World Trade Center Failure Analysis

(Re-edited several times, for syntax errors, clarity, broken links.)

This post contains images with emotional impact.

A new video about WTC popped on youtube which prompted me to write this blog post because i suspect the number of casualties by dust, unreported to this day, where many times more than those who died in the towers.

04/09/2019 Video is gone, can't find quickly a similar one without the offensive music. Here are some pictures showing the scale of the disaster brought by dust. I don't believe people could really survive in that dust for more than a few seconds.


Until WTC designed by architect Minoru Yamasaki and after, all high rise steel constructions were done in the "classic" fashion with structural vertical and horizontal rolled steel beams with cross reinforcement joints and numerous interior walls. As the looks suggests, this type of design is solid and can't be easily damaged.

WTC structure was made only of two so called tubular frames or cages, using about half the steel the old design uses. Outer frame was made of prefab panels that were actually made of three vertical, square section, rolled steel beams (2nd image below) welded together with other three huge pieces of sheet metal. This image, like many others, is tricky cause it suggests the building in the distance was built in a similar way. It only appears so because of its shape, no other building has ever been designed in this way.

The prefab panels themselves seem to be inspired from a Buddhist architecture ornament called Torana. (Torre means tower in  Spanish and Italian, and toro means bull with two horns of course).



Panels were put together in a new, revolutionary, also unique design: An outer tubular frame made of prefab inter-positioned panels (outer cage) and an inner core of "classical design" (inner cage), though only for elevator and shafts, with vast floors in between that were connecting and preventing the inner and outer cage to sway or buckle (bend) in or out.



Outer frame panels are connected together with four bolts at the end of each rolled steel square tube.

This type of joint would take a lot of vertical compression, as much as allowed by the rolled steel maximum compression load, some horizontal or side compression, limited by the bolts, (which have a cross section far less than of the cross section of the rolled steel) and could take almost no bucling (bending in and out of the cage wall) because of the prying effect on the bolts at the joint level.

Buckling and shear of the outer cage was was dealt with by inter-positioning of the of the panels and by floor trusses between inner and outer frame (cage) which allowed  the construction to stay vertically.

I tried to search to see how many bolts held together the structure and could not find. It's 12 per each prefab panel. Can't find how many panels either. What i found is many other analysis were blaming the bolts for the failure. But not those, the bolts holding together the floor trusses to the walls.

Even with this design (outer-inner cage) building would have behaved differently if the vertical square rolled beams making the outer cage where of one piece from bottom to top or anyways, fewer than one per 3 floors or assembled with a smaller square beam in between called "inner sleeve". This type of joint can take almost as much bending (side compression), shear and buckling as a continuous beam.

When assembled, however, the building had the appearance of outer cage beams being continuous also because of the aesthetic aluminum cladding installed on the outside on top of the each beam. From one of the images below it results some 258 vertical (interrupted every 3 floors) beams all around the building, which makes for 86 panels per each 3 floors, 110 floors, resulting approximately 4,730 prefab panels and 56,760 structural bolts (and nuts). Most of these bolts popped during cascading failure of the building, which apparently was designed in such a way that each the concrete floor turned into dust when falling onto next.

These are called bridge trusses making up the vast floor and connecting inner and outer cages. Thin, nothing like the sound, solid "classical" design seen in the second picture in this post (above), used in all high rise buildings before and after.

This design provided indeed ample floors with no walls in between.

Diagram (above): Constructional features of a prefabricated floor unit

(http://911research.wtc7.net/mirrors/guardian2/wtc/godfrey.htm)

21 Floor covering
22 In-situ concrete (4 inches)
23 Trough decking (1 1/2 ", ribbed)
24 Bar joist
25 Electrical services duct
26 Air-conditioning duct 

In this image after first impact on South Tower or WTC2 one can see prefab panels taken as a whole at least at one end, caused by failure of bolts. Pieces of the concrete floor missing.

This is a picture of the the exit area of the first hit tower. It was not until i have seen this picture that i realized the failure started at the concrete and steel components of the floors.

After impact, fuel spread across the vast floors caught fire and the expanding concrete and metal trusses making the floor heated by fire started to push, mainly alongside the trusses, and steel decking ribs on top, inner and outer cage against each other in the same time with floor buckling of the floors in other places creating a prying effect on the bolts connecting connecting trusses with the cages and those connecting panels with each other. Floor's structural role in stabilizing the sway of the outer cage in this case reverted to causing buckling of the cage caused by floor elongation (by heat expansion) and gradually breaking the bolts between panels and between cages and floors by prying effect. When enough of those bolts broke the floors started to fall onto each other.

Towers' "revolutionary" tubular design made of only two cages (tubes) (inner and outer) had several major design flaws.

Vast, relatively thin floors, where floors were/are also made of rolled steel beams played only a "minor structural role" compared to outer and inner frame, except sustaining selves, the concrete, and holding the outer cage to prevent sway or buckling. Without floor trusses and steel decking connecting inner and outer cage, the outer cage could not keep its shape, but sway, buckle, or bend inward or outwards and break.

About half of the weight of the floors was supported by a single shell or the outer cage with lack of redundancy. When that frame failed, there was nothing else to prevent the whole building from collapsing.

Ultimately, lack of inner walls and vastness of the floors due to unique design contributed to spreading of fuel and fire almost instantly to an entire half of the building (on several floors), when the floor expanded, heated by fire, and because of the length, the expansion was in the range of several feet.

Thermal expansion during hot summer days and the contraction in the winter times is the reason all bridges made of steel reinforced concrete have expansion gaps, while the roads themselves loose enough heat to the ground underneath not to expand and buckle. But if the temperature raised not with 20 or 50 degrees or whatever but with several hundred degrees, those gaps would not be enough. There is also a thermal inertia which prevents the bridge from heating all the way during the summer days while cooling during night time

Unusual hot summer may have been the cause for collapsing of that bridge in Genoa, Italy.

Another examples of metal structure that expand with heat was supersonic Concorde' fuselage. At 2 times the speed of sound, because of intense friction with the air, Concorde's (and other's supersonic planes) fuselage was expanding as much as one foot while of course the cabin's floor inside stayed at room temperature).

"heating had a significant impact on the construction of Concorde. Perhaps the most important issue designers had to contend with was the fact that heat causes materials to expand. I've seen different values on exactly how much the aircraft expanded, but most sources indicate that the air-frame stretched by 5 to 12 inches (12 to 30 centimeters) at Mach 2. Given the aircraft's normal length of 204 ft (62.2 m), that change amounts to little less than a 5% increase in the size of the Concorde fuselage."

http://www.aerospaceweb.org/question/planes/q0199a.shtml

Thermal expansion by heat was the direct cause of failure of only one or two floors. But when those floors fell on to the next one the accumulated weight of all the above floors accelerated by gravity lead to a cascade failure of all the other floors and corresponding walls of the cages. Concrete component of each floor, that was made by a certain recipe, was turning explosively into dust upon hitting the next floor.

There is little doubt in my mind that the towers were designed on purpose like a card castle, to create some day, when the right moments arrives, this type of spectacular frightening failure.

When re-editing this post and was searching for different shapes (sections) of rolled steel (for the purpose of further documenting this blog post) and on a site i found out some shapes are no longer available as a result of America's steel industry decline. There are probably also not many civil engineers left to deal with these kind of things or write on blogs or on forums and actually no more high rise buildings to be built. Or too few to matter.

Pareto's Principle

For a long time lately i thought i was cursed to only understand things of the past. Real time thinking was a unattainable task for me anymore. I remember when i was last time in dr.Boboia's office at Providence Scholls, i told her i cannot enjoy anymore anything in the present but only memories, everything else being the present Hell. And she completed with: It's good you have pleasant things to remember or something like that.

Real time thinking is only allowed to people with a thorough understanding of the times and reality they live in. I think.

For the first time in a long time i'm going try to react to a current event other than a response to my own blog posts.

For a few days now the Romanian newspapers keep a news about a mayor of a city in Romania  that seems to me to be home of some radical thinkers. She allegedly plagiarized from an Italian philosopher. I say philosopher because it is a tittle that is separated from the others attached to his Wikipedia entry. Alright. What's the big news? Besides proving one more time how bad is if one is assuming someone's else work, that unfortunately is nothing new?



Then something caught my eye in another Wikipedia entry associated with his name, by clicking on the link above, Pareto's principle. (God i wish my computer and internet was faster, maybe i'm going to order next speed, 20 mbps, right now i only have 7 and i thought the servers are not fast enough for this but i think in 2 years that changed).

Wow. So outdated. So much linked to the time period he lived in. So tributary and inseparable from his momentous state of mind. I thought philosophy, sociology and applied sociology was much more than that. A long time before the current post post-modern age when society was driven by an elite few.

Pareto defines the society he lives in based on some statistics pretending he discovered something.

I'm not going to go further with the analysis of thinking of a grown man who can theorize his own state of mind and make a principle out of it. I suspected for a long time that some educated people can take their own childish understanding of the surrounding reality, twist it a little bit, according to some rule they got obsessed by in some school or acquired through some random experience and make a philosophy out of it and project it in an ideology and give a raison d'etre to many others that simply don't have time or cannot afford the luxury to think. ("forgetting" to apply one of main principles of logic and that is verification through generalization - the main excuse after all could be he was probably mainly educated as an engineer). After all it's a temptation that we all fall in, the return to the innocent mind that allowed us the discovery of this world we live in, before we fell slaves to our own needs.

And start to manipulate their present reality by creating whole schools of thought and actions for those who are vulnerable and tempted because of the failure of other models, or any model that don't match with their state of mind.

The more different their model from current reality, the more radical their means of necessary actions are.

It's not 20-80 anymore. Those elites are gone mostly because of the last 2 WWs. It's everybody giving in and melting their personality into some huge entity and then bowing their egos to it. Some went so far and call this God or the collective subjective conscience that came out from the thinking of a single man 50 years or a century ago just because it fits their current psyche. Or because they think others might have had overlooked it at the time.

An entity that can handle everything for them better than themselves can. Some call it NWO. With its ancestors, communism and Nazism, usually under the form of dictatorships. That can build a whole new reality modeled on a whatever unfinished, unproven theory, like the one mentioned in the alleged plagiarism case above. If it can change the world? Of course it can and probably it already did. Bad luck for us if one of these incomplete theories merged with others of the same kind is the starting point leading historically to our current social reality cause there are probably much better models of reality we can resort to, and some i hope take as starting point our individuality and the presumption we don't have to give it up in order to exist as a society.

It is very intriguing why they brought this in the light of the current news paradigm and into the search engines' cache, and it occurs to me it may be yet another attempt into manipulating us into thinking that this may be a current model they use to manipulate us on daily bases.

I suspect the models currently used in applied computational sociology may very well be generated by computers using data from different digitized sources, even more simplified, similar to those used in modelling in engineering like finite elements, that cannot be understandable by a single human mind, ever changing, or even modelling our thoughts like a long string of Pavlovian reflexes. It might very well be, but it is applicable only for a current state of mind. Depending on a very unique combination of neurotransmitters unevenly distributed in different areas of the brain at a certain moment in time. (But then what is conscience, an illusion?)

Thus the need to continually manipulate the society to make it fit better on whatever theory they think they discovered. And the best way to do it is to keep it continuously in a collective trance or psychosis by creating on-demand, shocking news, and by repeating all kind of mantras, behind closed doors, and resulting in a cult like collective mind set-up. Being all close to the same state of mind would keep us with a similar distribution of neurotransmitters, and similar thought patterns, but it will also cut our minds' and society's natural redundancies. (I remember during communism a very common tendency in all conversations was the generalized need of reaching a consensus.)

Trouble is if they go too far with those and how far and if they can revert it back to human control and understanding. Some are saying we are already on a one way, no return road.

Or could they have brought it to public's attention through a back door like they often do, invoking this plagiarism case they might have constructed themselves so they can keep it in the news to test our reactions because they think they might just have found a new way in which they can apply the magic combination, 20-80, by considering themselves a new elite, based on ideology alone and not on history and inheritance of values, like it used to be during Pareto's time, that might in the future not even needing the rest of us, and trying to replace us with robots? So deja vu, except for the robots part.

But more worrying, these incomplete theories might be just psychological tricks, applied on large scale, letting us think they have a "strong" theory, that would bring humanity in its right place like it has never been before, thus the need for collectively experimenting, flattering to all that adhere to their organization, like through becoming an elite, just to better manipulate the whole of us until they reach their real purpose, whatever that might be though full of good intentions.

There are better ways to deal with individual's integration in a society. It only takes a set of rules and laws. The rules are applied in micro-society, within family and circles of friends. The laws, for the greater society, and as a last resort when one forgets his rules. That lets society grow little by little governed by its own naturally and historically generated principles.

I always asked myself, how can two people live together without giving up something if each can't stand him/her-self, not talking about a society? Is there any way to be part of a group without any giving in his own freedom, individuality and ego, without understanding the simple fact that he/she wants the same as every one of his kind?

How can some attempt to model a society when they could never model a single human brain? And probably we'll never could. (And if they are pretending they already did, please beware of tricks).

Living in a society is so complicated that it takes each a sophisticated, mature mind, a complete connection with the society one lives in, a complete understanding (or simply the wish to) of the rules, laws and the principles of this reality  - paradigm we each see differently.

October 24

1:00/3:00 Singurul motiv pentru care l-au băgat pe ăsta în știri (deja vu de atâtea ori) este că aduce cu primul nostru înotător nominalizat. Niște pixeli care spală alți pixeli, asta e. Însă... nu cumva... Otoniel, Ionel?...

1:07/3:07 Dacia a parcurs un drum lung până aici, dar în final au făcut-o prea bună și nu mai ajunge și la români.

3:13 Buzzers kinda work, moles don't come too much near the building, however, i see small areas with wet soil and when i step on those the smoke (or mold smell) inside subsides. There is at least one new dog poo, i can smell it. This stuff is evolutionary, is so powerful that it stinks even when it rains like right now.

3:17 Someone is definitely upstairs, though stuff in the car at that spot has not been touched yet...

3:28 Analysis of drive axle tells failure didn't happen very long ago. It was the little the car was driven by me and by the towing guy, at most one quart of a mile that created a small abrasion that has no depth, from the axle that was wobling and hitting something. 3:55/5:55 Situația cu profesorii mei din liceu e probabil generalizată în România și nu numai, în mediul universitar probabil toți din vârfuri sunt din ăștia, doctori, ingineri, profesori, decani etc.. Asta ar explica stagnarea, de decenii, din toate domeniile.

4:10 Just remembered something, Angela found in the mail today the missing bill from a credit card, the one that was supposed to be paid before 10th of this month. She figured this one in time, did not miss the payment, she's planning on following those more closely. Most likely, a doubling of the delayed delivery with FedEx (ingannare).