Do we agree the towers were designed to withstand jetliner crash?

[Animal]

The severe out of context audacity by the 9/11 truth movement, when they claim that a slow and low on fuel 707, or a tiny B-25, is at all comparable to a fast and fuel laden 756/767, is utterly astounding in its dishonesty, or in its shining display of utter ignorance.

To claim that the towers were specifically designed to withstand impacts is ridiculous when history shows that any calculations to that effect were done as an aside to the design project, after design had been finalized, and that no alterations to design were ever made due to these calculations.

At least that's my humble opinion.

That has always been my opinion as well. The towers were not specifically designed for aircraft impact, but some rough calcs were run after the fact and they were below the required design loads for wind. It certainly sounds sexier to say a building can withstand an aircraft impact than to say it was designed to withstand a 110 mph wind.

 

[davefoc]

Actually, she was designed to withstand a major collision. Had they sailed directly into that iceberg, at full speed, there would no doubt have been some casualties onboard as half a dozen yards of the bow was turned into scrap iron and everything was thrown around, but she would not only have remained floating, but would probably have been able to reach harbour under her own power.

As it were, the grazing blow opened up a long row of individually insignificant leaks, flooding two many watertight compartments.

Again, reality foiled theory.

Hans

Nothing you said is wrong but to add a little more detail: The Titanic was doomed when the bow dropped far enough below water level such that the bulkheads of the water tight compartments were over topped which was a big problem since the farther the bow went down the faster the water tight compartments aft of the damaged water tight compartments flooded until a really big problem happened when the flooded and flooding forward sections broke off from the still floating aft section*.

ETA: * Alternatively, the breakup of the Titanic wasn't caused by stress between the sinking the forward sections and the floating aft section. The midsection of the Titantic had been packed with nano thermite when it was built in Belfast because the saboteurs knew that even a glancing blow with an iceberg couldn't sink it. When the Titanic struck the iceberg and after an appropriate amount of time a saboteur ignited the nano thermite to sever the Titanic near the midline.

 

[tsig]

The severe out of context audacity by the 9/11 truth movement, when they claim that a slow and low on fuel 707, or a tiny B-25, is at all comparable to a fast and fuel laden 756/767, is utterly astounding in its dishonesty, or in its shining display of utter ignorance.

To claim that the towers were specifically designed to withstand impacts is ridiculous when history shows that any calculations to that effect were done as an aside to the design project, after design had been finalized, and that no alterations to design were ever made due to these calculations.

At least that's my humble opinion.

Your humble opinion is correct.

(Can you imagine the looks on the design team when they're told that the building has to survive an airplane impact?)

 

[tsig]

Nothing you said is wrong but to add a little more detail: The Titanic was doomed when the bow dropped far enough below water level such that the bulkheads of the water tight compartments were over topped which was a big problem since the farther the bow went down the faster the water tight compartments aft of the damaged water tight compartments flooded until a really big problem happened when the flooded and flooding forward sections broke off from the still floating aft section*.

ETA: * Alternatively, the breakup of the Titanic wasn't caused by stress between the sinking the forward sections and the floating aft section. The midsection of the Titantic had been packed with nano thermite when it was built in Belfast because the saboteurs knew that even a glancing blow with an iceberg couldn't sink it. When the Titanic struck the iceberg and after an appropriate amount of time a saboteur ignited the nano thermite to sever the Titanic near the midline.

I laugh at thermite. The rivets were filled with explosive to facilitate breakup when she would be scrapped.

 

[fess]

One thing that has always intrigued me is; why would an engineer such as John Skilling write a paper stating that the towers would survive a strike by a B-707 doing 600mph. With very little research, he would have known that the FAA imposes a speed restriction of 250mph for all aircraft under 10,000ft.

 

[tfk]

Here is the only post you'll ever need to read on the subject:

http://www.internationalskeptics.com/forums/showthread.php?p=6993609#post6993609

Short version:
- In 1964, a calculation inituated by the Port Authority of NY and NJ and signed of by a structural engineering firm concluded that the lateral force (shear stress) that the towers would be subjected to if a fully laden 707 crashed at 600 mph would not exceed the safety margin for the maximum lateral force from wind that the towers were designed for. This calculation did in no way take into account the structural damage at the impact floor or the fire situation. The question was merely: Would the tower be pushed over, i.e. break near its foot? And it would not (and it didn't).

- Another crude calculation considered the structural damage from cutting perimeter columns along the wingspan of a 707 - with no accounting for more damage to floors and core, and no consideration of fires. Again, it was found that the loads would redistribute to other columns and the towers would remain standing after a 707 cut perimter columns (and they did).

- But it is an urban myth that the towers were indeed designed to withstand the entire effects of a plane crash - an impossible task given the low computational powers in the early 60s. Remember, buildings were drawn with pencils on paper, and structural calculations carried out with slide rulkes and mechanical calculating machines - and certainly often by crunching numbers with pencil on paper.

Agreed. With a couple of provisos.

This story was in Glanz' "Cities in the Sky".

IIRC (& I believe I do), the folks that actually did the calculation was the PANYNJ, under Melvin Levy. And I think that it would be more accurate to say that the PANYNJ slipped their calculations into a memo from that engineering firm, rather than the firm "signed off" on the calculation.

Glanz described the 1st part as a shear calculation, which I find impossible to believe. That is, sliding the building horizontally off of its base. I believe that Glanz misunderstood something that his source of info told him, which is that shear load is calculated on the way to moment. Overturning moment is a sensible quantity to have calculated, not shear at the base.

And it turned out that the average force from the plane impact was actually greater (18 million pounds) than the max wind force (14 million pounds) at the base. But they decided that it was not "that much" greater.

That's a pretty lame analysis, but the whole exercise was a PR job to undercut Lawrence Wien, who was trying to get the WTC project halted, because it competed with his ESB.

But, since the gods have a sense of humor or mercy, it turns out that Levy & pals were right.
___

I've stated (adamantly, as usual) that there is no way that they could have been designed to the standard of "designed to survive plane impact." And I am unmoved by anything that either Skilling or Robertson said in the decades after construction.

The verb "designed for" inherently requires the ABILITY to design for something. If I don't have the ability to calculate a wing's lift, then I cannot design a machine to fly.

One could perform a bunch of calculations but, unless those calculations meet some level of rigor in answering the desired question, that does not (in my book) rise to the level of a real analysis.

They did an absolutely spectacular job in designing those buildings with the tools that they had. Looking at the uniformity of the stress levels in the columns prior to plane impact, calculated by NIST with supercomputer performance clusters, shows awesome skill & judgment on the part of the designers.

But there is no way to truthfully say "they were designed to take the impact."

It was an urban myth.

 

[tfk]

... The US Government already has killed billions of human beings in all kinds of stupid wars. ...

Care to offer a reference to substantiate this claim?

 

[MRC_Hans]

Nothing you said is wrong but to add a little more detail: The Titanic was doomed when the bow dropped far enough below water level such that the bulkheads of the water tight compartments were over topped which was a big problem since the farther the bow went down the faster the water tight compartments aft of the damaged water tight compartments flooded until a really big problem happened when the flooded and flooding forward sections broke off from the still floating aft section*.

ETA: * Alternatively, the breakup of the Titanic wasn't caused by stress between the sinking the forward sections and the floating aft section. The midsection of the Titantic had been packed with nano thermite when it was built in Belfast because the saboteurs knew that even a glancing blow with an iceberg couldn't sink it. When the Titanic struck the iceberg and after an appropriate amount of time a saboteur ignited the nano thermite to sever the Titanic near the midline.

Heheh. OK, Titanic (I think this thread forgot its rails long ago, so..):

The Titanic was designed to sail on with any 4 compartments flooded. However, the grazing collision with the iceberg caused leaks in 5 consecutive compartments. As these filled with water, the ship sank lower, and now the problem was that the watertight bulkheads did not extend all the way to the deck, so after a time, water started to overflow the watertight bulkheads and fill the undamaged sections. This was what doomed the ship. A head-on collision, while causing other, quite extensive damage, would only have compromized one or two comparments, and would hence have let the ship stay afloat.

The Titanic did not break up till the stern started to lift out of the water. As long as the whole length of a ship is supported by water, any sound construction can withstand the stresses, even if the load is unevenlt distributed. The trouble starts when parts leave the water. In this case, the water-filled front was sinking, and the stern was lifted out of the water (survivors reported seeing the propellers), and the stresses on the centre section that now had to carry the whole ship became too large. The Titanic broke apart about one third of its lengh from the stern, and the two sections eneded up on the bottom, some distance apart.

I have the figures and details, but I just moved, and I'm not sure I can find the book readily.

.... Seems most is here: http://en.wikipedia.org/wiki/RMS_Titanic

Hans

 

[tsig]

One thing that has always intrigued me is; why would an engineer such as John Skilling write a paper stating that the towers would survive a strike by a B-707 doing 600mph. With very little research, he would have known that the FAA imposes a speed restriction of 250mph for all aircraft under 10,000ft.

He didn't write such a paper. Have you read this thread?

 

[Animal]

One could perform a bunch of calculations but, unless those calculations meet some level of rigor in answering the desired question, that does not (in my book) rise to the level of a real analysis.

They did an absolutely spectacular job in designing those buildings with the tools that they had. Looking at the uniformity of the stress levels in the columns prior to plane impact, calculated by NIST with supercomputer performance clusters, shows awesome skill & judgment on the part of the designers.
.

It is amazing what earlier engineers did with slide rules, pencil and paper.

 

[fitzgibbon]

Equally knowledgable statements pronounced that rockets could not work in the vaccum of space due to there being nothing to push against and earlier than that, that passengers in wagons pulled by a proposed, new invention, the railroad engine, would asphyxiate due to lack of air when moving upwards of 30 mph.

The one about trains got me the first time I read it some years ago. I guess nobody'd ever stuck their heads out of a wagon window at speed or asked the coachman whether he'd had trouble breathing when at anything approaching a gallop.

Just goes to show how reliable common knowledge is

Fitz

 

[fess]

He didn't write such a paper. Have you read this thread?

Yes, I have read the thread. I didn’t say he DID write the paper, I said why WOULD he write such a paper.

 

[jaydeehess]

The one about trains got me the first time I read it some years ago. I guess nobody'd ever stuck their heads out of a wagon window at speed or asked the coachman whether he'd had trouble breathing when at anything approaching a gallop.

Just goes to show how reliable common knowledge is

Fitz

mercy me, I found it.
"Rail travel at high speed is not possible because passengers, unable to breathe, would die of asphyxia" - Dr. Dionysus Lardner1793-1859

 

[George 152]

One thing that has always intrigued me is; why would an engineer such as John Skilling write a paper stating that the towers would survive a strike by a B-707 doing 600mph. With very little research, he would have known that the FAA imposes a speed restriction of 250mph for all aircraft under 10,000ft.

The world is full of 'experts' in fields that don't translate into reality.
Especially when aviation is involved

 

[A W Smith]

read the chapter in entirety. They figured it wouldn't knock it over. They used the wind load calculations of the entire tower.

http://books.google.com/books?id=yE...ing at 600 miles&pg=PA131#v=onepage&q&f=false

 

[Miragememories]

"...I've stated (adamantly, as usual) that there is no way that they could have been designed to the standard of "designed to survive plane impact." And I am unmoved by anything that either Skilling or Robertson said in the decades after construction.

The verb "designed for" inherently requires the ABILITY to design for something. If I don't have the ability to calculate a wing's lift, then I cannot design a machine to fly.

One could perform a bunch of calculations but, unless those calculations meet some level of rigor in answering the desired question, that does not (in my book) rise to the level of a real analysis.

They did an absolutely spectacular job in designing those buildings with the tools that they had. Looking at the uniformity of the stress levels in the columns prior to plane impact, calculated by NIST with supercomputer performance clusters, shows awesome skill & judgment on the part of the designers.

But there is no way to truthfully say "they were designed to take the impact."

It was an urban myth."

bolding is mine

"supercomputer performance clusters" mindlessly flipping 0's and 1's, versus the finest engineering brains carefully and with cautious intelligence, working through the same physics but having to take more time and manually save their work.

Supercomputers offer huge time savings in the speed with which they can process calculations but they do not 'think' during the process.

Those original designers had to be very methodical and thorough. They did not risk unnoticed entry errors due to an over reliance on computer data.

With no available history of fire-related steel building collapses, the NIST attempted to determine how the WTC Twin Towers collapsed largely on the basis of a computer simulation that required months to run the numbers.

Based on what the NIST determined to be the real conditions, neither WTC1 or WTC2 would have collapsed in their computer model.

Not until the NIST significantly model-tweaked the Tower's weaknesses could they achieve the beginning of what they claim was the start of what we all observed.

We don't know if the NIST claim could be true because they stopped their model. How much the model adheres to or diverges from what was actually observed, the NIST has chosen not to say, claiming it was not a requirement of their original mandate.

Back to the point;

The quality of engineering work was exemplary in the 60's.

In addition, engineers had an enormous amounts of large aircraft collision data to draw on from WWII and the Korean War.

MM

 

[phunk]

bolding is mine

"supercomputer performance clusters" mindlessly flipping 0's and 1's, versus the finest engineering brains carefully and with cautious intelligence, working through the same physics but having to take more time and manually save their work.

Those supercomputers aren't mindlessly flipping 0s and 1s. They are flipping them according to the programming of those finest engineering brains. They do the calculations that those finest brains would need a lifetime to do by manually.

If your argument is that engineers can do better calculations by hand than a supercomputer, because they can think, then you're just wrong. The supercomputer is doing the same calculations, but in much more detail.

 

[DGM]

Based on what the NIST determined to be the real conditions, neither WTC1 or WTC2 would have collapsed in their computer model.

Not until the NIST significantly model-tweaked the Tower's weaknesses could they achieve the beginning of what they claim was the start of what we all observed.

Why do you feel the need to lie? Would you like to clarify what these "tweaks" actually were?

We don't know if the NIST claim could be true because they stopped their model. How much the model adheres to or diverges from what was actually observed, the NIST has chosen not to say, claiming it was not a requirement of their original mandate.

By "we" you mean you. Engineering shows they were correct.

Back to the point;

I doubt it.

The quality of engineering work was exemplary in the 60's.

Yes, it was

In addition, engineers had an enormous amounts of large aircraft collision data to draw on from WWII and the Korean War.

MM

Do you have a point? Did the buildings topple over?

 

[TjW]

We don't know if the NIST claim could be true because they stopped their model. How much the model adheres to or diverges from what was actually observed, the NIST has chosen not to say, claiming it was not a requirement of their original mandate.

Tell you what, MM. Get yourself some paper and divide 1 by six.

Come back when you've computed every digit. Because obviously, if you stop before you've calculated every digit, we won't know what the answer is.

 

[The Almond]

bolding is mine

"supercomputer performance clusters" mindlessly flipping 0's and 1's, versus the finest engineering brains carefully and with cautious intelligence, working through the same physics but having to take more time and manually save their work.

Really? Do you really have no understanding of finite element analysis? Do you understand how to compute numerical solutions to otherwise unsolvable problems? I'll answer those two questions for you: You don't. You've never taken an engineering class, and you have no concept of advanced mathematics. Please stop peddling your ignorance as fact.