World Trade Centre [WTC] Collapse

[Malachy Larkin]

Hello Everybody.

Im sorry to re-open old wounds but 8 years ago I posted on this topic.
Much has happened since.

I dont subscribe to conspiracy theories but

1] Serious questions remain unanswered re the technical cause of this collapse

2] Assume the 9/11 doubters are correct and insitu explosives were used to bring down the 3 towers.

3]What motive could there be for insitu explosives.


Re [3] Motive I speculate and thats all it is:

If a very tall building ,in a congested district of other tall buildings ,becomes structurally unstable [for whatever reason] and is in imminent danger of collapse , it could makes sense to have prepared charges installed in the structure to bring it down within its own footprint and LIMIT DAMAGE TO SURROUNDING STRUCTURES.

These explosives would be detonated by remote control only in a doomsday situation.

There are distinct advantages to having prepared charges in such situations principally limitation on loss of life and destruction to adjoining property.

Any views?

[Richard Haut]

Malachy, what you say makes sense - but the amount of time and number of personnel involved in laying demolition charges in three buildings of the size of WTC 1,2 and 3 begs the obvious questions - when were those charges placed, and WHY ?

to go to the considerable expense and trouble (and potential risks) of laying explosive charges in sound buildings in case they became unstable is of course a nonsense.

if you believe that such charges were laid, then the timescale alone means that they were placed before the 9.11 attacks.

[martin.hedin]

I dont know if I really should answear this, but I will give you my opinion.

What questions remain unanswered? You stumble on these conspiracy theories all over the internet, all of them claim that the collapse wasnt possible without explosives inside the building, or that the airplanes were missiles or something like that.

The theories claim that experts say that they cannot explain the collapse and so forth.

Now:

How are these experts?

What was wrong with the collapse?

What cuestions remain unanswered?

Show me an official study or article where a structural engineer justify their theories with calculations or atleast with some kind of scientifical or professional backing.

I dont think this discussion belongs on these forums until these cuestions are threated with realism and in a mature fashion.

The point is, I have newer seen this question being threated in any manner that I would devote any attention to it.

Have you?

[Richard Haut]

[Ed Ziomek]

Folks, (and good to hear from you Rich)...

I actually partially worked at the WTC 1 and 2 in my computer jobs.

The World Trade Center suffered from a huge architectural flaw, which at the time was considered sooooo innovative!

The outside skin was the majority supporting structure of the entire building. As I understand it, the inside of the building had no traditional supporting pillars running up and down.

When the intergrity of the outside structure was broken, i.e., the skin of the building's exterior, and the 2000 degree heat of airplane fuel started melting interior horizontal metal ceiling beams, there was nothing to hold the top floors from pancaking down onto the below floors. And the lower floors progressively had to contend with sledgehammer blows of upstairs floors collapsing ontop of each other.

Building 7 is the other controversy, not three, and my son was photographing the building at the time of the collapse (I think it fell the next day). He felt an earthquake like rumble, and a policeman ran past him screaming, "Run, its coming down". So for one side of Building 7, my son was the last human building to leave that area. Subsequent conspiracy theories say it was blown with explosives, but I don't believe it.

WTC 1 and 2 came down because a jet flew into a building that had no traditional interior supports. But who designs skyscrapers for a jetliner attack?

Side note, I videotaped a portion of the disaster from 10 miles away, and have refused to look at it even once. What is the point of a catastrophic, genocidal tragedy?

Architecturally on the other hand, this is a very valid topic, even today. But all genius ideas can be defeated by the age old saying "Nature sides with the hidden flaw".

[martin.hedin]

Ok, that caught my attention. But is there any developed thoughts or research on this, that you can read about? Has their been any study about the collapse of WTC 3?

This is what i meant in my post. Instead of loose arguments and mysteries, where are the studies from professionals?

Am I wrong for asking this?

I want to know if this is just a part of popular culture, or if someone actually has adressed these issues in a professional fashion.

[Richard Haut]

Question: who designs skyscrapers for a jetliner attack?

Answer: everybody

Ed

the risk of being hit by an aircraft has been a major concern for high-rise buildings for decades - from many reports, the designers of the WTC most certainly took account of the risk.

I remember the problem being discussed (specifically in terms of the risk of burning jet fuel going down lift shafts) when I was a child - and I am not exactly young now. Maybe nobody thought that anybody would be crazy enough to do it deliberately, but the risk of accident was serious - and apparently it formed part of the WTC design brief.

yes, I stand corrected - careless shorthand for the third tower: WTC7.

however, the possibility of a serious design flaw does matter. Is it the explanation ? Was the "structural skin" so integral to the building that being punctured by a plane destroyed the integrity of the building ? that I don't know - but it would make it more than serious as a flaw if it was the case because it would mean that the building was not able to fulfill the original brief (which included the risk of being struck by an airliner).

I am glad your son got out - but what did happen to WTC7 ? I have seen film and heard recordings that insist that there were explosives - and I have no idea. The problem is that no description of the fire or damage to WTC7 seems even close to causing collapse - UNLESS there was similarly a design flaw.

were the buildings simply too clever - using a system which went too far and, in extremis, could no longer perform ? It would explain the way that the towers came down.

there is without doubt a great deal about the attacks that we have not been told, or about which we have been lied to - but the physical facts of buildings that collapsed when, on the basis of their scale and design, they would certainly have suffered considerable damage, but also have remained standing is something that must be investigated.

would terrorists have known of, and wanted to take advantage of such a design flaw ? that's crazy isn't it ? not really - just remember what the bin Laden family do for a living: building contractors.

[Ed Ziomek]

Thanks Rich for the clarification, my mistake and my ignorance of course.

Martin...

There are Thousands of hours, thousands of scientific studies, forget the blogs.

This great one from the University of Sydney, Australia. Try Google search on “world trade center” collapse.

http://www.civil.usyd.edu.au/wtc.shtml

“It appears likely that the impact of the plane crash destroyed a significant number of perimeter columns on several floors of the building, severely weakening the entire system. Initially this was not enough to cause collapse.

Eventually, the loss of strength and stiffness of the materials resulting from the fire, combined with the initial impact damage, would have caused a failure of the truss system supporting a floor, or the remaining perimeter columns, or even the internal core, or some combination. Failure of the flooring system would have subsequently allowed the perimeter columns to buckle outwards. Regardless of which of these possibilities actually occurred, it would have resulted in the complete collapse of at least one complete storey at the level of impact.”

As another side note, when I was fixing computers within the WTC, 50th floor or so, one of the engineers who had a communications hole cut in the concrete flooring showed me the extract, shaped like a donut. It was extremely lightweight, and he said it was special featherweight concrete never before used until these buildings. In my hand, it was the weight of 1.5 donuts. Incredibly light.

[martin.hedin]

Thanks Ed,

Its funny, I did what you suggested just before reading your post. There seem to be many clear studies explaining all the big aspects about the collapse, even WTC 7.

The fact that only websites like thethruthbehinditall.com (or whatever) claim the these theories about the explosives are facts, and sites and organisations .gov types explains the collapse with actual studies, makes me more calm. I havent found any serious study showing the contrary.

Well, at least. Reading just biefly on these sites, i cant find any unanswered questions. WTC 7 for example is well studied and explained.

http://www.nist.gov/public_affairs/techbeat/tbx2008_1120_wtc7.htm

[Malachy Larkin]

Thank you all for responding to what after all is a very sensitive issue.

I did say I dont subscribe to the conspiracy theories and am inclined to believe much of the official report.
Questions still remain though.

Ed Ziomek makes a point that there were no central supports.This is not quite accurate.
There was a powerful steel core support of approx 50 enormous composite columns .spaced at close centres.
Many of these columns were about 2ft x 3ft. made of steel 5 inches thick!

Whats truly puzzling is why did this central core structure pulverize totally if the perimeter floors were just pancaking and sliding down between core and outer skin?
The core is visible partially as the floors pancaked but it too eventually crumbled into very small pieces.

[BTW the steel did not melt.,As is normal in fires, some steel softened and lost structural strength].

Its important to note that the core steelwork in the bulk of the buildings below the points of impact was not substantially as far as I know affected by fire,

The normal expectation therefore in this event after the pancaking would be to see 2 tall, albeit damaged core. structures standing proud of the pancaked floor debris .this did not happen.

The buildings were designed to take a hit from a Boeing 707 which is a substantial object.

[martin.hedin]

I saw a documentary on Discovery channel a few years ago. The explaination was that the main reason for the collapse was that the fireproofing was of poor quality, and had loosened from the steel structure over the years. So even if the structure was designed for an impact of an aircraft, the fireresistance wasnt up to the task at the time of the incident.

[Malachy Larkin]

Martin.

The bulk of steelwork in the towers cores below the zones of impact [ZOI}was unaffected by fire.
Some burning fuel did spill down one lift shaft as far as I know but the effects of this would be limited and localized.

All the fire protection remained in place below the ZOI.

Its clear to me therefor that the central loadbearing spines ie the cores in both towers below ZOI retained their structural integrity.

As per my last post,why did these cores pulverize in on themselves.
The only rational explanation I can come up with,in the absence of an explosion, must be related to the vertical connections between core columns.

Normally the plates connecting vertical loadbearing columns are designed to be at least as strong as the column itself. They would also be very very much stiffer and stronger than the connections to the floors.

Why would all these extremely robust and powerful vertical column connections shear like paper and allow the entire building to implode in virtual freefall?

Remember 100% of these massive steel core spines were intact and unaffected in the main stack of the towers below ZOI.

.

[Richard Haut]

pulverised - completely powdered - towers that fell at near freefall speed almost straight down.

the question is not to work out what might have happened, but how is such an effect possible.

and even when one considers what could be the explanation, there remains the contradiction of WTC7.

could WTC7 have been "pulled" because the damage was so great ? an irrelevant question because that would mean that demolition charges were already in place.

Ed's idea of a serious design flaw at least gives a possible explanation. If true, it is a massive flaw - and leads to the possibility that it was not simply an attack on the towers, but an attack specifically to hit that flaw in the design of the towers, in order to bring them down.

the sight of burning, damaged towers would have caused shock and concern, but might not have been accepted as a causus belli. The towers HAD TO COME DOWN.

the advantage for those planning the attack of a major design flaw would have been that the collapse could be caused by a comparatively simple attack. The strength of the central cores would need to have been, like the concrete (as Ed points out), very weak at upper levels.

and yet, even with such a serious flaw, would the towers have turned to powder and come down so completely and so fast ? If one accepts the design flaw as the reason for the failure to withstand the impact of an airliner, it still does not explain the extent of the destruction because the buildings at the lower levels cannot have been so weak without the buildings being in danger of collapse with or without an attack.

suppose there had been a major accidental fire - without aircraft. Were the buildings so weak that accidental damage would have compromised the structure ?

if the answer to that is "yes", then it also explains WTC7's collapse.

for architecture that is no joke.

and why might such a serious flaw be suspected ? because of the FIRST attack on the WTC some years before - an attack which the FBI themselves could have stopped and chose to allow to happen (from their own records).

that attack was, as far as I am aware, on the central core. What was the point ? If known to be very weak structures then it may have been thought that that would be sufficient to cause collapse by attacking at the logical point: the base. However the scale of the explosives were insufficient.

looking at inflated temperature figures and talking of floor fixings does not explain the collapse. However if these were indeed very weak structures then it is possible that the attack was undertaken to exploit that weakness.

why powder ? perhaps Ed held the answer in his hand - because that is all that the building was made of, powder with a bit of steel as a stiffener.

and suddenly it is architecture which finds itself in the frontline.

[Ed Ziomek]

Rich...

I personally am not tuned into all the nuances of all motives by the idiots and criminally insane mass murderers who planned the attack.


I do find it very compelling that their was a major meeting going on at 8AM that morning in the Windows of the World restaurant, with members of something that sounded like the World Bank or World Monetary Fund, or something in that financial category.

And how I know this is one of the CEOs of a major credit card company was due to be at that meeting, and decided to arrive fashionably 1 hour late, skipping the bagels and small talk, and of course, it saved his life.

Likewise, the FBI's retired, main OBL guy, who spent five years tracking that idiot, started his first day on the job as WTC security chief, that exact morning.

Normally, I am a peace loving guy, but for the clowns that planned it, hunt these mass murderers down if it takes one hundred years.

And have you noticed, no organized government wants anything to do with these sickos.

[Ed Ziomek]

Rich, I apologize.

Upon reading your comments a second and third time, I may have completely missed your point and responded from some other planet.

Let me retract my last comment and just sit back and listen.

Apologies.

Z