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Bushwacker
Relentless Limpet Shill
Joined: 07 Sep 2006
Posts: 1628
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 Posted: Wed Jan 03, 2007 11:39 pm Post subject: |
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| marky 54 wrote: | | Bushwacker wrote: | | marky 54 wrote: | | Bushwacker wrote: | | marky 54 wrote: | | Bushwacker wrote: | | marky 54 wrote: | | Bushwacker wrote: | | marky 54 wrote: | | by saying the concrete was light weight makes it harder to understand why the steel beams could'nt hold the weight. |
They did hold the weight perfectly well under normal conditions, it was only when the fire weakened them that they failed. |
yet the fire that weakened wtc7 had a low proberbility of accurance  |
WTF has that got to do with the strength of the floor trusses in the towers? |
it has'nt but a bit weird how they think fire weakening the steel to cause the collapse had a low proberbility of accurance in wtc7, whilst saying the fire in wtc1 and 2 weakened the steel. and the fire in wtc7 was burning all day and was raging if i use the words of critics. |
Please show where NIST said that, because I cannot find it. |
ah so the steel in wtc 1 and 2 wasnt weakened? or in wtc7? |
Eh? |
listen this is very simple. the steel columns in wtc 1 and 2 where weakened by fire , the fires burnt for 1 hour and 1hour 40min in each tower. and this helped to bring down the towers.
now lets look at the other steel building wtc7, their only explantion for wtc7 they said had a low proberbility of accurance, and that building was on fire all day with raging fires.
so if raging fires that burnt all day had a low proberbility of accurance for collapse in wtc7, why would that not be the case for wtc 1 and 2 to weaken the columns?
it obviously took all day to weaken the columns in wtc7 but only a fraction of time in comparison for wtc1 and 2. its a contridiction or the fire in wtc7 wasnt a raging fire either way there are lies floating around. |
Sorry, that just does not make sense. The towers and WTC7 were completely different types of building constructed in very different ways. The towers were hugely damaged by having the planes crashed into them, and the floors affected were then subject to severe fires, after vital fireproofing had been stripped from the structural steel by the crashes. WTC7 was certainly damaged, but not so severely and the fires were at first of lower intensity, before spreading widely and the fireproofing was, presumably, intact. There is no reason at all why the buildings should fall in the same time. You have still not said where the phrase "low probability of occurance" you keep quoting came from.
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".......some partial collapse [of WTC7] would not have been suspicious......." - chek |
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Bushwacker
Relentless Limpet Shill
Joined: 07 Sep 2006
Posts: 1628
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| Posted: Wed Jan 03, 2007 11:55 pm Post subject: |
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| physicist wrote: | | Bushwacker wrote: | | As I said earlier, I too know of no direct proof that the steel reached temperatures high enough to cause structural weakness. |
You see. I said we agreed about that.
| Bushwacker wrote: | | However, since the temperatures reached by similar fires are known, and the steel was in the fires, it is surely a reasonable inference that the steel reached the temperature of the fire. Photographs exist showing that floors in the buildings had failed in the fires, and since no other causative factor is known to be present, it is again a reasonable inference that they had failed owing to the fires to which they were subjected, in my view. |
I think your argument is becoming weak there. There have never been fires similar to those in the WTC. You will hear counter arguments about oxygen starvation and thermal conductivity keeping the temperature well below the level to cause weakness. However, we don't know what temperatures were reached. Was it 250 Celsius or 1000 Celsius? It would be mere speculation to say.
Let's face it. At present, we don't know what caused the collapses. Further investigation is warranted IMO.
You like to refer to the NIST reports but they have never tried to explain the fall speed which was, err, rather fast. |
The argument that the fires were starved of oxygen, when enormous holes had been torn in the sides of the buildings, is, shall we say, not very convincing. The jet fuel having been burnt off very quickly after impact, the fires became ordinary office fires, whose behaviour is well understood.
The investigation by NIST appears as thorough as is possible, and little scope appears left for further examination. A mechanism for collapse has been suggested that satisfies all the available evidence, no other suggested mechanisms do so. Certainly it would be good to have further evidence to substantiate or refute what has to remain only a theory, but from whence could it possibly be obtained?
I really have to doubt whether you have read anything of the NIST reports, which casts doubt on you view that they are inadequate. They have, for instance, commented on the speed on the collapse:
As documented in Section 6.14.4 of NIST NCSTAR 1, these collapse times show that:
“… the structure below the level of collapse initiation offered minimal resistance to the falling building mass at and above the impact zone. The potential energy released by the downward movement of the large building mass far exceeded the capacity of the intact structure below to absorb that energy through energy of deformation.
Since the stories below the level of collapse initiation provided little resistance to the tremendous energy released by the falling building mass, the building section above came down essentially in free fall, as seen in videos. As the stories below sequentially failed, the falling mass increased, further increasing the demand on the floors below, which were unable to arrest the moving mass.”
In other words, the momentum (which equals mass times velocity) of the 12 to 28 stories (WTC 1 and WTC 2, respectively) falling on the supporting structure below (which was designed to support only the static weight of the floors above and not any dynamic effects due to the downward momentum) so greatly exceeded the strength capacity of the structure below that it (the structure below) was unable to stop or even to slow the falling mass. The downward momentum felt by each successive lower floor was even larger due to the increasing mass.
From video evidence, significant portions of the cores of both buildings (roughly 60 stories of WTC 1 and 40 stories of WTC 2) are known to have stood 15 to 25 seconds after collapse initiation before they, too, began to collapse. Neither the duration of the seismic records nor video evidence (due to obstruction of view caused by debris clouds) are reliable indicators of the total time it took for each building to collapse completely
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".......some partial collapse [of WTC7] would not have been suspicious......." - chek |
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physicist
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Joined: 09 Jun 2006
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Location: zz
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| Posted: Thu Jan 04, 2007 12:06 am Post subject: |
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There's no need to keeping wasting bandwidth by quoting NIST reports. We all know where they are, have downloaded the pdfs and have got the T-shirt.
Your assertion that the fires were not oxygen-starved is highly doubtful. The black smoke is due to carbon particles, the product of incomplete combustion.
There's still no proof either way of what temperatures the steel reached.
I can't understand why you spend so much time on here since you clearly believe that it is all done and dusted (so to speak). |
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Bushwacker
Relentless Limpet Shill
Joined: 07 Sep 2006
Posts: 1628
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| Posted: Thu Jan 04, 2007 1:02 am Post subject: |
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| physicist wrote: | There's no need to keeping wasting bandwidth by quoting NIST reports. We all know where they are, have downloaded the pdfs and have got the T-shirt.
Your assertion that the fires were not oxygen-starved is highly doubtful. The black smoke is due to carbon particles, the product of incomplete combustion.
There's still no proof either way of what temperatures the steel reached.
I can't understand why you spend so much time on here since you clearly believe that it is all done and dusted (so to speak). |
It is no use simply downloading the files if you do not read them, and that seems to be why you need me to point out that, for instance, when you say that NIST have never tried to explain the fall speed, you are incorrect. You are quite free of course to disagree with them, but to make the comment you did is misleading, and we wouldn't want that, now would we?
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".......some partial collapse [of WTC7] would not have been suspicious......." - chek |
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Ignatz
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Joined: 14 Sep 2006
Posts: 918
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| Posted: Thu Jan 04, 2007 10:43 am Post subject: |
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| physicist wrote: |
There's no need to keeping wasting bandwidth by quoting NIST reports. We all know where they are, have downloaded the pdfs and have got the T-shirt.
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Some of us have. Some clearly haven't
| physicist wrote: |
Your assertion that the fires were not oxygen-starved is highly doubtful. The black smoke is due to carbon particles, the product of incomplete combustion.
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Which merely means that some part of the fire was inefficient. For example the areas on the fringes of the main fire, or on floors above that hadn't ignited. You know this perfectly well, yet choose to misrepresent the facts.
This, however, is irrefutable evidence of large areas of clean fire :
There are many others, as you well know.
| physicist wrote: |
There's still no proof either way of what temperatures the steel reached.
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Your continued use of the word "proof" bothers me a lot, coming as it does from a BA in Physics. Have you ever presented one grain of decent evidence yourself for, say, CD? In another thread I'm asking for mere evidence of columns cut in a CD. Why not have a dabble there? Use any sources you like.
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So remember - next time you can't find a parking spot, go to plan B: blow up your car |
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physicist
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Joined: 09 Jun 2006
Posts: 170
Location: zz
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| Posted: Thu Jan 04, 2007 11:48 am Post subject: |
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| Bushwacker wrote: | | It is no use simply downloading the files if you do not read them, and that seems to be why you need me to point out that, for instance, when you say that NIST have never tried to explain the fall speed, you are incorrect. You are quite free of course to disagree with them, but to make the comment you did is misleading, and we wouldn't want that, now would we? |
Well, my friend, I have read them but have not been able to find a section where they calculate the time of fall. Please enlighten me. |
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physicist
Moderate Poster
Joined: 09 Jun 2006
Posts: 170
Location: zz
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| Posted: Thu Jan 04, 2007 12:00 pm Post subject: |
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| Ignatz wrote: | | Your continued use of the word "proof" bothers me a lot, coming as it does from a BA in Physics. Have you ever presented one grain of decent evidence yourself for, say, CD? In another thread I'm asking for mere evidence of columns cut in a CD. Why not have a dabble there? Use any sources you like. |
Please don't keep going on about my qualifications. I'm beginning to wonder whether you have an intellectual inferiority complex or something.
The internet is awash with evidence for both fire-induced collapse and controlled demolition. I've got an open mind and I don't know yet what the cause was.
The problem with the official explanation is that no-one actually knows what temperature the steel reached - and never will.
I've been burning bright red-hot smokeless fuel on my fire grate for over 20 years and it still looks pretty good.
If it weren't for WTC7, I'd say that the balance of probabilities indicates a fire-induced collapse. However, the collapse of Building 7 puts a whole new light on everything. Of course, there were a lot of improbable events that happened on 9/11. |
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Bushwacker
Relentless Limpet Shill
Joined: 07 Sep 2006
Posts: 1628
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| Posted: Thu Jan 04, 2007 1:47 pm Post subject: |
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| physicist wrote: | | Bushwacker wrote: | | It is no use simply downloading the files if you do not read them, and that seems to be why you need me to point out that, for instance, when you say that NIST have never tried to explain the fall speed, you are incorrect. You are quite free of course to disagree with them, but to make the comment you did is misleading, and we wouldn't want that, now would we? |
Well, my friend, I have read them but have not been able to find a section where they calculate the time of fall. Please enlighten me. |
NIST NCSTAR 1-5A should enlighten you. I would warn you that it is an extremely large file, but of course you have already downloaded it.
NIST also comment: NIST estimated the elapsed times for the first exterior panels to strike the ground after the collapse initiated in each of the towers to be approximately 11 seconds for WTC 1 and approximately 9 seconds for WTC 2. These elapsed times were based on: (1) precise timing of the initiation of collapse from video evidence, and (2) ground motion (seismic) signals recorded at Palisades, N.Y., that also were precisely time-calibrated for wave transmission times from lower Manhattan (see NCSTAR 1-5A)............Neither the duration of the seismic records nor video evidence (due to obstruction of view caused by debris clouds) are reliable indicators of the total time it took for each building to collapse completely.
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".......some partial collapse [of WTC7] would not have been suspicious......." - chek |
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physicist
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Joined: 09 Jun 2006
Posts: 170
Location: zz
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| Posted: Thu Jan 04, 2007 2:23 pm Post subject: |
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| Bushwacker wrote: | NIST NCSTAR 1-5A should enlighten you. I would warn you that it is an extremely large file, but of course you have already downloaded it.
NIST also comment: NIST estimated the elapsed times for the first exterior panels to strike the ground after the collapse initiated in each of the towers to be approximately 11 seconds for WTC 1 and approximately 9 seconds for WTC 2. These elapsed times were based on: (1) precise timing of the initiation of collapse from video evidence, and (2) ground motion (seismic) signals recorded at Palisades, N.Y., that also were precisely time-calibrated for wave transmission times from lower Manhattan (see NCSTAR 1-5A)............Neither the duration of the seismic records nor video evidence (due to obstruction of view caused by debris clouds) are reliable indicators of the total time it took for each building to collapse completely. |
I said that they haven't calculated how long the towers would take to collapse according to their model. |
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Bushwacker
Relentless Limpet Shill
Joined: 07 Sep 2006
Posts: 1628
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| Posted: Thu Jan 04, 2007 4:43 pm Post subject: |
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| physicist wrote: | | Bushwacker wrote: | NIST NCSTAR 1-5A should enlighten you. I would warn you that it is an extremely large file, but of course you have already downloaded it.
NIST also comment: NIST estimated the elapsed times for the first exterior panels to strike the ground after the collapse initiated in each of the towers to be approximately 11 seconds for WTC 1 and approximately 9 seconds for WTC 2. These elapsed times were based on: (1) precise timing of the initiation of collapse from video evidence, and (2) ground motion (seismic) signals recorded at Palisades, N.Y., that also were precisely time-calibrated for wave transmission times from lower Manhattan (see NCSTAR 1-5A)............Neither the duration of the seismic records nor video evidence (due to obstruction of view caused by debris clouds) are reliable indicators of the total time it took for each building to collapse completely. |
I said that they haven't calculated how long the towers would take to collapse according to their model. |
Ah, that's what you meant. You are right, there was no model for the progressive collapse, AFAIK.
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".......some partial collapse [of WTC7] would not have been suspicious......." - chek |
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Johnny Pixels
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Joined: 23 Jul 2006
Posts: 932
Location: A Sooper Sekrit Bunker
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| Posted: Thu Jan 04, 2007 8:15 pm Post subject: |
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| physicist wrote: |
Your assertion that the fires were not oxygen-starved is highly doubtful. The black smoke is due to carbon particles, the product of incomplete combustion.
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Incomplete combustion does not mean low temperature, it just means you have more fuel than oxygen.
Eg
And look at the effects of this oxygen starved fire:
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I have come to believe that the whole world is an enigma, a harmless enigma that is made terrible by our own mad attempt to interpret it as though it had an underlying truth. - Umberto Eco
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marky 54
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