I found the missing Jolt.

[tfk]

Look, JS, you’re simply wrong about this.

One of the most desirable, most clever, most elegant thing that any designer can do is to get a single component to serve multiple function, JS.

You read, “A function of the hat truss was to support the antenna”, and read it as “THE ONLY function of the hat truss was to support the antenna.”

It’s just that simple.

You can fess up to that … or you can keep digging your hole deeper & deeper.

I am not going to argue with you...

The hallmark of someone who is quoting something with little depth of understanding.

You can take this up with Roberston, Skilling and Tomasetti. I am sure they would appreciate your wisdom. This is not MY assertion... I am reporting what I have read about the hat truss by the designers/engineers.

More “I’m just quoting & don’t really understand with any depth.”

you are twisting the explanation

Oh, really...??

I am twisting which explanation? Glanz’ explanation?

Well, here is the section (in its entirety) which I excerpted in my previous post.

Even the dampers would not be enough. Robertson and John Skilling had to go to Yamasaki and tell him that all of the experimental data they had been collecting indicated that the towers would still sway too much unless three separate structural modifications were carried out. Two of them would have an enormous impact on the architectural design of the building, Robertson said, before explaining that he would have to widen Yamasaki’s pinstripe columns slightly to make them stiffer. In part to ensure that the windows became no narrower than they already were, that meant widening the spacing between the columns slightly.

The increase in spacing was only an inch, so that each column would now be forty inches from its neighbor instead of three feet, three inches. But that tiny change meant that there would now be fifty-nine pinstripes per face instead of sixty-one, altering the look of the facade. The design was inherently stiffer for a given amount of steel, but that wasn’t the main reason for the change. The time the big towers took to sway back and forth was too long. It was too easy for the side-to-side push of the vortices to take on the same rhythm, generating huge oscillations. The structural changes would help shorten the jiggle: eleven seconds back and forth, still slower than the Empire State Building but an improvement nonetheless.

There was more, Robertson said. Still another element of his solution was a huge support structure called a hat truss that would sit atop each building and tie its core to its exterior. Already under discussion as a brace to hold up a soaring TV antenna on the north tower, the hat truss could add robustness to the entire building from top to bottom, Robertson knew, with a few tweaks in the design.

And finally, Robertson wanted to twist the orientation of the rectangular core— containing interior structural columns, fire stairwells, and elevators— in one of the towers. No longer true twins, the north tower’s core would run east-west, and the south tower’s north-south. The change would discourage the towers from dancing in unison.

Glanz, James; Lipton, Eric (2014-01-21). City in the Sky: The Rise and Fall of the World Trade Center (pp. 165-166). Henry Holt and Co.. Kindle Edition.

Please compare this verbatim excerpt to the excerpt I posted earlier & tell me what I “twisted”.

Then, perhaps, you can tell me how I am “twisting” the following verbatim excerpts from the NIST Report.

NCSTAR1-2A

3.2.8 Hat Truss Modeling
In both WTC 1 and WTC 2, a truss system referred to as a ‘hat truss’ was constructed between floor 107 and the roof. The hat truss system was intended to support the load of the antenna on top of the tower and to interconnect the exterior walls to the core.

If you’re still not clear on why it is a good idea to interconnect the core & external column, perhaps this quote will provide you with a little insight.

NCSTAR1-2A
Sec 4.2.3 pg. 74

“The hat truss system distributed both gravity loads and wind loads between the core and the exterior walls.”

Are you going to write to the NIST structural engineers, with your quote excerpt, and tell them “WRONG. It doesn’t ‘interconnect the exterior walls to the core’. And it doesn’t ‘distribute the wind loads between the core & exterior walls’. It ONLY supports the antenna. Because ... that's how I read THIS QUOTE.!”
__

read:

http://global.ctbuh.org/resources/p...e-design-features-and-structural-modeling.pdf'

Thanks for providing a reference which mentions the phrase “hat truss” one time, and says not one word about its function.

I am sorry Mr tfk... you are misinformed as to why the hat truss was employed in the twin towers.

Time to stop digging, JS.

Your comment about my "faking it" is both wrong & uncalled for.
And you know it.

You jumped the shark with what you thought was an opportunity to get a little payback for some of the times that I've been hard on you.

You jumped at the wrong time, guy.

You can step back, act like an adult, and rescind your comments.
Or not.

Whichever path you choose will have an impact on both how people view your response when you've been shown to be wrong about some trivial topic.

And it'll have an impact on our future interactions.

Your choice.

 

[beachnut]

http://the911forum.freeforums.org/collection-of-aircraft-debris-and-crash-site-photos-t524-15.html

thanks...

the freeforum.org has virus popups... i guess that is why it is free

Wow, paranoia and an inability to understand it crashed. I love the paranoia about the FBI and why they are hiding evidence.

Like the missing jolt nonsense, the lack of knowledge and logic prevails for the fantasy of not enough debris, debris disappeared, and the idiotic 93 shot down fantasy... the debris begins at the impact point. The debris is spread out in the direction the aircraft was going. For the missing jolt, Tony seems confused what a model would show, and what reality presents.

 

[tfk]

WTC2 didn't have an antenna so your argument doesn't apply in that case. Were there plans to install one that were abandoned?

Yeah, there were plans to install an antenna on WTC2, too.

For some reason, that never happened.

 

[JSanderO]

Look, JS, you’re simply wrong about this.

One of the most desirable, most clever, most elegant thing that any designer can do is to get a single component to serve multiple function, JS.

You read, “A function of the hat truss was to support the antenna”, and read it as “THE ONLY function of the hat truss was to support the antenna.”

It’s just that simple.

You can fess up to that … or you can keep digging your hole deeper & deeper.



The hallmark of someone who is quoting something with little depth of understanding.



More “I’m just quoting & don’t really understand with any depth.”



Oh, really...??

I am twisting which explanation? Glanz’ explanation?

Well, here is the section (in its entirety) which I excerpted in my previous post.



Please compare this verbatim excerpt to the excerpt I posted earlier & tell me what I “twisted”.

Then, perhaps, you can tell me how I am “twisting” the following verbatim excerpts from the NIST Report.



If you’re still not clear on why it is a good idea to interconnect the core & external column, perhaps this quote will provide you with a little insight.



Are you going to write to the NIST structural engineers, with your quote excerpt, and tell them “WRONG. It doesn’t ‘interconnect the exterior walls to the core’. And it doesn’t ‘distribute the wind loads between the core & exterior walls’. It ONLY supports the antenna. Because ... that's how I read THIS QUOTE.!”
__



Thanks for providing a reference which mentions the phrase “hat truss” one time, and says not one word about its function.



Time to stop digging, JS.

Your comment about my "faking it" is both wrong & uncalled for.
And you know it.

You jumped the shark with what you thought was an opportunity to get a little payback for some of the times that I've been hard on you.

You jumped at the wrong time, guy.

You can step back, act like an adult, and rescind your comments.
Or not.

Whichever path you choose will have an impact on both how people view your response when you've been shown to be wrong about some trivial topic.

And it'll have an impact on our future interactions.

Your choice.

First of all.... you have a very dismissive condescending attitude.

++++

Of course when they added the "hat truss" steel it added to the ALREADY existing steel framing of the mech floors which connected the core steel to the facade... in 16 additional locations. And of course they were able to employ diagonal members which make for rigidity. in the vertical axis where they were located.

The design intent for the hat truss was the support of the antenna. It was not designed to resist wind shear.... and I seriously doubt that 4 points of attachment to the spandrels on the 107th floor transferred much in the way of lateral loads to the core columns.

While you are writing to Lamont Doherty... take a few to contact Leslie Robertson and ask him why he used the hat truss... or ask him how he could support the antenna without the hat truss? The comm antenna was part of the original program for the tower.

Be happy believing that the hat truss were engineered to resist wind shear.

 

[tfk]

First of all.... you have a very dismissive condescending attitude.

Of course i have.
With you.

You were a 50-something year old architect who became a card-carrying 911 Truther & supporting member of AE911T.

That alone tells me that you're pretty damn clueless about structural engineering. Many of your posts here confirm that opinion.

There’s nothing unusual about that. There are lots of people here who aren’t familiar with those two topics. I don’t treat those folks with dismissive condescension.

There have been a subset of people here who were both clueless about those topics & simultaneously rude, petulant & insulting of my knowledge of the subject. I remember Bill Smith, Profanz, Childlike Empress, Christophera, femr, Tony Szamboti, and recently FalseFlag, to name a few.

I’m DAMN sure that I’ve been dismissive & condescending to all of them.

Not an accident, JS.
Nor an oversight.
Nor a result of getting mad or losing my self-control.
__

This could have gone an entirely different way, JS.

You could have said, "I think tfk's wrong about the wind shear part."

Then I would have responded with the two quotes that I did, showing that "resisting wind shear" was, in fact, a component of the hat truss design. And this would have passed unnoticed.

Nobody forced you down the "tfk is faking it" route.
That was your choice.

What would be your response to a petulant, rude French Literature graduate who told you that you were "faking it" regarding architecture?

Would you be inclined to concern yourself with the little prick’s self-esteem?

Of course when they added the "hat truss" steel it added to the ALREADY existing steel framing of the mech floors which connected the core steel to the facade... in 16 additional locations. And of course they were able to employ diagonal members which make for rigidity. in the vertical axis where they were located.

The design intent for the hat truss was the support of the antenna. It was not designed to resist wind shear.... and I seriously doubt that 4 points of attachment to the spandrels on the 107th floor transferred much in the way of lateral loads to the core columns.

"... 4 points of attachment ..."?
I think you'd better look at Fig 3-10 & 3-11 of NCSTAR1-6D.

I count at least 32 points of attachment (more likely 72) on the 107th floor.

16 points to the external columns.
At least 16 (but more likely 56) to the core columns.

"... to the spandrels ..."

And, for engineering reasons, I SERIOUSLY doubt that they attached those massive beams to the spandrels, and then depended on the tiny spandrel-to-column welds to transmit the loads to the columns. I very strongly suspect that they fixed the beams directly to the columns.

... contact Leslie Robertson ... ask him how he could support the antenna without the hat truss?

Strawman.
Nobody suggested otherwise, JS.

The comm antenna was part of the original program for the tower.

Strawman.
Nobody suggested otherwise, JS.

Be happy believing that the hat truss were engineered to resist wind shear.

And now, in an attempt to snatch extra defeat from the jaws of defeat, you're reduced to strawman arguments and lying about my statements.

I explicitly stated in my first post that it was designed to do both jobs: resist wind shear and support the antenna.

The only way you're continuing this fiasco is to:

1. ignore the fact that I said "... and to support the (antenna) tower on top" in my original post, and
2. ignore the two separate references that I provided that says that an additional purpose was to strengthen the tower against wind shear.

Good luck with that.

 

[rwguinn]

Gee whiz, tfk
Are you suggesting that an item can be designed to do more than one thing?
Next you'll be implying that airplane wings can be used to not only provide lift, but also act as fuel tanks, provide support for the engines, and control the rolling motions of an aircraft.

 

[JSanderO]

Of course i have.
With you.

You were a 50-something year old architect who became a card-carrying 911 Truther & supporting member of AE911T.

That alone tells me that you're pretty damn clueless about structural engineering. Many of your posts here confirm that opinion.

There’s nothing unusual about that. There are lots of people here who aren’t familiar with those two topics. I don’t treat those folks with dismissive condescension.

There have been a subset of people here who were both clueless about those topics & simultaneously rude, petulant & insulting of my knowledge of the subject. I remember Bill Smith, Profanz, Childlike Empress, Christophera, femr, Tony Szamboti, and recently FalseFlag, to name a few.

I’m DAMN sure that I’ve been dismissive & condescending to all of them.

Not an accident, JS.
Nor an oversight.
Nor a result of getting mad or losing my self-control.
__

This could have gone an entirely different way, JS.

You could have said, "I think tfk's wrong about the wind shear part."

Then I would have responded with the two quotes that I did, showing that "resisting wind shear" was, in fact, a component of the hat truss design. And this would have passed unnoticed.

Nobody forced you down the "tfk is faking it" route.
That was your choice.

What would be your response to a petulant, rude French Literature graduate who told you that you were "faking it" regarding architecture?

Would you be inclined to concern yourself with the little prick’s self-esteem?



"... 4 points of attachment ..."?
I think you'd better look at Fig 3-10 & 3-11 of NCSTAR1-6D.

I count at least 32 points of attachment (more likely 72) on the 107th floor.

16 points to the external columns.
At least 16 (but more likely 56) to the core columns.

"... to the spandrels ..."

And, for engineering reasons, I SERIOUSLY doubt that they attached those massive beams to the spandrels, and then depended on the tiny spandrel-to-column welds to transmit the loads to the columns. I very strongly suspect that they fixed the beams directly to the columns.

Hat trusses (or "outrigger truss") located from the 107th floor to the top of the buildings were designed to support a tall communication antenna on top of each building.[50] Only 1 WTC (north tower) actually had an antenna fitted, which was added in 1978.[58] The truss system consisted of six trusses along the long axis of the core and four along the short axis. This truss system allowed some load redistribution between the perimeter and core columns and supported the transmission tower."



Strawman.
Nobody suggested otherwise, JS.



Strawman.
Nobody suggested otherwise, JS.



And now, in an attempt to snatch extra defeat from the jaws of defeat, you're reduced to strawman arguments and lying about my statements.

I explicitly stated in my first post that it was designed to do both jobs: resist wind shear and support the antenna.

The only way you're continuing this fiasco is to:

1. ignore the fact that I said "... and to support the (antenna) tower on top" in my original post, and
2. ignore the two separate references that I provided that says that an additional purpose was to strengthen the tower against wind shear.

Good luck with that.

You are an arrogant condescending person.

I am older than you I suspect... and I an architect NOT a civil engineer. When I / we need an engineer we hire a consultant. I have worked with Severud, and Nordenson and other small shops. I worked for Emery Roth and Son when the towers were being built back in 1970. I don't work on high rises and I don't need to do engineering for them.

I don't care what your practice is... I suspect you haven't engineered any high rise buildings...

I did voiunteer to work for AE911T. At the time I knew nothing about them and assumed they wanted to do research into how the buildings collapsed.... build performance studies. It was in october 2009. I hadn't even heard of NIST at the time... and was not a member or participant nor read any web 9/11 forums. I met Tony that day and suggested to him to set up a meeting with Leslie Robertson. In no time Gage wanted me as a board member. Although I refused at first I acquiesced. Within 2 months I was kicked out because I did not sign on to their CD and thermite BS. I, of course discovered by being in the belly of the beast what their deal was. I never accepted CD... But at the time I didn't understand how the towers came down... And I suspect at that time you didn't either.

+++++

No it was not DESIGNED for the purpose to resist wind shear. If you can show that Robertson or Skilling said this... show me and I will retract this statement.

The hat truss was designed to support the antenna.

And YES as I wrote above the additional steel stiffened the upper mech floors... This was not needed I believe.

Please show us other buildings without antennas which have a hat truss to resist wind shear.

By the way... the facade columns were not very robust at the upper mech floors. The were more than the floors just below them. ALL mech floors had heavier steel than the floors below and above them

The outriggers were attached at a spandrel.. here's a drawing of the location of the outriggers... notice the alignment.

Teach us!

Maybe you want to edit the Wikipedia:

"Wind effects

The tube frame design using steel core and perimeter columns protected with sprayed-on fire resistant material created a relatively lightweight structure that would sway more in response to the wind, compared to traditional structures such as the Empire State Building that have thick, heavy masonry for fireproofing of steel structural elements.[59] During the design process, wind tunnel tests were done at Colorado State University and at the National Physical Laboratory in the United Kingdom to establish design wind pressures that the World Trade Center towers could be subjected to and structural response to those forces.[60] Experiments were also done to evaluate how much sway occupants could tolerate. Subjects were recruited for "free eye exams," while the real purpose of the experiment was to subject them to simulated building sway and find out how much they could comfortably tolerate.[61] Many subjects did not respond well, experiencing dizziness and other ill effects. One of the chief engineers Leslie Robertson worked with Canadian engineer Alan G. Davenport to develop viscoelastic dampers to absorb some of the sway. These viscoelastic dampers, used throughout the structures at the joints between floor trusses and perimeter columns, along with some other structural modifications reduced the building sway to an acceptable level.[62]

Hat trusses (or "outrigger truss") located from the 107th floor to the top of the buildings were designed to support a tall communication antenna on top of each building.[50] Only 1 WTC (north tower) actually had an antenna fitted, which was added in 1978.[58] The truss system consisted of six trusses along the long axis of the core and four along the short axis. This truss system allowed some load redistribution between the perimeter and core columns and supported the transmission tower."

 

[tfk]

Gee whiz, tfk
Are you suggesting that an item can be designed to do more than one thing?
Next you'll be implying that airplane wings can be used to not only provide lift, but also act as fuel tanks, provide support for the engines, and control the rolling motions of an aircraft.

This whole discussion is bizarre.

In talking about the hat truss, I remembered that I’d read (probably over a year ago) that someone said “in addition to supporting the antenna, it also played a key role in reducing wind sway by tying together the external & core columns.”

That was a new piece of info for me, that I hadn’t seen before. But as soon as I read it & thought about it, it made complete sense.

So, when it came up in this conversation, I mentioned what I’d read.

JSander has some issues with me, it appears.

His reply caught me by surprise. Perhaps it shouldn’t have, in retrospect.

It was frankly a stroke of pure luck that I found the reference in Glanz’ book, “City in the Sky”.

And then, looking thru the NIST report, I found that they confirmed Glanz’ assertion.

At this point, it doesn’t even matter if Glanz & NIST are correct. Although I believe 100% that they are.

I repeated, accurately, the assertions of some sources that I consider reliable. Glans, while a reporter, has been consistently reliable in his writing.

Then, when challenged by JSO, I cited those sources.

JSO’s assertions that I’m “making things up” or “faking things” is proven incorrect … merely by the existence of the sources.

Again, I believe whole-heartedly that those assertions are correct.

 

[beachnut]

...JSO’s assertions that I’m “making things up” or “faking things” is proven incorrect … merely by the existence of the sources. ...

He failed to read and comprehend what a hat truss does. After he posted references that the hat truss does and used for three things. Self debunking.

 

[Axxman300]

Should be pointed out the points and counter-points were made intelligently.

Neither JSO or TFK wrote "Proof?".

 

[JSanderO]

Glanz is not an engineer and reporter... he "parrots" what others tell him. He is not competent to evaluate the merits in many cases. His reports could be correct of not.

The only references about the design intent of the engineer, Robertson and Skilling was to support the antenna... which was linked to above.

Obviously the added steel and the diagonal members made the top stiffer and perhaps augmented the wind shear resistance stragegy employed which was essentially using the entire facade as plates to resist wind shear and the floor plate... with the dampers and the diagonal braces at the facade side of the floor trusses.

I suggest tfk cite a reliable direct source (the engineers) if he can that, the hat truss was designed to resist wind shear.

I also suggest he dial back his dismissive condescending ad hom remarks.

 

[JSanderO]

This whole discussion is bizarre.
....

So, when it came up in this conversation, I mentioned what I’d read.

JSander has some issues with me, it appears.

His reply caught me by surprise. Perhaps it shouldn’t have, in retrospect.
.....
At this point, it doesn’t even matter if Glanz & NIST are correct. Although I believe 100% that they are.

I repeated, accurately, the assertions of some sources that I consider reliable. Glans, while a reporter, has been consistently reliable in his writing.

Then, when challenged by JSO, I cited those sources.

JSO’s assertions that I’m “making things up” or “faking things” is proven incorrect … merely by the existence of the sources.
..

tfk you may have accurately CITED a source... but you didn't verify the actual information. So you technically weren't faking it or making it up... you just assumed something correct which, I believe was incorrect.

I could care less about YOU.... I am interested in the accuracy of the event, the engineering and so forth.

My "research" did not find that the hat truss was DESIGNED to resist wind shear.

All you have to do is get a quote from the engineers who designed the system to resist wind shear. That will settle it.

No Beachy... I did not fail to understand what the hat truss "did".

 

[Seymour Butz]

tfk you may have accurately CITED a source... but you didn't verify the actual information. So you technically weren't faking it or making it up... you just assumed something correct which, I believe was incorrect.

I could care less about YOU.... I am interested in the accuracy of the event, the engineering and so forth.

My "research" did not find that the hat truss was DESIGNED to resist wind shear.

All you have to do is get a quote from the engineers who designed the system to resist wind shear. That will settle it.

No Beachy... I did not fail to understand what the hat truss "did".

Your obstinacy to admitting that you're out of your depth here and have no idea what you're talking about is very telling.

I can't even begin to count the number of times you've gotten things wrong and yet still continue to argue your point. This is a regular pattern.

It's clear that Tom has provided a couple of sources that corrects what you're saying, yet you resist learning. And like a truther, you ask for more than Glanz's article or NIST's quote as evidence for Tom's point, yet your very own reference is no better, and you see no issues with that.

Why can't you see your own pattern of thinking?

You're often wrong, yet the pattern that others see is not seen by you. Do you not recognize that people ridicule you incessantly? Why do you think that is? Do you honestly believe that you have an insight that no one else does?

 

[Myriad]

All you have to do is get a quote from the engineers who designed the system to resist wind shear.

That's going to be difficult to do, considering that the engineers who designed the system were probably aware that wind shear (variation of wind velocity over displacement perpendicular to the wind direction) is an environmental phenomenon. Wind shear exists whether the building is there or not, and therefore the wind shear encountered by the building depends only on the positioning, shape, and dimensions of the building and not on its internal structure.

What you might have meant is resisting wind-shear-induced forces upon the structure, and/or the deleterious effects of same. (Any references to general stiffening of the structure or reducing the aptitude of the sway of the structure clearly implies increasing the resistance to those effects.)

If you find this objection pedantic, you might see the irony someday. Since this has turned out to be a semantic rather than an engineering argument anyhow, let's discuss the word "design."

I think it's reasonable to say that if a designer is aware that a design feature will have a certain consequence, and that consequence is desirable, then the designer has designed that feature to have that consequence. That's true whether or not the consequence is the designers' earliest or main objective for that feature.

Thus, to contradict a claim that a given feature was designed for a given consequence, one must show that either the feature is undesirable from the designer's point of view, or that the designer was not aware that it would have that consequence. Showing that the feature had other known advantages falls short.

Are you claiming the designers of the wtc towers were not aware that the hat trusses would have the effect of strengthening the structure against wind forces?

 

[BasqueArch]

tfk you may have accurately CITED a source... but you didn't verify the actual information. So you technically weren't faking it or making it up... you just assumed something correct which, I believe was incorrect.

I could care less about YOU.... I am interested in the accuracy of the event, the engineering and so forth.

My "research" did not find that the hat truss was DESIGNED to resist wind shear.

All you have to do is get a quote from the engineers who designed the system to resist wind shear. That will settle it.

No Beachy... I did not fail to understand what the hat truss "did".

[FONT=&quot]quoted from tfk’s post -[/FONT]
[FONT=&quot]Originally Posted by City In The Sky_Glanz [/FONT]
[FONT=&quot]Even the dampers would not be enough. Robertson and John Skilling had to go to Yamasaki and tell him that all of the experimental data they had been collecting indicated that the towers would still sway too much unless three separate structural modifications were carried out[/FONT][FONT=&quot]. Two of them would have an enormous impact on the architectural design of the building, Robertson said, before explaining that he would have to widen Yamasaki’s pinstripe columns slightly to make them stiffer. In part to ensure that the windows became no narrower than they already were, that meant widening the spacing between the columns slightly.

(BA-one) The increase in spacing was only an inch, so that each column would now be forty inches from its neighbor instead of three feet, three inches. But that tiny change meant that there would now be fifty-nine pinstripes per face instead of sixty-one, altering the look of the facade. The design was inherently stiffer for a given amount of steel, but that wasn’t the main reason for the change. The time the big towers took to sway back and forth was too long. It was too easy for the side-to-side push of the vortices to take on the same rhythm, generating huge oscillations. The structural changes would help shorten the jiggle: eleven seconds back and forth, still slower than the Empire State Building but an improvement nonetheless.

(BA-two) There was more, Robertson said. Still another element of his solution was a huge support structure called a hat truss that would sit atop each building and tie its core to its exterior. Already under discussion as a brace to hold up a soaring TV antenna on the north tower, the hat truss could add robustness to the entire building from top to bottom, Robertson knew, with a few tweaks in the design.

(BA-three)And finally, Robertson wanted to twist the orientation of the rectangular core— containing interior structural columns, fire stairwells, and elevators— in one of the towers. No longer true twins, the north tower’s core would run east-west, and the south tower’s north-south. The change would discourage the towers from dancing in unison.

Glanz, James; Lipton, Eric (2014-01-21). City in the Sky: The Rise and Fall of the World Trade Center (pp. 165-166). Henry Holt and Co.. Kindle Edition[/FONT]
[FONT=&quot]Originally Posted by NIST [/FONT]
[FONT=&quot]NCSTAR1-2A

3.2.8 Hat Truss Modeling
In both WTC 1 and WTC 2, a truss system referred to as a ‘hat truss’ was constructed between floor 107 and the roof. The hat truss system was intended to support the load of the antenna on top of the tower and to interconnect the exterior walls to the core. [/FONT]
[FONT=&quot] [/FONT]
[FONT=&quot]Originally Posted by NIST [/FONT]
[FONT=&quot]NCSTAR1-2A
Sec 4.2.3 pg. 74

“The hat truss system distributed both gravity loads and wind loads between the core and the exterior walls.” [/FONT]
[FONT=&quot] [/FONT]
JSO – Stay Down !

 

[beachnut]

...
No Beachy... I did not fail to understand what the hat truss "did".

You deny it helped with the effects of wind, and are wrong. That is a failure to understand what the hat truss did.

The major structure for combating the effects of wind, why the WTC towers could stand in a hurricane, the shell - the hat truss does help reduce the tendency of the core to bend - what bends the core? lol, you need to stop the BS and stick to the facts; facts you posted indirectly by reference when a person follows your quotes, and digs deeper.

 

[JSanderO]

Boys.... The hat truss was designed to support the antenna.

The antenna was part of the program.

I have already stated that adding the additional hat truss steel added strength... stiffness to the top of the building. However they designers did not deign a hat truss to resist wind forces. The floor slabs and the facade membrane along with the core itself was what the design was based on.

This may be semantics... but unless you show the designers intended the hat truss as the means to resist wind forces... you would be wrong... not that I care.

Get a statement from Robertson or Skilling. If you do then I stand corrected. If you don't you...and others don't know the main function of the hat truss.

Some more quotes:

"Structural design

The World Trade Center included many structural engineering innovations in skyscraper design and construction. The towers were designed as framed tube structures, with columns grouped around the perimeter and within the core. The perimeter columns supported virtually all lateral loads, such as wind loads, and shared the gravity loads with the core columns.

Hat trusses

Hat trusses (or "outrigger truss") located from the 107th floor to the top of the buildings were designed to support a tall communications antenna on top of each building. However, only WTC1 (north tower) actually had an antenna. The truss system consisted of six trusses along the long axis of core and four along the short axis. This truss system allowed some load redistribution between the perimeter and core columns and supported the transmission tower."

 

[skyeagle409]

The Towers and WTC 7 were demolished by removing the central cores for a large number of stories with some form of demolition devices. In the case of the towers, their perimeter corners were also cut to cause them to petal outward and minimize resistance.

That is false!

Structural and demolition experts do not agree with what you have claimed, and rightly so, especially in the absence of demolition explosions on video, audio, within the seismic data, and lack of demolition hardware within the WTC rubble.

To sum that up, there is not a shred of evidence that supports your demolition claim.

 

[beachnut]

Boys.... ... This truss system allowed some load redistribution between the perimeter and core columns and supported the transmission tower."..."

Are you saying the hat truss did not support wind loads?

 

[JSanderO]

Are you saying the hat truss did not support wind loads?

I did not say that.

I said it was designed to support the antenna and that the hat truss steel added stiffness which likely played a minor role in resisting some of the wind load.

What I wrote, which is what I read and cited I believe is correct.