Sure, even those not having much knowledge can make calculation. And that includes yourself.
No it is not impossible, but it is also as well impossible for such stunt and not one person involved been identified. Specially with all the suppose to be SOLID, UNDENIABLE proof all over.
You folks been insisting of a bomb. Won't get you no where until you provide bomb traces, what kind of bomb, where did it come from and who planted it.
Ever wonder why after the video and witness you folks hits a wall and your claim won't advance?
Alex Jones should move on from videos and witnesses, now it's time to verify and prove the videos and witness are valid, Agree?

I know, I can't wait either. Unfortunately we'll have to wait until the Sept 11th Anniversary.

Mainly because I am an engineer and can see how so many of the conspiracy claims make no sense in engineering terms. I can see nothing in the way the buildings collapsed that required controlled demolition, nothing that makes me see any necessity for mini-nukes, particle beam weapons, mis-identified airliners or any of the rest of the nonsense that you can read in this forum. Until the conspiracy theorists can come up with some actual evidence rather than a lot of innuendo and misunderstandings of how the physical world works, they have no case.

Oh, and as for your "use the altimeter" claim, what evidence do you have that the incoming aircraft were flying at a constant height?

what a joke! let me ask you this-- are you blind??-- have you lost your vision or is it impaired to the point of being legally blind?-- because that is the only excuse a legitamate engineer could possibly have for making such outrageous claims-- even dan rather and peter jennings who are not engineers have the common sense to call a duck a duck-- disregaurding the bush administrations propaganda of nukes and particle beams does not entitle you to claim ignorance on the other issues-- only a severly incompetent quack of an engineer could look at the collapse of bldg 7 and not conclude that it was imploded -- i also find it quite amusing to see you disinfo spin artists squirm under the weight of the barry jennings testimony that conclusively eliminates all doubt as to whether or not there were bombs in wtc 7 that were detonating BEFORE either tower collapsed and contributed to its imminent implosion-- never mind the fact that every eye witness made the same claim which can be backed up with documented video which is that there were secondary devices that can be clearly heard in multiple videos that you are making a conscience decision to ignore

Then surely the vast majority of the engineering world would be up in arms against the 9/11 conspiracy. But they're not - don't they have the internet?

Ok, I don't understand one thing. So there were bombs involved, controlled demolitions. I can believe that.

How does this prove that the government was involved?

So you can see that 9/11 as a false flag operation was possible.

It is interesting you raise the topic of people involved not being identified. Most people know that a number of the named 'hijackers' have been found alive. So who were the men on the airliners? The only ‘evidence’ we have of Bin Laden being involved is an obviously faked video tape supposedly found by US troops in Afghanistan. Then the FBI themselves have stated “The reason why 9/11 is not mentioned on Usama Bin Laden’s Most Wanted page is because the FBI has no hard evidence connecting Bin Laden to 9/11.” This also backed up by then director of the FBI Robert Mueller who said in a speech “The hijackers also left no paper trail. In our investigation, we have not uncovered a single piece of paper” So, whether you follow the official story or the conspiracy theory, the people involved have not been identified to a degree that would stand up in court

With 9/11 as an inside job it is safe to say that the perpetrators wanted absolutely to cover their tracks. Therefore why is it surprising there is no hard direct evidence linking anyone to the operation? There is though plenty of circumstantial evidence linking the likes of Donald Rumsfeld and Dick Cheney to the operation. Check Rumsfeld’s assertion that Flight 93 was shotdown and Cheney’s “the orders still stand” episode to get interested. Read up on their PNAC involvement and Rebuilding America’s Defences document for their motives.



It is amusing you accuse conspiracy theorists of a lot of innuendo when your own post is full of rhetoric and not much substance flyingswan. Can you, as an engineer, explain how the top portions of WTC1&2 crushed the rest of the structure at freefall speed? How did WTC7 collapse on itself due to fires and relatively minor damage to one face, also at freefall speed? Or how an explosion occurred in WTC7 before the twin towers had collapsed? If you can convincingly explain away those issues I am sure conspiracy theorists will be impressed. Incidently, my brother happens to be a qualified engineer and welder yet he cannot account for the collapse of the buildings without factoring in explosives.

I do totally agree with you on the mini-nukes and particle beam weapons (promoted by only a small percentage of conspiracy theorists) being farfetched.



Well, that was actually AROCES suggestion. I prefer the idea of the airliners being guided, as I outlined in my earlier post, to ensure they impacted the towers where required. I am not saying that I know exactly what did or did not happen, just suggesting ways that an inside job was very possible.



Assuming you accept the involvement of a controlled demolition Dr Who, who else do you think could have orchestrated the attack? Think who had the means and motive. Ask yourself who has benefited.

Why is it so unreasonable to believe that the terrorists could have planned the bombs and the controlled demolition?

Heh. I go with the "Boom boom boom boom" because many have presented Vids with one or two explosions as proof of CD when if one or two explosions of that size would have left some radiation.

As far as being drowned out I doubt it due to the vibrations. To cut that much steel it would have had to be a lot of explosives and that would have still been heard. If thermite/thermate was involved, why didn't it react to the impact of the planes? How did it cut the supports since it could only go down? How did that much thermite/mate get there? Where is the barium Nitrate?




Did a CD charge go off, or was it something else?

I have gone into these aspects in more detail in previous threads.
In sum: no-one on the conspiracy side has explained how fast the buildings should fall. My qualified opinion is that once the top floors start moving, the lower floors are loaded far beyond anything they were designed for and offer little resistance.
WTC7 had been burning for a long time before it collapsed. It had an added penthouse that reduced the structural margins. Eventually due to fire damage and thermal stresses the structure beneath the penthouse gave way and it collapsed into the building. A few seconds later, with a lot of interior structure now gone, the rest of the building collapsed very easily.
The witness inside WTC7 seemed to pack a lot of activities into the time between the impact and his "explosion". I am not convinced by his assertion that his "explosion" came before the tower collapse.

no the windsor tower burned for a long time--bldg 7 had isolated pockets limited to about 12-14 offices on one side of the building and burned for only a few hours-- and what do you have to say about the squibs caught in the video of the collapse running up the side of the building?

My theory is that if the terrorists could have posed as pilots and American citizens, then they could have easily posed as workers too and planted explosive demolition devices within the buildings. Could anyone explain to me why this would be an unreasonable theory?

I believe it is too radical to simply ASSUME that the Bush Administration was behind it all. So far I have seen concrete proof that the towers fell for other reasons than simply and airplane crash, but I have seen NO proof that the government had anything to do with it. To me, the theory that the U.S. government was involved is a paranoid reaction to a incredibly tragic event. But, I would love to be proven wrong, and I would greatly appreciate if anyone could show me some concrete PROOF of the U.S. false flag involvement.

Nope, I merely meant that it is always possible for some lunatic to try it or think about it, and it would have been busted on the planning stage alone. The thing is, you are giving too much admiration to the intelligence and smarts of our govt, thinking that there are those in the govt who is that brilliant and smart to pull such stunt without any trace.
I don't think so, and the difference is you think some in the govt are way too smart.

maybe because someone already snuck bombs in back in 93 and explosive k-9s were the norm-- did you know that our current presidents first oil company "arbusto energy" was financed by the bin ladens? did you know that there were wargames occuring on that morning that mimicked the real life scenario of hijacked aircraft attacking the wtc? are you aware that in the past two years norad had been activated 59 times without fail one of them being the vectoring of golfer paine stewarts plane in 16 minutes after he died when his plane lost compression?-- are you aware that the attack of the pentagon,which norad failed to defend and was attacked 45 minutes AFTER the SECOND tower was attacked eliminating all doubt as to the nature of the attack, required the commendeering of the plane by some one who had never been in a commercial cockpit and the perfect navigation across multiple states only to perform a 270 degree bank at 500mph perfectly leveling off in order to strike the pentagon on its side without even scraping the grass?(a feat compared to hitting the side of a nickel from that altitude compared to the wtc towers by a commercial pilot veteran who doubted he could perform the manuever with his experience) -- why would guilianni a former ny prosecutor immediately destroy evidence by shipping it to china under armed gaurd for recycling?(fire fighting engineering magazine had a word or two to say about that google it) -- then came the us military grade anthrax attack forcing the patriot acts approval without being read which had been already drafted and waiting in the wings for just such an event even prophecised by the pnac group in the paper"rebuilding americas defense" just weeks prior to the attacks-- the ensuing cover up is final nail in the coffin though as far as bush administration complicity goes

Maybe means you are making up a gossip.


And how did you know? No blogs please.


Who? Who were doing the wargames?


And you suggest we should have shot down a commercial airplane? And then call Bush and NORAD trigger happy?


FLIGHT SIMULATORS, you can easily learn maneuveing now with flight simulators.


How come Bin Laden and the terrorist not agreeing with you that it is not them??????

Sorry, that is wrong.
The intercept of Stewart's plane took over an hour. The time has been reported incorrectly by many sources due to a confusion with the time zones. Check for yourself in the official report from the NTSB here
http://www.ntsb.gov/Publictn/2000/AAB0001.htm
Last contact was made at 0927:18 EDT. Contact attempted at 0933:38 EDT. The controller continued to try to contact for an addition 4 and a half minutes. Then the first plane that made visual contact with the jet happened at 0952 CDT. 0952 CDT is 1052 EDT. The difference in time from 0938 EDT(4+ minutes after last contact) and 1052 EDT is 1 hour and 14 minutes.
Reference note 7 at the end of the report

The report continues on in Central Daylight time from then on as the flight had crossed time zones. It is also interesting to note that the first plane that made contact was an unarmed jet that was already airborne for a different mission and diverted. A jet dedicated to air defense would have possibly taken longer.

So is BIGFOOT, now let's have some specimen. Dead or alive.


And Bin Laden himself never cared to set the record straight, he just decided to take the blame and run for the rest of his life.
Ever wonder why Bin Laden disagreed with you then?


Fine, now you have your HARD EVIDENCE and it is braodcast in the entire world. Still no one is buying it, huh? Someone is being fooled here really by Alex Jones and the conspiracy theoriest.


The only way to asnswer your assumption is with proof of a bomb, and you have none.

If you think a building should withstand an uncontrolled fire that "burned for only a few hours", set fire to your own home and see how it does.

You see "squibs", I see overpressurised windows breaking as the internal collapse proceeds. These "squibs" occur after the penthouse moves.

As I said earlier…


Also why would terrorists go through the whole elaborate scheme of trying to make people think airliners brought the towers down?

The PNAC document, Rebuilding America's Defences, basically put, sets out a plan for the United States to remain the world’s leading power. It states that, "Further, the process of transformation, even if it brings revolutionary change, is likely to be a long one, absent some catastrophic and catalyzing event - like a new Pearl Harbor." Lo and behold, within 8 months of the Bush administration coming to power, including PNAC activists Rumsfeld, Cheney and Wolfowitz, we do indeed have their new Pearl Harbor in 9/11. Since then the rest of the plan, ie setting up permanent forward bases abroad and preserving a favourable balance of power in the middle-east, is playing out well.



I have already described in this thread how the demolition charges could have avoided being set off by the airliner impacts and also how the demolition charges could have been placed without detection. Regarding how thermite could have cut the supports – could it have been placed on horizontal beams or at the vertical joins between columns? I find it strange anyone could believe 500°C office fires covering limited floors could collapse the towers, then presume that 2500°C thermite reactions working at strategic points in the building could not.



Something else such as…?



I can answer that: the towers should not have fallen at all. Even if a collapse at some level began, due to the grid construction of the towers, it should only have been a partial collapse. Then, even if by some quirk the entire tower were to collapse it should not have been at freefall speed. I find it impossible to believe the top portion of the towers crushing the large majority of intact lower portion at freefall speed theory.



Would you say it was a bad building design? I mean, the entire building relying on a single column at the base of the penthouse to hold it up. I say "single column" as that is what NIST seem to be currently promoting. Also, was the steel in WTC7 not fireproofed?



Well the article does clearly say that after the explosion “They made it back up to level 8, where Barry Jennings had a view of the twin towers, both buildings were still standing.”



The Wikipedia entry for Arbusto Energy and CBC News have reported the Bush/Bin Laden links.



On 28th September 2001, in an Osama Bin Laden interview with Ummat newspaper based in Pakistan, he stated, “I have already said that I am not involved in the 11 September attacks in the United States. As a Muslim, I try my best to avoid telling a lie. I had no knowledge of these attacks, nor do I consider the killing of innocent women, children and other humans as an appreciable act.” Full transcript here.

Why is it the Western media never reported on this particular interview?

Bin Laden's family wealth came from construction business, and clearly they were just business men when they invested into Arbusto.
Why not allow the investment then?

[
He is not involved, and yet he decided to run and hide. Can you imagine if he can help out and pin down the US government as the ones behind 9/11?
Can you imagine if he can prove he was not the one? All you folks will be soooooooooooo right and Bush will be dead duck. But no, he hides not Bush and you folks are on this never ending conspiracy that you have no proof of.
And that is why the Western Media ignored YOUR official story or version.

Second aircraft hit the building banked, meaning a turn or adjustment was made at the very end to hit the building. For me that indictates no guiding device.

You don't seem to understand much about structures in general or how they respond to damage. Suggest you read a few of the engineering sites that cover 9/11.

None of the buildings were designed to survive what was inflicted on them that day, but then no-one expected such an attack. They were designed to comply with the building codes of the day. Fireproofing was there, but the combination of impact damage followed by fire meant that the fireproofing was damaged before the fire started. There were also reports that the fire was fed by a large store of diesel fuel in the building. Comparisons with other building fires don't take these factors into account.


What is more likely? That he was mistaken about the sequence of events, or that such a big event was missed by everyone else in the building at the time?

And they call conspiracy theorists crackpots even with official story believers coming out with things like this? First, Bin Laden would have no more proof than the rest of us who carried out 9/11. Second, his story would not have got a mention in the mainstream Western media (as his claim of innocence in Ummat did not). Third, he would not wish to remain visible for fear of ending up as Saddam Hussein has.

The majority of Western mainstream media is nothing more than a political tool, owned by a handful of individuals, making news easily manipulated to sway the masses to a certain persuasion, that is why nothing but the official story of 9/11 is reported. An example of this is Rupert Murdoch who controls 175(!) newspapers plus TV news channels in each of the US, UK and also Asia.

You aren't on the payroll of Rupert Murdoch are you AROCES? Don't answer that, it's just my joke.



Yes, though the 'bank' was not drastic. This video shows a guided missile whose flight-path was adjusted twice on the final run to its target. The airliners could have been guided in a similar way.



That was mainly waffle flyingswan. Back to the question I was trying to ask – are you really asserting that WTC7 was entirely dependent on a single structural column at the base of the East penthouse to keep it standing? Are you even asserting that the building was entirely dependent on a number of columns at the base of the East penthouse? That would be to suggest all the rest of the structural elements making up the walls, centre and whole West side, including all of the adjoining columns, bolts, rivets, weldings, through all 47 floors, were largely ineffective in supporting the building. Reading your theory: -

"Weakening of a single column causes global, freefall collapse of high rise, steel framed structures."

Flyingswan you're a genius - demolition companies across the world are going to hail you as a god when you reveal this little gem to them!



From reading what has been released, it would seem WTC7 had been largely evacuated after the first airliner impact, with the official and his escort possibly being the only people in the stairwell and within the vicinity of the explosion.

And what do you call the hundreds of HARD, CONVINCING, UNDENIABLE, SOLID, NAIL IN THE COFFIN PROOF that is all over the internet that will support and prove Bin Laden is innocent??????
Don't tell me you folks been kept silent, Rosie Odonell's mouth alone is as big as the entire media.
No one is listening to you and you can't admit that you basically have nothing but tabloids stuff.

What do you mean not drastic? A 767 can't bank like a fighter plane. That looks to me like it's almost at it's maximum bank angle.
Your video shows a missile homing on, change it's target and made a last second maneuver to hit the MOBILE tank. A passenger airline not traveling as fast as a missile and with a target 10,000X bigger than a tank and is not mobile does not need a last second maneuvering, if a homing device is applied.

As I said, you don't understand structures.

Every structure depends on a number of elements to support itself, and if some of those elements are damaged then the loads are redistributed through the remaining elements. This redistribution is not uniform, some of the remaining elements can carry much larger additional loads than others. The critical element is the one that is brought closest to its ultimate load. If there is a fire, then this critical element can be further weakened though the fire heating it or further loaded by thermal stresses, and it will also give way. The loads again redistribute, making another element the critical one. At some point you will reach the situation where a large part of the structure is depending on a critical element, and when this gives way, the structure collapses.

The witness mentions police and firefighters in the building.

I think the difference is with information on the internet you have to go looking for it, whereas with mainstream news outlets information is practically forced upon the public. That obviously leads to everybody knowing what the mainstream wants them to know but only some people knowing the rest. And I do think the vast majority of people who really know ‘the rest’ regarding 9/11 do believe an inside job took place.



The point was that you can make a guided missile or airliner, fly exactly how you want it to.



You seem to be implying there can never be a partial collapse of a structure, nor that it could topple sideways due to damage. I would have to disagree as seen here, here and here. I realise these buildings were not of the same design as WTC7 but surely similar principles apply in that if the load bearing structure gives way unevenly it must topple. Apart from that, I would agree that "at some point" with enough of the critical elements removed obviously a building will collapse one way or another.

What exactly was the factor of safety of WTC7 anyway flyingswan? Estimating a factor of safety of 2 (it is probably a lot higher than this) on the main columns, that would necessitate every single column needing to be weakened 50% just to reach its load bearing design capacity. Or even if fully half of the area of the building had severe fires then the columns in that area would need to be weakened 100% (melted) to reach its load bearing design capacity. Knowing that these fires were not engulfing the entire area of the building and cannot melt steel, neither of the above can be true.

So questions flyingswan - in your opinion, how many of the total main structural columns would have to be weakened, and by how much, for a collapse to occur as we saw with WTC7?



The witness mentions firefighters in the lobby but says the 23rd floor was evacuated. It would not be hard to believe they were the only two in the stairwell approaching the 6th floor when the explosion occurred.

What the heck else do you guys want? A daily all channel, all newspaper, prime time reporting of your accusation until everyone says, alright we believe you now???


Nope, you fly it excatly how it is suppose to be flown, NOT excatly how you want it.
An airline can't fly and maneuver like a missile.

I don't know the specific answer for WTC7, I am an engineer but not a structural specialist, but as I recall from my engineering education, buildings used to be designed to a factor of 5/3 (1.67).

If you had actually read/understood my last post, you would have realised that load redistibution due to damage is unequal. This means that some elements carry much the same load after damage, but others carry increased loads that can approach their ultimate load. "Every single column" is not affected in the same way, and your arguments from that basis are incorrect. In a damaged structure a small increase in temperature, well below melting point, can weaken an element so that it cannot carry the increased load, or the additional load due to thermal stresses can combine with the additional load due to damage to overload an element. I am not claiming that a collapse is inevitable, that of course depends on the extent of the initial damage and the further effects of fire. I am just saying that, as an engineer, I see nothing improbable in the way that WTC7 collapsed.

And no-one in the lobby heard an explosion elsewhere in the building?

do you see anything improbable about the head of security reporting bombs going off which killed people in wtc7 before the collapses occured? which is what this thread is about yet no one seems to want to reflect on the implications of-- why was this covered up??

... zzzzzz Perhaps it is not my understanding but instead that your explanations are not making much sense?

If you could attempt to answer the question - in your opinion, how many of the total main structural columns would have to be weakened, and by how much, for a collapse to occur as we saw with WTC7? - this would really enable me to understand your line of thought. Currently I am thinking you do not wish to answer the question, as when it is shown the vast and severe damage needed to be caused for WTC7 to collapse as we saw, it will be clear the fire theory is unrealistic.



All any disputers can offer is that the security official was mistaken. Mistaken he witnessed an explosion, mistaken the stairwell collapsed, mistaken the twin towers were still standing and mistaken he saw bodies in the lobby. That is all you will get out of official story followers because, as poor as it is, that is the only excuse they have.

You still don't seem to understand my point. Once damage occurs, it can spread because elements next to the damaged part can be very highly loaded and need little extra weakening or thermal stress loading to fail in turn, leading to the damage spreading. One failed structural element could be enough to start the process if the fire is severe, a minimal weakening due to heat could be enough to spread an initially large damaged region.

As I said, structures are not my speciality and I do not know enough about the construction of WTC7 to give a detailed answer, but I am an engineer and did learn structural theory when I was at college, which was a long time ago. That is why I suggest you ask the stuctural engineering experts at your local university. I am confident that they will agree that once a structure is damaged, any subsequent fire can cause the damage to spread by the process that I described.


No, just mistaken about the timing re the towers being still standing. The rest is consistent with the damage caused by the collapse. This is not a poor excuse, but plausible in that it would be difficult to fit all the activities he described into the time available if he was not mistaken about this one point.

If the firefighters were in the building already, is it safe to assume they were there because a huge jetliner loaded with fuel had smashed into the building?

And if a huge jetliner loaded with fuel had smashed into the building, wouldn't it be possible that people inside the building (especially stariwells which are perfect for transmitting sound) might hear several very loud noises that might later be described as "explosions"?

Or just another anti-American lying piece of #$@%@#$ nutjob.

how do you figure?? are you even aware of the activities described?-- he knows they were still standing because he had just left the main towers before going to bldg 7

Read the OP. He has to pick up the guy he's escorting, get across to WTC7, up to the 23rd floor (against the flow of those being evacuated), find that the people he's looking for have already been evacuated, make several phone calls, find his way down again past a destroyed staircase (down to the 6th, scramble over damaged area, up to the 8th, down to ground), witness the scene in the lobby, get 20 blocks away...all in, at most, just over an hour.

Your theory is not making sense because I do not see how a column can 100% fail before moving onto the next column which also 100% fails and so on; if we assume one column is destroyed, even as the column next to it weakens, other local columns must begin taking the load of the structure above it; the structure does not wait for one column to fully fail before transferring its load onto the remaining columns. I am led to believe, the maximum steel columns can be weakened by fires of the intensity we saw is 50% (being very generous). Then, even if every single column in half of the building was weakened to 50% I still do not believe a complete, virtually symmetrical, freefall collapse would occur.

So, approximately, in your opinion, in the moment before WTC7 collapsed, how many of the total structural columns had gone through this turn by turn weakening, and by how much were they weakened, for a collapse to occur as we saw?

This link describes the mechanics of the total collapse very well, issued by the JOM

http://www.tms.org/pubs/journals/JOM/0112/...Eagar-0112.html

It also agrees that there could not have been molten steel as a result of the very low temperatures that the JetA1 fuel was burning. Steel needs to be heated above 1500ºC for that to occur, and the JetA1 fuel would have been burning at c850ºC. However structural deformation of steel begins around 450º to 550ºC.

The fact that steel was reported to have been molten is a strong indication of another source of combustion.... Thermite heats to 4000ºC within seconds and would certainly be a contender. What concerns me is that Thermite is on sale to the General Public at $82.90 for a 5lb container, including the Magnesium strip to ignite it!!!!!

One other comment.... the Twin Towers would have been loaded with several Hazardous chemicals such as used in Printers, and for general household maintenance. i would be interested if anyone knows the qualities of these chemicals, and whether they are actually explosive, might account for explosions that were heard. Just a thought

I will try again. Under normal circumstances a structural element carries a load that is well below its ultimate strength. If neighbouring elements are damaged, the load is increased and may reach the ultimate load. This can occur immediately, as in a collapse, or at a later time if the structure is exposed to a fire which can either reduce the ultimate load through heating the element or increase the load by applying extra stress to the element from thermal expansion. When the applied load reaches the ultimate load the element breaks and no longer carries any load. At which point the loads on the remaining elements redistribute and the process repeats.

You are still trying to apply global figues to local phenomena. I have never said that the steel in any element needed to be weakened by 50%, just by enough to remove the residual margin between the extra redistributed load due to the damage and the ultimate load. For an element neighbouring the damaged part, this margin could be very small.

I do not know enough about the detailed structural design of WTC7 to attempt an answer to your question. However, if the building was built to a 5/3 safety factor, was undamaged, and uniformly heated, it would collapse after it had lost 40% of its strength.

I do not really care what you believe, as you obviously have no expertise in structural engineering. You obviously do not trust my, admittedly limited, expertise in this. I ask you again to contact some structural engineers and find out what they believe.

The above link is quite a strange piece as it at first admits itself the fires were not hot enough to collapse the towers: -



Then it goes on to partly blame “non-uniform” intensity of the fires for the collase: -



This seems to suggest the writer believes the Towers would have been fine had the fires burned uniformly.

‘The Collapse’ section of the article is vague in its explanation of how the towers came down, along the lines of the ‘pancake’ collapse theory, failing to account for the massive interior structural columns around which the towers were built. As can be seen from WTC construction photos, the immense core structure was erected first in sections supporting the rest of the building being built around it. How then the falling floors managed to drag down the very core that was designed to hold them up and support the building's weight, I will never know.

In any case, non of the above refers to WTC7 which this thread is aimed at.



Up until the last two sentences you were making sense. Due to fire, I do not agree that a structural element will suddenly break (lose 100% of its strength) and then pass its full load onto remaining elements. If we have a main structural column carrying a particular load, other local columns will already be taking a percentage of that load. Then, even as the main column is gradually being weakened, other nearby columns will simultaneously be taking on the extra load/stress. Surely you can agree to that?

Given the above is true, this would rule out the ‘domino’ effect you are suggesting. Then, even if half the columns in WTC7 were weakened approximately 50% (the maximum they could have been by fire) we would be nowhere near a total collapse of the building.



I have common sense, a good understanding of physics and a mountain of other evidence pointing out 9/11 as a false flag op, which is at the moment for me outweighing your “admittedly limited” expertise.

Here is what I found some structural engineers believe.

Massive columns don't automatically imply massive safety margins. The building's designers didn't make those columns so big just because they thought it would look cool. They're large because they HAVE to be -- they're carrying huge loads. Take a look at this weighlifter. He's massive, too.


He shouldn't have any problems carrying a small child, right? Imagine what might happen here, though, if that child suddenly ran over and jumped on one end of that barbell. He's already loaded near his limits, so a small change might just put him over his personal safety margin and cause a failure.


I'd agree that the loads would change, but not necessarily evenly. Some columns may take on more load, some columns may actually have their load reduced. It's a structures problem.


That's not at all correct. As flyingswan has said, you don't understand structures. Let's look at a simple example. Imagine a simple four-legged square table. Let's assume that all four legs are evenly-spaced and of equal length (so the table sits flat on the floor). Also assume for the moment that the legs are rigid and don't bend. Now, let's assume that we're designing this table to hold a maximum weight of 100 pounds (or kilograms if you'd prefer -- the units don't matter here). We'll assume that the weight is placed exactly at the center of the table so that all of the legs are evenly loaded. That gives us a scenario like this:



Makes sense, right? Each leg carries 1/4 of the load (25 pounds). Now, being good engineers, we want the legs to have a reasonable design margin so that the table doesn't collapse when carrying this load. Let's assume a safety factor of 2.0 and design the legs to carry a maximum weight of 50 pounds each.

So, let's look at what happens if we now break one of the four legs so that it can't carry any load. You seem to be assuming that the other three legs will take up the extra load evenly, giving us this situation:


That's not what happens, though. If you actually work the problem and balance the forces and moments, you find that the actual result with one broken leg is this:


When we break the front leg, the load in the back leg also goes to zero and the left and right legs take up all the load (50 pounds each). That puts them right at their design limit. If either one of those legs is further weakened by something like a fire, even just a few percent, the table will collapse.

Note that if we had used a safety factor of 1.8 and had designed the legs to hold a max weight of 45 pounds each, breaking the front leg would cause an immediate domino-effect total collapse of the entire table.

While we're at it, let's look at what happens if the table sags a bit when we break the front leg. Let's assume that the initial damage causes the table to tilt a bit toward the broken leg, shifting our 100 pound load forward 20% of the distance from the center to the corner. Because the load is now off-center towards the broken leg, the table wants to tip forward. Let's assume we've bolted the back leg to the floor to keep the table from tipping over. We now have the back leg in tension and the right and left legs in compression:



We have to pull down on the back leg with a 20 pound force to keep the table from tipping over. That increases the loads in the other two legs to 60 pounds each. Those two legs are carrying a total load greater than the weight sitting on the table!

To keep things simple here, I've assumed that we completely fail the front leg so that its load goes to zero. The same principles apply, though, even if we just weaken or warp the front leg so it carries less load. The rest of the structure will not necessarily take up that extra load evenly.


I'm afraid your "common sense" is leading you astray. The response of a building to fire and other damage is an enormously complicated structures problem. Simple assumptions, like an even distribution of loads, will not give you the correct answer.

What needs to be understood is the behavior of fires and structures. Fires are a progressive, random, asymmetrical phenomenon. That's why buildings can only be structurally damaged by fires in a progressive, random, asymmetrical fashion.

No structurally stable building can instantly collapse to the ground, symmetrically, at free-fall speed, simply from fire and/or damage. None.

That goes for any type of structure. A wood framed house. A concrete apartment. Or a steel framed highrise.

No structural fire has ever caused an instantaneous, symmetrical, total collapse of the structure. Millions of house fires, apartment fires, office fires, etc. have occurred in the past 100 years. Two world wars, and hundreds of other conflicts, resulting in tens of thousands of buildings being ravaged by bombs and fires. Many of these buildings were in much worse shape than the towers and WTC 7 were.

And none of them suddenly collapsed symmetrically to the ground at free-fall speed.

The only way such an event could happen from fire and/or damage is if the building was intentiionally designed to completely collapse with some kind of master trigger pin, linked to every critical support in the building.

Since that was (obviously) not how the WTC buildings were designed, the only other method possible is through controlled demolition.

NIST would like us to believe that the WTC buildings were designed like gigantic Rube Goldberg contraptions. (ie: like a "Mousetrap" game)

Oh dear, another one who is trying to apply common sense to a situation where it is of limited use.

Turbonium, your common sense is inadequate in this situation. Please go and ask a structural engineer.

A few structural engineers out of hundreds of thousands worldwide, and none of them appears to have put their opinions to the test by publishing their calculations.

a few?? someone around here is experiencing a critical case of denial-- did i just hear that common sense doesnt apply?


http://www.ae911truth.org/

Is that sorta like when NIST stopped their investigation at the point of collapse initiation, mostly because it's common sense that the towers would subsequently collapse to the ground within the next 10 to 18 seconds, so "why should they bother"?

Common sense is sometimes regarded as an impediment to abstract and even logical thinking. This is especially the case in mathematics and physics, where human intuition often conflicts with probably correct or experimentally verified results.

When I noted that no structural fire has ever caused an instantaneous, symmetrical, total collapse of a structure, that isn't a point of "common sense". It's based on the established facts, historical records, documented scientific studies, etc. "Common sense" would be someone saying "It's impossible for WTC 7 to collapse like that from fires. Just look at it", without adding any evidence to support that claim.

You and NIST are really the ones who have a big problem to deal with here. The collapse of WTC 7 cannot be validated by historical precedent, experimental replication, or even just good old, unscientific, "common sense".



Thanks for the suggestion, flyingswan, but you're the one who really needs to consider it.

How many of those 130 are structural engineers? I count as an "engineering professional", though as I've said several times above, I don't count myself as a structural expert, and neither are architects. Even if all 130 were structural engineers, it is still a pitifully small proportion of the worldwide structural engineering population.