Building Collapse (World Trade Centre)

uprising2

Hello I hope this is the right forum for this, anyway can I ask you engineer's on here if you think the twin towers should have fell like the official explanation says it did, no impact resistance, 10 floors per second reduced to rubble.
Is it possible?, or do you think there had to be other "extra's" needed?.

https://www.youtube.com/watch?v=s04VUk_41r8

REFLINE1

uprising2 wrote: »

Hello I hope this is the right forum for this, anyway can I ask you engineer's on here if you think the twin towers should have fell like the official explanation says it did, no impact resistance, 10 floors per second reduced to rubble.
Is it possible?, or do you think there had to be other "extra's" needed?.

https://www.youtube.com/watch?v=s04VUk_41r8

Haha Jim Corr is posting on boards Eng forum

uprising2

REFLINE1 wrote: »

Haha Jim Corr is posting on boards Eng forum

No its a serious engineering question, architects and engineers are raising questions, so if you have nothing relevent to add don't add anything.


COPY AND PASTE:

Richard Gage, AIA, is a San Francisco Bay Area architect and a member of the American Institute of Architects. He is the founding member of AE911Truth. He has been a practicing architect for over 20 years and has worked on most types of building construction, including numerous fire-proofed steel-framed buildings
http://www.ae911truth.org/aboutus.php

https://www.youtube.com/watch?v=oO2yT0uBQbM

Prenderb

NIST (US National Institute of Science and Technology) carried out a review of the collapse...available here.

To answer your question, my thoughts currently are on the "yes, it could have" side of things. First of all, it did. There were no pictures or videos released showing any "extras." I reckon that once one floor collapsed there were 20 floors or so worth of dead load impacting on the collapsing building, which is a lot of dead load.

uprising2

Prenderb wrote: »

NIST (US National Institute of Science and Technology) carried out a review of the collapse...available here.

That review is a couple of years old, does it mention that thermite has been found in the dust?, does it "really" explain the collapse?.

The Open Chemical Physics Journal
http://www.bentham-open.org/pages/content.php?TOCPJ/2009/00000002/00000001/7TOCPJ.SGM

Prenderb

Material submitted by members of the public was tested according to that article/paper, and the material apparently exhibited properties (fairly closely are words used in the article) matching properties of thermite.

Same paper describes this dust as containing iron, aluminium, silicon, carbon and oxygen. All those elements are abundant in the environment we all live in, let alone in a 110 storey-building which, in its being impacted at high speed by a plane with some kerosene in it, the building itself being set on fire and subsequent collapsing, might have imparted huge levels of energy (kinetic and electromagnetic) into those elements causing them to react and form these particles.

If it was thermite, would it not have been used up in the chemical reaction that it would have been used for?

uprising2

PRESS CONFERENCE 19th February 2010, please look at the video's.
Are you an engineer?, what level and experience do you have, what do you specialise in?.
I'm here looking for an engineer's conclusion, not to get into a meaningless game of some sort, I don't want links to this or that report, I'm looking for personal theories, understanding and logic, or more to the point in your personal opinion are these people talking rubbish?, if so, why.

Here's a press conferance from lastweek, if it was all sorted and explained I doub't these people would still be going on about it.

Prenderb

uprising2 wrote: »

I'm here looking for an engineer's conclusion

I think you have your conclusion to be honest. I've offered you my opinion, as you requested. FWIW I have a relevant background, but I won't be able to give you what you wanted - you seem to have plenty of links and videos of people who want to challenge the "establishment" point of view. I'm fairly sure from your response to my NIST link that you won't accept any of my links or views!

uprising2

Prenderb wrote: »

I think you have your conclusion to be honest. I've offered you my opinion, as you requested. FWIW I have a relevant background, but I won't be able to give you what you wanted - you seem to have plenty of links and videos of people who want to challenge the "establishment" point of view. I'm fairly sure from your response to my NIST link that you won't accept any of my links or views!

I have got my conclusion, I've looked at the evidence and footage and double checked everything before coming to this conclusion.
Thank you for your reply, but do you honestly believe this is possible from 2 planes?, wouldn't high winds put much more strain on the building, why was there no resistance as each floor hit the one below?. It simply doesn't make sense and I came here to see if it can easily be explained by somebody with experience in this field of work.

civdef

The search function will probably show hundreds of occasions this has been discussed over the last few years, including a number of times on the engineering section.

bnt

Since you already know about http://www.ae911truth.org/ , what would you expect us to add here on an Irish forum?

OSiriS

I believe this is a more fitting place for your post. This matter has been discussed to death, and conspiracy theorists are always able to come out with these so-called "experts" to corroborate their beliefs. Judging by your posts, you seem to be fishing for an engineer to agree with you, rather than actually looking for an opinion.

uprising2

bnt wrote: »

Since you already know about http://www.ae911truth.org/ , what would you expect us to add here on an Irish forum?

Some basic knowledge of collapse for starters, a viable explanation of how it was possible that it did simply collapse and nothing else was needed (explosives, thermite, etc), or somebody to say it's a lie how they say it happened because of X, Y or Z, just basically some for and against debate, I don't want to drag it into Conspiracy theorie, just stick to the actual science behind the collapse and if its possible that it could collapse at freefall speed, and keep collaping all the way down on its steel and concrete structure far beyond the impact area's and as the top section of one of the towers actually toppled over so there wasn't as much impact force from that tower.

https://www.youtube.com/watch?v=DXh5u62oJCU

uprising2

OSiriS wrote: »

I believe this is a more fitting place for your post. This matter has been discussed to death, and conspiracy theorists are always able to come out with these so-called "experts" to corroborate their beliefs. Judging by your posts, you seem to be fishing for an engineer to agree with you, rather than actually looking for an opinion.

No that link is not where my post should be, I'm looking for an engineer's opinion.
Seem's like a few of you here made up your minds or simply accepted the official report without question, I'm only focusing on one event and the engineering failures of the building that I just don't buy, or building 7 for that matter, I would just like the opinion of a qualified/experienced engineer and discuss how such failings could have occured, because there hasn't been a full every avenue exhausted investigation, and defies intelligence, inderstanding and reason, how they supposedly came down.
Again I don't want to discuss any conspiracy just the engineering science behind the collapse.

civdef

I'm a fire engineer. I agree with the NIST findings. I can't think of a single competent professional in my field who doesn't.

Happy?

uprising2

civdef wrote: »

I'm a fire engineer. I agree with the NIST findings. I can't think of a single competent professional in my field who doesn't.

Happy?

So the fire brought down the buildings at free fall speed?, why was there no resistance as one floor slammed into the next?, surely if you accept the NIST findings you'll have a reasonable explanation why there was no resistance delay, surely each of the floors should have had some resistance and slowed down the collapse, and wouldn't it have been much easier for the top above the "melted steel" to flop over rather than fall directly down, and how do you explain the force that threw debris up and out as the collapse was occuring.

This picture shows the top above the fire as it collapses, its clearly falling to one side.

mawk

2 feet of rebarred concrete floor wouldnt put up an awful lot of resistance when faced with a few petajoules of potential&kinetic energy on it. the fall starts slowly and builds to near free fall speed because each floor that fails added god knows how many extra tonnes to the weight hitting the floor below

any tall building is designed to fail safely in a catastrophic event. it would be beyond stupid to have tall buildings in a city that could easily fall sideways. Structural engineers are not children building towers from lego.

uprising2

mawk wrote: »

2 feet of rebarred concrete floor wouldnt put up an awful lot of resistance when faced with a few petajoules of potential&kinetic energy on it. the fall starts slowly and builds to near free fall speed because each floor that fails added god knows how many extra tonnes to the weight hitting the floor below

any tall building is designed to fail safely in a catastrophic event. it would be beyond stupid to have tall buildings in a city that could easily fall sideways. Structural engineers are not children building towers from lego.

If you bothered to read the thread or look at the video's you would see that qualified architects and engineers are raising these questions and implying that the building shouldn't have collapsed like that, if your equally qualified or higher qualified than these people please put your case forward, if your just giving your random thoughts on how you believe it should be, don't bother, I posted this in engineering for a reason.

"The fall starts slowly", does it really?.....

bnt

uprising2 wrote: »

Some basic knowledge of collapse for starters, a viable explanation of how it was possible that it did simply collapse and nothing else was needed (explosives, thermite, etc), or somebody to say it's a lie how they say it happened because of X, Y or Z, just basically some for and against debate, I don't want to drag it into Conspiracy theorie, just stick to the actual science behind the collapse and if its possible that it could collapse at freefall speed, and keep collaping all the way down on its steel and concrete structure far beyond the impact area's and as the top section of one of the towers actually toppled over so there wasn't as much impact force from that tower.

So, are you saying that you can't get all that from the AE911 site, and have to come here for that? Quitethe vote of confidence in those architects and engineers, eh?

uprising2 wrote: »

No that link is not where my post should be, I'm looking for an engineer's opinion.
Seem's like a few of you here made up your minds or simply accepted the official report without question
...
Again I don't want to discuss any conspiracy just the engineering science behind the collapse.

Or maybe some of us are aware that a thorough, detailed explanation of the event would consume time that we just don't have? Or maybe we are aware that whatever we say will be met with an argument, which would require us to spend inordinate amounts of time on arguing with you, and for what? Who benefits? Or maybe some of us have moved on, and struggle to see any lasting, global, relevant significance in the events of September 11, 2001 CE. For example, what about the shoddy building standards in Haiti that killed approx. 200,000 people on 12 January? Wouldn't you call that a greater crime against humanity?

You accuse us of "accepting the official report without question", yet you say you're not looking for a conspiracy theory? Well, I do have questions about the official report, but I'm not going say a word in public until I have thoroughly investigated them. I'm quite prepared for the possibility I'm completely barking up the wrong skyscraper tree, because I don't know enough detail and don't have the time to go in to it. Better to be quiet and thought a fool, than to open my mouth and confirm it. It remains an academic exercise that will have to wait for time and energy on my part, something that might never happen for me.

mawk

uprising2 wrote: »

"The fall starts slowly", does it really?.....

yes. It does. Now i may only be a qualified engineer whereas you have read some websites that are more exciting than text books; but my own humble opinion, the speed of stationary.. Is something I would call slow.

uprising2

mawk wrote: »

yes. It does. Now i may only be a qualified engineer whereas you have read some websites that are more exciting than text books; but my own humble opinion, the speed of stationary.. Is something I would call slow.

If its stationary it obviously hasn't started yet, has it, so we'll start again.
Take a look at this and just open your mind for a minute and ask is this possible.

dan_d

Okay. I'm probably going to be wasting my time here, but anyway.

Start with the fact that the building was designed at a time when a plane that size, let alone with that fuel load was not heard of. The buildings were designed to withstand a plane hitting it.....but not that size of plane. Taking into account the impact and the heat from the explosions.....these things may not have been built into the original calcs at the magnitude they occurred at.

Following that we have no real idea of what sequence events occurred at at high level in those towers. One of your links (which I might point out, is still disturbing to look at) suggests explosions concealed by the falling debris. What if the "explosions" forcing debris out the windows was just the floors internally in the building collapsing on top of each other "sandwich like" and forcing both the contents of the floors and some structural elements out the windows? (Similar to putting powder on one of your palms, then clapping your hands together....a puff of powder would come out around your hands). I'm not sure what you're looking for here. Would you have preferred that they fell sideways? And if not, exactly what are you proposing? That someone somewhere knew this was going to happen on that days and somehow orchestrated the collapse of the towers from inside....assuming the friggin great jumbo jet didn't do the job??

I appreciate that you're simply looking for conclusions from a technical point of view...work away. But maybe a large number of the people here have simply moved on - it's 9 years later now and well, to be honest, apparently there are plenty of other people out there researching what happened. Are you an engineer???(and for your information I am....a civil and structural engineer). I suspect that we may pose all the theories out there to you, but unless they tie in with whatever your theories are, you'll reject them. What exactly are your theories?

Prenderb

dan_d wrote: »

Okay. I'm probably going to be wasting my time here, but anyway.

Yeah, I decided that earlier. Then I read this, and this, so now I'm not so sure. :rolleyes:

OP, you've made it plain (to me)that you're not going to entertain any of the engineers (including my own) responses to your questions. Why did you ask them? We've tried to be reasonable with you, and have responded in a somewhat interested and positive way to your original post, but you're having none of it, and instead of engaging with our opinions you just post more video evidence! I'm surprised this thread hasn't been moderated yet.

sprinkles

Okedoke. This has been done to death and as with any credible conspiracy theory there are going to be "experts" who can claim that things should have happened in one way or another. (and when I say credible I do not mean I believe in the conspiracy theories, just that they do raise some valid questions).

In my honest professional opinion (I am a structural engineer who has worked on the design of tall buildings - although not to this scale) it is a big coincidence that both buildings fell vertically within a very small footprint and in hindsight it was a damn lucky coincidence too! Designing the buildings for such a collapse scenario would have been extremely difficult. Given the height of the buildings even the wind could have resulted in the buildings listing to one side when in free fall, not to mention the overhanging weight of the top floors. That said however the buildings did collapse in a small footprint. It is very possible that the dead load above the impact zone coupled with the structural failure at the floors hit led to the progressive collapse without the need for any external influences.

Now if you are looking for someone here, with no intimate knowledge of the design or the resulting investigations to make a call on whether or not it was an inside job so to speak then you are wasting your time. The most anyone can say with any degree of certainty is that the 2 towers were hit with 2 planes and both suffered extensive structural damage which led to their collapse. There are unanswered questions for sure, but none we are likely to ever get answers to.

mawk

uprising2 wrote: »

If its stationary it obviously hasn't started yet, has it, so we'll start again.
Take a look at this and just open your mind for a minute and ask is this possible.

I happened to be over there when it happened, so while I didnt happen to be there to see them fall irl, I did see the aftermath and every possible video during the media bombardment. So embedding a youtube clip is not going to make me change my mind.

As to whether i think it could have been possible. Yes I do. Have you ever seen a load extension diagram for a steel member? You put force on it and it deforms elastically put more and it eventually reaches it's elastic limit. The point at which any more deformation becomes perminant. The vast majority of the members strength lies in its elastic limit. Once the for exceeds this point the very quickly deforms and as it deforms it loses its ability to support it's load. The bar will then break at a force considerably below its original safe threshold. The heat from the fire is not enough to directly melt the steel but its enough to rob some of the ultimate tensile limit which causes the building to go from standing to falling very quickly.
Imagine stretching some chewing gum, the more you have already stretched it, the less you have to pull to stretch it even more. Metal works the same.
First year materials..

Yes its very handy the fell in their own footprints, whether by design OR luck. I dont know which for any certainty.

uprising2

dan_d wrote: »

Start with the fact that the building was designed at a time when a plane that size, let alone with that fuel load was not heard of ?

So there was no aircraft larger than a boeing 757 in 1964?, when was the B52 brought into service?. The production of the B52 had actually finished when the plans for the WTC were being drawn.

sprinkles wrote: »

There are unanswered questions for sure, but none we are likely to ever get answers to.

Thanks.

While I'm on the WTC subject, do the theories of how the 2 towers fell also extend to WTC7, does any engineer not have a problem with how this building fell?.

Personally I can't accept these fairytales being spread by the "official" report.

Krieg

If I say "I don't believe the report",
Will you go away?

uprising2

Krieg wrote: »

If I say "I don't believe the report",
Will you go away?

That would be easier than actually thinking I suppose, seriously does nobody here find it a bit "wrong" what happened or is it easier to deny things that make you feel uncomfortable.















I find it unbelievable that nobody HERE finds it suspicious that these two buildings fell like they did.

How did the centre core disintegrate, seriously, look at the pictures and ask yourself "Is this possible?", if anybody who has or seeks a career in engineering doesn't find this suspicious, well I don't know what to say to be honest. I'm amazed and speechless.

3DataModem

uprising2 wrote: »

I'm amazed and speechless.

please god let this be true




On another note, a b25 actually did hit the empire state building in 1945.

argosy2006

Building 7 is the real mystery .. it just fell, nothing hit it,

uprising2

Here's an animation, how any engineer cannot question how the centre core collapsed is beyond me, WTC 7 is a story all of it's own, but even ignoring that, I cannot see how anybody can explain away how the 2 towers collapsed, the floor falling on floor is one thing, but how on earth did the inner core collapse on itself simultaniously, it's impossible as far as I'm concerned.

https://www.youtube.com/watch?v=qJ11i6fi7KQ

Victor

uprising2 wrote: »

it's impossible as far as I'm concerned.

And your qualifications sir?

uprising2

Victor wrote: »

And your qualifications sir?

I left school at 15, 3 business's, phd in life, masters in common sense, thinking of going back to do my junior cert.

Are you actually saying you don't have a problem with the centre core collapsing/disintigrating?.
I'm amazed, to what standard are engineer's taught?, is it part and parcel of the qualification not to question major failing's?, the very people who should have a problem with this fairytale are the very one's either turning a blind eye or don't understand the things they should.

C.D.

uprising2 wrote: »

I left school at 15, 3 business's, phd in life, masters in common sense, thinking of going back to do my junior cert.

Are you actually saying you don't have a problem with the centre core collapsing/disintigrating?.
I'm amazed, to what standard are engineer's taught?, is it part and parcel of the qualification not to question major failing's?, the very people who should have a problem with this fairytale are the very one's either turning a blind eye or don't understand the things they should.

I have been reading this with interest- I strongly believe that the a inquisitive mind willing to challenge the status quo and conventional thinking, combined with critical analysis skills are the bedrock upon which Engineering is built.

I don't dispute there that appears to be some ambiguity about what it was that caused the collapse of the two towers. However, I often find that conspiracy theorists do not possess the above traits and when presented with information that conflicts with their desire to see a conspiracy theory in everything, instead of evaluating the information critically, they dismiss it, pouring scorn over those who supplied the information by questioning their 1) education 2) affiliation (i.e. they have vested interests aligned with the perpetrators of the conspiracy).

I am seeing this right now- somebody with no formal Engineering qualification, no professional qualification and no academic qualification comes on here asking for the opinions of Engineers. When said Engineers present opinions that differ from your own you start to question to what standard they are educated. I will say this for us all: Those of us who are Engineers here are most certainly taught and educated to a much higher standard than you. If anybody should be questioning their own failings, personal or otherwise, I believe it should be you.

The lack of respect shown by you and the public in general to Engineers is a pet hate and stems from the fact that the guy who comes to connect my washing machine to the water mains is, as one poster here put it an "Edgineer hurhur".

As an FYI, I am educated to degree level and work in Biomedical Engineering. So while I do not have the expertise a Structural Engineer might have in these matters, our skillsets in terms of thinking, evaluation and understanding of mechanical concepts would be very similar.

Pembily

uprising2 wrote: »

Some basic knowledge of collapse for starters, a viable explanation of how it was possible that it did simply collapse and nothing else was needed (explosives, thermite, etc), or somebody to say it's a lie how they say it happened because of X, Y or Z, just basically some for and against debate, I don't want to drag it into Conspiracy theorie, just stick to the actual science behind the collapse and if its possible that it could collapse at freefall speed, and keep collaping all the way down on its steel and concrete structure far beyond the impact area's and as the top section of one of the towers actually toppled over so there wasn't as much impact force from that tower.

My father and grandfather (both engineers - grandfather was part of the team who safely demolished Nelson's Pillar) had this discussion. The way they expalined it to me (also an engineer) was that it the Twin Towers had a steel support down the middle, surrounded by concrete and off this there were metal supports on which each floor was built - this metal core would have been protected by the concrete under normal heating but avaition fluid heats higher and as the plains were fairly full with fluid the core melted quickly causing the floors to collapse in a compact downwards action!!!

There is a thing called self weight - this would have caused the force you say didn't exist from the towers!!!!!!!

mawk wrote: »

I happened to be over there when it happened, so while I didnt happen to be there to see them fall irl, I did see the aftermath and every possible video during the media bombardment. So embedding a youtube clip is not going to make me change my mind.

As to whether i think it could have been possible. Yes I do. Have you ever seen a load extension diagram for a steel member? You put force on it and it deforms elastically put more and it eventually reaches it's elastic limit. The point at which any more deformation becomes perminant. The vast majority of the members strength lies in its elastic limit. Once the for exceeds this point the very quickly deforms and as it deforms it loses its ability to support it's load. The bar will then break at a force considerably below its original safe threshold. The heat from the fire is not enough to directly melt the steel but its enough to rob some of the ultimate tensile limit which causes the building to go from standing to falling very quickly.
Imagine stretching some chewing gum, the more you have already stretched it, the less you have to pull to stretch it even more. Metal works the same.
First year materials..

Exactly - perfectly explained and it is first, second, third and fourth year materials in Mech Eng!!!

uprising2 wrote: »

I left school at 15, 3 business's, phd in life, masters in common sense, thinking of going back to do my junior cert.

We all have phd's in life - build a bridge and get over it!!!

uprising2 wrote: »

Are you actually saying you don't have a problem with the centre core collapsing/disintigrating?.

Will be shot down for this but any way as you have no formal education in this specific area what makes you so qualified to say the core collapsing
was not perfectly natural under those specific conditions???

uprising2 wrote: »

I'm amazed, to what standard are engineer's taught?, is it part and parcel of the qualification not to question major failing's?, the very people who should have a problem with this fairytale are the very one's either turning a blind eye or don't understand the things they should.

I am amazed how an non engineer is quesitoning what many qualified engineers have said on this thread ALONE - it wasn't conspiracy - the building failed cos of the exteme conditions it was put under and as already stated - no engineer would have designed that building to be protected against a plain of that size or a fire of the heat and extent!!!!!

Ciaran500

uprising2 wrote: »

So there was no aircraft larger than a boeing 757 in 1964?, when was the B52 brought into service?. The production of the B52 had actually finished when the plans for the WTC were being drawn.

You should know this. The towers were designed to take a strike from a slow flying plane lost in fog, just like the Empire State building crash. They were never designed to have an airliner hit and at high speed.

Pembily

Ciaran500 wrote: »

You should know this. The towers were designed to take a strike from a slow flying plane lost in fog, just like the Empire State building crash. They were never designed to have an airliner hit and at high speed.

Exactly - you are dealing with American arrogance - their thoughts are no one would ever attack the Twin Towers!!!

C.D.

Ciaran500 wrote: »

You should know this. The towers were designed to take a strike from a slow flying plane lost in fog, just like the Empire State building crash. They were never designed to have an airliner hit and at high speed.

While I don't know the mindset of the designers of the Towers, this is commonplace practice in Engineering. For mainstream application (i.e. not military, NASA etc.) you design for 99.9% of the possible events that could put your structure/machine/device at risk. Designing for the other 0.1% is generally not economically feasible due to the small chance of it happening and the significant work and cost involved in trying to accommodate that risk.

It is safe to say that having to design a skyscraper to survive the impact of an airliner, the added weight and the resulting fire would result in a significantly different structure and I do not think anyone could really fault those who designed the towers many decades ago for not building a skyscraper to survive this. I think any Engineer here would be able to appreciate how considerable the forces involved in an airliner crashing are considering their speed and mass.

Penn

As a semi-regular on the Conspiracy Theories forum, I've written about this topic before. But I'll quickly give my reasons for believing the official story. To clarify, I am a Building Surveyor. Part of my course was Structural Design and Detailing. As part of my job, I regularly design steel beams and columns etc, albeit on a much smaller scale. But just applying the principles of structural design will be used to demonstrate my points.

Firstly, the building did not collapse as a result of the fire. It collapsed as a result of fire, and the fact that it was hit by a plane. Skyscrapers are designed to withstand the impact of a plane, but that is taking into consideration that the impact of a plane would be accidental and the plane would be attempting to slow down and divert. These planes were flown at full force into these buildings.

Structural steel members are designed to withstand fires for a certain period in order to allow the safe evacuation of the building and to try to allow the firemen to extinguish the fire before the structural integrity of the building is compromised to prevent the building collapsing. To give the required fireproofing to the steel, different methods can be used. The problem is, due to the impact of the planes, it is highly likely that a lot of the fireproofing (for example, the steel being cased in concrete) would have been compromised and the steel exposed to the fire.

With the amount of structural steel which would be required for this type of building, each member is dependant on the other members around it. Removing one places additional loading on the others, and also causes the forces acting upon those members to change (eg. a column with additional loading and with support at the top removed may start to be pushed outwards, pulling other members with it).

So with a number of the steel members being displaced by the impact of the plane, and more members with reduced fire-proofing being weakened by the fires, it is entirely plausible that the top section above the impact zones would collapse down onto the rest of the building.

As far as resistance of the lower floors goes, I ask you this.... How much do you think 25 floors of a skyscraper weighs? The building is designed to carry this load, but not when the load is collapsing onto it. For example, I can carry a bag of coal. But if someone drops a bag of coal on me, either it or me is ending up on the floor. And I don't agree that there was 'no' resistance. With the amount of debris and dust, it cannot be said for definite that there was no resistance. That building did not fall at 'free-fall' speed. I'm sorry, but it didn't. But remember that with every floor which collapsed, the weight falling onto the floor below increases, and more members of the structure are being displaced or removed, so less resistance is possible.

As for WTC7, the building was not only hit by falling debris from the other towers, but also vibrational energy from the impact of 2 skyscrapers falling nearby. Then with the fires which started in that building, as I said, steel is designed to withstand fire for a certain amount of time, but the fires in WTC7 were allowed to continue burning as the building had already been evacuated, and they wanted to focus efforts elsewhere. The building collapsed after 5 o'clock, about 7 hours after the collapse of the first tower, and had been pretty much burning continuously. With the damage caused by the falling debris, and the way the building was designed, the building collapsed. It can be seen from videos that a 'kink' appeared in the roof just before it collapsed. This would have been caused by the steel under it collapsing first. This indicates that the internal structure collapsed before the external structure, which would also have lessened the so-called 'resistance'

Also, the logistics of wiring up the buildings for a controlled demolition, whether it be explosives or nano-thermites or whatever, is next to impossible. The work to bring 3 building down by controlled demolition could not have been undertaken without being noticed is just plain illogical.

Anyway, like I said, I'm not a full structural engineer or anything, just know the basics of structural design. But from the knowledge I have, I believe it is entirely plausible that the buildings were taken down in accordance with the official reports.

C.D.

uprising2 wrote:

So there was no aircraft larger than a boeing 757 in 1964?, when was the B52 brought into service?. The production of the B52 had actually finished when the plans for the WTC were being drawn.

Saying that because there were B52's (or planes of that size) in service meant that the Towers should have been built to survive impact by them is like saying that because there are M1 Abrams tanks (weight of >60t) in service in the US means that all US cars should be designed to survive crushing from tanks of similar size to M1's.

In the 1960's and even today, airliners crashing into skyscraper is extremely rare, more so than I'd say M1 tanks crushing cars. It is quite simply a non-argument and defies logic that anybody would use such absurd reasoning to arrive at such a conclusion.

Of course skyscrapers design should factor in the likelihood of a plane crashing into it. But that is exactly it, you analyse the probability of events/failure modes and design for the ones that exceed predefined risk threshold. As paddyirishman85 has mentioned, planes of that size flown at full speed crashing into a tower is an extremely rare event.

uprising2

C.D. wrote: »

I have been reading this with interest- I strongly believe that the a inquisitive mind willing to challenge the status quo and conventional thinking, combined with critical analysis skills are the bedrock upon which Engineering is built.

I don't dispute there that appears to be some ambiguity about what it was that caused the collapse of the two towers. However, I often find that conspiracy theorists do not possess the above traits and when presented with information that conflicts with their desire to see a conspiracy theory in everything, instead of evaluating the information critically, they dismiss it, pouring scorn over those who supplied the information by questioning their 1) education 2) affiliation (i.e. they have vested interests aligned with the perpetrators of the conspiracy).

I am seeing this right now- somebody with no formal Engineering qualification, no professional qualification and no academic qualification comes on here asking for the opinions of Engineers. When said Engineers present opinions that differ from your own you start to question to what standard they are educated. I will say this for us all: Those of us who are Engineers here are most certainly taught and educated to a much higher standard than you. If anybody should be questioning their own failings, personal or otherwise, I believe it should be you.

The lack of respect shown by you and the public in general to Engineers is a pet hate and stems from the fact that the guy who comes to connect my washing machine to the water mains is, as one poster here put it an "Edgineer hurhur".

As an FYI, I am educated to degree level and work in Biomedical Engineering. So while I do not have the expertise a Structural Engineer might have in these matters, our skillsets in terms of thinking, evaluation and understanding of mechanical concepts would be very similar.

Great post, but it doesn't explain how anything collapsed, I may not have your education but I most probably have a higher IQ.
I don't have a lack of respect for engineer's but I have looked into how they supposedly collapsed and it just doesn't fit, its a story straight from hans christian anderson.
Some architects and engineer's are also saying what I'm saying and putting their careers and reputation's on the line in doing so.

aleybert

uprising2 wrote: »

Great post, but it doesn't explain how anything collapsed, I may not have your education but I most probably have a higher IQ.
QUOTE]

Brilliant! Gullible AND thick as a plank!

C.D.

uprising2 wrote: »

Great post, but it doesn't explain how anything collapsed, I may not have your education but I most probably have a higher IQ.
I don't have a lack of respect for engineer's but I have looked into how they supposedly collapsed and it just doesn't fit, its a story straight from hans christian anderson.
Some architects and engineer's are also saying what I'm saying and putting their careers and reputation's on the line in doing so.

My post does not purport to explain how they collapsed. As I said I am not a structural engineer, my post concerned you, your posting style and your attitude to members of this forum who have made some great and informative posts on this issue.

While I believe that it was an act of terrorism, I am willing to listen to the arguments of the other side and make an objective decision- something you are not willing to do.

And do not flatter yourself. Not only do your posts lack clear logic, rational thinking or any evidence of objectivity (let alone intelligence), but you resort to personal insults on your hypothesis that you have a higher IQ than me. Not only do you have no way of proving this, but IQ has been consistently shown to be a poor measure of intelligence. Indeed you might "have looked into" the matter, but mainstream "DIY Engineering" websites will not give you the deep appreciation of Engineering fundamentals that eduction or experience will.

aleybert

Hang on, whats this thread doing in this forum.
Shouldn't it be with the UFO and Bigfoot forums?

C.D.

aleybert wrote: »

Hang on, whats this thread doing in this forum.
Shouldn't it be with the UFO and Bigfoot forums?

Sorry to be the bearer of bad news, but Bigfoot died when the plane he was on crashed into the World Trade Centre Towers.

aleybert

C.D. wrote: »

Sorry to be the bearer of bad news, but Bigfoot died when the plane he was on crashed into the World Trade Centre Towers.

And wasn't it the UFO that caused the crash...:p

uprising2

Pembily wrote: »

My father and grandfather (both engineers - grandfather was part of the team who safely demolished Nelson's Pillar) had this discussion. The way they expalined it to me (also an engineer) was that it the Twin Towers had a steel support down the middle, surrounded by concrete and off this there were metal supports on which each floor was built - this metal core would have been protected by the concrete under normal heating but avaition fluid heats higher and as the plains were fairly full with fluid the core melted quickly causing the floors to collapse in a compact downwards action!!!

There is a thing called self weight - this would have caused the force you say didn't exist from the towers!!!!!!!

Ok for starters, "Two days after the original damage, Irish Army engineers blew up the rest of the pillar after judging the vestigial structure to be too unsafe to restore. This planned demolition caused more destruction on O'Connell Street than the original blast, breaking many windows."

The way they explained it to you?, can you not think for yourself?, the core did not melt, the temperature was not hot enough to melt steel, so the core did not melt quickly like you say, are you just repeating what you were told?, because there is a total lack of understanding just there.

Exactly - perfectly explained and it is first, second, third and fourth year materials in Mech Eng!!!

Well how come you, after all your years of education can still say the core melted, that it was explained to you, you can't see any problem with the core collapsing, have you no input yourself?

We all have phd's in life - build a bridge and get over it!!!

:rolleyes:

Will be shot down for this but any way as you have no formal education in this specific area what makes you so qualified to say the core collapsing
was not perfectly natural under those specific conditions???

No amount of education can give intelligence, the core collapsing was not natural because the specific conditions you believe are false, again I repeat the core DID NOT MELT.

I am amazed how an non engineer is quesitoning what many qualified engineers have said on this thread ALONE - it wasn't conspiracy - the building failed cos of the exteme conditions it was put under and as already stated - no engineer would have designed that building to be protected against a plain of that size or a fire of the heat and extent!!!!!

I'm also amazed that a so called engineer cannot even get the basics right to begin with.
The building was designed to take a plane crash and fire!
<A shape=rect name=engineers>
Statements by Engineers

Engineers who participated in the design of the World Trade Center have stated, since the attack, that the Towers were designed to withstand jetliner collisions. For example, Leslie Robertson, who is featured on many documentaries about the attack, said he "designed it for a (Boeing) 707 to hit it." [SIZE=-1]2 [/SIZE] Statements and documents predating the attack indicate that engineers considered the effects of not only of jetliner impacts, but also of ensuing fires.
<A shape=rect name=skilling>John Skilling

John Skilling was the head structural engineer for the World Trade Center. In a 1993 interview, Skilling stated that the Towers were designed to withstand the impact and fires resulting from the collision of a large jetliner such as Boeing 707 or Douglas DC-8.
Our analysis indicated the biggest problem would be the fact that all the fuel (from the airplane) would dump into the building. There would be a horrendous fire. A lot of people would be killed, ... The building structure would still be there. [SIZE=-1]3 [/SIZE]
A white paper released on February 3, 1964 states that the Towers could have withstood impacts of jetliners travelling 600 mph -- a speed greater than the impact speed of either jetliner used on 9/11/01.
The buildings have been investigated and found to be safe in an assumed collision with a large jet airliner (Boeing 707—DC 8) traveling at 600 miles per hour. Analysis indicates that such collision would result in only local damage which could not cause collapse or substantial damage to the building and would not endanger the lives and safety of occupants not in the immediate area of impact. [SIZE=-1]4 [/SIZE]
http://www.911research.wtc7.net/wtc/analysis/design.html#engineers

uprising2

Ciaran500 wrote: »

You should know this. The towers were designed to take a strike from a slow flying plane lost in fog, just like the Empire State building crash. They were never designed to have an airliner hit and at high speed.

Given the differences in cruise speeds, a 707 in normal flight would actually have more kinetic energy than a 767, despite the slightly smaller size. Note the similar fuel capacities of both aircraft. The 767s used on September 11th were estimated to be carrying about 10,000 gallons of fuel each at the time of impact, only about 40% of the capacity of a 707.
<A shape=rect name=engineers>Statements by Engineers

Engineers who participated in the design of the World Trade Center have stated, since the attack, that the Towers were designed to withstand jetliner collisions. For example, Leslie Robertson, who is featured on many documentaries about the attack, said he "designed it for a (Boeing) 707 to hit it." [SIZE=-1]2 [/SIZE] Statements and documents predating the attack indicate that engineers considered the effects of not only of jetliner impacts, but also of ensuing fires.
http://www.911research.wtc7.net/wtc/analysis/design.html

uprising2

Pembily wrote: »

Exactly - you are dealing with American arrogance - their thoughts are no one would ever attack the Twin Towers!!!

See above!

uprising2

C.D. wrote: »

While I don't know the mindset of the designers of the Towers, this is commonplace practice in Engineering. For mainstream application (i.e. not military, NASA etc.) you design for 99.9% of the possible events that could put your structure/machine/device at risk. Designing for the other 0.1% is generally not economically feasible due to the small chance of it happening and the significant work and cost involved in trying to accommodate that risk.

It is safe to say that having to design a skyscraper to survive the impact of an airliner, the added weight and the resulting fire would result in a significantly different structure and I do not think anyone could really fault those who designed the towers many decades ago for not building a skyscraper to survive this. I think any Engineer here would be able to appreciate how considerable the forces involved in an airliner crashing are considering their speed and mass.

https://www.youtube.com/watch?v=U6H4GaNhTfA

aleybert

You ARE Jim Corr.:p