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peer review.

slow speed design would survive


ref said:
I think their point is, that the towers were overdesigned to withstand an impact even up to 600mph, even if this speed is not physically possible for a 707. I have heard this one before. It is not exactly known what is the origin of this claim, was it exaggeration to calm down the critics, or were there actual calculations to prove it. Calculations have never been found.
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My point is the towers were not design to withstand a high speed impact. This is proven by statements form the lead engineer. They picked the most likely accident at the time. Slow speed lost in the fog, low fuel. I agree this is the most likely accident for the WTC. The high speed impacts were not in the design. No, the towers were not over designed to withstand the impact. They were designed to withstand the slow speed impact. I have to say the WTC fell due to the impact of high speed planes (and the entire system of events associated with a high speed impact of fuel laden jet). I agree this is very complicated, but if they designed for high speed they would be standing, fire systems would survive, stairwells would survive, or their backup systems would be in place. That is what design is about. I understand what you think they are saying, but they are really saying see, they were suppose to survive, but it was CD that did it. You understand what you are saying but you can not say the towers survived the impact, you can only say they stood long enough to save some people.

ref said:
Needless to say, the towers did withstand the plane impacts. So there is no point the truthers can make. In the 1993 interview, Skilling did not mention the speed of the aircraft.
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No the towers did not survive the impacts. Survive a bullet wound means you are well and alive days later, years later. The towers fell due to high speed impacts of aircraft. If the speeds had been close to 180 mph to 220 mph the WTC towers would be here.

ref said:
As for the lead engineer, I would still say it is hard to say who it was. Skilling had his name even in the company name. He was known. I don't know, if it's known what the division of tasks between these two engineers was. But it makes no difference. We all saw what happened.
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Robertson is the man. He put his signature of the line. He is responsible and understands the WTC towers. He says slow speed, I have to agree, after doing simple energy models of the towers, anyone can see why the towers would survive a slow speed impact and were doomed when the speed goes up.

This not trivial, the impacts on 9/11 were 7 to 11 times greater than design, that is significant. That in the engineer world becomes a big thing. An order of magnitude, a major point in design, and when your design points are exceed by ten times, things are on the edge and fail.

The other major point here is, the truther world is using the 600 mph design point to show there were explosives used to bring down the WTC since they were designed to withstand a 600 mph impact. This is not a point you can say, SO? It is a fact the design was for slow speed impact.

If you say, "so what", and let them push hearsay bs all day, you let them have their CD ideas gain merit. As Robertson tell all, the design was a slow speed impact, then the fuel and aircraft would be falling to the ground, and only localize damage. But Robertson can see with his experience the aircraft impacts destroyed his work. They did not stand but they did hold up until most could leave.

The 9/11 truth will twist this point, it shows me they will use unsupported hearsay to push their agenda, like realcddeal.
 
Greening. That's as simple and succinct as I can get. The next order of magnitude does little to the overall. The only way to seriously change the outcome after initiation is to prove the lower floors were capable of withstanding much more kinetic energy than he has proposed. If someone does they will spark my attention, and a few others I assume.
 
Beach,

I'm not saying I agree with the 600mph design. I just know why they claim that. It is because of that Port Authority paper that can also be seen in the NIST report. I agree with Robertson, and you for that matter.
 
ref said:
Beach,

I'm not saying I agree with the 600mph design. I just know why they claim that. It is because of that Port Authority paper that can also be seen in the NIST report. I agree with Robertson, and you for that matter.
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Link to this "paper" claiming 600mph?
If you can't produce it, you are prevaricating. Stop it.
 
realcddeal said:
Engineers would design for worst case scenarios with something like the Twin Towers. If those aircraft could be pushed to the speeds you are discussing above then they would design for that possibility. Obviously, they could move at 600 MPH at 1300 feet. Only Leslie Robertson says it was simply for an airplane lost in the fog. That is only what happened to the Empire State Building. There are also other eventualities like an out of control aircraft. The 707-320B also had more thrust than the 767-200ER. Who says there couldn't have been a problem with the throttle? These things would need to be considered.
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Read a 102 Minutes and you will see that they did not design the WTC with the worst case scenario in mind.
 
realcddeal said:
beachnut said:
I was an aircraft mechanic in the U.S. Navy in the late 1970's and we had accidents where pilots were killed due to throttle linkage having a problem. So laugh on the floor all you want while you deny reality. While these problems are rare they do happen and those of us who actually design things for a living have to take them into account.
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The fact that you worked on aircraft in the Navy means what? What is your knowledge of the throotle system on the 767?
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rwguinn said:
Link to this "paper" claiming 600mph?
If you can't produce it, you are prevaricating. Stop it.
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I already said, it is in the NIST report. You can find it, I'm sure. It's no use attacking like that. You should know, that I in no way support these theories, as you can see in my post.

ETA: http://wtc.nist.gov/NISTNCSTAR1-2.pdf appendixes, pages 420-422.
 
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The existence of a design-time high-speed impact study -- not a requirement -- is a persistent rumour. NIST investigated and could find no evidence of its existence:

NCSTAR1 pg. 55 said:
A Port Authority document indicated that the impact of a Boeing 707 aircraft flying at 600 mph was analyzed during the design stage of the WTC towers. However, the investigators were unable to locate any documentation of the criteria and method used in the impact analysis and were thus unable to verify the assertion 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." Since the ability for rigorous simulation of the aircraft impact and of the ensuing fires are recent developments and since the approach to structural modeling was developed for this Investigation, the technical capability available to The Port Authority and its consultans and contractors to perform such an analysis in the 1960s would have been quite limited.
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I'll go one further. The study referred to was probably a simple calculation of aircraft momentum versus overturning moment of the building. It is unlikely that the structure was considered at any level of granularity. It is absolutely inconceivable that the fires were considered at all.

Robertson's comments are the standard to beat. As indicated previously, he knew better than anyone what the design requirements were. That's because it was his job. If he says they weren't designed to absorb such a ridiculous amount of punishment, we should believe him, unless we have extraordinary evidence to the contrary. We do not.
 
I agree completely with Mackey. My comment was made for the sole purpose of saying, that this has been mentioned in the NIST report, even if there is no evidence or calculations to prove it. I decline commenting any more on this matter ;)
 
ref said:
I agree completely with Mackey. My comment was made for the sole purpose of saying, that this has been mentioned in the NIST report, even if there is no evidence or calculations to prove it. I decline commenting any more on this matter ;)
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I absolutely agree with all the above.
Sorry for misunderstanding you.:o
 
People always seem to forget the human factor when quoting recolections. A casual inquiry into what thought went into the construction prior to 9/11 can not be held as factual. We all have a tendancy to boast when asked to what ends we went to in accomplishing a task. As an avid fisherman I cannot stress this enough. The story I tell of the 110 lbs sturgeon I caught would not hold up in court.
 
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