<p>excerpted from:</p>
<p><a href="http://911research.wtc7.net/essays/nist/index.html#analysis%5B/url%5D">http://911research.wtc7.net/essays/nist/index.html#analysis</a></p>
<p>"...Previous government reports have minimized, hidden, or denied the existence of the Towers' core columns. The FEMA report contained misleading descriptions and illustrations minimizing and hiding the core columns, and it made no mention of beams connecting the core columns. The 9/11 Commission Report denied their existence entirely, claiming that "the interior core of the [Twin Towers] was a hollow steel shaft, in which the elevators and stairwells were grouped.</p>
<p>NIST continues in the tradition of Core Denial, with a number of misrepresentations, including, apparently, in the computer models that it supposedly used to simulate collapse initiation. Figure 6-9 shows sections of the global model for both the North and the South Towers. Both show the core columns to be thinner than the perimeter columns. But we know that the perimeter columns had outside dimensions of about 13.5 by 14 inches, and that most of the core columns had much larger dimensions. The outer row of core columns in each Tower apparently measured 56 by 22 inches for most of its height. We might forgive NIST for skimping on the dimensions of the core columns at the 100th floor of the North Tower, since the box columns apparently transitioned to smaller H-columns around the 100th floor, but their use of tiny core columns on the 85th floor of the South Tower is clearly in error...</p>
<p>Assuming the premise of the official explanation, the total collapses of the Twin Towers and Building 7 were the largest, most unexpected, and least understood failures of engineered steel structures in the history of the world. NIST's Report, like FEMA's 2002 report, presents the appearance of explaining the collapses of the Twin Towers, but in reality it doesn't explain them at all. Flatly asserting that "global collapse" inevitably follows "collapse initiation," the Report implies that the only issue worthy of study is how the jet impacts and fires led to collapse initiation -- an issue to which it devotes well over one hundred pages. Thus, the Report makes two fundamental claims, the first explicit and the second implicit:</p>
<pre><code>* The impact damage and fires caused the tops of the Towers to lean and then begin to fall (collapse initiation).
* Once initiated, the collapses proceeded to total collapses.
</code></pre>
<p>NIST goes to great lengths to support the first claim, but commits numerous omissions and distortions in the process. It remains quiet about the second claim, except for its vague rehash of the pile-driver theory. This is indefensible, given NIST's charge to investigate the collapses. Accepting that claim requires us to believe:</p>
<pre><code>* That the collapses of WTC 1, 2, and 7 are the only examples of total progressive collapse of steel-framed structures in history.
* That those collapses were gravity-driven despite showing all the common physical features of controlled demolitions. In the cases of the Twin Towers, those features included the following:
- Radial symmetry: The Towers came straight down, blowing debris symmetricaly in all directions.
- Rapid descent: The Towers came down just slightly slower than the rate of free-fall in a vacuum.
- Demolition waves: The Towers were consumed by synchronized rows of confluent explosions.
- Demolition squibs: The Towers exhibited high-velocity gas ejections well below the descending rubble.
- Pulverization: The Towers' non-metallic components, such as their concrete floors, were pulverized into fine dust.
- Totality: The Towers were destroyed totally, their steel skeletons shredded into short pieces, most less than 30 feet long.
</code></pre>
<p>All of these features are seen in conventional controlled demolitions. None have ever been observed in steel-framed buildings collapsing for any reason other than controlled demolition.</p>
<p>What are the chances that a phenomenon other than controlled demolition would exhibit all six features never observed elsewhere except in controlled demolitions?</p>
<p>NIST avoids asking this and other questions by implying that they don't exist. It uses the false assertion that partial collapse will inevitably lead to total collapse (couched in the ill-defined terms of "column instability," "global instability," "collapse initiation," and "global collapse") to imply that nothing about the actual collapses is worth considering.</p>
<p>To shield the reader from the evidence of controlled demolition, NIST fills hundreds of pages with amazingly realistic plane crash simulations, tedious details about fire tests and simulations, and long lists of recommendations for improving building safety. It calls its event narrative of each Tower, which starts with the jet impact and ends at the point that "collapse ensued," the "probable collapse sequence," but it is neither probable nor a collapse sequence.</p>
<p>NIST's misleadingly named "probable collapse sequence" is a mirage, masking the explosive reality of the collapses with a cinematic account of the crashes and fires. NIST's theory stops at the moment that the "upper building section began to move downwards," thus avoiding the longer timeline of the truss-failure theory and any overlap with the time span in which the demolition-like features appear. Despite NIST's theory being even more incredible than its predecessors (with spreading "column instability" triggering "global collapse" in an instant) it works better as a mirage because its timelines stop short of the collapses.."</p>