9/11 was an inside job

[hardalee]

In tube building design, the outer columns (the tube) does support gravity load, usually 50 percent or so of the gravity loads in the best types. The compression of these outer columns helps resist the bending force from the lateral loads.

The rest of the columns take gravity load with a little lateral load due to interaction as the building sways and the center core around the elevator banks takes the rest as shear walls.

 

[Grumpy]

Carcano

I looked up tubular building systems, and they are specifically designed to resist LATERAL loads like wind pressure, not vertical gravity loads.

Then you haven't "looked up" tube frame buildings, as they ARE designed to hold vertical as well as wind loads, their cores may or may not take any wind loads(in WTC the cores in the towers only had vertical loading, WTC 7 had a mix, with the three columns holding up the East Penthouse(79, 80 and 81)tied in to the external frame in a rigid fashion by the floor trusses).

A building that completely collapses in a few seconds MUST experience a failure of the majority of its vertical gravity load bearing support columns.

No, not in the real world. All that has to happen is that enough of that strength is lost(through damage or fire)so that the remaining strength is insufficient to hold that load, whether that is half the columns, or only a few(which is much more likely to be the case). Buildings are only built with sufficient strength to carry the load plus a safety factor. It only takes losing a few columns among dozens to use up that safety factor(especially if they are right next to each other)and any further erosion of that strength means failure. Once gravity drops the top a few feet the kinetic energy overwhelms the remaining strength, gravity always wins.

Grumpy

 

[Rhaedas]

That makes no sense. A skyscraper has to do both. The problem is that different sources use language in different vague and ambiguous ways and it gets interpreted in varying ways by different people.

He's talking about additional load. Why would a skyscraper needs to be designed to hold additional weight beyond what a full building would be, plus a safety factor? It's not like gravity will increase. Whereas wind has a huge force laterally, particularly on a large square, flat surface. Look at the new Freedom Tower's design for ways to reduce this, and allow for less concern (so less material) for countering these forces.

 

[psikeyhackr]

You're right. It is not your fault the NIST report is regarded as real research. You haven't even read it, opting instead to word search and frown at the fact that certain buzzwords aren't used as many times as you'd like.

I know for a fact Grumpy already addressed this, so the fact that you simply repeat the same insanely-held notions despite having been corrected means you aren't any different than the "no planers" yourself.

"Concrete" is a buzz word?

"Center of gravity" is a buzz word?

I read every usage of concrete in the entire report. Usually that meant reading the entire paragraph or more in the vicinity to understand why they were discussing it. There were more than 3,000 occurrences. If anything what I found odd was how often they repeat the same sentence or entire paragraph. I would not be surprised if 20% of the NIST report is just repetition of the same thing.

I did the same for steel. I found the three instances where they say "roughly 200,000 tons of steel". There was nothing like that for concrete. In four years no one has come back at me saying where the NIST specifies the total for the concrete and said how much and where it is in the report. But a number of people have CLAIMED it is there and then accuse me of being lazy. So why can't they come up with a number?

This business involve the psychological fixation on authority. That is a bigger problem than 9/11.

Grumpy has been silent on his admission that the top of the south tower rotated.

psik

 

[Balerion]

Concrete is a buzz word?

"Center of gravity" is a buzz word?

I read every usage of concrete in the entire report. Usually that meant reading the entire paragraph or more in the vicinity to understand why they were discussing it. There were more than 3,000 occurrences. If anything what I found odd was how often they repeat the same sentence or entire paragraph. I would not be surprised if 20% of the NIST report is just repetition of the same thing.

I did the same for steel. I found the three instances where they say "roughly 200,000 tons of steel". There was nothing like that for concrete. In four years no one has come back at me saying where the NIST specifies the total for the concrete and said how much and where it is in the report. But a number of people have CLAIMED it is there and then accuse me of being lazy. So why can't they come up with a number?

This business involve the psychological fixation on authority. That is a bigger problem than 9/11.

Grumpy has been silent on his admission that the top of the south tower rotated.

psik

So in other words, you didn't read it. You skimmed it. Yet you're here criticizing it.

I think that's all that needs to be said.

 

[Grumpy]

psikeyhackr

Grumpy has been silent on his admission that the top of the south tower rotated

I never denied it. It is a fact that the top block of Tower 2 rotated AROUND IT'S CENTER OF GRAVITY, with the top part going one way and the bottom part going the opposite way SHEARING ALL CONNECTIONS(in the core and perimeter frame)WITH THE REST OF THE BUILDING. Gravity did the rest.

Grumpy

 

[psikeyhackr]

I never denied it. It is a fact that the top block of Tower 2 rotated AROUND IT'S CENTER OF GRAVITY, with the top part going one way and the bottom part going the opposite way SHEARING ALL CONNECTIONS(in the core and perimeter frame)WITH THE REST OF THE BUILDING. Gravity did the rest.

Grumpy

I didn't say you denied it. I said you were silent.

So how do you explain it? What was the moment of intertia of 29 stories. What supplied the energy to rotate it and shear 283 columns? The building only deflected 15 inches when the plane hit it and then oscillated for 4 minutes.

In fact what do you have as a source supporting your statement that the top portion rotated around its center of gravity? If no one ever specifies where it is then how can anyone know?

psik

 

[psikeyhackr]

So in other words, you didn't read it. You skimmed it. Yet you're here criticizing it.

I think that's all that needs to be said.

You think you could read 10,000 pages and notice what was not there without looking for it specifically. Why not just look for it from the start? What are electronic documents for? Searching and reading the searched portion is not skimming. Yeah, I criticize it for what I know isn't there. Grumpy talks about the center of gravity of the top of the south tower but that is not in the NIST report either.

So I want to know his source for this rotation around the center of gravity. But then maybe he is just making it up.

psik

 

[Balerion]

You think you could read 10,000 pages and notice what was not there without looking for it specifically. Why not just look for it from the start? What are electronic documents for? Searching and reading the searched portion is not skimming. Yeah, I criticize it for what I know isn't there. Grumpy talks about the center of gravity of the top of the south tower but that is not in the NIST report either.

So I want to know his source for this rotation around the center of gravity. But then maybe he is just making it up.

psik

So you think they put it in a PDF so you don't have to read it all?

Again, 'nuff said.

 

[Aqueous Id]

I criticize it for what I know isn't there.

You criticize it because you're a clueless nut.

You pretend to address science. You apparently have never even worked in building construction, much less the complexities of design. You certainly couldn't touch engineering with a 10-foot pole. Thus you have missed a lot of useful information already given to you. You speak a lot about mass and gravity, but unless I overlooked it, you have blindly ignored that, at this very highest level of analysis, this event was a horrific demonstration of conservation of energy.

A missile hits a tower and conveys all of its kinetic energy, plus the heat of the exploding fuel. It imparts shock. The building reacts. Things bend and break. Rivets, struts, trusses, pins and cables exceed their design limits and snap and pop loose. Bolts shear. Welds break. Cantilevered beams are stressed beyond limit and fracture and crack. The concrete slabs on the upper levels shatter and pulverize. The building has a frequency response and so it rumbles and shakes, softening up the lower levels, and it oscillates, imparting huge torsion and shear stresses on the lower beams which crack and pop their anchors. And then the entire upper mass, minus whatever was ejected, all the particles that were flying laterally, are opposed by the far wall, and they recoil, as the far wall shatters. At this point that aggregate of flying building parts achieves lateral equilibrium and comes to rest on the rapidly disintegrating upper frame. A second huge impulse is delivered when all of this debris comes crashing down on the "floor". But there is no floor. Just more time to accelerate. To these dynamics add the pressure of exploding fuel, which further shatters the upper slabs, and the white-hot thermal blast, which liquefies the re-bar and fasteners, and liberates the upper floors to drop.

I think that when you get to the point that you understand that what Bin Laden did was to drop a building onto a building, using an aircraft as a shear, a bomb, an incendiary device and a missile, you can stop trying to invent science to prop up your nutty half-wit dreams that "the government" is a demon. The day you pin this squarely on Bin Laden, and be grateful to the brave people who responded, is the day you move on.

Get over it: you're simply wrong. You know nothing about science, your "model" is a joke, and so you've screwed up your whole rationale for reaching this conclusion. If this were a homework assignment, you'd get an F. So what next? I say bail out. You've got nothing going for you. You're simply out of your league.

 

[psikeyhackr]

So you think they put it in a PDF so you don't have to read it all?

Again, 'nuff said.

The physics of 9/11 happened on 9/11, long before they even started working on that report. Skyscrapers must support their own weight therefore the distributions of concrete and steel are relevant to the physics problem.

What is stopping you from reading the report and telling us where they specified the total amount of concrete?

I told you they specified in three places that the distribution of weight was important to analysing the impact, but then they did not do it. Here is some of what they had to say:

NCSTAR 1-2A Baseline == distribution of mass

The wind loads were calculated on the basis of 2.5 percent total damping. This value includes the intrinsic damping of the structural systems plus the supplemental damping provided by the dampers.

The differential static and dynamic shears between successive levels were calculated and distributed using two different methods:

• The static wind load to be applied to each floor was determined from the shear diagram.
• The dynamic wind load to be applied to each floor was based on the distribution of mass over the tower height, the fundamental mode shape, and the dynamic component of the lateral wind-induced sway at the roof.

Note that for α = 90 degrees, coefficients were not found in the microfilm of the WSHJ Wind Reports for calculating the static component of the wind forces for WTC 1. Accordingly, the static coefficients were deduced from data for the α = 270 degrees, for WTC 2. By observation of the static coefficient data, it was determined that the basic data for the two towers is shifted by 180 degrees.

Considering the 24 different wind directions and the four combinations of the static and dynamic components of the N-S and E-W components of the building forces listed below, there were 96 different wind load cases for each tower.

= = = = = = = = = = = = = = = = = =

NCSTAR 1-5D Ceilings.doc == weight distribution

2.4.3 Single Impulse Excitations
Accurate estimation of the tower’s motion during the airplane impact required detailed knowledge of the geometry, weight distribution, and impact velocity of the aircraft, as well as detailed knowledge of the geometry, weight distribution, and structural strength of the tower. At the time of this test series (fall 2003), much of this information was unknown, and the impact motion could only be roughly estimated. To allow this estimate to be made quickly, many simplifying assumptions were made regarding the nature of the impact.

= = = = = = = = = = = = = = = = = =

NCSTAR 1-2 Ch 1-6 == mass distribution

The densities of specific materials were scaled to obtain the desired magnitudes for the service live loads and superimposed dead loads. The densities of the tower contents (workstations and gypsum walls) were scaled by the appropriate ratios to obtain the desired distribution of live loads in the core and truss floor areas. The densities of all the remaining tower structural components were scaled proportionately to obtain the desired superimposed dead loads. These additional loads were important for obtaining an accurate mass distribution in the towers and inertial effects in the impact response. The in-service live load used was assumed to be 25 percent of the design live load on the floors inside and outside the core.
The in-service live load was selected based on a survey of live loads in office buildings (Culver 1976) and on engineering judgment. The uncertainty in the amount of in-service live load was accounted for in the sensitivity analyses (Chapter 8 of NIST NCSTAR 1-2B) and in the global impact simulations (Chapter 7
of this report).

= = = = = = = = = = = = = = = = = =

NCSTAR 1-2B Chap 1 thru 8 == mass distribution

E.8 UNCERTAINTY ANALYSES
The objectives of the uncertainty analyses were to assess the effect of uncertainties associated with the aircraft and WTC towers parameters on the level of damage to the towers after impact and to determine the most influential modeling parameters that affect the damage estimates. Uncertainty arises in these analyses from the following key parameters:

• Aircraft impact parameters: aircraft speed, horizontal and vertical angles of incidence, orientation, and location of impact.
• Material properties: high strain rate material constitutive behavior and failure criteria for the towers and the aircraft.
• Aircraft mass and stiffness properties, and the jet fuel distribution in the aircraft.
• Tower parameters: structural strength and mass distribution, connection and joint positions relative to impact and joint failure behavior.
• Nonstructural building contents that may share in absorbing energy imparted by the aircraft impact.

An important source of uncertainty that is not listed in these key parameters is the inaccuracy associated with mathematical or numerical models. The inaccuracies of models, also known as modeling errors, are deterministic in nature, but are often treated as random variables to characterize the effects of the analysis methodologies on the calculated response. All of these variables did not necessarily have a significant effect on the estimated impact damage to the WTC towers.

= = = = = = = = = = = = = = = = = =

NCSTAR 1-2B Chap 9 thru 11 == mass distribution

11.8 UNCERTAINTY ANALYSES
The objectives of the uncertainty analyses were to assess the effect of uncertainties associated with the aircraft and WTC towers parameters on the level of damage to the towers after impact and to determine the most influential modeling parameters that affect the damage estimates. Uncertainty arises in these analyses from the following key parameters: (1) aircraft impact parameters (speed, horizontal and vertical angles of incidence, orientation, and location of impact), (2) material properties and failure criteria for the towers and the aircraft, (3) aircraft parameters (mass and stiffness properties, and jet fuel distribution), (4) tower parameters (structural strength and mass distribution, connections behavior), and (5) nonstructural building contents that may share in absorbing energy imparted by the aircraft impact.
Another important source of uncertainty is the inaccuracy associated with mathematical or numerical models. These uncertainties, also known as modeling errors, are deterministic in nature, but are often treated as random variables to characterize the effects of the analysis methodologies on the calculated response. All of these variables did not necessarily have a significant effect on the estimated impact damage to the WTC towers.

Notice how the last two are repetitions of the same information but formatted differently. My searches turned up a lot of that. That report is very fluffed up but fails to ask obvious questions.

How much have you read? Does this mean it must all be true and correct because you have not read it?

psik

 

[psikeyhackr]

A missile hits a tower and conveys all of its kinetic energy, plus the heat of the exploding fuel. It imparts shock. The building reacts. Things bend and break. Rivets, struts, trusses, pins and cables exceed their design limits and snap and pop loose. Bolts shear. Welds break. Cantilevered beams are stressed beyond limit and fracture and crack. The concrete slabs on the upper levels shatter and pulverize. The building has a frequency response and so it rumbles and shakes, softening up the lower levels, and it oscillates, imparting huge torsion and shear stresses on the lower beams which crack and pop their anchors. And then the entire upper mass, minus whatever was ejected, all the particles that were flying laterally, are opposed by the far wall, and they recoil, as the far wall shatters.

The building had to be designed to withstand wind shear forces from any direction. The difference with an aircraft impact is that it is concentrated in a small area but it is over quickly. The buildings might have to withstand high winds for hours or even days.

The towers were designed to sway 36 inches at the top in a 150 mph wind. So that might come to 26 inches at the 81st floor where the plane impacted the south tower. The empirical data from the NIST indicates the building deflected 15 inches and then oscillated for four minutes.

Your physics drama is so impressive! I notice you don't actually include any hard data about anything.

psik

 

[Carcano]

That makes no sense. A skyscraper has to do both.

Yes and thats why skyscrapers have both.

A system of internal support columns for vertical gravity loads, and an external perimeter that resists lateral winds loads.

 

[Rhaedas]

The building had to be designed to withstand wind shear forces from any direction. The difference with an aircraft impact is that it is concentrated in a small area but it is over quickly. The buildings might have to withstand high winds for hours or even days.

The towers were designed to sway 36 inches at the top in a 150 mph wind. So that might come to 26 inches at the 81st floor where the plane impacted the south tower. The empirical data from the NIST indicates the building deflected 15 inches and then oscillated for four minutes.

You forgot what happened after the plane slammed into...no, THROUGH the building. Even if there is debris danger from a hurricane, it won't do what a fully fueled, full speed impact of a 767 will do internally.

Oh right, that had no effect to the tower.

 

[Read-Only]

Yes and thats why skyscrapers have both.

A system of internal support columns for vertical gravity loads, and an external perimeter that resists lateral winds loads.

Right! And that's not even to mention the effect of hundreds of tons of burning jet fuel !

 

[psikeyhackr]

Right! And that's not even to mention the effect of hundreds of tons of burning jet fuel !

10,000 gallons is 33 tons according to the NIST and half of that was burned off in the initial fireball.

psik

 

[Rhaedas]

10,000 gallons is 33 tons according to the NIST and half of that was burned off in the initial fireball.

Which set other things on fire. Never used diesel to start a burn pile, have you? Works nicely...

 

[psikeyhackr]

Which set other things on fire. Never used diesel to start a burn pile, have you? Works nicely...

Jet fuel is kerosene. But there was not hundreds of tons.

psik

 

[Rhaedas]

Jet fuel is kerosene. But there was not hundreds of tons.

Which has close characteristics to diesel. I never used Jet A to start a bonfire myself. And it wasn't the jet fuel that burned for an hour, so why do you needs tons? Missing the point?

 

[psikeyhackr]

Which has close characteristics to diesel. I never used Jet A to start a bonfire myself. And it wasn't the jet fuel that burned for an hour, so why do you needs tons? Missing the point?

The point is enough steel could not have been heated to weaken in two hours to collapse regardless.

That is why you exaggerate the quantity of jet fuel.

If the steel was equally distributed there would have been 900 tons on each level. So even if there was only 450 tons of steel it still conducts heat. It would have been conducted to floors without fires. So the argument that planes could bring the buildings down in less than two hours has always been absurd.

psik