popular mechanics explanation of what happened to building 7
September 2021: For the past 20 years, conspiracy theories well-nigh the September 11, 2001 terrorist attacks against the United states have swept the nation. The devastation of the Twin Towers in New York Urban center, for instance, was an within job, according to "truthers" who have propagated the merits for two decades.
It was in this climate that Popular Mechanics first took on the job of debunking 9/11 myths. Our first report appeared as the cover story for the March 2005 outcome. The reporting grew into a 2006 volume with a forwards by Sen. John McCain, which was updated in 2011. Below, you'll notice a lightly-edited version of the section on the Globe Trade Center.
Twenty years later, nine/xi conspiracy theories linger on. In the years post-obit the report of this publication, truthers would launch of variety of attacks on Popular Mechanics, accusing the magazine of being a tool of the federal government and drawing tinfoil-hat diagrams to tie Popular Mechanics to the Bush Administration and the supposed big conspiracy. If all this nonsense accomplished anything, it was to presage our electric current era of "culling facts" and attacking the messenger whenever the message clashes with one's predetermined behavior.
The collapse of both World Trade Center (WTC) towers—and the smaller WTC seven a few hours later on—initially surprised even some experts. But subsequent studies take shown that the WTC's structural integrity was destroyed by intense burn down also every bit the severe damage inflicted by the planes.
However, that explanation hasn't swayed conspiracy theorists, who fence that all three buildings were wired with explosives in advance and razed in a series of controlled demolitions.
Widespread Damage
CLAIM: The first hijacked airplane crashed through the 94th to the 98th floors of the World Merchandise Center's 110-story North Tower; the 2d jet slammed into the 78th to the 84th floors of the 110-story Southward Tower. The touch and ensuing fires disrupted elevator service in both buildings. Plus, the lobbies of both buildings were visibly damaged before the towers collapsed. "There is NO WAY the impact of the jet acquired such widespread harm 80 stories beneath," claims a posting on the San Diego Independent Media Center website (sandiego.indymedia.org). "Information technology is OBVIOUS and irrefutable that OTHER EXPLOSIVES (... such as concussion bombs) HAD ALREADY BEEN DETONATED in the lower levels of tower 1 at the aforementioned time every bit the plane crash."
FACT: Post-obit up on a May 2002 preliminary report past the Federal Emergency Management Agency (FEMA), the National Plant of Standards and Engineering science (NIST)—a branch of the U.S. Department of Commerce—released another study in spring 2005. NIST shared its initial findings with Popular Mechanics at the time, and fabricated its pb researcher available to our squad of reporters.
The NIST investigation revealed that aeroplane debris sliced through the utility shafts at the N Tower'southward cadre, creating a conduit for called-for jet fuel—and fiery destruction throughout the building. "It's very difficult to document where the fuel went," says Forman Williams, a NIST adviser and a combustion expert, "but if it'south atomized and flammable and gets to an ignition source, it'll get off."
Called-for fuel traveling down the elevator shafts would have disrupted the elevator systems and caused extensive harm to the lobbies. NIST heard offset-person testimony that "some elevators slammed right down" to the ground floor. "The doors cracked open on the anteroom floor and flames came out and people died," says James Quintiere, an engineering professor at the University of Maryland and a NIST adviser. A similar observation was made in the French documentary 9/11 by Jules and Gedeon Naudet. As Jules Naudet entered the North Tower lobby, minutes after the kickoff aircraft struck, he saw victims on fire, a scene he found too horrific to film.
"Melted" Steel
CLAIM: "We take been lied to," announces the website AttackOnAmerica.cyberspace. "The first lie was that the load of fuel from the aircraft was the crusade of structural failure. No kerosene fire can burn hot plenty to melt steel." The posting is entitled "Proof Of Controlled Demolition At The WTC."
FACT: Jet fuel burns at 800 to 1500 degrees Fahrenheit, not hot enough to cook steel (2750 degrees Fahrenheit). However, experts concur that for the towers to collapse, their steel frames didn't need to cook, they simply had to lose some of their structural strength—and that required exposure to much less oestrus. "I take never seen melted steel in a building burn down," says retired New York deputy fire chief Vincent Dunn, author of The Collapse Of Called-for Buildings: A Guide To Fireground Safety. "But I've seen a lot of twisted, warped, bent and sagging steel. What happens is that the steel tries to expand at both ends, just when it can no longer expand, it sags and the surrounding concrete cracks."
"Steel loses most l per centum of its force at 1100 [degrees Fahrenheit]," notes senior engineer Farid Alfawak-hiri of the American Institute of Steel Construction. "And at 1800 [degrees] it is probably at less than ten percent." NIST as well believes that a great deal of the spray-on fireproofing insulation was likely knocked off the steel beams that were in the path of the crashing jets, leaving the metal more vulnerable to the heat.
But jet fuel wasn't the only thing called-for, notes Forman Williams, a professor of engineering at the University of California, San Diego, and ane of seven structural engineers and fire experts that Popular Mechanics consulted. He says that while the jet fuel was the catalyst for the WTC fires, the resulting inferno was intensified past the combustible material inside the buildings, including rugs, curtains, piece of furniture and paper. NIST reports that pockets of fire hit 1832 degrees Fahrenheit.
"The jet fuel was the ignition source," Williams tells Popular Mechanics. "Information technology burned for maybe ten minutes, and [the towers] were still standing in 10 minutes. It was the rest of the stuff called-for afterward that was responsible for the heat transfer that eventually brought them down."
Puffs of Grit
Claim: As each tower collapsed, clearly visible puffs of dust and droppings were ejected from the sides of the buildings. An advertisement in The New York Times for the book Painful Questions: An Analysis Of The September 11th Attack made this merits: "The concrete clouds shooting out of the buildings are not possible from a mere collapse. They practice occur from explosions." Numerous conspiracy theorists cite Van Romero, an explosives skillful and vice president of the New Mexico Constitute of Mining and Applied science, who was quoted on 9/11 by the Albuquerque Journal equally saying "there were some explosive devices within the buildings that acquired the towers to collapse." The article continues, "Romero said the collapse of the structures resembled those of controlled implosions used to demolish old structures."
FACT: Once each belfry began to collapse, the weight of all the floors higher up the collapsed zone bore down with pulverizing force on the highest intact flooring. Unable to blot the massive energy, that floor would neglect, transmitting the forces to the flooring below, allowing the plummet to progress downwards through the building in a chain reaction. Engineers call the process "pancaking," and information technology does not require an explosion to begin, according to David Biggs, a structural engineer at Ryan-Biggs Associates and a member of the American Society of Civil Engineers team that worked on the FEMA report.
Like all role buildings, the WTC towers contained a huge book of air. Every bit they pancaked, all that air—forth with the concrete and other debris pulverized by the force of the plummet—was ejected with enormous energy. "When you lot have a pregnant portion of a floor collapsing, it'south going to shoot air and concrete dust out the window," NIST lead investigator Shyam Sunder tells Pop Mechanics. Those clouds of dust may create the impression of a controlled demolition, Sunder adds, "merely it is the floor pancaking that leads to that perception."
✅ Get the Facts: 9/11 Conspiracy Theories
Sabotage skillful Romero regrets that his comments to the Albuquerque Journal became fodder for conspiracy theorists. "I was misquoted in maxim that I thought information technology was explosives that brought down the building," he tells Popular Mechanics. "I but said that that's what information technology looked similar."
Romero, who agrees with the scientific conclusion that burn triggered the collapses, demanded a retraction from the Journal. It was printed Sept. 22, 2001. "I felt like my scientific reputation was on the line." But emperors-apparel.com saw something else: "The paymaster of Romero's enquiry plant is the Pentagon. Directly or indirectly, force per unit area was brought to bear, forcing Romero to retract his original statement." Romero responds: "Conspiracy theorists came out saying that the government got to me. That is the farthest thing from the truth. This has been an albatross around my cervix for three years."
Seismic Spikes
Claim: Seismographs at Columbia University'due south Lamont-Doherty World Observatory in Palisades, New York, 21 miles north of the WTC, recorded the events of 9/xi. "The strongest jolts were all registered at the beginning of the collapses, well earlier falling debris struck the globe," reports the website WhatReallyHappened.com. A columnist on Prisonplanet.com, a website run by radio talk prove host Alex Jones, claims the seismic spikes (boxed area on Graph 1) are "indisputable proof that massive explosions brought down" the towers. The site says its findings are supported by two seismologists at the observatory, Won-Young Kim and Arthur Lerner-Lam. Each "sharp fasten of curt duration," says Prisonplanet.com, was consistent with a "demolition-style implosion."
Revisionists say sharp spikes (graph one, above) mean bombs toppled the WTC. Scientists disagree with the claim.
FACT: "There is no scientific basis for the conclusion that explosions brought downwards the towers," Lerner-Lam tells Pop Mechanics. "That representation of our work is categorically wrong and non in context."
The written report issued past Lamont-Doherty includes diverse graphs showing the seismic readings produced by the planes crashing into the two towers every bit well as the later collapse of both buildings. WhatReallyHappened.com chooses to display merely one graph (Graph 1), which shows the readings over a xxx-minute time bridge.
On that graph, the 8- and 10-second collapses appear—misleadingly—as a pair of sudden spikes. Lamont-Doherty'southward xl-2d plot of the same information gives a much more detailed pic: The seismic waves—blue for the South Belfry, red for the North Tower—start small and then escalate every bit the buildings rumble to the ground. Translation: no bombs.
WTC seven Collapse
Claim: Vii hours after the two towers fell, the 47-story WTC 7 collapsed. According to 911review.org: "The video clearly shows that it was not a collapse subsequent to a fire, but rather a controlled demolition: amongst the Internet investigators, the jury is in on this 1."
WTC 7 stands amid the rubble of the recently complanate Twin Towers. Damaged by falling debris, the building and then endures a burn down that rages for hours. Experts say this combination, not a demolition-mode implosion, led to the roofline "kink" that signals WTC 7'southward progressive collapse.
FACT: Many conspiracy theorists point to FEMA's preliminary written report, which said there was relatively light impairment to WTC 7 prior to its plummet. With the benefit of more fourth dimension and resources, NIST researchers now support the working hypothesis that WTC 7 was far more compromised by falling droppings than the FEMA report indicated. "The most important thing we found was that there was, in fact, concrete damage to the s face of building seven," NIST'due south Sunder tells Popular Mechanics. "On about a third of the confront to the centre and to the bottom—approximately x stories—about 25 pct of the depth of the building was scooped out." NIST also discovered previously undocumented damage to WTC 7's upper stories and its southwest corner.
NIST investigators believe a combination of intense fire and severe structural impairment contributed to the collapse, though assigning the exact proportion requires more research. But NIST'due south analysis suggests the fall of WTC 7 was an case of "progressive collapse," a process in which the failure of parts of a structure ultimately creates strains that cause the entire building to come down. Videos of the fall of WTC 7 prove cracks, or "kinks," in the edifice's facade just earlier the two penthouses disappeared into the structure, i after the other. The entire edifice fell in on itself, with the slumping east side of the construction pulling down the west side in a diagonal plummet.
According to NIST, at that place was ane chief reason for the building'south failure: In an unusual design, the columns nearly the visible kinks were carrying uncommonly large loads, roughly 2000 square feet of floor area for each floor. "What our preliminary analysis has shown is that if you take out only one column on one of the lower floors," Sunder notes, "it could cause a vertical progression of collapse and then that the entire section comes down."
There are ii other possible contributing factors yet under investigation: First, trusses on the fifth and seventh floors were designed to transfer loads from 1 gear up of columns to some other. With columns on the southward face obviously damaged, high stresses would likely have been communicated to columns on the building'southward other faces, thereby exceeding their load-begetting capacities.
Second, a fifth-flooring burn burned for up to seven hours. "There was no firefighting in WTC 7," Sunder says. Investigators believe the fire was fed by tanks of diesel that many tenants used to run emergency generators. Most tanks throughout the building were fairly small, but a generator on the 5th floor was continued to a large tank in the basement via a pressurized line. Says Sunder: "Our current working hypothesis is that this pressurized line was supplying fuel [to the fire] for a long period of fourth dimension."
WTC seven might have withstood the concrete impairment it received, or the fire that burned for hours, but those combined factors—forth with the building's unusual construction—were plenty to prepare off the concatenation-reaction collapse.
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Source: https://www.popularmechanics.com/military/a6384/debunking-911-myths-world-trade-center/
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