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Title: Why the towers fell: Two theories [by a civil engineer]
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URL Source: http://www.vermontguardian.com/commentary/032007/TwinTowers.shtml
Published: Mar 1, 2007
Author: William Rice
Post Date: 2007-04-17 16:30:39 by honway
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Why the towers fell: Two theories By William Rice William Rice, P.E., is a registered professional civil engineer who worked on structural steel (and concrete) buildings in Boston, New York, and Philadelphia. He was also a professor at Vermont Technical College where he taught engineering materials, structures lab, and other building related courses, Posted March 1, 2007 Having worked on structural steel buildings as a civil engineer in the era when the Twin Towers were designed and constructed, I found some disturbing discrepancies and omissions concerning their collapse on 9/11. I was particularly interested in the two PBS documentaries that explained the prevailing theories as determined by two government agencies, FEMA and NIST (National Institute of Science and Technology). The first (2002) PBS documentary, Why the Towers Fell, discussed how the floor truss connectors failed and caused a “progressive pancake collapse.” The subsequent 2006 repackaged documentary Building on Ground Zero explained that the connectors held, but that the columns failed, which is also unlikely. Without mentioning the word “concrete,” the latter documentary compared the three-second collapse of the concrete Oklahoma City Murrah Federal Building with that of the Twin Towers that were of structural steel. The collapse of a concrete-framed building cannot be compared with that of a structural steel-framed building. Since neither documentary addressed many of the pertinent facts, I took the time to review available material, combine it with scientific and historic facts, and submit the following two theories for consideration. The prevailing theory The prevailing theory for the collapse of the 110-story, award-winning Twin Towers is that when jetliners flew into the 95th and 80th floors of the North and South Towers respectively, they severed several of each building’s columns and weakened other columns with the burning of jet fuel/kerosene (and office combustibles). However, unlike concrete buildings, structural steel buildings redistribute the stress when several columns are removed and the undamaged structural framework acts as a truss network to bridge over the missing columns. After the 1993 car bomb explosion destroyed columns in the North Tower, John Skilling, the head structural engineer for the Twin Towers, was asked about an airplane strike. He explained that the Twin Towers were originally designed to withstand the impact of a Boeing 707 (similar in size to the Boeing 767). He went on to say that there would be a horrendous fire from the jet fuel, but “the building structure would still be there.” The 10,000 gallons of jet fuel (half capacity) in each jetliner did cause horrendous fires over several floors, but it would not cause the steel members to melt or even lose sufficient strength to cause a collapse. This is because the short-duration jet fuel fires and office combustible fires cannot create (or transmit to the steel) temperatures hot enough. If a structural steel building could collapse because of fire, it would do so slowly as the various steel members gradually relinquished their structural strength. However, in the 100-year history of structural-steel framed buildings, there is no evidence of any structural steel framed building having collapsed because of fire. Let’s assume the unlikelihood that these fires could weaken all of the columns to the same degree of heat intensity and thus remove their structural strength equally over the entire floor, or floors, in order to cause the top 30-floor building segment (South Tower WTC #2) to drop vertically and evenly onto the supporting 79th floor. The 30 floors from above would then combine with the 79th floor and fall onto the next level down (78th floor) crushing its columns evenly and so on down into the seven levels below the street level. The interesting fact is that each of these 110-story Twin Towers fell upon itself in about ten seconds at nearly free-fall speed. This violates Newton’s Law of Conservation of Momentum that would require that as the stationary inertia of each floor is overcome by being hit, the mass (weight) increases and the free-fall speed decreases. Even if Newton’s Law is ignored, the prevailing theory would have us believe that each of the Twin Towers inexplicably collapsed upon itself crushing all 287 massive columns on each floor while maintaining a free-fall speed as if the 100,000, or more, tons of supporting structural-steel framework underneath didn’t exist. The politically unthinkable theory Controlled demolition is so politically unthinkable that the media not only demeans the messenger but also ridicules and “debunks” the message rather than provide investigative reporting. Curiously, it took 441 days for the president’s 9/11 Commission to start an “investigation” into a tragedy where more than 2,500 WTC lives were taken. The Commission’s investigation also didn’t include the possibility of controlled-demolition, nor did it include an investigation into the “unusual and unprecedented” manner in which WTC Building #7 collapsed. The media has basically kept the collapse of WTC Building #7 hidden from public view. However, instead of the Twin Towers, let’s consider this building now. Building #7 was a 47-story structural steel World Trade Center Building that also collapsed onto itself at free-fall speed on 9/11. This structural steel building was not hit by a jetliner, and collapsed seven hours after the Twin Towers collapsed and five hours after the firemen had been ordered to vacate the building and a collapse safety zone had been cordoned off. Both of the landmark buildings on either side received relatively little structural damage and both continue in use today. Contrary to the sudden collapse of the Twin Towers and Building #7, the four other smaller World Trade Center buildings #3, #4, #5, and #6, which were severely damaged and engulfed in flames on 9/11, still remained standing. There were no reports of multiple explosions. The buildings had no pools of molten metal (a byproduct of explosives) at the base of their elevator shafts. They created no huge caustic concrete/cement and asbestos dust clouds (only explosives will pulverize concrete into a fine dust cloud), and they propelled no heavy steel beams horizontally for three hundred feet or more. The collapse of WTC building #7, which housed the offices of the CIA, the Secret Service, and the Department of Defense, among others, was omitted from the government’s 9/11 Commission Report, and its collapse has yet to be investigated. Perhaps it is time for these and other unanswered questions surrounding 9/11 to be thoroughly investigated. Let’s start by contacting our congressional delegation. William Rice, P.E., is a registered professional civil engineer who worked on structural steel (and concrete) buildings in Boston, New York, and Philadelphia. He was also a professor at Vermont Technical College where he taught engineering materials, structures lab, and other building related courses.
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#1. To: honway, ALL (#0)
First of all John Skilling was NOT the head structural engineer for the WTC towers. Leslie Robertson is the head structural engineer of record. He was the one who moved to New York to do the design. Mr Skilling remained in Seattle. Second, did Mr Rice fail to note the difference in the speed of the planes assumed in the design and the ones that hit the towers? That difference corresponds to a factor of 7 (or more) difference in the impact energy of the planes. There was NO consideration of fire after the plane impact in the design. Leslie Robertson stated that fire resulting from a plane impact was NOT considered in the design. If Mr Rice thinks otherwise, he is wrong. Melting of steel is not the theory of NIST. Wrong again. First, the fires were NOT of short duration (didn't he read the NIST report like he claimed?) and second how hot does he think the temperatures have to get to weaken steel? The fires in the Windsor Tower in Madrid reached 1400 F and that was without jet fuel to start it. There are plenty of examples of temperatures in fires in ordinary office building reaching those temperatures or even higher. Or does Mr Rice actually think steel strength is unaffected at these temperatures? If so, then I question his credentials. Also, does he think the numerous engineers who did analysis with codes that are generally agreed to be the state of the art in fire engineering are incompetent or wrong when they concluded temperatures in the towers reached nearly 2000 F? Apparently Mr Rice overlooked the likelihood that fireproofing in the towers was extensively damaged by the impacts? And how fast does Mr Rice think unprotected steel strength responds to temperatures of ... say ... 1400 F or higher? This is the silliest statement yet. If that were the case, then why are there fire codes on steel structures? Why is there so much effort (and cost) to protect steel members from fire? The fact is that steel framed building HAVE collapsed due to fire. Mr Rice is simply WRONG. Again, we find Mr Rice claiming a theory that NIST does not promote. What Mr Rice is doing is putting forth a STRAWMAN ... something false to knock down. In fact, if Mr Rice had done as much research of the matter as he claims, he'd know that the theory is that sagging floors broke sections of the outer wall columns and THAT is what led to the collapse. Obviously, he didn't. ROTFLOL! Where has this guy been the last 5 years? How can he claim the towers collapsed in ten seconds if he read the NIST reports as he claimed? If he looked at ANY non-conspiracy website he'd see the towers took 15 seconds or so to collapse. Videos and photos prove this. Even some conspiracy leaning websites admit this. And he should know this IF he's done ANY research besides visiting the more extreme conspiracy websites. This alone is good reason to doubt this individuals competence or opinion. The collapse of WTC 7 was not sudden. Firemen have said they knew it was going to collapse hours before it did because they could see it deforming. This is more conspiracy nonsense. NO ONE who was an eyewitness has said they found POOLS of molten metal at the base of the elevator shafts. If this is so, why hasn't ONE demolition expert in the entire world come forward to say it? Afterall, it should be so obvious when someone like Mr Rice even knows it. Does Mr Rice think they are all part of the conspiracy? ROTFLOL! honway, can you provide proof that any of this is true? Can you perhaps point me to a resume or a university where he got his degree? And who did he work for while working on those structures? Pardon me if I'm now a little skeptical. Let's see what the Vermont Technical College website says. His name isn't listed as faculty or staff: http://catalog.vtc.edu/content.php?catoid=12&navoid=225 . Why is that? In fact, a search of their website doesn't turn up the name William Rice anywhere. Why is that?
[BAC] First of all John Skilling was NOT the head structural engineer for the WTC towers. Leslie Robertson is the head structural engineer of record. He was the one who moved to New York to do the design. Mr Skilling remained in Seattle. As usual, BAC's source is missing. My source is not. NIST Report, Chapter 1, page 1, paragraph 1.1, reads in relevant part: NIST Report, Chapter 1, page 6, reads in relevant part: ------- [BAC] did Mr Rice fail to note the difference in the speed of the planes assumed in the design and the ones that hit the towers? That difference corresponds to a factor of 7 (or more) difference in the impact energy of the planes. BAC, exactly how much in excess of 600 mph did you determine that the planes were moving when they struck the towers? According to the NIST Report, Chapter 2, page 20, paragraph 2-3, WTC-1 was hit by a plane "[m]oving at about 440 mph..." According to the NIST Report, Chapter 3, page 38, paragraph 3-2, WTC-2 was hit by a plane moving "540 mph...." ------- [BAC] He went on to say that there would be a horrendous fire from the jet fuel, but “the building structure would still be there.” There was NO consideration of fire after the plane impact in the design. Leslie Robertson stated that fire resulting from a plane impact was NOT considered in the design. If Mr Rice thinks otherwise, he is wrong. Do recall that, "(Some time after completion of the construction, Skilling, Helle, Christiansen, and Robertson, and then Leslie E. Robertson Associates (LERA) assumed that role. [structural engineer])" ------- [BAC] The 10,000 gallons of jet fuel (half capacity) in each jetliner did cause horrendous fires over several floors, but it would not cause the steel members to melt or even lose sufficient strength to cause a collapse. Melting of steel is not the theory of NIST. Melting steel happened. Relevant theories attempt to explain how it happened. -------
Rather than dishonest and snide remarks, you should pay more attention to the facts and what's been posted on this forum. I've provided links to back my assertion up over and over in previous threads here at 4um (not to mention uncounted times at LP). If you weren't paying attention, NC, that's your problem. You didn't even use your browser because if you had you would know I was right. The fact is Leslie Robertson was the LEAD STRUCTURAL ENGINEER. Skillings ran the company and was not even in NYC where the design was done. http://www.nae.edu/nae/bridgecom.nsf/weblinks/CGOZ-58NLCB?OpenDocument "Reflections on the World Trade Center, Leslie E. Robertson, ... snip ... The lead structural engineer reflects on the rise and fall of the World Trade Center towers." http://web.mit.edu/civenv/wtc/PDFfiles/Chapter%20I%20History.pdf "Robertson was the most influential engineer on the project and assumed the position of lead structural designer of the towers. Robertson had as much influence on the form of the building as anyone apart from Yamasaki himself." http://www.asce.org/pressroom/news/display_press.cfm?uid=1349 "Leslie E. Robertson, lead structural engineer for the World Trade Center Towers, will be honored with a 2003 Outstanding Projects and Leaders (OPAL) award for lifetime contributions in design. The award will be presented on Thursday, May 1, at the American Society of Civil Engineers' (ASCE) fourth annual OPAL awards gala at the Omni Shoreham Hotel in Washington, D.C. http://www.pbs.org/wgbh/nova/wtc/about.html ""Building on Ground Zero" features candid interviews with leading construction and safety experts, investigators, architects, and engineers—including Leslie Robertson, lead structural engineer of the original World Trade Center and Shanghai's new World Financial Center, and Jake Pauls, occupants advocate and evacuation specialist. And there are dozens more where that came from. Does NOT say that Shillings was the lead structural engineer. Skilling got mentioned because he owned the company. It was Robertson and those under him who were responsible for 99% of the actual design. This was a back of the envelope calculation done AFTER the design was complete. Robertson is on the record stating that the towers were DESIGNED for an impact in fog at low speed (180 mph). http://www.nae.edu/nae/bridgecom.nsf/weblinks/CGOZ-58NLCB?OpenDocument "Reflections on the World Trade Center, Leslie E. Robertson, ... snip ... The lead structural engineer reflects on the rise and fall of the World Trade Center towers. ... snip ... It was assumed that the jetliner would be lost in the fog, seeking to land at JFK or at Newark. To the best of our knowledge, little was known about the effects of a fire from such an aircraft, and no designs were prepared for that circumstance. Indeed, at that time, no fireproofing systems were available to control the effects of such fires." You might want to read the history of what went on back then before sticking your foot further in your mouth: http://scott-juris.blogspot.com/The%20Height%20of%20Ambition%20Part%20Four.pdf "The Height of Ambition: Part Four September 8, 2002 By JAMES GLANZ and ERIC LIPTON ... snip ... But Robertson still had one more set of structural calculations to perform. Lawrence Wien, who was continuing his fight against the towers, had begun to remind New Yorkers publicly of a Saturday morning in July 1945, when a B-25 bomber, lost in the fog, barreled into the 79th floor of the Empire State Building. Most of the 14 people who died were incinerated by a fireball created when the plane's fuel ignited, even though the fire was quickly contained. The following year,another plane crashed into the 72-story skyscraper at 40 Wall Street, and yet another one narrowly missed the Empire State Building, terrifying sightseers on the observation deck. Wien and his committee charged that the twin towers, with their broader and higher tops, would represent an even greater risk of mid air collision. They ran a nearly full-page ad in The Times with an artist's rendition of a commercial airliner about to ram one of the towers. ''Unfortunately, we rarely recognize how serious these problems are until it's too late to do anything,'' the caption said. The Port Authority was already trying to line up the thousands of tenants it would need to fill the acres of office space in the towers. Such a frightful vision could not be left unchallenged. Robertson says that he never saw the ad and was ignorant of the political battle behind it. Still, he recalls that he addressed the question of an airplane collision, if only to satisfy his engineer's curiosity. For whatever reason, Robertson took the time to calculate how well his towers would handle the impact from a Boeing 707, the largest jetliner in service at the time. He says that his calculations assumed a plane lost in a fog while searching for an airport at relatively low speed, like the B-25 bomber. He concluded that the towers would remain standing despite the force of the impact and the hole it would punch out. The new technologies he had installed after the motion experiments and wind-tunnel work had created a structure more than strong enough to withstand such a blow. Exactly how Robertson performed these calculations is apparently lost - he says he cannot find a copy of the report. Several engineers who worked with him at the time, including the director of his computer department, say they have no recollection of ever seeing the study. But the Port Authority, eager to mount a counter attack against Wien, seized on the results -- and may in fact have exaggerated them. One architect working for the Port Authority issued a statement to the press, covered in a prominent article in The Times, explaining that Robertson's study proved that the towers could withstand the impact of a jetliner moving at 600 miles an hour. That was perhaps three times the speed that Robertson had considered. If Robertson saw the article in the paper, he never spoke up about the discrepancy. No one else issued a correction, and the question was answered in many people's minds: the towers were as safe as could be expected, even in the most cataclysmic of circumstances. There were only two problems. The first, of course, was that no study of the impact of a 600-mile-an-hour plane ever existed. ''That's got nothing to do with the reality of what we did,'' Robertson snapped when shown the Port Authority architect's statement more than three decades later." First of all, BAC did not say that. That was a quote from the thread's article to which I responded. THIS was my response. All of which is true. After the plane impacts (even at close to 600 mph) the building structure was still there. It was the fuel induced FIRE that caused the problem. It was "horrendous". It did kill a lot of people. And it ultimately collapsed the damaged structure. Skilling NEVER said that they analyzed what that fire would do to the towers or whether they would survive that fire. Indeed, at that time they did the design of the towers, they did not have the tools to determine that. Again, I did not say that. I was quoting an assertion in the article. That is true. NISTs theory for the collapse of the towers does not require melting steel. Perhaps. Likely. But when did it melt? And what caused that melting. The odd thing is that not one expert in fire or steel anywhere in the world has come forward to express the impossibility of ORDINARY fires in the rubble melting that steel. And I'm still waiting to hear your theory for what kept that steel molten for 6 weeks or more. Because it sure wasn't the thermite bombs you seem to believe went off on 9/11. Thermite bombs don't work that way.
It is a White Paper from 1964. Groundbreaking occurred two years later in 1966. http://wtc.nist.gov/media/Public%20Transcript%20021204%20Final1_withlinks.pdf Transcript of NIST Public Meeting in New York City - February 12, 2004 Shyam Sunder, National Institute of Standards and Technology the lead investigator for the federal building and fire safety investigation of the World Trade Center disaster: We have some documents from 1964 that suggest that. The impact scenario that was considered is a Boeing 707 traveling at 600 miles an hour. There's another document a month later that considers an aircraft impact at the 80th floor of one of the towers. http://en.wikipedia.org/wiki/World_Trade_Center Construction Groundbreaking for the construction of the World Trade Center was on August 5, 1966. In 1970, construction was completed on One World Trade Center, with its first tenants moving into the building in December, 1970. Tenants first moved into Two World Trade Center in January 1972. http://en.wikipedia.org/wiki/White_paper A white paper is an authoritative report. White papers are used to educate customers, collect leads for a company or help people make decisions. They can also be a government report outlining policy.
http://en.wikipedia.org/wiki/Design_and_construction_of_the_World_Trade_Center "On September 20, 1962, the Port Authority announced the selection of Minoru Yamasaki as lead architect, and Emery Roth & Sons as associate architects.[26] Yamasaki came up with the idea of twin towers. To meet the Port Authority's requirement to build 10 million square feet of office space, the towers would each be 110-stories tall. Yamasaki remarked that the "obvious alternative, a group of several large buildings, would have looked like a housing project".[27] Yamasaki's design for the World Trade Center was unveiled to the public on January 18, 1964, with an eight-foot model.[27] So there is NO POSSIBLE WAY that any White Paper from 1964 affected the DESIGN. You don't know what you are talking about nolu_chan.
So there is NO POSSIBLE WAY that any White Paper from 1964 affected the DESIGN. Yamasaki was the architect. He did not do the engineering. The design of the building did not end with the display of an 8-foot model. But if you say so... After the design was BAC-complete, engineering concepts were explained to the New York Architectural League by the Big Boss Structural Engineer, John Skilling, a partner in Worthington, Skilling, Helle and Jackson. From Engineering News Record The concept was explained to the New York Architectural League by John Skilling, a partner in Worthington, Skilling, Helle and Jackson, of Seattle, consulting structural engineers on the World Trade Center (see p. 124). April 2, 1964
And you think they wait to determine what the underlying major structure is until AFTER the Architect unveils the DESIGN to the public? ROTFLOL! Here are some signs from the same article that the design was well underway much earlier than 1964. "The exterior walls will comprise giant Vierendeel trusses, designed to act like huge cantilevered hollow tubes. They will be pre-assembled in units two stories high and about 10 ft wide, spliced at mid-height of the columns and midspan of the deep spandrel beams. The closely spaced columns will consist of 14-inch-sq hollow box sections, providing high torsional and bending resistance. ... snip ... July 9, 1964" Well clearly the design was well underway by July 1964. "Four New York City construction companies will independently review construction techniques planned for the two 110-story towers at the World Trade Center ... snip ... April 16, 1964" Gee, in April 1964 they are already awarding bids to construction folks to REVIEW construction techniques. So they must know what they were going to build. "The Port of New York Authority will. pay architects Minoru Yamasaki & Associates and Emery Roth & Sons an extra $800,000 over the initial $1.5-million fee for designing the World Trade Center in New York City. The new contract covers further design refinements for the superstructure of the twin 110-story towers, studies of integration of the PATH railroad station into the project. October 15, 1964" Hmmm ... in October 1964, they were already awarding more money for REFINEMENTS of the design. "HOW COLUMNS WILL BE DESIGNED FOR 110-STORY BUILDINGS ... snip ... April 2, 1964" Gosh, according to that article in April 1964 they already have all the major dimensions that we know about the structure ... the size of its members ... the response to loads ... the variations in steel strength over the height. So what did Skillling really do? "NEW YORK'S 110-STORY TOWERS ... Most local designers and builders want to know more about the New York World Trade Center and its sky-shattering heights (ENR Jan. 23, p. 33), but they generally like what they've seen so far. ... snip ... James Ruderman, consulting structural engineer "The structural design of the tower buildings shows a commendable job of rethinking, where ideas were given a lot of thought and not just treated routinely." ... snip ... January 30, 1964." Oh my gosh ... in January of 1964 a structural engineer is commenting on the structural design. He must have had something to comment on. Here's a real puzzler for you, NC. The White Paper written by Skilling that you are making such a big deal about was released February 3, 1964. So if the concept was just being explained to Skilling in APRIL of that year, how did he manage to do a detailed analysis to show that the structure could survive a 600 mph commercial jet impact back in February? Hmmmmmmm???? I anticipate that question will go just as unanswered as my question about what kept the molten steel molten 6 weeks after the collapse ... or my question about whether that photo of debris proves Steven Jones is a liar. ROTFLOL!
No moron. You said at #34, "So there is NO POSSIBLE WAY that any White Paper from 1964 affected the DESIGN." A whole bunch of things could, and most certainly did, change in the design after 1964. What I said at #36 was, "The design of the building did not end with the display of an 8-foot model." In your idiocy, you asserted that prior to the White Paper in 1964, the design had been COMPLETED. Now in a bait and switch, in order to try to extract your sorry butt from your display of gross public dumb, you assert, "some signs from the same article that the design was well underway much earlier than 1964." Referring to the White Paper of February 3, 1964, you blathered at #18, "This was a back of the envelope calculation done AFTER the design was complete." That the design was UNDERWAY prior to 1964 would in no way support your prior claim that "there is NO POSSIBLE WAY that any White Paper from 1964 affected the DESIGN." Also, at #18, you did not say the design was UNDERWAY prior to the White Paper, you explicitly stated the White Paper was "done AFTER the design was complete." [BAC upper case emphasis.] AFTER 1964, Robertson's original engineering design plan had to be scrapped because tests in 1965 showed the buildings would sway beyond the limits of human tolerance. As Glanz and Lipton wrote in the New York Times, "Even today, Robertson has no trouble conjuring what two towers full of seasick office workers would have meant: 'A billion dollars right down the tube.' So he went back to work." The Height of Ambition: Part Four * * * Using exterior columns rather than interior ones for lateral stiffness not only increased the building's floor space; it also let Robertson reduce the total amount of structural steel in the building by at least 30 percent. The steel in the tightly spaced columns became as thin as a quarter-inch toward the top, where it had less load to carry. Robertson had succeeded in achieving his main goals for these exotic steel trees. But in designing what would become the feathery branches of those trees -- the floors -- he pushed even further toward lightweightness and cost savings. Rather than the massive beams or heavy framings that serve as horizontal floor supports in virtually every large steel office tower, Robertson chose bar-joist trusses -- airy, weblike networks of thin steel bars and angle irons topped with corrugated decking. Those trusses, which spanned as much as 60 feet, had two critical roles: they held up the concrete floors, and they provided lateral support to the exterior columns, keeping them from buckling under the load they carried. According to Robertson's figures, the trusses worked as well as heavy traditional girders and beams in performing those roles under ordinary circumstances. What he did not take into account was the extraordinary conditions of an intense, violent fire. Girders and beams would be far superior under those circumstances. Thin steel elements heat up and soften faster than thick ones. But in recent conversations, Robertson has said that architects generally handle anything dealing with fire in building projects, not engineers, so he did not think about this reduction in safety. Robertson and the Port Authority made another choice that proved fateful decades later. They chose not to use thick masonry or cement to encase the three escape stairways in each tower but rather light sheets of gypsum. Although the gypsum was extremely resistant to fire, and less likely than masonry to crack when the building swayed in the wind, it would work only if it remained intact -- and it was much more susceptible to being shaken loose or damaged by an explosion or any other kind of unexpected impact. There was another factor that Robertson had to take into account: the swaying motion of his buildings. The lightweight steel skeletons would not only put people unnaturally high in the air, as all skyscrapers do. They would let the buildings sway back and forth in the wind, like the biggest, leafiest trees ever planted. Heavy masonry-clad high-rises like the Empire State Building had never had to deal with this problem. For that reason, engineers had never measured how much swaying motion humans could stand before they became dizzy, seasick, frightened or disoriented. To answer that question, Robertson turned to an expert in human perception in Eugene, Ore. -- a spot as far removed from the New York press as he could find. Paul Hoffman, a psychologist, agreed to perform a secret series of experiments to find out just how much swaying motion was too much. Hoffman purchased a small office building in downtown Eugene and in the summer of 1965 put an ad in the local paper offering free eye checkups at a ''vision research center.'' But it was actually an elaborate ruse: the optometrist who conducted the eye exams was one of Hoffman's employees, Paul R. Eskildsen. And as each patient stared at triangles projected on the wall, a hidden technician would trigger a giant set of hydraulics underneath the room that heaved it back and forth like a big saltshaker. ''This is a strange room,'' one patient said, according to Eskildsen's detailed notes. ''I suppose it's because I don't have my glasses on. Is it rigged or something? It really feels funny.'' Patient after patient reacted the same way -- becoming dizzy and confused soon after the eye exam began. Humans, Hoffman discovered, were much more sensitive to motion than anyone had realized. A few inches of sway over 5 or 10 seconds set off psychophysical alarm bells. ''The people who were most surprised of all were the engineering firm and the Port Authority,'' Hoffman says. First, Port Authority officials trooped out to Eugene. Old photos show them milling around the little optometrist's office, looking flummoxed. Then they insisted on redoing the experiments by swinging a makeshift office on cables inside one of the Lincoln Tunnel's ventilation towers on Manhattan's West Side. ''It was a big packing crate, is what it was, that they had dolled up to look like an office,'' says Eskildsen, who traveled to New York for the new round. ''I had two guys outside who pushed the room. It was hilarious.'' About 40 Port Authority officials rode in the contraption. The results were the same. Wind-tunnel experiments in Fort Collins, Colo., confirmed that Robertson's initial design would sway far beyond those human tolerances, says Jack Cermak, then a professor of civil engineering and the director of the wind-tunnel laboratory at Colorado State University. Even today, Robertson has no trouble conjuring what two towers full of seasick office workers would have meant: ''A billion dollars right down the tube.'' So he went back to work. * * * But Robertson still had one more set of structural calculations to perform. Lawrence Wien, who was continuing his fight against the towers, had begun to remind New Yorkers publicly of a Saturday morning in July 1945, when a B-25 bomber, lost in the fog, barreled into the 79th floor of the Empire State Building. Most of the 14 people who died were incinerated by a fireball created when the plane's fuel ignited, even though the fire was quickly contained. The following year, another plane crashed into the 72-story skyscraper at 40 Wall Street, and yet another one narrowly missed the Empire State Building, terrifying sightseers on the observation deck. Wien and his committee charged that the twin towers, with their broader and higher tops, would represent an even greater risk of midair collision. They ran a nearly full-page ad in The Times with an artist's rendition of a commercial airliner about to ram one of the towers. ''Unfortunately, we rarely recognize how serious these problems are until it's too late to do anything,'' the caption said. The Port Authority was already trying to line up the thousands of tenants it would need to fill the acres of office space in the towers. Such a frightful vision could not be left unchallenged. Robertson says that he never saw the ad and was ignorant of the political battle behind it. Still, he recalls that he addressed the question of an airplane collision, if only to satisfy his engineer's curiosity. For whatever reason, Robertson took the time to calculate how well his towers would handle the impact from a Boeing 707, the largest jetliner in service at the time. He says that his calculations assumed a plane lost in a fog while searching for an airport at relatively low speed, like the B-25 bomber. He concluded that the towers would remain standing despite the force of the impact and the hole it would punch out. The new technologies he had installed after the motion experiments and wind-tunnel work had created a structure more than strong enough to withstand such a blow. Exactly how Robertson performed these calculations is apparently lost -- he says he cannot find a copy of the report. Several engineers who worked with him at the time, including the director of his computer department, say they have no recollection of ever seeing the study. But the Port Authority, eager to mount a counterattack against Wien, seized on the results -- and may in fact have exaggerated them. One architect working for the Port Authority issued a statement to the press, covered in a prominent article in The Times, explaining that Robertson's study proved that the towers could withstand the impact of a jetliner moving at 600 miles an hour. That was perhaps three times the speed that Robertson had considered. If Robertson saw the article in the paper, he never spoke up about the discrepancy. No one else issued a correction, and the question was answered in many people's minds: the towers were as safe as could be expected, even in the most cataclysmic of circumstances. There were only two problems. The first, of course, was that no study of the impact of a 600-mile-an-hour plane ever existed. ''That's got nothing to do with the reality of what we did,'' Robertson snapped when shown the Port Authority architect's statement more than three decades later. The second problem was that no one thought to take into account the fires that would inevitably break out when the jetliner's fuel exploded, exactly as the B-25's had. And if Wien was the trade center's Cassandra, fire protection would become its Achilles' heel. * * * [nc - there are at least a few more problems. Robertson's assertion of being unaware of the Wein ad and the political battle is not credible. Perhaps Robertson performed only an imaginary study consisting of nothing more than some propaganda released to the press, or he blew smoke at the architect. A prominent article in the New York Times explained that Robertson's study proved that the towers could withstand the impact of a jetliner moving at 600 miles an hour. There can be no credible assertion of unawareness by all concerned in the building of the WTC and no correction was issued. Robertson's three decades late assertion that he considered only a plane going 180 mph is not credible.] Compare with BAC drivel at #18
The design of the major structural elements of the towers surely had to have been completed by February 1964. Otherwise, Skilling could not possibly have completed an analysis of the structure's ability to survive a high speed plane crash that he published a White Paper about on February 3, 1964. You can't have it both ways NC. Either the White Paper is simply nonsense based on an incomplete design or the design (as far as what would be necessary to determine the resistance of the towers to plane impact) was completed by February 3, 1964. And since it must have taken some time to do the analysis that is claimed and write the White Paper, that would imply the design was essentially finished before January 1964. But he didn't change the essential structure during that revision. The revision must have consisted of very few changes because the articles you linked and quoted from 1964 and earlier show design details (size of columns, spacing, steel strengths, etc) that agree quite well with the final design. And indeed, the article you quote doesn't say the revision involved changes in the major structure. Your article is telling us that contrary to what the CT community has been saying, the WTC tower design was MORE vulnerable to fire than other steel skyscrapers (which usually uses girders and beams)? Well ... perhaps that explains why they were the first skyscrapers to collapse due to fire. Oh my goodness ... yet another difference between the WTC tower design and most other skyscraper designs. One that again makes the towers MORE vulnerable to fire if a plane crash has occurred. Are you finally admitting that it was Robertson's design ... not Skilling's. Good for you. Again, what YOU posted says Robertson did look at the tower's performance for a low speed plane lost in fog, not a high speed impact. And one more point ... this points out that Robertson, like Skilling, did an analysis AFTER the design was done. Crash of planes into the towers was apparently not a DESIGN LOAD so it is incorrect to claim that the towers were DESIGNED for even this plane crash. It's just fortuitous for them that calculations showed the towers would survive a plane impact. Otherwise, they might have had to redesign the whole tower. Right? New technologies? That doesn't sound like he just added thickness to steel members or increased the steel strengths, does it? Let's see ... what could they be talking about? Maybe the outrigger space frame which linked the outside wall to the services core? No ... that was part of the initial concept. Wait! I know what they are talking about. http://www.nae.edu/nae/bridgecom.nsf/weblinks/CGOZ-58NLCB "A viscoelastic damping system was invented and patented to ameliorate the wind-induced dynamic component of building motion by dissipating much of the energy of that motion . . . acting more or less like shock absorbers in an automobile. With these dampers, we could control the swaying motion without having to use large quantities of structural steel. This was the first time engineered dampers were used to resist the wind-induced swaying motion of a building." Now my question to you is this. Do you think those viscoelastic dampers significantly affected the resistance of the towers to plane impact? Or increased it's fire resistance? Or affected the way the tower would collapse once fire did its thing? No? Then I don't know why you even bring this up in this debate other than muddy the waters and keep folks from seeing the essential issues. Fine. If you want to claim that no study of the tower's resistance to aircraft impact was performed, that's ok with me. Because I thought it is the CT community that insists the towers were DESIGNED to survive multiple high speed plane crashes. What are you going to do, NC ... just ignore the real mystery here? The link YOU PROVIDED tells us that the concept for the towers was just explained to Skilling in April of 2004. Yet he published his White Paper (where you claim he did a design analysis of the towers) in February 3, 1964. Impossible? Yes.
Actually, it was the architects and engineers, per a white paper and an unchallenged article in the New York Times, by which questions about the safety of the soon to be built WTC were addressed to assuage the public. They claimed that the building would withstand a hit by a Boeing 707 at 600 mph. Maybe they lied, or maybe they actually designed the WTC to sustain a hit by the largest jetliner then in the sky going at 600 mph. It is only repeating what was said contemporaneously and publicly. Either they did it or they lied about doing it.
And it did. At least close to a 600 mph impact by a comparably sized plane. Nope. They didn't. We have proof. The towers survived the impact. Nope. They did not. The lead structural engineer states that the structure was designed for a 180 mph impact. The ANALYSIS that was done to see it might survive a 600 mph impact was done AFTER the design of the major structural elements. I think I proved that. You tried to pull a fast one here, NC, AND YOU GOT CAUGHT.
[nolu_chan #49] [BAC #51] Nope. They didn't. We have proof. The towers survived the impact. ----- BAC, you are still a lying piece of crap. As an editor, however, you are quite creative. ... Such a frightful vision could not be left unchallenged. Robertson says that he never saw the ad and was ignorant of the political battle behind it. Still, he recalls that he addressed the question of an airplane collision, if only to satisfy his engineer's curiosity. For whatever reason, Robertson took the time to calculate how well his towers would handle the impact from a Boeing 707, the largest jetliner in service at the time. ... Exactly how Robertson performed these calculations is apparently lost -- he says he cannot find a copy of the report. Several engineers who worked with him at the time, including the director of his computer department, say they have no recollection of ever seeing the study. ... One architect working for the Port Authority issued a statement to the press, covered in a prominent article in The Times, explaining that Robertson's study proved that the towers could withstand the impact of a jetliner moving at 600 miles an hour. ... If Robertson saw the article in the paper, he never spoke up about the discrepancy. No one else issued a correction, and the question was answered in many people's minds: the towers were as safe as could be expected, even in the most cataclysmic of circumstances. There were only two problems. The first, of course, was that no study of the impact of a 600-mile-an-hour plane ever existed. "That's got nothing to do with the reality of what we did," Robertson snapped when shown the Port Authority architect's statement more than three decades later. The second problem was that no one thought to take into account the fires that would inevitably break out when the jetliner's fuel exploded, exactly as the B-25's had. [BAC] The ANALYSIS that was done to see it might survive a 600 mph impact was done AFTER the design of the major structural elements. I think I proved that. No. The press release about a purported analysis, the report of which seems to have been eaten by the dog, occurred in response to a near full-page ad in the New York Times challenging the safety of the WTC design. I think I've proved that.
If you want us to believe that, then prove to us the Skilling's White Paper actually says they DESIGNED the towers for those loads. All the sources I've seen that claim first hand knowledge of the paper's contents simply say it said they did an ANALYSIS of the towers for that case. There is a difference. And you have two choices where the White Paper is concerned given the date it was released ... February 3, 1964. Either it analyzed a structure whose major dimensions had already be determined (in which case how much effect could it have had on the design?) or it was a wag that ASSUMED dimensions that had not yet been determined (in which case, how good could that analysis really be)? One more thing. The Skilling paper was 3 pages long. How detailed an analysis could it possibly be given such a short length? And what tools did they actually use to do that analysis? The truth is that you don't know. In fact, have you actually seen the Skilling White Paper? Well here: http://pilotsfor911truth.org/WTC.html "I found photostat images of WTC designer John Skilling's 3 page 1964 White Paper on a German website and posted the links over on the UK911 board. ... snip ... Lucky I saved them" Well what do you know. That paper wasn't ONLY about a plane crash calculation. In fact, it contained eleven numbered points, and only ONE, pertained to that subject. And ALL it said is this: "3. The buildings have been investigated and found to be safe in an assumed collision with a large jet airliner (Boeing 707-DC 8) traveling at 600 miles per hour. Analysis indicates that such collision would result in only local damage which could not cause collapse or substantial damage to the building and would not endanger the lives and safety of occupants not in the immediate area of impact." That's ALL. There are NO details given to show the nature of that analysis (and considering how limited impact analysis tools were in those days, perhaps much of that analysis was actually hand waving designed to satisfy the customer and public). The word DESIGN is not used in that paragraph. It says the buildings have been INVESTIGATED and found to be safe. Which seems to imply an analysis AFTER the design was completed. And I don't challenge that possibility or the conclusion that Skillings reached. After all, the towers did survive the impact of the planes. The local damage from the impact did NOT cause collapse. It was the fires combined with that damage that NIST (and modern analysis tools) say caused the collapse. And curiously enough, that white paper doesn't even mention the threat of fire from the impact. Yet the CT community has been trying to suggest Skilling said the structure was also designed to handle the fire from that airplane crash. Well, having discounted Robertson's statements, the only piece of physical evidence you have to even prove an analysis was done for a commercial jet doesn't even mention the word fire. And also note that the paper, dated February 3, 1964, states: "The structural analysis carried out by the firm of Worthington, Skilling, Helle and Jackson is the most complete and detailed of any ever made for any building structure. The preliminary calculations alone cover 1200 pages and involve over 100 detailed drawings." It goes on to talk about the towers being "designed" for different loads. The word "designed" is used repeatedly. And you wanted us to believe that the essential dimensions of the structure hadn't already been determined by the start of 1964. I think this memo proves you wrong, NC. Robertson also said: http://scott-juris.blogspot.com/The%20Height%20of%20Ambition%20Part%20Four.pdf "He says that his calculations assumed a plane lost in a fog while searching for an airport at relatively low speed, like the B-25 bomber. He concluded that the towers would remain standing despite the force of the impact and the hole it would punch out. " Sure, NC. Based on a white paper that has ONE paragraph claiming that but where, again, there appear to be no other documents proving such a calculation actually took place. A paper that clearly appears to be a public relations ploy to alleviate concerns about the towers. And a white paper that doesn't say the towers were DESIGNED for that load. Oh ... and one more thing. SO WHAT? The truth is that if the towers were designed for a plane impact (like the CT community insists without actually being able to prove it), then the towers performed as expected. But nowhere in either Robertson's or Skilling's account is there evidence that the towers were designed to handle the fire that would result from such a collision. Indeed, designers in those days simply did not have the analysis tools to address such a problem with any confidence. That is the part of the story that the CT community simply leaves out in their haste to make the government and bombs the culprit in the collapse. Actually, it is only a part of the story they leave out. Fine. If you want to claim no Robertson study was done, that's ok with me. But remember, the CT community is the one that insists the towers were *designed* to withstand multiple jet impacts (which none of the actual participants in the design claimed). And if you discount the Robertson claim, all you are left as evidence is that one paragraph in Skilling's 3 page White Paper. Which is dated February 3, 1964. Which doesn't appear to have actually used the word "design". Which has no details about that analysis either. And here is yet another source for you to ignore and discount: http://www.skyscrapersafety.org/html/article_11092001.html "Skilling's firm got the commission, and Robertson, then thirty-five, moved to New York to open a new office, and to supervise the structural aspects of the building's construction. In 1983, the Seattle office and the New York office split, becoming two separate firms. Skilling (who died in 1998) and Robertson later argued about who was more responsible for the structure of the towers. "These are guys with big egos, and things got a little testy between them regarding who was ultimately responsible for the design," says Jon Magnusson, the chairman and C.E.O. of the Seattle-based firm, which is now called Skilling Ward Magnusson Barkshire. "Skilling said, 'It was me,' Robertson said, 'It was me,' but I think the truth is that both of them made a significant contribution." ... snip ... "He also designed the buildings so they would be able to absorb the impact of a jet airliner: "I'm sort of a methodical person, so I listed all the bad things that could happen to a building and tried to design for them. I thought of the B-25 bomber, lost in the fog, that hit the Empire State Building in 1945. The 707 was the state-of-the-art airplane then, and the Port Authority was quite amenable to considering the effect of an airplane as a design criterion. We studied it, and designed for the impact of such an aircraft. The next step would have been to think about the fuel load, and I've been searching my brain, but I don't know what happened there, whether in all our testing we thought about it. Now we know what happens-it explodes. I don't know if we considered the fire damage that would cause. Anyway, the architect, not the engineer, is the one who specifies the fire system."
[BAC post of SKILLING White Paper] "The buildings have been investigated and found to be safe in an assumed collision with a large jet airliner (Boeing 707 - DC 8) travelling at 600 miles per hour. Analysis indicates that such collision would result in only local damage which could not cause collapse or substantial damage to the building and would not endanger the lives and safety of occupants not in the immediate area of impact." [nc quoting] "* A prominent story appears in the New York Times explains that study proved that the towers could withstand the impact of a jetliner moving at 600 miles an hour." [BAC] Sure, NC. Based on a white paper that has ONE paragraph claiming that but where, again, there appear to be no other documents proving such a calculation actually took place. ------- SKILLING's White Paper says "the buildings have been investigated." It does not say SKILLING performed the investigation. SKILLING's White Paper says "Analysis indicates...." It does not say SKILLING performed the analysis. The New York Times report, sourced to an architect working on the WTC, attributes the study to . ROBERTSON now claims he cannot find the ROBERTSON study analysis report. If you want the report, ask ROBERTSON what ROBERTSON did with the ROBERTSON study analysis report. By the way, the White Paper also contains the following:
There is a difference between analysis and design. One can do an analysis of something after the design of that something is essentially done. When one designs, one sizes members, etc to carry DESIGN loads. But in this case, it sounds more like they did an analysis after the fact to determine if the already designed structure would survive a load that was not part of the design. And it is true that it doesn't say that Skilling performed the analysis (although the CT community has been trying to claim that's what the White Paper was ... HIS work as an expert). Perhaps Skilling was just referring to the analysis that Robertson did ... and misreported the speed of the aircraft wrong. Afterall, it wouldn't the first time that a CEO has misrepresented the work done by underlings. Fine, this would fit the above scenario. So it turns out there wasn't ever a Skilling analysis? ROTFLOL! And Robertson is VERY CLEAR about his work having related to a plane lost in fog flying at 180 mph ... not 600 mph on a clear day. It's been 40 years. Do you keep everything you've ever written, Nolu? Really?
[BAC] And Robertson is VERY CLEAR about his work having related to a plane lost in fog flying at 180 mph ... not 600 mph on a clear day. When the material was first released to the press it was very clear that Robertson's analysis involved a Boeing 707 traveling at 600 mph. The newspaper article based on Robertson's purported work and Skilling's white paper based on Robertson's purported work have the same, precise content. The goal was to counter the argument made by the owner of the Empire State Building that the WTC design was unsafe with regard to being hit by a jetliner. Assuring the public that the building could withstand a hit by The Spirit of St. Louis at 180 mph would have been worse than useless. [BAC] It's been 40 years. Do you keep everything you've ever written, Nolu? Really? Had I done an analysis 40 years ago proving that the WTC, the most important project of my lifetime, could withstand a hit by a Boeing 707 traveling at 600 mph, and "that such collision would result in only local damage which could not cause collapse or substantial damage to the building and would not endanger the lives and safety of occupants not in the immediate area of impact," if I could not find the paperwork today, I would be able to replicate the analysis and prove the point again. The towers withstood the impact just as Titanic withstood the impact with the iceberg. Aye cap'n, it wasn't the iceberg got 'er, it was the water! It's been 40 years. Do you believe that Robertson not only lost the report but has forgotten how to do the analysis?
That is false, NC. The only evidence to support the contention that a 600 mph case was examined is a single paragraph in a White Paper that does not mention Robertson's name. But Robertson states with complete certainty on his part that his analysis was for 180 mph in fog ... and he gives a quite logical reason why that number was chosen. An impact in fog is possible, a impact on a clear day is highly unlikely. A plane will not be flying at full speed in fog. For that matter, commercial jets don't normally fly at 600mph in clear weather AT LOW ALTITUDE. Any way you look at it, the REASONABLE thing to do was look at a low speed impact. For that reason, I believe Robertson ... and not Skilling or an unidentified architect at the Port Authority (who both were playing politics and might have exaggerated what was done because they were trying to quiet public concern). Yeah ... sure you would, NC. And you didn't answer my question. ROTFLOL!
You are once again "forgetting" the article in the New York Times. The Skilling White Paper and the New York Times article sourced to a WTC architect provide the same precise information, that Robertson assured that the towers could withstand the impact of a jetliner moving at 600 miles an hour. Robertson name was used, and he was identified as the source of the analysis.
#105. To: nolu_chan, ALL (#104)
I didn't forget that article. I specifically said I don't believe the claim of the unnamed Port Authority architect that is mentioned by the NYT. You don't happen to have the name of the Port Authority architect, do you? No? Well perhaps you can tell everyone how often a commercial jet flies at 600 mph a thousand or so feet above the earth's surface? Afterall, you are the one saying that Robertson would rationally have used that instead of a low speed plane as the case of concern. So do commercial jets fly at 600 mph at a 1000 feet altitude ANYTIME they are flying (and remember, this was PRIOR to concerns about terrorists using hijacked planes as WMD) over cities ANYWHERE? Hmmmmmmm????
Top • Page Up • Full Thread • Page Down • Bottom/Latest After the 1993 car bomb explosion destroyed columns in the North Tower, John Skilling, the head structural engineer for the Twin Towers, was asked about an airplane strike. He explained that the Twin Towers were originally designed to withstand the impact of a Boeing 707 (similar in size to the Boeing 767).
He went on to say that there would be a horrendous fire from the jet fuel, but “the building structure would still be there.”
The 10,000 gallons of jet fuel (half capacity) in each jetliner did cause horrendous fires over several floors, but it would not cause the steel members to melt or even lose sufficient strength to cause a collapse.
This is because the short-duration jet fuel fires and office combustible fires cannot create (or transmit to the steel) temperatures hot enough.
If a structural steel building could collapse because of fire, it would do so slowly as the various steel members gradually relinquished their structural strength.
However, in the 100-year history of structural-steel framed buildings, there is no evidence of any structural steel framed building having collapsed because of fire.
Let’s assume the unlikelihood that these fires could weaken all of the columns to the same degree of heat intensity and thus remove their structural strength equally over the entire floor,
The interesting fact is that each of these 110-story Twin Towers fell upon itself in about ten seconds at nearly free-fall speed.
Contrary to the sudden collapse of the Twin Towers and Building #7
The buildings had no pools of molten metal (a byproduct of explosives) at the base of their elevator shafts.
only explosives will pulverize concrete into a fine dust cloud
William Rice, P.E., is a registered professional civil engineer who worked on structural steel (and concrete) buildings in Boston, New York, and Philadelphia. He was also a professor at Vermont Technical College where he taught engineering materials, structures lab, and other building related courses.
#15. To: BeAChooser, Minerva, Paul Revere, tom007, SKYDRIFTER, Critter (#1)
To fulfill all the functional, aesthetic, and economic desires for this concent, innovative archetecture was needed, In 1962, the firm of Minoru Yamasaki & Associates was hired to perform the architectural desighn which was first unveiled in 1964. The team also involved Emory Roth & Sons, P.C., as the architect of record. The structural engineering was by Worthington, Skilling, Helle and Christiansen. (Some time after completion of the construction, Skilling, Helle, Christiansen, and Robertson, and then Leslie E. Robertson Associates (LERA) assumed that role.)
Skilling and his team rose to the challenge of providing the required load capacity within Yamasaki's design concept. They incorporated an innovative framed-tube concept for the structural system.
A three-page white paper, dated February 3, 1964, described its findings: “The buildings have been investigated and found to be safe in an assumed collision with a large jet airliner (Boeing 707—DC 8) traveling at 600 miles per hour. Analysis indicates that such collision would result in only local damage which could not cause collapse or substantial damage to the building and would not endanger the lives and safety of occupants not in the immediate area of impact.”
In the wake of the WTC bombing, the Seattle Times interviews John Skilling who was one of the two structural engineers responsible for designing the Trade Center. Skilling recounts his people having carried out an analysis which found the Twin Towers could withstand the impact of a Boeing 707. He says, “Our analysis indicated the biggest problem would be the fact that all the fuel (from the airplane) would dump into the building. There would be a horrendous fire. A lot of people would be killed.” But, he says, “The building structure would still be there.” [Seattle Times, 2/27/1993]
#18. To: nolu_chan, ALL (#15)
[BAC] First of all John Skilling was NOT the head structural engineer for the WTC towers. Leslie Robertson is the head structural engineer of record. He was the one who moved to New York to do the design. Mr Skilling remained in Seattle.
As usual, BAC's source is missing. My source is not.
NIST Report, Chapter 1, page 1, paragraph 1.1, reads in relevant part:
NIST Report, Chapter 1, page 6, reads in relevant part:
[BAC] did Mr Rice fail to note the difference in the speed of the planes assumed in the design and the ones that hit the towers? That difference corresponds to a factor of 7 (or more) difference in the impact energy of the planes.
BAC, exactly how much in excess of 600 mph did you determine that the planes were moving when they struck the towers?
A three-page white paper, dated February 3, 1964, described its findings: “The buildings have been investigated and found to be safe in an assumed collision with a large jet airliner (Boeing 707—DC 8) traveling at 600 miles per hour.
[BAC] He went on to say that there would be a horrendous fire from the jet fuel, but “the building structure would still be there.”
There was NO consideration of fire after the plane impact in the design. Leslie Robertson stated that fire resulting from a plane impact was NOT considered in the design. If Mr Rice thinks otherwise, he is wrong.
He says, “Our analysis indicated the biggest problem would be the fact that all the fuel (from the airplane) would dump into the building. There would be a horrendous fire. A lot of people would be killed.” But, he says, “The building structure would still be there.” [Seattle Times, 2/27/1993]
[BAC] The 10,000 gallons of jet fuel (half capacity) in each jetliner did cause horrendous fires over several floors, but it would not cause the steel members to melt or even lose sufficient strength to cause a collapse.
Melting of steel is not the theory of NIST.
Melting steel happened.
#28. To: BeAChooser (#18)
This was a back of the envelope calculation done AFTER the design was complete.
Buildings are not designed to withstand the impacts of fuel laden commercial airliners. However, in the case of the World Trade Center, it was a consideration. The structural safety of the towers in an aircraft collision was considered in the original design.
#34. To: nolu_chan, ALL (#28)
"This was a back of the envelope calculation done AFTER the design was complete."
It is a White Paper from 1964. Groundbreaking occurred two years later in 1966.
#36. To: BeAChooser (#34)
Yamasaki's design for the World Trade Center was unveiled to the public on January 18, 1964, with an eight-foot model.[27]
http://911research.wtc7.net/mirrors/guardian2/wtc/eng-news-record.htm
#38. To: nolu_chan, ALL (#36)
"Yamasaki's design for the World Trade Center was unveiled to the public on January 18, 1964, with an eight-foot model.[27]"
[BAC] - So there is NO POSSIBLE WAY that any White Paper from 1964 affected the DESIGN.
Yamasaki was the architect. He did not do the engineering.
The design of the building did not end with the display of an 8-foot model.
The concept was explained to the New York Architectural League by John Skilling, a partner in Worthington, Skilling, Helle and Jackson, of Seattle, consulting structural engineers on the World Trade Center (see p. 124).
April 2, 1964
#39. To: BeAChooser (#38)
http://tinyurl.com/2vm8fu
The New York Times, Sunday Edition
September 8, 2002
The Height of Ambition: Part Four
By JAMES GLANZ and ERIC LIPTON
#45. To: nolu_chan, ALL (#39)
In your idiocy, you asserted that prior to the White Paper in 1964, the design had been COMPLETED.
Referring to the White Paper of February 3, 1964, you blathered at #18, "This was a back of the envelope calculation done AFTER the design was complete."
AFTER 1964, Robertson's original engineering design plan had to be scrapped because tests in 1965 showed the buildings would sway beyond the limits of human tolerance. As Glanz and Lipton wrote in the New York Times, "Even today, Robertson has no trouble conjuring what two towers full of seasick office workers would have meant: 'A billion dollars right down the tube.' So he went back to work."
What he did not take into account was the extraordinary conditions of an intense, violent fire. Girders and beams would be far superior under those circumstances. Thin steel elements heat up and soften faster than thick ones.
They chose not to use thick masonry or cement to encase the three escape stairways in each tower but rather light sheets of gypsum. Although the gypsum was extremely resistant to fire, and less likely than masonry to crack when the building swayed in the wind, it would work only if it remained intact -- and it was much more susceptible to being shaken loose or damaged by an explosion or any other kind of unexpected impact.
Wind-tunnel experiments in Fort Collins, Colo., confirmed that Robertson's initial design would sway far beyond those human tolerances,
Still, he recalls that he addressed the question of an airplane collision, if only to satisfy his engineer's curiosity. For whatever reason, Robertson took the time to calculate how well his towers would handle the impact from a Boeing 707, the largest jetliner in service at the time. He says that his calculations assumed a plane lost in a fog while searching for an airport at relatively low speed, like the B-25 bomber. He concluded that the towers would remain standing despite the force of the impact and the hole it would punch out.
The new technologies he had installed after the motion experiments and wind-tunnel work had created a structure more than strong enough to withstand such a blow.
Robertson's assertion of being unaware of the Wein ad and the political battle is not credible. Perhaps Robertson performed only an imaginary study consisting of nothing more than some propaganda released to the press, or he blew smoke at the architect.
#49. To: BeAChooser (#45)
If you want to claim that no study of the tower's resistance to aircraft impact was performed, that's ok with me. Because I thought it is the CT community that insists the towers were DESIGNED to survive multiple high speed plane crashes.
#51. To: nolu_chan, ALL (#49)
They claimed that the building would withstand a hit by a Boeing 707 at 600 mph.
Maybe they lied,
or maybe they actually designed the WTC to sustain a hit by the largest jetliner then in the sky going at 600 mph.
#82. To: BeAChooser (#51)
Maybe they lied, or maybe they actually designed the WTC to sustain a hit by the largest jetliner then in the sky going at 600 mph.
----- Maybe they lied,
Maybe they lied, or maybe they actually designed the WTC to sustain a hit by the largest jetliner then in the sky going at 600 mph.
Read again my statement, and what you quoted of it, and then your preposterous response. They [Lawrence Wein, then owner of the Empire State Building, and committee] ran a nearly full-page ad in The Times with an artist's rendition of a commercial airliner about to ram one of the towers. "Unfortunately, we rarely recognize how serious these problems are until it's too late to do anything," the caption said.
Robertson's story is less convincing than an Alberto Gonzales performance.
But when the towers were built, the people were publicly assured, in the New York Times, that Robertson's study proved that the towers could withstand the impact of a jetliner moving at 600 mph... much as they would later be assured that the air atop Robertson's Rubble, at ground zero, did not pose a health hazard.
#84. To: nolu_chan, ALL (#82)
maybe they actually designed the WTC to sustain a hit by the largest jetliner then in the sky going at 600 mph.
Robertson says he never saw the ad but just out of his engineer's curiosity calculated that the towers would handle the impace from a Boeing 707, the largest jetliner then in service.
* A prominent story appears in the New York Times explains that Robertson's study proved that the towers could withstand the impact of a jetliner moving at 600 miles an hour.
* When the towers are hit by a plane and fall to the ground, Robertson says he cannot find a copy of his precious report.
* The director of Robertson's computer department has no recollection of any such study.
* The dog ate his homework.
#86. To: BeAChooser (#84)
"7. The design has been reviewed by some of the most knowledgeable people in the construction industry. In a letter to John Skilling, the Structural Engineer for the World Trade Center, the Chief Engineer of the American Division of U.S. Steel Corporation said: ...."
#87. To: nolu_chan, ALL (#86)
"SKILLING's White Paper says "the buildings have been investigated." It does not say SKILLING performed the investigation."
SKILLING's White Paper says "Analysis indicates...." It does not say SKILLING performed the analysis.
The New York Times report, sourced to an architect working on the WTC, attributes the study to ROBERTSON.
ROBERTSON now claims he cannot find the ROBERTSON study analysis report.
#101. To: BeAChooser (#87)
#103. To: nolu_chan, ALL (#101)
[BAC] And Robertson is VERY CLEAR about his work having related to a plane lost in fog flying at 180 mph ... not 600 mph on a clear day.
When the material was first released to the press it was very clear that Robertson's analysis involved a Boeing 707 traveling at 600 mph.
" [BAC] It's been 40 years. Do you keep everything you've ever written, Nolu? Really?"
Had I done an analysis 40 years ago proving that the WTC, the most important project of my lifetime, could withstand a hit by a Boeing 707 traveling at 600 mph, and "that such collision would result in only local damage which could not cause collapse or substantial damage to the building and would not endanger the lives and safety of occupants not in the immediate area of impact," if I could not find the paperwork today, I would be able to replicate the analysis and prove the point again.
#104. To: BeAChooser (#103)
That is false, NC. The only evidence to support the contention that a 600 mph case was examined is a single paragraph in a White Paper that does not mention Robertson's name.
One architect working for the Port Authority issued a statement to the press, covered in a prominent article in The Times, explaining that Robertson's study proved that the towers could withstand the impact of a jetliner moving at 600 miles an hour. ... If Robertson saw the article in the paper, he never spoke up about the discrepancy. No one else issued a correction, and the question was answered in many people's minds: the towers were as safe as could be expected, even in the most cataclysmic of circumstances.
Replies to Comment # 104. You are once again "forgetting" the article in the New York Times.
End Trace Mode for Comment # 104.