Re: Responce To Occrider
Ok! Sorry it took so long to respond, but I had a lot of technical reading to do. Anyway the questions you posed are of perfect specificity. I don't want to get into tangentals such as government planes scrambling, Israeli spies in the area, etc., when we're focusing on the structural integrity of the building. So let's get to it ...
quote: | Originally posted by stevieboy32808
Sorry to sound like a broken record, but there have been other high rise buildings such as the First Interstate Bank Building in downtown LA, One Meridian Plaza in Philadelphia, and the Windsor Building in Madrid, Spain which burned way longer than WTC did. In addition, the original architects and engineers of the towers were shocked at the collapse of the towers because they specifically designed the towers to withstand multiple plane crashes and not just one. No building has ever collapsed due to a fire.
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The examples you raised might pose as valid supporting arguments for a theory that the World Trade Centers were not brought down by fire except that the argument seems to make two assumptions. The first is that neither of those buildings are the world trade centers. If building A survives a fire and building B survives a fire of similar conditions are we to presume that building C would survive the exact same fire? A better example would be building A and building C are built in the exact same architectural manner with the same type of materials, therefore it would be likely that building C would also survive a fire. The second assumption that that argument makes is that all 3 fires are similar in nature. That in my mind is the biggest flaw in the argument. I would argue that the conditions created in the World Trade Center were nothing like any of the fires you mentioned and these distinct conditions contributed and amplified the effect that the World Trade Center fire had on the structural integrity of the World Trade Center. I shall get into the specifics of these conditions later in my argument.
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Here is a letter from Underwriters Laboratories (the company that certified the steel componets used in the constuction of the World Trade Center towers) directly from the horse’s mouth who knows the properties of the steel used to built the towers. I don’t think I can get any more specific than this letter:
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Well I did my research on this letter and as it turns out, Kevin Ryan was not speaking for Underwriters Laboratories, he in fact stated that he was speaking for himself, and he was not in charge of their structural analysis or material science division. The exact position Ryan held at UL at the time of interest is "Site Manager at UL's water testing business, Environmental Health Laboratories."
UL subsequently fired him and stated that: "UL does not certify structural steel, such as the beams, columns and trusses used in World Trade Center," said Paul M. Baker, the company's spokesman. The company went on to say that Ryan "was not involved in that work and was not associated in any way with UL's Fire Protection Division, which conducted testing at NIST's request." Therefore, we have a subject matter expert supposedely speaking for the company when in fact he is not speaking for the company, and he is not a subject matter expert at all. Enough background research on the guy, let's analyze his claims.
Ryan's key contention is that the NIST reports that "most perimeter panels (157 of 160) saw no temperature above 250C." Therefore the fire was not hot enough to melt the steel. Ryan seems to pull this data from NISTs paint analysis test of the the steel recovered from the WTC:
http://wtc.nist.gov/pubs/NISTNCSTAR1-3Draft.pdf
Now the power point presentation doesn't say all that much. It doesn't really go into specifics except to say what was analzyed. The broader report can be found here:
http://wtc.nist.gov/pubs/NISTNCSTAR1-3Draft.pdf
It's 184 pages but it's a good read that seems to provide comprehensive analysis with context. The findings that only 3 of 160 exterior panels which experienced temperatures above 250C represented only 3% of the panels involved in the fire and therefore could not be considered representative of all the columns on the floor. Furthermore, the core columns studied represented less than 1% of the core columns involved in the fire and thus they too cannot be considered representative of all the core columns involved in the fire. And remember, these were paint tests ONLY. Much of the steel could not be tested because all their paint had been stripped off of them (which is what one would imagine a fire to do but that's speculation on my part). All of this is on page 94 of the NIST report if you'd like to follow along. Thus Ryan's argument took data out of context.
The NIST simulations indicated a much higher temperature range and it can be found here:
http://wtc.nist.gov/pubs/NCSTAR1-5ExecutiveSummary.pdf
You'll find the description of a model, based on thermodynamics (and with office material as the main source of burning material), with temperature map examples on the 10th and 12th pages. If you notice there's large sub-250C areas. If only 3% of panel columns and less than 1% of core columns recovered it's completely viable that these were recovered from a sub-250C area. Thus it would be erroneous to extrapolate based upon that the danger of misrepresenting the complete picture.
In addition, Ryan treats all steel from the WTC as if it were the same without addressing the real questions that should be asked. We don't care whether the temperatures were hot enough to melt steel. What we want to know is at what temperatures do specific load bearing structures fail due to a combination of temperature and stressed gravity loads. The NIST test analysis concludes that:
The trust top chord begins to yield in compresssion around 300C due to the difference in coefficient of thermal expansion between steel and lightweight concrete. At approximately 340C, web diagonals begin to buckle and the horizontal displacement of the exterior column reverses and begins to decrease. At 400C knuckles start to fail sequentially from both interor and exterior supports towards the center. With the loss of compositite action the floor begins to sag an increasing rate. Eventually at about 500C, with the truss sagging almost 20 in., the bolts at the interior connector are found to shear. At 560C, the exterior columns begin to displace inward, and the truss begins to act as a catenary. At 650C, the truss walks off the interior seat while the interior end of slab remains ... At roughly 660C the gusset plate fracture at the exterior end which precipitates vertical failure of the exteriror seated connection.
YOu can find all that in this in-depth analysis here:
http://wtc.nist.gov/progress_report_june04/chapter2.pdf
And that's all at normal load as if the structural integrity of the WTC were not damaged at all. Their tests show that knuckles begin failing at 2.4 times dead load and most knuckles fail at 3 times dead load, and that's without any effect from temperature. In the WTC we see a double effect of temperature as well as increased dead load to compensate for structural damage done to the WTC ... but I'll get to that in the next paragraph.
However, THIS is the type of in-depth engineering analysis I want from a critic of the NIST explanation. Saying something as simple as "oh umm the temperature wasn't hot enough to melt steel so the WTCs couldn't have been brought down" means absolutely nothing to me because it's MUCH MUCH more complicated than that. That's like me trying to delve into nuclear physics with a high school education. Would you work in a building designed by a high school graduate? I want a counter analysis of floor truss response due to gravity load and uniform heating that delves into each steel component. Because THAT'S the level of detail we need and should expect. Wouldn't you agree?
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***Oh and regarding this quote you made:
So the other burning office buildings I’ve mentioned did not have combustibles such as rugs, curtains, furniture and paper? Sorry, but the other buildings would have come down if this was the case. Besides “some independent investigators dispute this claim, saying kerosene-based jet fuel, paper, or the other combustibles normally found in the towers, cannot generate the heat required to melt steel, especially in an oxygen-poor environment like a deep basement.
Eric Hufschmid, author of a book about the WTC collapse, Painful Questions, told AFP that due to the lack of oxygen, paper and other combustibles packed down at the bottom of elevator shafts would probably be “a smoky smoldering pile.”
Experts disagree that jet-fuel or paper could generate such heat.
This is impossible, they say, because the maximum temperature that can be reached by hydrocarbons like jet-fuel burning in air is 1,520 degrees F. Because the WTC fires were fuel rich, as evidenced by the thick black smoke, it is argued that they did not reach this upper limit.The hottest spots at the surface of the rubble, where abundant oxygen was available, were much cooler than the molten steel found in the basements."
Kind of weird that the most of the heat after the collapse was in the lower basement columns rather than the oxygen rich surface rubble above, which further cements my suggestion that explosives had to be planted in the WTC.
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Ah back to your office examples. Yes those offices had similar combustibles to the world trade center and yet they did not collapse. But remember my analogy where I pointed out that required an assumption that fire A equalled fire B equalled fire C? I would be willing to bet that the fireproofing in all the offices that you referenced remained intact. When the planes impacted the towers, they didn't just stop at the side of the building. They did a significant amount of damage inside the building to the structural integrity and critical things such as removed fireproofing. Here are several simulations of the progression of the planes through the buildings:
http://realex.nist.gov:8080/ramgen/...ne_segment_1.rm
http://realex.nist.gov:8080/ramgen/...ne_segment_2.rm
However, the best part is that we can simply rely on photographic evidence to see the nature of some of the damage done. From external photographs you can clearly see structural damage done as well as fireproofing damage (sorry about their size and the sideways view):
Now we can't peer inside to specifically see the type of damage on the interior but I would argue that it is somewhat similar to the outside in causing significant damage to the structure while knocking off fireproofing. As a matter of fact we can infer this damage based upon the outside structure tilting and bowing due to the stress on the structural integrity of the building:
Now remember back to what I said of the test anlayses done on the trusses with respect to temperature and gravity load? It certainly looks like there a significant amount of stress in excess of normal load that when in combination with the temperature contributed to a perfect storm scenario of sorts that resulted in the overall collapse. Photographs show that the walls of the north tower to have deformed by as much as 140 centimetres just a few minutes before collapse and the walls of the south tower to have arched by 50 cm. Therefore I would contend that extreme gravity loads on these trusses along with predicted fire damage to unfireproofed steel is a much more reasonable explanation. I think I'm only touching the surface really because the entire NIST report is some 1000 pages long and this is data I've found by skimming maybe a third of the report.
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Yes and you’re right. I was wrong. The spikes in the seismic data remain unexplained. If you look at the graph below there are two pairs of waveforms:
The 2 small waveforms are the impacts of the 2 planes hitting the towers and then there are the 2 unusual spikes that occurred after the impacts. The spikes are the main debate. Do you remember the WTC 1993 bombing? A truck bomb blew up on the 2nd level basement of one of the towers, but the seismic data from that blast did not register on the Richter scale because the bomb was not coupled to the ground. These 2 spikes suggest that there was “something” coupled to the ground which caused the seismograph to record these sudden waves. I used this argument to back up my suggestion that explosives were that “something” which caused the towers’ collapse. Although since this is still being investigated I cannot comment further on the report until more solid evidence comes along.
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Ah yes I've seen this graph before. Let's be clear. You're talking about this area that I circled?
I would actually say that is one spike that stands out from the rest. The second one within the circle is kind of iffy and doesn't stand out that much from other "outliers" further down. But let's just say it's an outlier as well. Notice the time. They both happened at around 9:05am. So the controlled demolitions went off at 9:05am and the towers later went down at 10am and 10:30am. Can you describe any controlled demolition explosives that have this time delay capability? Why didn't the towers go down immediately after these controlled demolitions? I don't understand the engineering behind such "controlled demolitions." Furthermore notice the size of these spikes. The planes explosions most certaintly weren't "coupled" to the ground. They impacted the side of the building and the seismic shock wave had to transverse the entire length of the building before they hit the ground. Yet their spikes are significantly higher than the anomalies. Yet these anomalies that were explosives coupled to the ground barely registered? There's something that doesn't seem quite right about that. Sure I'm speculating but then again so are you.
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I’ll probably give you this one if you can tell me what type of plane was it that your friends saw. Was it a Boeing passenger plane or a private jet which can only carry 15 people or so? I would be more willing to believe this if a private jet which caused the Pentagon hole. It’s just that the neatly punched hole and the lack of damage to the pentagon lawn did not convince me that it was a passenger plane. A classic physics example is a baseball hitting a window. It does a whole lot more damage than a bullet. The bullet only causes a bullet hole in the window. This is because the faster the particle, the more localized the damage. A plane would have done a lot more damage.
Regarding the latter statement you made, I've tried my best to present you with the facts "one argument at a time" and nothing baseless. I also can honestly tell you that I'm not a government shill and that my conclusions are in accordance with the research I gathered. |
I'm beat and it's drinking time ... I'll try to answer this one tomorrow. Cheers.
edit: Christ I'll try to resize the pictures so they're not as annoying but that's not happening until tomorrow.
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Retro ...
Last edited by occrider on Dec-10-2005 at 02:49
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