Why collapse building 7

The then published reports had claimed that building fires were growing and spreading throughout the multiple floors, which became the ultimate reason for the collapse of the buildings. Before the official investigative report was published, some conspiracy theorists argued that the third tower was "brought down" in a controlled demolition as it was not hit by a plane.

Some theorists continue to argue even after the government refuted the claims constantly. The building was utterly important due to the presence of the Secret Service, the CIA, the Department of Defense and the Office of Emergency Management, which was supposed to coordinate any response to terrorist attacks. Even after 20 years since the deadly attacks, some conspiracies continue to contest the government claims but so far, no concrete evidence has been provided to support them and theories remain Such a collapse would have some features similar to that of a progressive collapse.

WTC 7 was a more typical tall building in the design of its structural system. It was not struck by an aircraft. The collapse of WTC 7 was caused by a single initiating event-the failure of a northeast building column brought on by fire-induced damage to the adjacent flooring system and connections-which stands in contrast to the WTC 1 and WTC 2 failures, which were brought on by multiple factors, including structural damage caused by the aircraft impact, extensive dislodgement of the sprayed fire-resistive materials or fireproofing in the impacted region, and a weakening of the steel structures created by the fires.

Since WTC 7 was not doused with thousands of gallons of jet fuel, large areas of any floor were not ignited simultaneously as they were in the WTC towers. Instead, separate fires in WTC 7 broke out on different floors, most notably on Floors 7 to 9 and 11 to The WTC 7 fires were similar to building contents fires that have occurred in several tall buildings where the automatic sprinklers did not function or were not present.

The collapse of WTC 7 is the first known instance of a tall building brought down primarily by uncontrolled fires. The fires in WTC 7 were similar to those that have occurred in several tall buildings where the automatic sprinklers did not function or were not present. These other buildings, including Philadelphia's One Meridian Plaza, a story skyscraper that burned for 18 hours in , did not collapse due to differences in the design of the structural system.

Factors contributing to WTC 7's collapse included: the thermal expansion of building elements such as floor beams and girders, which occurred at temperatures hundreds of degrees below those typically considered in current practice for fire-resistance ratings; significant magnification of thermal expansion effects due to the long-span floors in the building; connections between structural elements that were designed to resist the vertical forces of gravity, not the thermally induced horizontal or lateral loads; and an overall structural system not designed to prevent fire-induced progressive collapse.

There were some differences between the fires in WTC 7 and those in the referenced buildings, but these differences were secondary to the fire factors that led to the collapse of WTC 7: 1 Fires in high rise buildings typically have a single point of origin on a single floor, whereas the fires in WTC 7 likely had a single point of origin on multiple 10 floors; 2 ; fires in other high rise buildings were due to isolated events, whereas the fires in WTC 7 followed the collapse of WTC 1; 3 water was available to fight fires in the other high rise buildings, but the water supply to fight fires in WTC 7 was impaired; and 4 while the fires in the other buildings were actively fought by fire fighters to the extent possible, in WTC 7, no efforts were made to fight the fires.

The differences in the fires were not meaningful for the following reasons. By the time that WTC 7 collapsed, the fires in WTC 7 had advanced well beyond the likely points of origin on multiple floors i. Additionally, in each of the other referenced buildings, the fires burned out several floors, even with available water and fire fighting activities except for WTC 5. Thus, whether the fire fighters fought the WTC 7 fires or not is not a meaningful point of dissimilarity from the other cited fires.

WTC 7's collapse, viewed from the exterior most videos were taken from the north , did appear to fall almost uniformly as a single unit. This occurred because the interior failures that took place did not cause the exterior framing to fail until the final stages of the building collapse. The interior floor framing and columns collapsed downward and pulled away from the exterior frame.

There were clues that internal damage was taking place, prior to the downward movement of the exterior frame, such as when the east penthouse fell downward into the building and windows broke out on the north face at the ends of the building core. The symmetric appearance of the downward fall of the WTC 7 was primarily due to the greater stiffness and strength of its exterior frame relative to the interior framing.

In the draft WTC 7 report released Aug. This time period is 40 percent longer than the 3. During the public comment period on the draft report, NIST was asked to confirm this time difference and define the reasons for it in greater detail.

To further clarify the descent of the north face, NIST recorded the downward displacement of a point near the center of the roofline from first movement until the north face was no longer visible in the video. Numerical analyses were conducted to calculate the velocity and acceleration of the roofline point from the time-dependent displacement data.

The instant at which vertical motion of the roofline first occurred was determined by tracking the numerical value of the brightness of a pixel a single element in the video image at the roofline. The analyses of the video both the estimation of the instant the roofline began to descend and the calculated velocity and acceleration of a point on the roofline revealed three distinct stages characterizing the 5.

This analysis showed that the 40 percent longer descent time—compared to the 3. During Stage 2, the north face descended essentially in free fall, indicating negligible support from the structure below. This is consistent with the structural analysis model which showed the exterior columns buckling and losing their capacity to support the loads from the structure above.

In Stage 3, the acceleration decreased as the upper portion of the north face encountered increased resistance from the collapsed structure and the debris pile below.

While the partial or total collapse of a tall building due to fires is a rare event, NIST strongly urges building owners, operators, and designers to evaluate buildings to ensure the adequate fire performance of structural systems.

Of particular concern are the effects of thermal expansion in buildings with one or more of the following characteristics: long-span floor systems, connections that cannot accommodate thermal effects, floor framing that induces asymmetric forces on girders, and composite floor systems, whose shear studs could fail due to differential thermal expansion i.

Engineers should be able to design cost-effective fixes to address any areas of concern identified by such evaluations. Several existing, emerging, or even anticipated capabilities could have helped prevent the collapse of WTC 7. The degree to which these capabilities improve performance remains to be evaluated.

Possible options for developing cost-effective fixes include:. NIST is recommending that building standards and codes be strengthened beyond their current intent to achieve life safety to prevent structural collapse even during infrequent building fires like those in WTC 7 when sprinklers do not function, do not exist, or are overwhelmed by fire.

Yes, this possibility was investigated carefully. NIST concluded that blast events inside the building did not occur and found no evidence supporting the existence of a blast event. In addition, no blast sounds were heard on the audio tracks of video recordings during the collapse of WTC 7 or reported by witnesses. As independent, impartial fact checkers, we rely on individuals like you to ensure the most dangerously false inaccuracies can be called out and challenged.

Bad information ruins lives. You deserve better. By Grace Rahman. Share this: Twitter Facebook. Thank you, to all of you for being so focused. Common sense says that random fires can not possibly bring a steel frame building down symmetrically at near free fall speed.

Thousands of dollars are being spent to prove the obvious and dozens of people are having to jump through hoops because of a criminal cover-up. Not many want to accept the fact that the high-rise architects and engineers know what they are doing, that fires generally will stay on the floor they started on.

Hopefully will be the year that this story from finally breaks. Thank you for reporting this. A refreshing bit of courageous journalism despite the nearly two decades conspiracy of silence.

Amidst our current global uncertainties, we must seek truth and integrity to ensure freedom and justice, it is the birthright of our humanity. There is so much proof that this is true. And yet we sit and except it as normal. What have we become?

This may be a bit extreme, however, until the reasons can be validated as to how an object that is not in motion can have an amount of inertia to move in downward and outward at free fall, in a pyroclastic cloud of dust and the ejection of thousands of tons of steel sideways well over feet, that all building must come to an end and the subject of physics must be suspended.

I am ashamed of science in general as it has become a perverse form of modeling using false assumptions and reverse engineered outcomes that are not possible nor repeatable using what we used to know as the scientific method. Thank you for this. Yes, thank you for your fearless journalism! The truth necessarily should set The People freaked! But free nonetheless.

Thanks for publishing this! On September 11, , the world witnessed the total collapse of three large steel-framed high-rises. Since then, scientists and engineers have been working to understand why and how these unprecedented structural failures occurred. If one of my students had written either of the NIST reports not only would I have failed them but I would also have had them thrown out of my programme for serious violation of research ethics both in fabrication and falsification of evidence together with failure to supply sufficient information for me to be able to reproduce their results which is an essential requirement for any scientific report.

There are two hypotheses on offer — Fire and Controlled Demolition. Dr Hulsey and his colleagues have demonstrated that it was not fire. Then after the building collapsed, where was the evidence of all the steel having been cut.

Cutting steel columns leaves the ends of columns cut and it would be obvious to any one of the hundreds of people on the site afterwards.

Thank you for this article. Thank you for doing your jobs as journalists. The only respectable news website on the internet who has reported on this. The ownership and those in charge of security at the WTC complex are the prime suspects. Why am I not surprised such fair coverage came from a Canadian institution rather than one from the US, with its misguided penchant to support Amnerican exceptionalism.

This is awesome news but the Sheople are still in passive mode, waiting to be told what to think or how to respond to a yet complicit mainstream media determined to keep them in the dark and under established, corporate control. They shame all of us. It should come with their jobs and commitment to science.

But they are, alas, meek and afraid; to stand up to whom? The truth is not nearly so fragile as they would like us to believe. The truth will stand up to any and all questioning. An excellent article — thank you. The UAF report makes intersting reading and follows thorough investigation of mutliple failure scenario possibilities to find those that fit the best.

Importantly their dynamic analysis of the controlled demolition scenario produces a visual collapse that perfectly matches that seen in the video evidence from that fateful day — something the NIST investigation completely failed to do.

Make money for Richard Gage. This report is to energize the base, and get donations flowing, nothing more. I really enjoyed your article. This creates a paradox in which no one will listen to you if no one will listen to you. Well thank you Mr. Harvey for listening. As an architect I am following this matter for the last 19 years.

This information has been out there all the time. I am happy to see that despite all the time the process of finding the truth is still progressing. Same will happen to the COVID 19 happenings, which are disputed by scientists and medical practitioners all over the world. Actions speak louder than words. Yet, what we hear from world leaders concerning Civil engineering students at the University of Victoria in B.

Canada will face a shortage of at least 10, workers in nationally recognized Economists offered contrasting visions of the construction marketplace in t Pre-Bid Projects.

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