Yet another Truther Tirade - any takers?

[Horatius]

...and you're wrong again.....

[link]

I have now read the link. Let me stay with my words.

One initial answer to this came from Leslie Robertson, lead structural engineer of the WTC. According to his account the assumption was that the collision would be with a relatively slow-moving 707, lost in fog:

The two towers were the first structures outside of the military and nuclear industries designed to resist the impact of a jet airliner, the Boeing 707. It was assumed that the jetliner would be lost in the fog, seeking to land at JFK or at Newark.
http://www.nae.edu/nae/bridgecom.nsf/weblinks/CGOZ-58NLCB?OpenDocument

The full document includes a graphic indicating the 707 impact speed was indeed estimated to be 290 km/h (around 180 mph), which compares with “flight speeds of 470 to 590 mph upon impact” for the 9/11 attacks.

So you're comfortable contradicting one of the guys involved in designing the building in the first place?


Okay.

 

[daws59]

anyone clinging to the fairy tale of the towers were designed to withstand high speed plane impacts is under the delusion that the towers mockups (models) were tests for that they were not.
they also forget that structures are calculations, lots of them.
in the case of the wtc those calculations were catastrophically inaccurate.

 

[Michal]

Here's my source:

Quote:
Henry Guthard, engineer and one of [WTC designer] Yamasaki's original partners who also worked as the project manager at the [WTC] site, said, "To hit the building, to disappear, to have pieces come out the other side, it was amazing the building stood. To defend against 5,000 (sic) gallons of ignited fuel in a building of 1350 feet is just not possible.

[snurl]

You are batting zero as far as citable facts go.

be asured, it is extreemly rare to hear such statements from professionals. It is also unwise. Most often answer is: "at the moment I do not know what happened. I would have to study this in detail, to understand"

 

[Newtons Bit]

of course it did exist ... there were no computers (available) though

No it did not. Finite Element Analysis was still in its infancy and the number elements required to analyze a structure such as the WTC numbers in the millions.

You can't do that by hand.

 

[twinstead]

be asured, it is extreemly rare to hear such statements from professionals. It is also unwise. Most often answer is: "at the moment I do not know what happened. I would have to study this in detail, to understand"

Dude. This guy was one of the designers of the towers! How much more professional can one get? It sounds like to me that you are arguing from simple personal incredulity and not in any professional capacity.

 

[Michal]

So you're comfortable contradicting one of the guys involved in designing the building in the first place?


Okay.

believe me, he knew what he was saying in this interview



... it is 2am back in the place where I leave ... I need to go hug my teddy bear

 

[Michal]

No it did not. Finite Element Analysis was still in its infancy and the number elements required to analyze a structure such as the WTC numbers in the millions.

You can't do that by hand.

tensor calculus did exist and a lot of solid structures were based on this

 

[Grizzly Bear]

I'd like to know where the lack of analysis on post-impact fires constitutes a serious omission. From what I understand designing for impact alone even with the towers not being bound to local building codes went far beyond what any requirements dictated at the time. The way the towers were built there doesn't seem to have been any way to design for a fire event immediately following a significant impact trauma; sprinkler systems were severed, Gypsum wall board is relatively fragile and broken apart easily by the crashes, and SFRM is as well with direct impact events.


That said... I go back to what I posted earlier; they stood long enough for most people that COULD evacuate, do so. That's an engineering success in the design; it saved lives -- thousands of them.

 

[Newtons Bit]

tensor calculus did exist and a lot of solid structures were based on this

This is non-sequitur. Finite Element Analysis requires setting up a matrix to describe the entire structure. The matrix row and height lengths are equal to the number of elements * the number of degree of freedom. A basic element for a 3D structure is 9 DOF. One would need a single element for each column, each beam and each truss for a simple but roughly accurate analysis. However this is for every single floor. That's 100's of elements per floor, perhaps 10,000 for the entire building. You're looking at a 100,000x100,000.

This is what is necessary just for the static structural analysis. A much larger number of elements will be necessary to model the dynamic and non-linear behavior of the structure. Which is iterative, so you have to solve in many many many times.

It's not possible without computers.

Oh, and Tensor Calculus may be useful for solid mechanics (such as rock behavior, soil behavior, etc). It's not pertinent to the analysis of isotropic structural elements.

 

[Horatius]

believe me, he knew what he was saying in this interview



... it is 2am back in the place where I leave ... I need to go hug my teddy bear

Okay, go to bed, because that response just makes no sense whatsoever.

 

[Michal]

This is non-sequitur. Finite Element Analysis requires setting up a matrix to describe the entire structure. The matrix row and height lengths are equal to the number of elements * the number of degree of freedom. A basic element for a 3D structure is 9 DOF. One would need a single element for each column, each beam and each truss for a simple but roughly accurate analysis. However this is for every single floor. That's 100's of elements per floor, perhaps 10,000 for the entire building. You're looking at a 100,000x100,000.

This is what is necessary just for the static structural analysis. A much larger number of elements will be necessary to model the dynamic and non-linear behavior of the structure. Which is iterative, so you have to solve in many many many times.

It's not possible without computers.

Oh, and Tensor Calculus may be useful for solid mechanics (such as rock behavior, soil behavior, etc). It's not pertinent to the analysis of isotropic structural elements.

I had a lectures with one of the tensor calculus fathers. Believe me, with use of this method you can create a lot ... a lot more than just a rock or soil. I remember him enumerating bridges, buildings and other difficult structures that were designed with use of this method, some spectacular ones were designed by him.

Sure, Finite Element Analysis is a very good method, but not the only one and there were other methods in the past allowing to produce fine structure ... but I think we are going off topic now ...

 

[Michal]

Could you provide some sort of factual basis that they did not perform a robust finite element analysis? The NIST reports have all sorts of documentation showing exactly how they performed said analysis and the conclusions generated. I'm referring to the actual pages and chapters.

understood, do you want me to go through the report once again or the Alienenity input is sufficient for you.

Originally Posted by Alienenity
2) Weakened the structure of the building.
For NIST's models to work, both computer and lab tests, they had to remove nearly all of the silica/ceramic fireproofing over a large area of the floor. Second (this is the damning part), they had to remove 50% of the trusses and cross-members to initiate a global collapse. They even state in their reports that they had to use extreme measures to duplicate the results (a so-called "worst-case scenario). The probable scenarios couldn't create the results.

clearly, it is not about finite element analysis, but the preliminary criteria for the calculations.

 

[funk de fino]

understood, do you want me to go through the report once again or the Alienenity input is sufficient for you.

Originally Posted by Alienenity
2) Weakened the structure of the building.
For NIST's models to work, both computer and lab tests, they had to remove nearly all of the silica/ceramic fireproofing over a large area of the floor. Second (this is the damning part), they had to remove 50% of the trusses and cross-members to initiate a global collapse. They even state in their reports that they had to use extreme measures to duplicate the results (a so-called "worst-case scenario). The probable scenarios couldn't create the results.

clearly, it is not about finite element analysis, but the preliminary criteria for the calculations.

Read and then link the relevant pages or sections in the report.

 

[TruthersLie]

This is not true. The poster presents luck of basic designing and construction knowledge. Most of high raise schemes are designed to resist different worst case scenarios, i.e. big passenger jet hitting the building. This building was no exception.

Ummm No they are not.

They are designed with certain specifics in mind and then over designed. If you build in certain areas you then take those areas in mind (tokyo for earth quakes, texas for tornados, florida hurricanes, etc)

Until 9/11 no one designed residential buildings to withstand a 500 mph impact from a jet liner.

Please provide a citaiton to support this BS.

 

[TruthersLie]

of course it did exist ... there were no computers (available) though

again waiting for any citation to support your claims.

got ciations?

I eagerly await your thesis.

 

[TruthersLie]

I have heard this before ... what would mean a serious omission in the preliminaries ... just can not believe this was the case.

Got it.


do you have any factual information or is it just going to be arguments from ignorance and incredulity?

 

[Michal]

Well, it seems you have much time to spend on this forum … much more then I do. Unfortunately I have other duties to do mean time … and in addition our colleague Newtons Bit asked me a specific question. As far as he sounds professional I have decided to follow his request to go through the NIST report. It looks our discussion may get further than the offending each other or trash talking.

 

[TruthersLie]

Well, it seems you have much time to spend on this forum … much more then I do. Unfortunately I have other duties to do mean time … and in addition our colleague Newtons Bit asked me a specific question. As far as he sounds professional I have decided to follow his request to go through the NIST report. It looks our discussion may get further than the offending each other or trash talking.

You are the one making massive (and unfounded) claims.

Please provide a citation to support your claim.

I eagerly await your thesis.

why do you do what all twoofs do? spew crap and then run away?

You make the claim that all buildings are built to that standard esp wtc... it should be EASY to find a citation to support your claim.

I eagerly await your thesis.

 

[Travis]

I will help you.

In order to conduct the real study you need to:

1. find out what happened
2. find out what was the preliminary damage (study the genuine percentage of the damaged elements
3. carry out simulation
4. find out if the outcome is coherent with the final real state.

it is not professional to consider 50%, 60%, 30% or any other random percentage of damaged elements for the test.

This differs from what NIST did how?

 

[triforcharity]

Well, it seems you have much time to spend on this forum … much more then I do. Unfortunately I have other duties to do mean time … and in addition our colleague Newtons Bit asked me a specific question. As far as he sounds professional I have decided to follow his request to go through the NIST report. It looks our discussion may get further than the offending each other or trash talking.

Well then, we will see you in about a month. Feel free to ask questions about things you don't understand. There are many here who can help you understand those types of things.