTAR 1A p. 36 [pdf p. 78]
To get the shear studs on the floor beams to fail, NIST assumed high steel temperatures and applied the heat in 1-1/2 seconds over the entire north east part of floor 13. This method does not allow for heat dispersal or beam sagging.
NIST heated the floor beams, but not the slab. Since concrete expands at 85% the rate of steel, leaving this expansion out of the calculations of the failure of the shear studs is fraudulent.
"The girder and beam temperatures were assumed to be 500 °C and 600 °C, respectively, and the slab was assumed to remain unheated."– NCSTAR 1-9 Vol.1 p. 349 [pdf p. 393]
"Ramping of the temperatures for the beams and the girder then commenced at 1.1 s, leveling off at temperatures of 600 °C for the beams and 500 °C for the girder at 2.6 s. These temperature histories were prescribed uniformly for all nodes of the beams and the girder, respectively." NCSTAR 1-9 vol.1 p.352 [pdf p. 396]
"The first failures observed were of the shear studs, which were produced by axial expansion of the floor beams, and which began to occur at fairly low beam temperature of 103 °C. … When the beam temperatures had reached 300 °C, all but three shear studs in the model had failed due to axial expansion of the beams, leaving the top flanges of the beams essentially unrestrained laterally." NCSTAR 1-9 Vol.1 p. 352 [pdf p. 396]
"This analysis demonstrated possible failure mechanisms that were used to develop the leading collapse hypothesis further. The failure modes in this model were incorporated into the 16 story ANSYS and 47 story LS-DYNA analyses." NCSTAR 1-9 Vol.1 p. 353 [pdf p. 397]
NIST assumes that it took an hour and a half for the fires, started by burning debris from WTC 1, - 350 feet away - to develop into a 2MW (megawatt) fire.
NIST applied the arbitrarily increased temperature for 4 hours of heating, starting at noon.
"The choice of a 2 MW fire at 12:00 noon was a somewhat arbitrary initialization of the simulations, but there is little visual evidence of how the fires behaved in the time period between 10:28:22 a.m. and 2:00 p.m. … starting the calculations at noon was convenient in that the simulation time was the same as the actual clock time." NCSTAR 1-9 Vol.2 p. 377 [pdf p. 39]
"The building response is examined at 3.5 h and 4.0 h of heating. At 3.5 h, the floor systems had fire-induced damage and failures of some connections, beams, and girders. After 4.0 h of heating, there was substantially more damage and failures in the WTC 7 structural floor system, particularly in the northeast region surrounding Column 79. The structural condition at these two times illustrates how the structure developed sufficient fire-induced damage to reach the collapse initiation event." NCSTAR 1-9 Vol.2 p. 493 [pdf p. 155]
In their scenario, the damage and the collapse would have occurred at 4:00 p.m.
Building Response at 4.0 h
"On Floor 13 (Figure 11–35), all four of the north-south girders attached to Columns 79, 80, and 81 had failed, due to either buckling or girder walk off of the bearing seat at Columns 79 and 81." NCSTAR 1-9 Vol.2 p. 504 [pdf p. 166]
"Fire-induced thermal expansion of the floor system surrounding Column 79 led to the collapse of Floor 13, which triggered a cascade of floor failures. … This left Column 79 with insufficient lateral support, and as a consequence, the column buckled eastward, becoming the initial local failure for collapse initiation." NCSTAR 1A p. 22 [pdf p. 64]
NIST failed to account for beam sag that would have prevented the floor beams from expanding lengthwise more than 5.392 inches at 600o C.
NIST stated that the floor beams in the northeast section of Floor 13 did not exceed 600o C.
"A girder was considered to have lost vertical support when its web was no longer supported by the bearing seat. The bearing seat at Column 79 was 11 in. wide. Thus, when the girder end at Column 79 had been pushed laterally at least 5.5 in., it was no longer supported by the bearing seat." NCSTAR 1-9 Vol.2 p. 527 [pdf p. 189]
"The bearing seat at Column 79 was 11 12 in. wide. Thus, when the girder end at Column 79 had been pushed laterally at least 5.5 6.25 in., it was no longer supported by the bearing seat." June 2012 Text Changes to the NIST Reports
In admitting that the seat was 12 inches wide, NIST has admitted that thermal expansion could not have caused the girder to fail and therefore their hypothesis fails.
Note that the maximum expansion is 5.728 inches at 654o C because loss due to sagging exceeds elongation due to thermal expansion after that.
NIST ignored its own finding:
"Temperatures were uniform (within 1°C) across the bottom flange and web, but the top flange temperature was less by up to several hundred degrees because the slab acted as a heat sink." NCSTAR 1-9 Vol.2 p. 391 [pdf p. 53]
Thermal expansion would cause the bottom flange to expand more than the top flange, forcing the beam to bow downward. The NIST hypothesis does not allow for downward bowing.
NIST finally released the structural and shop drawings in January 2012, pursuant to a FOIA request. They can be downloaded here:
9/11 researcher David Cole went through the hundreds of drawings and found drawing 1091 which shows the girder seat was 12 inches wide (as noted above), not the 11 inches claimed in the final report. He also found drawing 9114, which shows flange stiffeners at the column 79 end of the girder between column 44 and 79.
NIST omitted these flange stiffeners that would have prevented the bottom flange from folding as required for their collapse to begin. The girder would have to be pushed almost all the way off the seat, not just half way, before the bottom flange would buckle.
“Walk-off failure of beams and girders was defined to occur when … the beam or girder was pushed laterally until its web was no longer supported by the bearing seat. … the beam was assumed to have lost support, as the flexural stiffness of the bottom flange was assumed to be insufficient for transferring the gravity loads.” NCSTAR 1-9 Vol. 2 p. 488 [pdf p. 150]
The flange stiffeners are on the Frankel drawings, but not on the NIST drawings in the final report.