Compilation of Provable Evidence on the Structural Collapse of WTC 1, 2, and 7

Given the increased traffic here these days, I wanted to compile information regarding the physics of the collapse of WTC 1, 2, and 7 on September 11, 2001, for reference to those who may be new here and as a reminder to us all. To avoid the ‘argumentative’ tone of some new users, I thought it would be constructive to limit this compilation to an engineering analysis only – physical laws cannot be argued. I’ve been motivated lately to start having more upfront discussions about 9/11 with people, where appropriate, and have signed and given my statement to the Architects & Engineers for 9/11 Truth petition (I’m a degreed engineer). Most of the data presented here is from AE911truth.org, I encourage you to check out the site as it’s very well sourced (it also has a lot of PDFs, which I give warnings for throughout).

A practicing architect or engineer holds the civic duty to take every step necessary to ensure the safety of the public; if a miscalculation or oversight makes it all the way into the final assembly of the system at hand, then people can be injured or die through critical failure modes resulting from that oversight. A major aspect of accomplishing the necessary level of safety is to follow the scientific method – data leads to conclusion, not vice versa. Unfortunately, the tragic events of 9/11 immediately obfuscated the data and drew the public eye to an “obvious” conclusion. So, let’s take a look at some data.

Data: factual information used as a basis for reasoning, discussion, or calculation. Merriam-Webster

WTC 1 & 2

Lack of Deceleration - Newton’s Third Law is well known: for every action, there is an equal and opposite reaction. When a hammer hits a nail, for example, not only is the nail pushed into the wood, but the same force exerted on the nail by the hammer is also exerted on the hammer by the nail, causing the hammer to rebound slightly. The backwards motion of the hammer is imperceptible, but measurable. In the case of WTC 1 & 2, think of the hammer as the section of floors above the plane impact and the nail as the remainder below. Even if the infamous jet fuel argument were true, the top floors would measurably decelerate upon impacting the static floors below, as predicted by Newton in 1687. This did not occur in the slightest – the roofline of the buildings descended at constant acceleration. Source 1 (PDF warning), Source 2 (PDF warning)

Lack of Debris - To make modern skyscrapers so tall, they must obviously be built very strong to support the loads above. While building materials and techniques have vastly improved the strength to weight ratio over the years, the fact remains that buildings are really fucking heavy. Each Twin Tower weighed an estimated billion pounds. BILLION. Fun fact, a Boeing 767 clocks in at around 400,000 lbs. The weight of WTC 1 & 2 was primarily composed of structural steel and concrete, which we are led to believe collapsed into a stack of ‘pancakes’ as successive floors impacted. For this to be true, the volume of concrete composing the 110 floors would have left a debris pile 20 stories tall, when in fact the actual debris pile was about 2 stories tall and mostly mangled steel. The concrete was pulverized, resulting in the pyroclastic-like clouds storming the streets surrounding the buildings (not to mention each building’s neat fall into its own footprint through the path of highest resistance). Source 1 (PDF warning), Source 2

Presence of Heat - Black smoke seen coming from both towers is suggestive of an oxygen deprived fire, but it’s hard to be certain. Consequently, the temperature of the fire, and therefore steel within, is unknown. Structural steel will not transition to a liquid state below 1130C, so the fires inside must have been that hot to produce the molten steel pouring out of the buildings. NIST claims, however, that no molten steel was present, and that this was only aluminum (despite the glaring lack of aluminum within the buildings). They also fail to address the molten and red hot steel present in the debris pile for the proceeding week. The clear presence of molten steel mandates temperatures higher than those currently explained in the official models. Source 1 (PDF warning), Source 2 (PDF warning)

WTC 7

Free Fall Collapse - The third building to fall into its own footprint on 9/11 did so despite no plane impact, and it did so at free fall acceleration for 100 feet. To explain the fact that it collapsed at all, NIST relied on office fires alone in their finite element model, the inputs for which have never been released to the public. What is known about NIST’s model shows that they made multiple omissions in structural considerations. As for the free fall – they do not even address it. Source 1 (PDF warning), Source 2 (PDF warning), Source 3 (PDF warning)

Controlled demolition explains every point listed, FEMA and NIST reports do not. It is the only logical conclusion based on the data alone.

There is much more to be learned about September 11th, beyond what I've listed here. I kept it to what I believe to be beyond debate, based on physical laws. Hopefully the results of University of Alaska's upcoming study on the probability of office fires bringing down WTC7 will shed a much needed light in this regard.

TL;DR Accepted structural analyses for the collapse of WTC 1 & 2 do not properly account for the lack of deceleration, lack of debris, and presence of motel steel. Similarly, WTC 7 analyses are inadequate to explain the free fall collapse of the building, and make several structural omissions in modeling why the collapse occurred at all. Considering all of this data, controlled demolition is the only possible cause of total structural failure in all three buildings.