9/11 media happenings

[Crispy]

I'd like to see that. I'd also like to see a qualatative analysis, however basic, of the actual difference conduction would have made to loacl steel temperatures.

 

[MikeMcc]

Right, well let's at least wrap up that question by quoting one of TA's own posts, which he claims proves me wrong.

Nope, you haven't understood it mate. The core is quite capable of taking the whole weight of the building, and then some, presumably with a large factor of redundancy. The space frame is not claimed to be at all necessary to keep the building up. What it is doing is correcting the problem of the outside of the building compressing more than the central core when the building is loaded - i.e.

'First, gravity-induced vertical deformations between the columns of the services core and the columns of the outside wall were made equal at the top of the building; 'at other levels, the differential deformations were ameliorated' - translates as fixes the levels at the top of the building so the top floor won't tilt at all, it can't quite get a perfect result lower down but will help minimise the problem

The next bit proves that the core would stay up by itself (as if it is needed):

"Second, wind-induced overturning moments were resisted in part by the columns of the services core, thus providing additional lateral stiffness"

That means that the core was helping the building deal with lateral forces - which implies that it was stabilising the building, not the building stabilising it. eh Crispy?

"Finally, the weight of, and the wind-induced overturning moment from the rooftop antenna (440 feet tall) was distributed to all columns in the building . . . adding additional redundancy and toughness to the design."

Pretty easy to understand. Icing on a cake. Note the 'additional redundancy and toughness'. Also note that a very simple steel rod can easily go to a height of 440 feet without buckling! Never mind thousands of tons of latticed H-sections over a wide footprint.

You said it.

How does the fact that the structure distributed the loads of the rooftop antenna across all of the columns (core and perimeter) show that the core could survive as a free standing structure without the additional bracing of the perimeter columns and floor trusses?

Or that the because the structure as a whole (rather than the core on its own) provided bracing against the wind loading shown anything other than the building was designed to work as a whole?

the wikipedi article on the WTC (Source) states quite clearly that:

A very light, economical structure was built by keeping the wind bracing in the most efficient area, the outside surface of the building, thus not transferring the forces through the floor membrane to the core, as in most curtain-wall structures.

In another quote of yours

Original design claims

* "... inherent capacity to resist unforeseen calamities."
* For the perimeter columns ... "live loads on these columns can be increased more than 2,000% before failure occurs."
* One "could cut away all the first story columns on one side of the building, and partway from the corners of the perpendicular sides, and the building could still withstand design live loads and a 100 mph wind from any direction."

-- All quotes from Engineering News-Record, 1964

All this shows is that the perimeter structure was well designed to redistribute loads especially ones that are nice and carefully planned. Remember that the core doesn't carry the wind loading. The disaster had a major impact and fire that weakened the structure over many floors, damaged the core and affected the whole area of the structure, not just a clinical severing along one side of one floor.

So what are you saying that you've proved?

 

[Jazzz]

Yes BTL. I emailed them asking to clarify their modelling of the steel conduction and to their credit they obliged with a reply of some detail.

I sent this

Hi,

I wonder if I could ask a question about the modelling of the fires in the World Trade Center. I understand that the model took account of heat being conducted along steel members but the report says that only the floors around the impact area were modelled. But was the effect of heat being conducted down the columns away from the modelled floors (92-99 North Tower, 78-83 South Tower) and to the rest of the building taken into account? i.e., the effect of the steel elsewhere in the building being a 'heat sink' for the fires.

The section I have seen -http://wtc.nist.gov/pubs/NCSTAR1-5ExecutiveSummary.pdf - is unclear to me and I hope I can ask for elucidation.

thanks

this was the reply

"wtc@nist.gov"
to me
Jan 29 (20 hours ago)


Dear ******

NIST modeled the thermal response of the steel two floors below and two
floors above the floors on which there were fires. The bottom of the
columns one floor below the bottom fire floor and the tops of the
columns one floor above the top fire floor were essentially at ambient
temperature.

Sincerely,

The NIST WTC Investigation Team

 

[MikeMcc]

So they've said that their model doesn't show that the heat was conducted away in the timescale that they were looking at

 

[Bob_the_lost]

Yes BTL. I emailed them asking to clarify their modelling of the steel conduction and to their credit they obliged with a reply of some detail.

I sent this



this was the reply

Which is nice, now if you can provide the missing logical leap of faith required to prove that this model was therefore constructed to prove that it wasn't done with explosives...?

 

[Crispy]

So that shows that the heating was localised, which we already knew. Heated steel is weakened so that it is easier to make it perfom plasticly, at which point a slow deformation process can take point, up to the point where there is no more capacity, whereapon the top section collapsed, exerting completely irrestable forces on the structure below. etcetera.

 

[Jazzz]

...
So what are you saying that you've proved?

The statement

"Second, wind-induced overturning moments were resisted in part by the columns of the services core, thus providing additional lateral stiffness"
shows that the core was able to resist lateral loads and was serving to 'stiffen' the building. That and the fact that it was well able to take gravity loads in excess of its own weight shows that it would stand up for itself. The proportion of lateral loads taken by the core compared the outside isn't an issue.

 

[Bob_the_lost]

So that shows that the heating was localised, which we already knew. Heated steel is weakened so that it is easier to make it perfom plasticly, at which point a slow deformation process can take point, up to the point where there is no more capacity, whereapon the top section collapsed, exerting completely irrestable forces on the structure below. etcetera.

No no no! They only modeled the heat movement through +/- two floors, thus ignoring the rest of the building!!![/loonery]

Of course that would be the words of someone who has no idea about thermal conductivity. Like, i dunno, Jazzz?

 

[Bob_the_lost]

The statement

"Second, wind-induced overturning moments were resisted in part by the columns of the services core, thus providing additional lateral stiffness"
shows that the core was able to resist lateral loads and was serving to 'stiffen' the building. That and the fact that it was well able to take gravity loads in excess of its own weight shows that it would stand up for itself. The proportion of lateral loads taken by the core compared the outside isn't an issue.

additional != sufficent
in part != in totaility

 

[MikeMcc]

The statement

"Second, wind-induced overturning moments were resisted in part by the columns of the services core, thus providing additional lateral stiffness"
shows that the core was able to resist lateral loads and was serving to 'stiffen' the building. That and the fact that it was well able to take gravity loads in excess of its own weight shows that it would stand up for itself. The proportion of lateral loads taken by the core compared the outside isn't an issue.

Yes it is because you contend that the core could support the entire gravity load of the building!

Except you also posted that it was only designed to support it's own mass (+50%) and 250% of the dead load that it was intended to support. It certainly does mean that it's going to survive when loaded to 64 times it's design load!

 

[TheArchitect]

None of this waffle counters my proof that the core was designed could take the entire gravity load of the building, when you said otherwise. You were wrong!

Well Jazz, innacurate as ever. Let's take another look at my post and bold the sections that actually disprove your absurd theory that the core could carry the entire gravity load of the building:

Of course it turned out that 600% had been plucked out of the air, and you've since started using 100% instead. It's a funny old game, eh?

Your working hypothesis is that the load from the facade and floor failures should have redistributed to the core via the hat trusses, and that the core should have been able to take these increased loads because of the safety factors.

One of the first things we have to understand is what we mean by safety factor: the ratio of the breaking stress of a structure to the estimated maximum stress in ordinary use.

However it is important to understand that the loads/forces found on a complex structure such as WTC may be acting in any number of ways; for example horizontal bending or overturning moments, or gravity loads.

In the same vein, there is a difference between the safety factor of an individual part of a structure andthe structure as a whole. It is perfectly possible for a steel beam to have a high factor of safety against (say) buckling under vertical (gravity) loads but a different figure for other forces.

To claim a figure of 600%, or 200%, or 50% as a global safety factor therefore just betrays how little you understand the subject. 600% against what? Which kind of forces? How are they acting? We can therefore only really understand the performance of the structure through global modelling.

Unlike Jazz, NIST actually do this - and not once, but three times. They look at the original design calculations, modern design calculations, and then a more forgiving global model of their own. The latter tells us that:

- Core columns in WTC typically had a Demand to Capacity Ratio (DCR) of 0.83 with around 10.6% of components exceeding design capacity under normal conditions.

- Hat Truss Columns had a typical DCR of 0.59, with 14.3% exceeding design capacity (some by DCRs of up to 1.95).

Other elements of the trusses had lower DCRs, however a truss is only as strong as the weakest member so we can set these to one side.

Now the section you quote Jazz, from page 133 of the PDF file, doesn't model the structural performance or indeed individual components. It's actually just a note of the NYC and Port authority design codes. So they don't actually prove anything very much.

So where does this take us:

Well, Hat Trusses may have had up to 0.4 "spare DCR" however this is in respect of design loads. The purpose of the hatt trusses was not to cantilever loads from envelope to carr, but even if it was then it certainly wasn't capable of taking double the design load.

But even if it had been, the INTACT core only had some 0.17 "spare" DCR. that's only about 20%, and we need to bear in mind that some of the core structure already exceeded calculated capacity.

Now Jazz, you then CONTINUE to overlook some fundamental issues here:

1. We know that about a third of the core columns in each building were badly damaged or completely severed, further reducing the ability of the core to accept any loads.

2. Further damage would have occured to core structures during the collapse from both debris impacts and from dislodgement/failure at floor connections.

3. Despite this, we also know that some of the lower cores stood for 15 to 20 seconds following the main collapse.

So, in summary:

- Your 600% claim for structural safety factor of the core is rubbish

- Your reworked figure of 200% is rubbish

- Your claim that the hat trusses had sufficient spare capacity is rubbish

- Your claim that the core should have held the loads is rubbish.

Just to be clear, Jazz, these figures are PRIOR to the collapse. The redundant DCR (that's essentially the safety factor) in the core actually far less than 200% and in a proportion exceed design loading.

Or in other words, the post directly disproved your argument.

I think the problem is that you don't understand structural engineering, bending moments, safety factors, and all the other things necessary to produce a cogent argument.

 

[TheArchitect]

I have been attacked for making the assertions that 1) the core could stand up for itself 2) it could take the full gravity load of the building.

Both of which it could easily do so as has been proved.

1. But you haven't proven that the core could act as a stable free standing component You have failed to produce any meaningful technical argument in support of this absolutely ludicrous claim, in stark contrast to the detailed explanation of the structural model provided.

2. Gravity load issues were disproved in yesterday's post, a copy of which is above with highlighted sections for the hard of thought.

I'm sorry to have to point out to TA that he was quite wrong, and indeed you were too Crispy, and also the architects you showed the core to in your lunch break!

But you haven't shown any such thing, Jazz.

In fact I think it forms a rather good test of which side of the debate has a feel for the structure, and which is trying to rationalise a bizarre collapse.

Yes, but it's not you. You consistently fail to understand (or wantonly ignore) the technical arguments. You claim an understanding of mechanics but patently do not. You make up ridiculous safety factors and - get this - don't actually see what's wrong with that!!! You misquote articles, then cherry pick quotes from papers which actually debunk your own theory!

In short, all you have demonstrated - to everyone here - is your own ignorance.


But what would Crusty and I know? After all, we're only university qualified construction professionals who actually studied things like building structures and employ that expertise every day. I'd much rather believe someone who simply events facts like "600%".....

 

[TheArchitect]

The statement

"Second, wind-induced overturning moments were resisted in part by the columns of the services core, thus providing additional lateral stiffness"
shows that the core was able to resist lateral loads and was serving to 'stiffen' the building. That and the fact that it was well able to take gravity loads in excess of its own weight shows that it would stand up for itself. The proportion of lateral loads taken by the core compared the outside isn't an issue.

Jazz,

Can you please explain to us what you think a wind-induced overturning moment actually is?

 

[TheArchitect]

To get back perhaps more to the title of the thread - media happenings - William Rodriguez, the last civilian to escape the WTC towers and a hero credited with saving many lives that day is doing a speaking tour of the UK. He's in London on February 6th.

Tour schedule here

He selflessly refused instructions to leave the towers five times on 9/11 and equally selflessly he's turned his back on an very easy political life courtesy of the USG for the chance to honestly tell his story about what happened that day.

about William Rodriguez

Translation:

Hi, I'm Jazz! I'm getting my arse kicked because of my failure to post a even remotely competent technical response to the various points and am now going to change the subject.

Later I may make up patently false "facts" and then get upset when they are identified as such.

 

[TheArchitect]

Jazz avoids the questions

Still waiting Jazz:

Jazz

Since you like to claim that we - and in particular yours truly - misrepresent you when we debunk...sorry, respond to...your theories, I have a challenge for you.

Present us your theory about what hapennd on 9/11.

This includes at least:

- What flew into the towers.

- Why did they fall

- In case of controlled demolition: please show how the buildings where prepped, how it was possible to do that within the time limits, why nobody saw the prepped walls, how the dynamite and the wires survived the planes' impacts and why no traces of dynamite were found afterwards.

- Please explain why such a destruction would work without the slightest problems even though there has never been any building brought down that was even nearly as large as the towers, everything was done in a rush and therefore had to been done very sloppy, and even though everything went perfect.

- What flew into Pentagon

- Does that match with the eyewitnesses observations?

- What was the purpose of the attack?

- Who is involved into the conspiracy?

- How have the engineering communities across the globe been silenced?

- What do you think happened to WTC7?

This just to start with.

Please explain in detail and with your own words. No links to CT sites accepted. Any articles, etc. will be checked in order to ensure quotes are accurate. Any calculations will be checked. Unsupported speculation will be ignored.

Are you up to the challenge?

 

[detective-boy]

Can you please explain to us what you think a wind-induced overturning moment actually is?

Is this one?

 

[TheArchitect]

Is this one?

Nope

It might be the result of one, however......

 

[TheArchitect]

Gone a bit quiet, Jazz.

Trying to figure out how you missed the fact that the core will not, in fact, support the enture gravity load of the building as you claimed?

Please, please, please let the delay be due to you actually doing some structural calculations for a change.....making up figures is just so dull.

 

[MikeMcc]

Yes it is because you contend that the core could support the entire gravity load of the building!

Except you also posted that it was only designed to support it's own mass (+50%) and 250% of the dead load that it was intended to support. It certainly does mean that it's going to survive when loaded to 64 times it's design load!

The model also only modelled the deformation of the column sections, it didn't model the sheering stresses on the bolts holding adjacent sections together. Since the forces were enough to exceed the loadings by 64 times I assume that the sheer stresses were absolutely ridiculous given that bolts aren't designed to take high loadings radially.

 

[Jazzz]

The model also only modelled the deformation of the column sections, it didn't model the sheering stresses on the bolts holding adjacent sections together. Since the forces were enough to exceed the loadings by 64 times I assume that the sheer stresses were absolutely ridiculous given that bolts aren't designed to take high loadings radially.

Sure MikeMMC. What occurs after collapse initiation is something I haven't demonstrated in my argument about the core standing up for itself although I've made many comments about that elsewhere. The point about that is that - as you can still see - it's something that I was strongly challenged on, and indeed TA is still inside some weird space where he thinks he is 'debunking' the point, although my proof of it is cast iron, and making huge C&Ps of his own posts which just don't seem to connect with my posts at all. It's a bit sad as I can enjoy a discussion about this with many other posters here yourself included but it's really a waste of time if the thread is weighed down like this.

 

[Techno303]

Sure MikeMMC. What occurs after collapse initiation is something I haven't demonstrated in my argument about the core standing up for itself although I've made many comments about that elsewhere. The point about that is that - as you can still see - it's something that I was strongly challenged on, and indeed TA is still inside some weird space where he thinks he is 'debunking' the point, although my proof of it is cast iron, and making huge C&Ps of his own posts which just don't seem to connect with my posts at all. It's a bit sad as I can enjoy a discussion about this with many other posters here yourself included but it's really a waste of time if the thread is weighed down like this.

Arf!

 

[editor]

Sure MikeMMC. What occurs after collapse initiation is something I haven't demonstrated in my argument about the core standing up for itself although I've made many comments about that elsewhere. The point about that is that - as you can still see - it's something that I was strongly challenged on, and indeed TA is still inside some weird space where he thinks he is 'debunking' the point, although my proof of it is cast iron, and making huge C&Ps of his own posts which just don't seem to connect with my posts at all. It's a bit sad as I can enjoy a discussion about this with many other posters here yourself included but it's really a waste of time if the thread is weighed down like this.

Could you tell me precisely how many floors you believe had been invisibly wired with invisible explosives please, Jazzz, and give the floor numbers?

 

[beesonthewhatnow]

Jazzz, your "cast iron" proof has all the sturctural integrity of a jelly.

Are you really so arrogant that you believe you are better qualiied to talk on this subject than qualified architects and structural engineers?

 

[tarannau]

Gawd, he's still going delusionally on. How much of a numpty does he have to make of himself before he admits that he doesn't really understand what he's blagging about.

 

[Jazzz]

Jazzz, your "cast iron" proof has all the sturctural integrity of a jelly.

Are you really so arrogant that you believe you are better qualiied to talk on this subject than qualified architects and structural engineers?

On the subject of whether the core could stand up for itself, and whether it was capable of taking the entire gravity load of the building, yes that's proved (posts #745 and #1123 respectively). Crispy appears to accept both as he hasn't quibbled with either of those posts. I can't account for TA. As tarannau says, "I don't know how much a numpty he is going to make of himself before he admits he doesn't really understand what he is blagging about"

 

[Crispy]

Proved? No. Possible? Maybe. But then, as I think I've said four times now, there were other infuences at work. Impact damage and fire weakening brought the capacity of the core below the applied loads (which were already higher than normal) = collapse. This is what happened and you don't need a 'spark' demolition.

 

[Bob_the_lost]

On the subject of whether the core could stand up for itself, and whether it was capable of taking the entire gravity load of the building, yes that's proved (posts #745 and #1123 respectively). Crispy appears to accept both as he hasn't quibbled with either of those posts. I can't account for TA. As tarannau says, "I don't know how much a numpty he is going to make of himself before he admits he doesn't really understand what he is blagging about"

#1179 dealt with your claims of proof quite nicely i think. Then again you still seem to be working on the delusion that the core was a tightly bundled group of massive steel beams, when it wasn't.

 

[Jazzz]

#1179 dealt with your claims of proof quite nicely i think. Then again you still seem to be working on the delusion that the core was a tightly bundled group of massive steel beams, when it wasn't.

Your post #1179 does nothing of the sort. The core doesn't has to be shown to be able to take ALL lateral loads from the finished WTC in order to show that it was stiff on its own.

 

[Jazzz]

Proved? No. Possible? Maybe. But then, as I think I've said four times now, there were other infuences at work. Impact damage and fire weakening brought the capacity of the core below the applied loads (which were already higher than normal) = collapse. This is what happened and you don't need a 'spark' demolition.

Well, where have I gone wrong then in the proofs of those two questions which have become something of a battleground?

 

[8den]

#1179 dealt with your claims of proof quite nicely i think. Then again you still seem to be working on the delusion that the core was a tightly bundled group of massive steel beams, when it wasn't.

This thread is reminding me of an old joke

An American visitor to Lindores Abbey was being shown round by the abbot when a monk shouted out “64!”

All the other monks roared with laughter.

Another then called out “15!” — again much laughter.

“What’s going on?” asked the visitor.

“They know each other’s jokes inside out” said the abbot. “So rather than tell them each time, they’ve numbered them. If one calls out a number, they think of the joke and laugh. Have a go...”

The visitor called out “45!” and there was a small ripple of polite laughter.

“I’m afraid,” said the abbot, “that’s not very funny. Try again.”

So, the visitor called out “56!” and there was uproar.

“Must have been a good joke,” he said.

“Yes,” said the abbot wiping his eyes. “And we’ve never heard it before.”

Only y'know, Jazz's claim about post #745 proving him right is even funnier