Why WTC 1 and 2 collapsed on their own taking WTC 7 without explosives

Towers 1 and 2 of the World Trade Center were struck on the morning of September 11th, 2001. Video evidence reviewed by NIST showed that the planes struck so hard, that WTC 2 actually shook for four minutes after it was struck. It visibly shook for four minutes. This was the first of many things to cause the fatal collapse of the WTC 1 ,2 and eventually WTC 7 from damage inucurred during the collapse of WTC 1 and 2.

The first tower was struck, andthe airliners mass took multiple support columns along with it. These support columns created the main core the WTC and provided the ability to create a structure such as the WTC, which was over 950% "air" creating a commercial builders dream. This was the dream of the Rockefellers and early designs of the WTC were created to build one tower, and was later changed to 2. With the support structure damaged, the building slowly but steadfastly began to buckle from the upper floors down.

www.ara.com...

The link provides a video that shows the damage that was done to the inner support columns of the WTC. It was found that 33 of the 59 perimeter columns in WTC 1 were destroyed and 29 of 59 in WTC 2 after the impact of the airliners. This means that half of the support for the upper floors were damaged in both towers.

It is stated that it is a testament to the building that it actually stood for that long as the weight was redistributed after the inner column failure .A team for Silverstien Properties created a report on the collapse for his insurance on the Trade Center. It includes a few pictures that show the structural colllpase and buckling of the towers. This information was also reviewed by FEMA ad NIST. Please follow the below link.

www.construction.com...

As far as eyewitness accounts and pictures, there were 5 NYPD helicopters who all reported seeing buckling and a shift in the upper structure of the WTC towers. This is included in the NIST report and the 9/11 Commission report. It was added because they needed to show the breakdown of communication, and if the NYPD would have been able to directly contact the FDNY on the ground, they may have been able to evacuate sooner and saved more of their own that were still inside.

This is taken directly from the NIST report. This is four of many reports of structure shift and seeing critical structure failure outside the building in the impacted floors.

wtc.nist.gov...

Condition of WTC towers:
• At 9:30 am, a FDNY Chief Officer inside WTC 1 feels the building
move and makes the decision that the building is no longer safe.
• At 9:49 am, NYPD helicopters provide a radio report stating that “large
pieces” are falling from WTC 2.
• At 10:07 am, NYPD aviation units warn that WTC 1 may collapse.
• At 10:20 am, NYPD aviation unit reports that WTC 1 is leaning to the
south.

The towers, as explained earlier, was more than 95% air, so this is why the structure seemed to go straight down. There was nothing to prevent it from collapsing. Please read more about it here.

www.tms.org...

Now, after the collapse, their was damage to WTC 7 that most people seem to not recognize, and there is a NIST report that is due in 2006 that will use infomration that was provided in part by Silverstien Properties. A firefighter made the following statement that

" The most important operational decision to be made that afternoon was the collapse (Of the WTC towers) had damaged 7 World Trade Center, which is about a 50 story building, at Vesey between West Broadway and Washington Street. It had very heavy fire on many floors and I ordered the evacuation of an area sufficient around to protect our members, so we had to give up some rescue operations that were going on at the time and back the people away far enough so that if 7 World Trade did collapse, we [wouldn't] lose any more people. We continued to operate on what we could from that distance and approximately an hour and a half after that order was [given], at 5:30 in the afternoon, World Trade Center collapsed completely" - Daniel Nigro

This shows that there was prior knowledge of WTC 7 structural failure, and this should fit into the 'pull it' theory, were they were actually 'pulling' the rescue operatives back. They had evacuated WTC 7 just after the collapse due to damage but the FNDY and PA were continuing to use it as a staging area for the rescue and then recovery operation.
According to NIST, this is the damage that was sustained.
ttp://wtc.nist.gov/pubs/WTC%20Part%20IIC%20-%20WTC%207%20Collapse%20Final.pdf
There was minimal damage when WTC 2 collapsed, but After WTC 1 collapsed the following was reported.
􀂉 Heavy debris on Vesey Street and WTC 7 Promenade
􀂉 No heavy debris observed in lobby area, white dust coating
􀂉 SW Corner Damage – floors 8 to 18
􀂉 South face damage between two exterior columns - roof level
down 5 to 10 floors, extent not known
􀂉 South Face Damage –
• middle 1/4 -1/3 width south face, 10th floor to ground
• large debris hole near center around 14th floor
• 1/4 width south face, above 5th floor, atrium glass intact
• 8th / 9th floor from inside, visible south wall gone with more
damage to west, 2 elevator cars dislodged into elevator lobby


More than 1/3 of the WTC 7 was damaged after the collapse of WTC 1 and 2 were complete. Major portions of the lower levels were also destroyed after WTC 1 collapsed. The fires in the WTC 7 raged for over 7 hours. Fireproofing allows for a maimum of 2 hours of protection which shows that the structure was on fire and slowly collapsing due to structure failure and fires raging on floors 6 through the upper 30's. One final note, it took 33 seconds for the WTC 7 to collapse, it was not in an instant as shown in so many videos recordings posted on the web that show the final collapse of WTC 7. This is included in the FEMA report, chapter 5. The link is below.

www.fema.gov...


THis is a view that is not accepted by many in this community, but hopefully with it all together in one place, some of the conspiracy cloud may be lifted, and we can concentrate on proving that flight 93 was shot down. That is another thread.

how did the collapse of the WTC towers cause a collapse of one-third of 7 world trade's floors? if that's true, it sounds like 7 WTC was an accident waiting to happen. can the structure of a properly constructed office building utterly FAIL because the equivilent of a 4.0 earthquake shakes it for ten seconds?

please consider the implications of what you are claiming.

Good post esdad71 theres alot of interesting information to look over here. Its important to see other points of view a welcomed change of pace.

I also totally agree with you I also feel the "flight 93 was shot down" theory gets horribly overshadowed by other 9-11 theories. If people put half the effort into that one as some of the others we might be able to get to the bottom of it.


[edit on 22-3-2006 by ShadowXIX]

Towers rock back and forth all the time, they are supposed to. Explosives brought those towers down, that is the only logical explanation. You are just trying to get people upset so they will continue to post on this thread and you will earn some points. You don't even know what you are talking about and you aren't even qualified to talk about this subject. Here is a little experiment for you: get 2 steel marbles and setup a tower with 110 floors and use tissues for the floors. Drop both marbles at the same time from the same height, one next to the tower and one over the top of the tower. If they reach the floor at the same time then i will shut up.

On 9/11 the towers fell at free fall speed, meaning if i dropped a coconut off the side it would reach the bottom at the same time as the towers. This is impossible, they said the floors broke one at a time and broke each other as they fell, energy will be lost each time and there is no way it could fall at freefall speed. Do you honestly believe concrete has the same resistance as air? Swing through the air and then hit the wall and see for yourself. It should have taken at the very least, 60 to 110 seconds, but it should never have fallen. If steel buildings could fall like that without explosives then demolition companies would not exist.

Why is it more logical to believe a massive conspiracy that laced the entire building with exposives, while no one noticed.


As to the oft repeated "free fall" speed of the collapses here is a beautiful illustration.




Apologies to those who have seen this image a number of times, as long as people keep claiming free fall collapses this picture will continue to haunt us all.


Esdad brings up some very good points about WTC 7 that are often overlooked on conspiracy sites. They usually show a picture of a fire barely burning out a couple of windows.

The reality is that WTC 7 had massive damage from the collapse of two 110 story buildings in close proximity.

BTW he said 1/3 of the building was damaged, not that 1/3 of the floors had collapsed.

Originally posted by NinjaCodeMonkey
Towers rock back and forth all the time, they are supposed to. Explosives brought those towers down, that is the only logical explanation.

And having a plane slam into each tower, causing vast amounts of damage is no longer an acceptable cause for their collapse? Is not a logical cause for their collapse?
Towers are designed to rock back and forth in the wind. Not the same thing as being hit by a 767 that then goes on to destroy internal support columns. And let's not forget that there were two processes involved in the fall of each of the towers - the fall of the internal structure and the fall of the outer skeleton. Of course you're going to see differences in the pictures of the collapse.

I wondered this and considered this to be true...until I did some research.

If WTC 7 fell down because of damage from WTC 1&2, then it would have fallen over instead of straight down.

I have looked for every picture and/or video of other buildings that collapsed for whatever reason. They ALL fell crooked, not straight down. The only buildings I saw fall straight down were demolitions. All others fell crooked or partially fell.

I cannot ignore that.

I could easily dismiss 911 as a conspiracy if it wasn't for the way WTC 7 fell. To me, that is the key piece that points to something other than the official story.

If the answer as to why WTC 7 fell was so straightforward it seems surprising that NIST would make public statements saying they couldn't figure out why it collapsed and then take (so far) almost 5yrs to investigate it.

And as for the alleged 'proof' offered in the picture to refute free fall --- the pieces seemingly falling independently and at a faster rate than the rest of the falling mass (i.e., the upper floors) --- you can try but this is not proof. Why you ask with incredulity?

The falling upper floors started their descent with a velocity = 0. That is, the building was standing, something happened and then the mass began to fall. There was no downward force (other than the pull of gravity) acting on this mass when it began its fall. As the mass fell it began to accelerate at some rate up to the maximum of 32.15ft/sec/sec. If a piece of material was at rest (say a filing cabinet on a lower floor) and it was hit by a falling piece of debris it would absorb some of that falling debris' energy and as a result accelerate faster than gravity as it begins its fall. The object that hit it would slow. So now the filing cabinet is falling at a rate = acceleration from impact + 32.15ft/sec/sec.

Within the falling mass there are objects falling faster than free fall (because they absorbed energy from colliding objects) and others (the ones that hit them) that slow down because they transfered some of their accumulated energy. This is the Law of Conservation of Momentum/Energy. What is important is the measure of the velocity of the mass as a whole --- timed from the beginning of the collapse to the end.

Again, the Law of Conservation of Momentum requires that as the falling upper floors took out the structures below it the force required to take out those structures (the pancake theory) would have to come from the velocity of the falling mass (absent some additional outside force). This would cause the falling mass to slow as the energy required to overcome the resistance of those structures would have to be subtracted from the velocity of the falling upper floors. This would repeat for each subsequent floor.

We know without question that the lower floors would offer resistance since they were supporting until the upper floors hit them. Additionally, a vast quantity of pulverized concrete was created. The energy used to pulverize this concrete would also have to have come from the velocity of the falling mass. Conservation of Energy and Conservation of Momentum again requires that the falling mass be slowed by a force equal to that required to pulverize the concrete, twist the beams, etc.

All of the energy that deformed the materials (steel, concrete, etc.) as well as the energy needed to overcome the resistance of the still at least partially intact lower floors had to come from the energy of the falling mass. If the falling mass gave up some of its energy to affect these deformations it HAD to slow down. It didn't.

So there's an explanation for your faster falling pieces. Now if you added some energy to the collapse (or removed some resistance) with say... oh I don't know... an explosion or two. The fall would make perfect scientific sense.

I never read the NIST report. How did they explain the molten steel and the glowing metal found in the debris weeks after the collpase? Jet fuel?

Good post, esdad. I would like to clarify something though. The exterior columns and the interior core split the gravity loads about 50/50/ so that if 50 % of the columns on one face were damaged, that represented about 7% of the total (ignoring any damage to the core). However, It should be pointed out that this damage was not evenly distributed throughout the structure. In face, since it was concentrated in one area, the redistribution of the load paths puts inordinate stress on the adjacent columns, spandrels and beams.

In addition, a number of floor slabs were also directly damaged by the impact. Since the floor slabs served the function of stabilizing the exterior columns from buckling, this damage also severely weakened the structure.

I would also like to point out that the top of WTC 2 was tilted out of plumb after the impact.

Originally posted by NinjaCodeMonkey
Towers rock back and forth all the time, they are supposed to.

Yes, towers rock in the wind. A few feet at the most. This however was by far in excess of that.

Accounts from survivors from above the impact zone on WTC 2 indicate that the building tipped so far over, they thought it was going to fall. Additionally the shock of the impact and the rocking motions caused the interior walls to crack, doors to pop out of the frames and the tiles, lights and ductwork to fall out of the ceilings.

One other issue with the claim that the debris fell at free fall speed is the act that most measurements of the collapse speed are in fact measurements of the speed of the descent of the dust and debris ejected from the building envelope.

Since these materials are outside the building, it stands to reason they will fall at normal free fall speeds. For the case of the dust, the speed at which it falls would be a function of the particle size. Since we can validly assume that the range of particle sizes extended from large chunks and pieces to fine dust, the decent speed of the dust and debris would range from free fall all the way to suspended fine particles.

Thus the cloud of debris on the outside of the building envelope should decend at free fall speeds.

However, this same cloud of debris obscures the progress of the collapse front of the building structure, so that its true speed can not be reasonably ascertained. It is close to free fall, but not necessarily at true free fall speed.

Furthermore it can easily be shown that the ratio of the resistance of the structure to deformation and failure to the energy imparted to deformation of the structure by the falling building mass rapidly decreases to trivial levels early on in the collapse process.

Originally posted by HowardRoark
so that its true speed can not be reasonably ascertained. It is close to free fall, but not necessarily at true free fall speed.

Couldn't we take all the numerous siesmographs and come up with a reasonable number? I mean if the graphs are truelly just the fall of the building, then wouldn't that be a reasonable figure for the fall time?

Furthermore it can easily be shown that the ratio of the resistance of the structure to deformation and failure to the energy imparted to deformation of the structure by the falling building mass rapidly decreases to trivial levels early on in the collapse process.

Can you show this please? If it can easily be shown, then you shouldn't have a problem. Just curious about this.

Originally posted by Griff

Originally posted by HowardRoark
so that its true speed can not be reasonably ascertained. It is close to free fall, but not necessarily at true free fall speed.

Couldn't we take all the numerous siesmographs and come up with a reasonable number? I mean if the graphs are truelly just the fall of the building, then wouldn't that be a reasonable figure for the fall time?

No.

The duration of the seismograph signal has nothing to do with the duration of the collapse.

The duration of the seismograph signal is a function of the distance of the monitoring station from the source and the intervening geology.

If you go by that assumption, then according to See figure 3 of this report, based on the MANY graph, the north tower collapse took 20 seconds.

The seismic signal was generated by the impact of the falling mass with the ground.

Originally posted by Griff

Furthermore it can easily be shown that the ratio of the resistance of the structure to deformation and failure to the energy imparted to deformation of the structure by the falling building mass rapidly decreases to trivial levels early on in the collapse process.

Can you show this please? If it can easily be shown, then you shouldn't have a problem. Just curious about this.

One way to look at this would be to calculate the impact energy of a falling object. While I don’t think it is strictly correct to assume that the a single floor failed in the sense that the top of the building fell 12 feet then hit the next floor. Instead the failure was a group of floors to start with as the columns buckled inward.

Nevertheless, it is worthwhile to calculate the impact energy of an object falling a given distance.

We can play with this handy calculator to run a bunch of scenarios.

Assume a I kg object falls 3 meters. If the distance traveled after the impact is 0.1 meter, the impact force would be about 294 Newtons, the equivalent of about 30 kg, or 30 times the initial weight. That is well above the design limits for a single floor. Let’s say that the floor flexible enough to absorb some of the energy.

If we change the amount of travel after the impact to 1 meter, or one third of the floor to ceiling height then the force of the impact would be three times the initial weight, but since you have severely weakened the structure by allowing it to deform, you’ve dramatically reduced it’s failure load.

IN any case, that floor will fail, and there will be excess momentum that will be applied to the impact of the next floor. That excess momentum will quickly build up so that after a dozen or so floors, the resistance to the impacts become trivial compared to the force of the impact.

In reality, the failure was a buckling failure. This means that the failure wasn’t really one of successive impacts, but rather one where the columns successively lost their load carrying ability due to the deformation of their geometry. A signature characteristic of buckle failures is the speed at which they propagate.

cee.mit.edu...



[edit on 22-3-2006 by HowardRoark]

Originally posted by esdad71
The first tower was struck, andthe airliners mass took multiple support columns along with it. These support columns created the main core the WTC and provided the ability to create a structure such as the WTC, which was over 950% "air" creating a commercial builders dream.

I'm guessing you meant 95%.

The link provides a video that shows the damage that was done to the inner support columns of the WTC. It was found that 33 of the 59 perimeter columns in WTC 1 were destroyed and 29 of 59 in WTC 2 after the impact of the airliners. This means that half of the support for the upper floors were damaged in both towers.

Ok, a few things are wrong here.

· The perimeter columns were not "the inner support columns."

· 31 to 36 of the 240 perimeter columns were knocked out in the impact region of WTC1 according to FEMA.

· Around 23 of the 240 perimeter columns in the region of the WTC2 impact were knocked out according to FEMA.

Source 1 (FEMA) (Section 2.2.1.1 for WTC1; 2.2.2.2 for WTC2)
Source 2 (9/11 RS)

These numbers still stand, and no one has ever really disputed them because you can count them for yourself in the actual images.

That's not even half of the perimeter columns. That's less than 15% of the perimeter columns in either case, which would be less than 7% of the support columns in either tower, total. The core columns likely wouldn't be damaged by any parts of the jets except the engines, because the rest of the planes would've been too far broken up by the time they reached the thick core structures. That means about 2 core columns out of the better part of 50 in either tower at most.

It is stated that it is a testament to the building that it actually stood for that long as the weight was redistributed after the inner column failure .

Given that the column damage was not 50% but more like 7% or less, I wouldn't assert this.

The towers, as explained earlier, was more than 95% air, so this is why the structure seemed to go straight down. There was nothing to prevent it from collapsing. Please read more about it here.

How can you put on that this is logical? It's such a stupid excuse for symmetry that I hardly know how I can address it on a level that would make any sense to you.

First of all, what does 95% represent here? Are you saying that 95% of the mass of the towers was air (which would be a very stupid assumption, and yet seems to be more in line with what you're suggesting), or that the area of the towers mostly consisted of open air? Do you even know which it is?

I can tell you right now that 95% of the mass of the towers was not air. Of all the either 200,000 tons or 500,000 tons or however much they weighed, I am willing to bet you anything that most of that was NOT air, but steel, concrete, and solid materials.

And further, the parts of the buildings that were falling were constructed of the same stuff, and even more air I would venture because they were not required structurally to handle the same loads as the lower floors. It wasn't like a solid block of steel was falling upon a bunch of toothpicks with a lot of air in between.

Now, after the collapse, their was damage to WTC 7 that most people seem to not recognize, and there is a NIST report that is due in 2006 that will use infomration that was provided in part by Silverstien Properties.

Then I would wait for that report. As it stands, there is no evidence of either severe fires or structural damage threatening of global collapse of WTC7, unless it was built ridiculously under the standards required by law in NYC for skyscrapers.

More than 1/3 of the WTC 7 was damaged after the collapse of WTC 1 and 2 were complete.

I doubt this is true, and I know that you don't have any evidence for it.

Fireproofing allows for a maimum of 2 hours of protection which shows that the structure was on fire and slowly collapsing due to structure failure and fires raging on floors 6 through the upper 30's.

Can you post some pictures of these intense fires?

I won't contest whatever you say about fireproofing, because it's irrelevant anyway. Steel only loses critical strength when heated to around 600 C and above. Hydrocarbon fires, which would have been the type of fire in WTC7, will burn at a sustained 825 C ABSOLUTE MAX, meaning in the absolute best conditions for a hydrocarbon fire. Even at these temperatures sustained, which likely weren't reached, there still has to be energy heat energy transferred between the fire and steel columns to heat the steel beyond 600 C for an actual failure. It'd have to be more like 700 or 800 C, when steel loses up to 80% or so of its strength, unless, again, the buildings were built extremely hapharzardly and illegally. I've seen no evidence of this, and the fact that they were allowed to open seems evidence enough to the contrary.

For fires under 825 C to heat steel to above 600 C, to even 700 C, would require pretty unusual conditions. First, almost no energy (heat) could be transferred and carried away by the air, in smoke or etc. That alone pretty much kills the theory of heat-related collapse to anyone thinking realistically here. But further than that, you have the steel conducting the heat as it does, away from the source and further up/down/across the lengths/widths/whatever of the whole columns.

Here are a couple pics of the fire in WTC7:




I'm sure most people here have seen all the other skyscraper fires, which have been much more severe than any in the WTC, and lasted much longer, and yet suffered no critical damage in the least. That includes steel skyscrapers. These fires were pathetic in terms of skyscraper fires. And again, all of the damage from the WTC Tower collapses was external. The whole of WTC7 was not relying on a few parts of its exterior to stand; no one would build a skyscraper like that, and no one would be allowed to in such a crowded area.

One final note, it took 33 seconds for the WTC 7 to collapse, it was not in an instant as shown in so many videos recordings posted on the web that show the final collapse of WTC 7. This is included in the FEMA report, chapter 5. The link is below.

The time taken for the roof to reach the ground was not 33 seconds. This time would still be subject to laws of gravity, unfortunately.

[edit on 22-3-2006 by bsbray11]

Nice try, and I appreciate your comments.

1. You are talking about perimeter columns, not core columns. You should make sure what you type is correct.

2. I provided links in the post that take you to the firefighters and show pictures of the fires and some damage. The name of the firefighter is there and you can contact him if you want, I'll take his word on it since he was there. His name is Daniel Nigro. Also, the damage is from the NIST report.

3. You do not understand the air concept and that is OK, I don't need it explained to me and obviously you do not understand. It may seem like to many things to piece together at once.

4. I am glad you think that fire proofing is irrelevant, since it is somehting that is mandatory, and the WTC were all not up to code.

5. Can you name ONE skyscraper, designed the same way as the WTC, that survived a fire and a hit from an airliner?

6. Look into the NIST WTC 7 report, there are early versions on the web, and it will describe the structure, and the changes that were made. These eventually led to collapse 7 hours after the towers were hit.


oh, by the way, got that demolition evidence yet?

1. You are talking about perimeter columns, not core columns. You should make sure what you type is correct.

What I said was correct. I discussed both the perimeter and core columns in my post above. You should understand that there are no figures for the core columns and any statements on their conditions would be speculation only, from any side.

2. I provided links in the post that take you to the firefighters and show pictures of the fires and some damage. The name of the firefighter is there and you can contact him if you want, I'll take his word on it since he was there. His name is Daniel Nigro. Also, the damage is from the NIST report.

Provide whatever evidence NIST offers here (preferably photographic, and NIST has had thousands to choose from). I don't care what the firefighter says, either, unless he's also a structural engineer or can at least tell the difference between superficial damage to a structure and damage threatening a global collapse.

3. You do not understand the air concept and that is OK, I don't need it explained to me and obviously you do not understand. It may seem like to many things to piece together at once.

Ok, wtf. You can at least try to discuss this like an adult before withdrawing into this kind of crap.

I asked whether the figure of 95% air reflected MASS or AREA.

Can you answer that simple question? (Hint: 95% of the buildings' weights didn't consist of air. )

4. I am glad you think that fire proofing is irrelevant, since it is somehting that is mandatory, and the WTC were all not up to code.

Refer to my comments on steel integrity and heat, which you've ignored here.

5. Can you name ONE skyscraper, designed the same way as the WTC, that survived a fire and a hit from an airliner?

No, because no matter how similar a building may be to the construction of the WTC, you'll call foul on whatever differences are there.

The Caracas Tower was a steel skyscraper that suffered a 17-hour long, 26-floor fire without major damage. But again, you'll call foul somewhere, I'm sure.

6. Look into the NIST WTC 7 report, there are early versions on the web, and it will describe the structure, and the changes that were made. These eventually led to collapse 7 hours after the towers were hit.

Prove it.

[edit on 22-3-2006 by bsbray11]

I am providing information, I don't have to prove anything. The people who did the research do that for me, if you would read it.

You should follow the link i gave and it will explain the columns for you, that is why i gave it to you.

You care not to believe FEMA and NIST, that is fine. What about the group of scholars that was put together by Siverstien properties, who came to the same conclusion. Can you beleive them?

The firefighter was a witness, and you do not need to be a structural engineer to read these reports.

Keep on living in denial and again I will ask, where is your proof of demolition?

[edit on 22-3-2006 by esdad71]

Originally posted by esdad71
I am providing information, I don't have to prove anything.

Esdad, I'm putting you back on ignore. I honestly hope that you aren't an adult.

youtube.com...


this is an excellent video

Originally posted by bsbray11
The Caracas Tower was a steel skyscraper that suffered a 17-hour long, 26-floor fire without major damage. But again, you'll call foul somewhere, I'm sure.

FOUL



That is not true and you know it. :p :p :p