I'm pretty sure you're strawmanning NIST's claims. They were aiming for "close enough". Replicating the exact conditions was and still is impossible, given the large number of unknowable factors, and is an appeal to impossible perfection, especially in light of such questions Truthers usually dodge such as "how did They make sure their explosives were not knocked out of the building or disrupted by the plane impacts?" Even if it was possible to predict the damage the plane and fire might do, even the slightest plane impact variation (height, speed, bank, yaw, angle, etc.) or fire variation could change the damage and thus cause catastrophic damage to the charges. It is orders of magnitude easier for the hypothetical plan to go wrong than it is for it to go right.
Do we agree the towers were designed to withstand jetliner crash?
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I'm pretty sure you're strawmanning NIST's claims. They were aiming for "close enough". Replicating the exact conditions was and still is impossible, given the large number of unknowable factors, and is an appeal to impossible perfection, especially in light of such questions Truthers usually dodge such as "how did They make sure their explosives were not knocked out of the building or disrupted by the plane impacts?" Even if it was possible to predict the damage the plane and fire might do, even the slightest plane impact variation (height, speed, bank, yaw, angle, etc.) or fire variation could change the damage and thus cause catastrophic damage to the charges. It is orders of magnitude easier for the hypothetical plan to go wrong than it is for it to go right.
Please source this one. Good luck.
jaydeehess
Penultimate Amazing
This program did the calculations that would have been required by any method to achieve that level of accuracy. It, as you said, took months for these calcs to be done in the computer and thus given the differential in speed of calculations between human and computer, it would have taken years or even decades for a team of engineers to do the same using paper and pencil. In actual fact these human claculators would also not be allowed to use slide rules since these do not calculate beyond a few significant digits which in many cases would not be enough. They would be restricted to doing many calculations long hand.
GIVEN that the WTC tower designs were already finished when the rough calculations were done concerning aircraft impact, you now seem to be trying to imply that the design team then spent years/decades on how a large liquid fule spill on several consecutive floors would have affected the steel of the structure.
That is simply ridiculous. A new level of special pleading by you MM.
Using best case scenario the model does not show collapse so one then tweaks inputs to determine at what point collapse woukd occur. One assumes that one's engineering is correct and has been entered in the program properly. In fact if it had not, if a decimal place was shifted left or right, then the result would have been immediately obvious and slight tweaking of inputs would have made little difference. If the program was wrong then the most likely result is it shows something like a building that either stays intact in much the same way Wile E. Coyote stays suspended in the air until he notices no support beneath him, or a building that would have fallen over if Tweety Bird perched on one corner.
?? You mean the stopped it at initial collapse because after that point the variables become so great and the possibilities of the location/position/condition of connections and structural members becomes so chaotic that it is impossible for even a team of supercomputers to come up with anything usable?
Back to the point;
Finally a point of agreement
You'll be back with these studies, right?
Oystein
Penultimate Amazing
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Yes, but in some things, like FEA simulations, you can't substitute computing power except with more computing power.
You are of course right that "garbage in - garbage out" is true even if you have lots of computing power, but to comclude the reverese that you get non-garbage results if you enter non-garbage into no computer power is invalid. You surely need careful thinking either way, but computrer power is in any case vastly superior to no computer power.
So you present a false dichotomy where your only options are
1. good input, little computer power
2. bad input, much computer power
and your conclusion that the engineers in the 60s were able to model plabe crash + power correctly because they employed option 1. is invalid on at least counts. You are missing of course 3. good input, much computer power and 4. bad input, little computer power. 2 and 3 were unavaolable in 1964, you haven't shown yet that the engineers in 1964 used good input, and you haven't shown (and are wrong to assert) that without computer power they could have found a good result.
Maybe.
Now you need to show that the engineers who did that calculation that determined the towers wouldn't topple had this data available and actually used it in their calculations.
Did they, MM? Yes? Or no?
Animal
Master Poster
One further point. Though the engineering done on towers was great engineering AT THE TIME, it would not necessarily be considered great engineering at the PRESENT TIME In the 30-40 years that have passed, the amount of knowledge with regard to materials, etc has expanded greatly.
Miragememories
Banned
Prior to 9/11, what structural-steel engineering advances occurred in those "30-40 years" that argues against the WTC Twin Towers being sufficiently well-engineered to absorb the impact of those aircraft?
Which disproves the structural integrity provided by engineered-protection against aircraft with Boeing 707 specs very similar the Boeing's that actually struck them?
MM
tsig
a carbon based life-form
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They absorbed the impacts and remained standing.
Oystein
Penultimate Amazing
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I think Animal made a pretty general statement, not specifically with plane strikes in mind. Just as previous posters, perhaps excepting yourself, who expressed the sentiment that the towers were well engineered, made a general statement and none specifically geared towards plane crash resistance, even though the fact that, in retrospect, the design did in fact resist plane crashes both in theory (1964, Robertson, NIST, Purdue...) and practice (2001) bears witness to that general sentment.
These opinions do not imply that the towers were designed with an objective to withstand 600 mph plane strikes, nor do they imply that they could have been designed with plane strikes plus ensuing fires, nor does this in any way, shape or form acknowledge that anyone claimed they would resist the fires following a high-speed impact indefinitely, or that such a claim could have been based on calculations that were possible in 1964.
Because the facts remain:
- Resistance to 600-mph-crashes was not a design objective
- Resistance to fires started by 707 crashes was not a design objective
- It was impossible in 1964, due to lack of computer power, to determine how the towers would respond to any scenario of a 707 crashing at high speed and dumping fuel that ignites horrendous multi-floor fires.
Since these are the facts under discussion in this thread, you should in your further replies address these, and not so much any general appreciation of the engineering achievement.
No one is arguing that the twin towers weren't sufficiently well-engineered to absorb the impact of the aircraft due to the simple historical fact that they did, in fact, absorb the impact and remained standing, albeit with some non-trivial structural damage.
What is being argued is that any conclusions reached by engineers in the 60's would not have included much in the way of accurate predictions regarding the progress and effects on the structure of large fires in the buildings, because the tools to make accurate predictions were not sufficiently advanced at that time, even though it was an important topic and people were working on it.
I post this not because I think you don't understand this, but simply to see how you'll try to spin it.
What is being argued is that any conclusions reached by engineers in the 60's would not have included much in the way of accurate predictions regarding the progress and effects on the structure of large fires in the buildings, because the tools to make accurate predictions were not sufficiently advanced at that time, even though it was an important topic and people were working on it.
I post this not because I think you don't understand this, but simply to see how you'll try to spin it.
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DGM
Skeptic not Atheist
So, what do you think. Does Skillings statements make the buildings impervious to collapse under the circumstances of 9/11, thus proving controlled demolition?
If not, what's the whole point of this? Could it just be more "truther" sales propaganda?
You left out the specifications of the design.
Are you always wrong, or only trying to push the lie of CD again? The structure was able to withstand a 707 at 180 mph. Not impacts at 470 mph, and 590 mph. You see, the low speed impacts would not damage the core; high speed impacts damage the core. Low speed impacts no major insulation loss, high speed impacts a lot of insulation lost.
You can't support your nonsense with physics, or reality.
What are you trying to do? Oh, support some delusional theory about 911. Good luck
Flight 11 not 180 mph, 470 mph, 7 times more KE=1/2mv2
Flight 175 not 180 mph, 590 mph, 11 times more KE=1/2mv2
Did you do the physics?
http://www.nae.edu/Publications/Bri...ecurity/ReflectionsontheWorldTradeCenter.aspx
http://www.nae.edu/File.aspx?id=7345
What speed was the design for?
Seeking to land at JFK - means 180 mph.
Designed for 180 mph. Fire from a low speed impact would not be like on 911, most the aircraft would remain outside the WTC - the design would stop the aircraft at less than 200 mph.
The fact the WTC could resist a 180 mph impact, can't be used for your failed CD claims, the crazy inside job nonsense.
Miragememories
Banned
Why would engineers in the 60's not be up to the task presented by those aircraft crashes?
Obviously, the Twin Towers stabilized immediately after the impacts.
Without major trauma to the core below the impact zones, there was no engineering reason to expect either Tower to become structurally de-stabilized.
No more planes to crash so the official hypothesis was left with office cubicle fires.
And so you argue that the engineers of the 60's were not equipped to design against the level of fire destruction hypothesized in the NIST FINAL WTC Report.
Engineers, whom in their wildest dreams, could never imagine the Twin Towers suffering fountain-like collapses after 56 and 102 minutes of office cubicle fires.
Both cores collapsed in seconds during the creation of those fountains.
Fires do not allow the necessary 'sledge-hammer drop' of each upper section.
Without a uniform core removal starting below each impact zone, the off-balance collapses, which started as upper section topples, would have continued to topple and the global collapses would not have occurred..
MM
DGM
Skeptic not Atheist
So, what do "truthers" think about this?
These two bridges were designed by Leon Moisseiff. He also designed this:
So, how did this happen?
Could it be he just didn't have the technology to understand every possible factor that may effect his design?
These two bridges were designed by Leon Moisseiff. He also designed this:
So, how did this happen?
Could it be he just didn't have the technology to understand every possible factor that may effect his design?
There is definitely some "spinning" going on in this response.
Since we are talking about the design of the towers, I assume you understand HOW they were designed and built? That is a very important aspect in understanding how they fell.
First off, the towers were not designed to take the impact that they received on 9/11. Aircraft impacts were indeed considered possible because of the Empire State building accident. Thus, they kept accidental aircraft impacts in mind while designing the buildings. They were in no way designing the buildings to withstand kamikaze pilots, hell bent on causing maximum destruction.
As for, considering the damage done by fire. Of course the engineers 40 years ago couldn't calculate that damage as well as we can today. If science and engineering hasn't made any progress in 40 years, we seriously have a problem on our hands. Also, the calculations done at that time may not be applicable to the building as it sat in 2001. For example, the calculations made for the burning of office contents would have had a much smaller amount of plastics and a larger amount of metals. Most things in an office today are plastic or have a large plastic content. Not so in the early 70's. Plastics have a high rate of heat release. Plastics are in the 15,000 to 22,000 btu/lb heat content range. Gasoline has a 22,000 btu/lb heat content rate. So plastics can burn about as hot as gasoline. That is something that could not have been considered at that time.
And speaking of the office fires, you refer to them as "office cubicle fires". As to try to diminish the size of the fires. These were LARGE office buildings that contained LARGE amounts of "office contents". They were impacted by LARGE planes, which left LARGE holes in the buildings to fuel the LARGE fires with oxygen. So, lets not pretend that these fires were insignificant.
As for the collapses themselves, this statement is completely incorrect:
There is plenty of video evidence that shows the cores, below the impact level, stood well after the building had collapsed around it. This, in it's self, proves that the core was not weakened or removed by some pre-planted CD.
I noticed you left out the damage caused by a 150 ton airliner going 500 mph. That damage coupled with the large fires was indeed enough to weaken the building.
And as for the last statement, that the top of the building should have toppled over. That just shows that you need to study how buildings are constructed and how the laws of physics act upon them. I would suggest a conversation with a structural engineer. They should be able to explain that a building is not ONE piece, and will not perform as such when it is damaged.
Mark F
Graduate Poster
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And lets not forget the other major factor MM keeps dodging - the large-scale removal of fire resistant insulation from structural steel. Would this have been accounted for in anything done in 1964? I suspect not.
That's very true. Any calculations (or tests, if any were done,) would have been made with fire proofing applied.
The whole "fireproofing of steel" still seems to escape those that argue that fire can't damage steel. First of all, if steel was unaffected by fire, builders wouldn't go through the time and expense it takes to fireproof a building. Second, fireproofing does not protect the steel, or whatever is being protected, indefinitely. Whether it be sheet-rock or spray on foam, it is there to hold back the fire so the occupants can vacate and fire fighting to take place. I believe the industry standard is 2 hours. Someone correct me, if that is wrong. So, the thought that a fireproofed steel structure is impervious to fire is frankly mind boggling.
There is even evidence that the fireproofing in the towers was deteriorating before 9/11.
http://www.debunking911.com/fires.htm
If the fireproofing was falling off from age and the movement of the towers, obviously a 500mph aircraft impact would have finished the job.
jaydeehess
Penultimate Amazing
Fact is that they were not specifically instructed, and no one up to 2001 ever was, to design the towers to the spec of being able to withstand a 600 MPH crash on an aircraft.
However the design that was erected was determined, as it was being built, to be able to withstand an aircraft crash.
The tower never was structurally destabilized as a whole. It came apart from the impact floors on down.
Thousands of gallons of liquid acellerant spread out over several levels ignited widespread office fires on each of these floors, sprinkler systens were compromised from impact, fire insulation on the steel was compromised in areas of the impact.
the width and levels of office fire involved within seconds of impact was what would not be expected to occur for several HOURS in a typical office fire in a high rise structure........
.......and you belittle this with the phrase "cubicle fires".
That has to be one of the absolute worst cases of sophistry I have seen in a while, and I have been discussing the CiT on another thread so that's saying something.
Correct, and unless you can demonstrate that the ability to model such a fire and its effect on the structure was available in the 1960s you are out to lunch on this MM.
What do you consider the task presented by those aircraft crashes to be?
There are no rational engineers who support your speculation.
