NIST Officially Admits Freefall Speed re:WTC 7!!

dr. jones was sent actual steel from the towers.
just a little fact correction for anchordude (sorry i don't remember your handle, and i don't feel like hitting the back button).

p.s. i don't trust dr. jones. i think he may be a gatekeeper.

Originally posted by billybob
dr. jones was sent actual steel from the towers.
just a little fact correction for anchordude (sorry i don't remember your handle, and i don't feel like hitting the back button).

p.s. i don't trust dr. jones. i think he may be a gatekeeper.

Where is the documented?
I read his analysis and in thre he talks about reports of and basis his inforamtion off of others.

To the best of my knowledge niether the FBI nor any other governmental agency released any evidence to thrid parties.

Where did he get it then?

Originally posted by Griff

Originally posted by Achorwrath
15% based on what?

Actual observation.

Where did you get this information can you show me?

NIST

The tower lost 8 floors ( 93 to 101) worth of integrity on one side the side that feel first. from the curtain wall to at least the core steel beams.

First, you question where I get an observable fact, then you go on and tell me something non-observable?

Second, they did not start failing on the sides that were hit. Look at the tilt of tower 2. It is tilting AWAY from the side that was hit.

Now you have stated that you are a structural engineer (or at least working on being one) what does this type of support loss mean to you?

It means the towers would stand. As they did.

You should know that the loss of that much of the support system (remember the outer curtain wall (later sway control) is supported by the floor beams conncting from the outer wall to the inner core supports.

Can you show how 8 floors worth of support loss to less than 8% of the building causes "massive" damage and collapse?

Now you have up to 8 floors that are compromised along a single axis of support.

Was it the weak or strong axis?

You are making an assumption about the type of steel used,

No, I'm not. It was A-36 construction steel for the columns.

typically steel used in construction has only 2.1% carbon meaning that its solidus point is 1130. Steal looses 50% strength at 1/2 its solidus point; this case 565C

Well, now that your site has been called out as incorrectly saying that a major loss of integrity happens at 300C, you move the goal posts.

Just remember that for the official story to be true, the steel would have to reach over 600C not the fire temperature.

Can you point to the evidence that this happened?

But can loose as much as 30% stregnth with as little at 350C.

Can you site this information? And is 30% strength loss significant with a FOS greater than 2.5?

Please remember that airplane fires have been logged at temperatures of up to 3000F due to the burning of accelerants and the metal of the aircraft.

Temperature of fire and temperature of steel in a fire are 2 totally different things.

How were the temperatures of the metal tested can you link that?

NIST.

I think the biggest thing that is overlooked is the damage to the building, it is not a typical building it was built with a central core and an outer colum support for sway they then tied the floor beams into the outer colums to add support to them. Once that support was damaged it weakened the whole building.

And what happened to the lateral support within the core itself?

[edit on 3/16/2009 by Griff]

There is no lateral support in the core,
the core is only desgined to support the wieght of the floors. The outer curatin wall and the floor beams were all that contained lateral sway

The towers were designed as framed tube structures, which provided tenants with open floor plans, uninterrupted by columns or walls. This was accomplished using numerous closely-spaced perimeter columns to provide much of the strength to the structure, along with gravity load shared with the core columns. The elevator system, which made use of sky lobbies and a system of express and local elevators, allowed substantial floor space to be freed up for use as office space by making the structural core smaller. The design and construction of the World Trade Center twin towers involved many other innovative techniques, such as the slurry wall for digging the foundation, and wind tunnel experiments.

Underlined by me to stand out.
source

The WTC team took a slightly different approach. They decided to build long "tubes," where all the support columns would be around the outside of the building and at the central core of the building. Essentially, each tower was a box within a box, joined by horizontal trusses at each floor.

The outer box, measuring 208 feet by 208 feet (63x63 m), was made up of 14-inch (36-cm) wide steel columns, 59 per building face, spaced just over 3 feet (1 m) apart. On every floor above the plaza level, the spaces between the columns housed 22-inch (56-cm) windows. Yamasaki, who had a pronounced fear of heights, felt that the small windows made the building feel more secure. The columns were covered with aluminum, giving the towers a distinctive silver color. The inner box at the core of each tower measured about 135 feet by 85 feet (41x26 m). Its 47 heavy steel columns surrounded a large open area housing elevators, stairwells and restrooms

source

Yamasaki and engineers John Skilling and Les Robertson worked closely, and the relationship between the towers' design and structure was clear. Faced with the difficulties of building to unprecedented heights, the engineers employed an innovative structural model: a rigid "hollow tube" of closely spaced steel columns with floor trusses extended across to a central core. The columns, finished with a silver-colored aluminum alloy, were 18 3/4" wide and set only 22" apart, making the towers appear from afar to have no windows at all.

Source

Originally posted by Achorwrath
There is no lateral support in the core,

[atsimg]http://files.abovetopsecret.com/images/member/1d2d3b64e0fd.jpg[/atsimg]

Source: NIST

Those beams within the core structure give the core lateral support.

[edit on 3/16/2009 by Griff]

[edit on 3/16/2009 by Griff]

Originally posted by Griff

Originally posted by Achorwrath
There is no lateral support in the core,

[atsimg]http://files.abovetopsecret.com/images/member/1d2d3b64e0fd.jpg[/atsimg]

Source: NIST

Those beams within the core structure give the core lateral support.

[edit on 3/16/2009 by Griff]

[edit on 3/16/2009 by Griff]

As I have mentioned NIST got a lot wrong, that is one of them. Note how they show I Beams in the central core; WTC towers 1 & 2 used BOXED STEEL BEAMS not I-Beams hence that drawing is highly suspect.
The designers did not intend for the cntral core to do much other than maintain gravity support. the outer curtain wall provided lateral sway, it was later decided that just the outer wall was not enough and they needed to tie the floor beams to the central core to maintain lateral control. also not in the engineering information that the outer collums provided "much of the building strength"

Next looking at the diagram above think about how much of that floor structure and central core would be damaged by the impact of an airplane. now carry that across eight floors.

Yes the damage will not be identical but each of the eight impacted (I think WTC 2 actually had nine damaged floors) floors is now no longer providing complete support for the rest of the building.

so again you have lost a good deal of lateral support and potentially gravity support for everything about the 93rd floor.
I made an esitmate that was from memory and making assumptions that each floor was roughly 3400 tons there are 17 floors above the 93rd meaning that those floors were now trying to support about 54,000 tons.

It is highly likely that even a 10% reduction in the strength of the supporting beams caused by the fire could bring the top of the building down on top of the rest as seen in the video footage of the collapse.

One other thing to mention, they concrete slabs used for the floors were not part of the beam grid they were placed on top of them. This weight further impacts the damaged support and the missing outer support colums.




[edit on 17-3-2009 by Achorwrath]

reply to post by Achorwrath


The outer columns could not provide both lateral movement and carry most of the vertical weight.

It's obvious the central structure of 48 massive columns provided the majority of the vertical support, and the outer mesh structure, that was designed to move laterally, helped take the lateral load.

If you did it the other way the buildings wouldn't have even been able to hold themselves up. If you made the outer columns big enough to take the vertical load then they wouldn't be able to move when the building swayed. The building moves the most on it's outer walls when it sways right? So why would you make the outer columns take the vertical load?
It wouldn't work.

And you're making an assumption about the planes damaging the central columns. There is NO proof of this and physics tells us the damage would very minimal if any at all. Learn some basic physics.

When two objects collide the forces are equal on both objects, the object with the least mass will sustain the most damage. Aluminum aircraft against construction steel, do the math...

[edit on 3/16/2009 by ANOK]

Originally posted by ANOK
reply to post by Achorwrath

 

Dude you are just waaay wrong.

If you knew anything about engineering, or construction, you would know why your idea of how the towers were constructed is wrong.

The outer columns could not provide both lateral movement and carry most of the vertical weight.

It's obvious the central structure of 48 massive columns provided the majority of the vertical support, and the outer mesh structure, that was designed to move laterally, helped take the lateral load.

If you did it the other way the buildings wouldn't have even been able to hold themselves up. If you made the outer columns big enough to take the vertical load then they wouldn't be able to move when the building swayed. The building moves the most on it's outer walls when it sways right? So why would you make the central columns take the lateral load?
It wouldn't work.

And you're making an assumption about the planes damaging the central columns. There is NO proof of this and physics tells us the damage would very minimal if any at all. Learn some basic physics.

When two objects collide the forces are equal on both objects, the object with the least mass will sustain the most damage. Aluminum aircraft against construction steel, do the math...

Are you forgetting inertia/kinetic energy?
I never said the outer wall made up the gravity support, in fact I think all along I have said Lateral support. but as the floor beam tied into both the outer curtain colums and the cnetral core (with nothing supporting them in between) I do not see how you can possibly expect the central core to bear all of that wieght


Hmmm since impact force = mass x acceleration

We have a maximum take off wieght of 449,064 Pounds so lets say it was 70% loaded meaning 313,344.8 Lbs now we multiply this by 70% maximum speed 568Mph 397.6 Mph.

Srouce for weight and Max Cruising Speed

So that means the 767 hit the tower with approximately 124,585,892.48 Pounds of force.

This could be a higher or lower number but as I do not have the exact speed or wieght at impact on hand I can only estimate the impact force.

Do you really think there was no damage to the central core after that?
rememer the central core was not designed to take lateral sawy and the building would have made a huge shift, after all the body in motion (the plane) would have tried to impart its inertia/kinetic energy into the body at rest (the building)

people in the upper floors reported being thrown to the ground after the impact.
the elevators and stairs were damaged (as reported by firefighters and people that were in the upper floors) this means the central core was compromised remember all stairwells and elevators were in the central core.

Edited to correct incorrect wording



[edit on 17-3-2009 by Achorwrath]

I want to make sure to remind all the participants here we are talking about NIST admitting that YES WTC 7 did fall at free fall speed which is not possible without a complete lack of resistance.

We are not talking about WTC 1&2. However my point of view on 1&2 is that logically the buildings should have toppled towards the side of the damage.

I can't remember off hand but one of those towers 1 or 2 began to topple then all resistance disappeared miraculously and the damaged upper floors of the building suddenly straightened itself and fell basically into its own footprint.

How could this happen without the core columns being cut or removed?? I just don't see it! THE BUILDINGS SHOULD HAVE TOPPLED!!!! THERE WAS TOO MUCH RESISTANCE BELOW FOR THAT NOT TO HAPPEN!!!

But again this article is about WTC 7 falling at free fall speed as acknowledged by NIST. Impossible unless ALL resistance is removed!!!

Maybe someday some official will explain the implications of this admission to the sleeping public.

Since this thread is about WTC7, I'll address that building only. Since it was full of government workers (FBI, Secret Service, etc.), it could have been openly rigged for demolition without fear of being outed. If you notice in the videos, the other buildings didn't go down as cleanly as 7, suggesting a less professional job of rigging them. I do think the government story of terrorists flying planes into the building is accurate, but I believe that the government had foreknowledge of the attacks and rigged the buildings to "help" them go down after the planes hit.

You are right, sorry I got side tracked talking about the damage to the WTC7 from the debris of WTC 1 & 2.

The near free fall (94%) was only for about 2.2 seconds.
This is easy to account for if you think about it.

Not only that but as has been show in this thread there were multiple double floors.

In fact it was posted in this thread tat WTC7 was built to have sections of flooring removed to accomodate this.

How does multiple double floors fit into this? It throws a kink into the math

If floors 16 and 17 (for example) were a single space then the collapse would have appeared to be in "freeall" while those impacted each other.
How long do you think it would take for those to impact?

Also do you think that multiple double floor offices would have weakened an already under supported structure?


Why is it that the double floor offices are never brought into this event?


[edit on 16-3-2009 by Achorwrath]

Originally posted by Achorwrath
As I have mentioned NIST got a lot wrong, that is one of them. Note how they show I Beams in the central core; WTC towers 1 & 2 used BOXED STEEL BEAMS not I-Beams hence that drawing is highly suspect.

The steel box columns changed to H-columns well before the impact floors, so that is correct for a typical floor that was hit by the planes.

But, the columns are not the point. Those lines that connect those columns represent beams that connect the columns. Which give lateral support. Period.

There would be no way in hell they would design those inner columns with no lateral support. Ever hear of Euler and his buckling equation?

So, just because someone didn't come out and tell you that the core had it's own lateral support, you can clearly deduce it if you know engineering design and also from the information given to us by NIST.

Without lateral support, those columns would buckle under their own weight.

So, when you say the core had no lateral support, you are incorrect. Period.

It is highly likely that even a 10% reduction in the strength of the supporting beams caused by the fire could bring the top of the building down on top of the rest as seen in the video footage of the collapse.

Have ANY math to back this up?

One other thing to mention, they concrete slabs used for the floors were not part of the beam grid they were placed on top of them. This weight further impacts the damaged support and the missing outer support colums.

One thing to mention is that you are again incorrect. A composite floor system is part of the beam grid. The concrete has truss knuckles imbedded into it that cause the whole system to act as one. Look it up

Originally posted by Achorwrath
Hmmm since impact force = mass x acceleration

We have a maximum take off wieght of 449,064 Pounds so lets say it was 70% loaded meaning 313,344.8 Lbs now we multiply this by 70% maximum speed 568Mph 397.6 Mph.

Srouce for weight and Max Cruising Speed

So that means the 767 hit the tower with approximately 124,585,892.48 Pounds of force.

How does speed equal acceleration?

This could be a higher or lower number but as I do not have the exact speed or wieght at impact on hand I can only estimate the impact force.

To estimate the impact force you would need acceleration, not speed.

reply to post by Achorwrath


Just because floors were double spaced doesn't take away the columns and their resistance to keep the building up.

Or do you want us to believe that those double floors had no columns (interior and exterior)?

Originally posted by Griff

Originally posted by Achorwrath
As I have mentioned NIST got a lot wrong, that is one of them. Note how they show I Beams in the central core; WTC towers 1 & 2 used BOXED STEEL BEAMS not I-Beams hence that drawing is highly suspect.

The steel box columns changed to H-columns well before the impact floors, so that is correct for a typical floor that was hit by the planes.

But, the columns are not the point. Those lines that connect those columns represent beams that connect the columns. Which give lateral support. Period.

There would be no way in hell they would design those inner columns with no lateral support. Ever hear of Euler and his buckling equation?

So, just because someone didn't come out and tell you that the core had it's own lateral support, you can clearly deduce it if you know engineering design and also from the information given to us by NIST.

Without lateral support, those columns would buckle under their own weight.

So, when you say the core had no lateral support, you are incorrect. Period.

It is highly likely that even a 10% reduction in the strength of the supporting beams caused by the fire could bring the top of the building down on top of the rest as seen in the video footage of the collapse.

Have ANY math to back this up?

One other thing to mention, they concrete slabs used for the floors were not part of the beam grid they were placed on top of them. This weight further impacts the damaged support and the missing outer support colums.

One thing to mention is that you are again incorrect. A composite floor system is part of the beam grid. The concrete has truss knuckles imbedded into it that cause the whole system to act as one. Look it up

The composite floor system used open web bar trusses. These have nowhere near the regidity or strength of a Box Beam or I/H beam.


Journal of Enginerring

Not the concerns for mounting. does anyone know how these were attached? There are some that say welded but I have also read bolted. Either can be affected by impact.

Steel Joists

Note is says that Steel Joist have a life of over 60 years. meaning they were at roughly their half life.

Originally posted by Griff

Originally posted by Achorwrath
Hmmm since impact force = mass x acceleration

We have a maximum take off wieght of 449,064 Pounds so lets say it was 70% loaded meaning 313,344.8 Lbs now we multiply this by 70% maximum speed 568Mph 397.6 Mph.

Srouce for weight and Max Cruising Speed

So that means the 767 hit the tower with approximately 124,585,892.48 Pounds of force.

How does speed equal acceleration?

This could be a higher or lower number but as I do not have the exact speed or wieght at impact on hand I can only estimate the impact force.

To estimate the impact force you would need acceleration, not speed.

Perhaps the formual for Kentic Engery would be better?

The speed of impact of AA Flight 11 has been estimated to be 470 mph = 689 ft/s.
The speed of impact of UA Flight 175 has been estimated to be 590 mph = 865 ft/s.

The kinetic energy released by the impact of AA Flight 11 was
= 0.5 x 395,000 x (689)^2/32.174
= 2.914 billion ft lbs force



The kinetic energy released by the impact of UA Flight 175 was
= 0.5 x 395,000 x (865)^2/32.174
= 4.593 billion ft lbs force

Now many will say that the WTC was designed to survive an impact by a 707 (which has a greater potential Kinetic energy)

However even the desingers admit they did not design it for a full speed impact but to account for a lost plane (like the ones that hit the empire state building and 40 wall street) so lets slow the 707 down

300MHP - 440Fps (roughly half max crusie speed)
Max take off wieght 336,000
0.5 x 336,000 x (440)^2/32.174
1.010903213 billion ft lbs force

The two planes hit at lest 2 times and 175 hit at almost 4 times this force



[edited to place ^ in formual to represent squaring the number and to add in comparative force of slow moving 707]

[edit on 17-3-2009 by Achorwrath]

Originally posted by Griff
reply to post by Achorwrath

 

Just because floors were double spaced doesn't take away the columns and their resistance to keep the building up.

Or do you want us to believe that those double floors had no columns (interior and exterior)?

and if the colums are compromised? As is indicated by the video? remember there was only central support all the way through the center of the building.
The exterior support colums did not start until Floor 5

[edit on 17-3-2009 by Achorwrath]

Originally posted by Achorwrath

Originally posted by Griff

One thing to mention is that you are again incorrect. A composite floor system is part of the beam grid. The concrete has truss knuckles imbedded into it that cause the whole system to act as one. Look it up

The composite floor system used open web bar trusses. These have nowhere near the regidity or strength of a Box Beam or I/H beam.

This has nothing to do with what I said.

You said the concrete floor was laid on the beams. I corrected you and told you that the concrete has truss knuckles inbedded in it to cause it to act as a whole structure.

[atsimg]http://files.abovetopsecret.com/images/member/075ee678df94.jpg[/atsimg]

[atsimg]http://files.abovetopsecret.com/images/member/378d86f80312.jpg[/atsimg]

Those are from NIST.

Notice the knuckles extend 3-inches into the 4-inch concrete slab?

Originally posted by Achorwrath
The kinetic energy released by the impact of AA Flight 11 was
= 0.5 x 395,000 x (689)^2/32.174
= 2.914 billion ft lbs force

Your units don't work.

1/2mv^2 would equal lbs x ft^2/sec^2

Not ft-lbs force.

Again, you are mixing up force with energy (which has the units of Joules (lb-ft^2/sec^2)).

The two planes hit at lest 2 times and 175 hit at almost 4 times this force

Again. Pick one. Either energy or force. They are NOT the same.

Originally posted by Achorwrath
and if the colums are compromised? As is indicated by the video? remember there was only central support all the way through the center of the building.
The exterior support colums did not start until Floor 5

OK. So, you just shot yourself in the foot.

If the exterior columns didn't start until the fifth floor, then any damage to the exterior columns would be negligible when considering the interior columns. Since the interior columns would be used as 100% of the gravity resistance.

[edit on 3/17/2009 by Griff]