What exactly does NIST say about collpase times

[JSanderO]

Why does this matter?

Let's look at several recent catastrophes to see if we can learn something about how authorities behave and account for what occurred.

Katrina
BP Deep Water Horizon
Fukushima
Sandy

All involved massive damage to the environment, loss of life and property. All involved various engineered structures which failed.

None of these cases did the authorities seem to find any accountability for the engineering or those who conceived the structures that failed which led to damage to the environment, loss of life and property.

I would argue that in the case of all 4 of these examples engineers, planners, agencies with jurisdiction over design and safety failed and SHOULD have been held accountable including individuals who directly made the engineering, planning and approval decisions.

We can go into the details of the specific engineering, planning and approval and probably construction failures.

But the reason I raise this topic is that the authorities in my opinion failed to find an negligence on the part of those who made engineering, planning and approval decision with respect to the WTC buildings.

Who or what got blamed? Hijackers and fires.

That strikes me as an avoidance of some accountability much like we saw in Katrina,
BP Deep Water Horizon, Fukushima and Sandy. The authorities are just getting around to some wrist slapping of BP and it looks like no one will face criminal penalties.

That's why.

 

[DGM]

I don't accept that the fires on 13 did in 79, 80 and 81. My proposal for consideration is that these three column were linked/connected to TT#1 and TT#2 down on floors 5-7 and the failures of 79, 80 and 81 were a CONSEQUENCE of the transfer truss failure.

If memory serves the reason for discounting this was the fact it effected the EPH first and not the exterior of the building (in as much).

I'll see if I can find the relevant arguments.

 

[JSanderO]

If memory serves the reason for discounting this was the fact it effected the EPH first and not the exterior of the building (in as much).

I'll see if I can find the relevant arguments.

DGM,
If you took a few minutes to review the sequence of failure I presented all beginning with the failure of TT#1 and eventually the last thing to go was the collapse of the facade. See my post #31 in this thread for a summary.

Isolating one failure ... except the initiating one... in a progressive structural failure will not include ALL the observables. True, column 79, 80 and 81 did not DIRECTLY impact the curtain wall / face of the tower. Their failure DID cause EHP to drop. But it didn't cause WPH to drop... That was caused by failures on the west side around TT3.

The failures off TT1, 2 and 3 pulled in the braced framed in the east ands west under the perimeter column and they all pulled in the 8 MG27's and so that accounts for 3 of the 4 sides supporting the curtain wall/perimeter columns.

Blame the trusses for the whole thing.

 

[DGM]

DGM,
If you took a few minutes to review the sequence of failure I presented all beginning with the failure of TT#1 and eventually the last thing to go was the collapse of the facade. See my post #31 in this thread for a summary.

Isolating one failure ... except the initiating one... in a progressive structural failure will not include ALL the observables. True, column 79, 80 and 81 did not DIRECTLY impact the curtain wall / face of the tower. Their failure DID cause EHP to drop. But it didn't cause WPH to drop... That was caused by failures on the west side around TT3.

The failures off TT1, 2 and 3 pulled in the braced framed in the east ands west under the perimeter column and they all pulled in the 8 MG27's and so that accounts for 3 of the 4 sides supporting the curtain wall/perimeter columns.

Blame the trusses for the whole thing.

I have been reading all along. I think you're discounting other effects as to what the failure of the transfer trusses would cause (and cases where it's shown what it would take for them to fail).

I don't have time right now to get into it so we will have to agree to disagree.

Likely this weekend I'll be able to get into other effects I would expect to happen. Until then.

 

[JSanderO]

I have been reading all along. I think you're discounting other effects as to what the failure of the transfer trusses would cause (and cases where it's shown what it would take for them to fail).

I don't have time right now to get into it so we will have to agree to disagree.

Likely this weekend I'll be able to get into other effects I would expect to happen. Until then.

DGM,

Admittedly a complex discussion and a complex cascading chain of events/failures. My supposition is the splices failed or that's where it began... Once a truss chord / member is discontinuous it's toast. You may recall that the ASCME recommended that NIST the performance of connections under fire stress and I don't know that they actually did. Note bene that the buildings structural engineer Cantor offered his theory that it was diesel fires that weakened those trusses. He was not specific and clearly there is no data from in that region. But they were field erected and members were field bolted together. That is a place to look at... failure of the bolts that held the plates that held the members that made up the trusses that supported 40 stories of columns on top of them.

One might wonder why Cantor would incriminate his own trusses (design)? He will assert that they were fine were it not for the diesel stored which was a post Cantor design project. This was associated with the Salomon Bros renovation and the creation of Guiliani's OEM. So his claim is essentially... yeah the trusses failed... but whomever decided to site the diesel there made the boneheaded decisions.

Regardless, NIST didn't even think there was a think of interest below floor 8 and there was a report that ALL the diesel was recovered. Do you believe that? If you do I have a bridge to sell you.

 

[Miragememories]

"Note bene that the buildings structural engineer Cantor offered his theory that it was diesel fires that weakened those trusses. He was not specific and clearly there is no data from in that region. But they were field erected and members were field bolted together. That is a place to look at... failure of the bolts that held the plates that held the members that made up the trusses that supported 40 stories of columns on top of them.

One might wonder why Cantor would incriminate his own trusses (design)? He will assert that they were fine were it not for the diesel stored which was a post Cantor design project. This was associated with the Salomon Bros renovation and the creation of Guiliani's OEM. So his claim is essentially... yeah the trusses failed... but whomever decided to site the diesel there made the boneheaded decisions.

Regardless, NIST didn't even think there was a think of interest below floor 8 ---

--- and there was a report that ALL the diesel was recovered.

Do you believe that?

If you do I have a bridge to sell you."

Given the wealth of information accumulated by the NIST, would they have not given more credence to the stored diesel fuel if they had found justification?

You make a poor case for your primary failure point.

MM

 

[DGM]

Regardless, NIST didn't even think there was a think of interest below floor 8 and there was a report that ALL the diesel was recovered. Do you believe that? If you do I have a bridge to sell you.

I don't believe it was NIST that reported all the diesel was recovered. I also know they looked into fires and cause on all floors. They found no interest below 8. Big difference, right?

 

[JSanderO]

Given the wealth of information accumulated by the NIST, would they have not given more credence to the stored diesel fuel if they had found justification?

You make a poor case for your primary failure point.

MM

I didn't say diesel WAS the proximate cause. I said Cantor thought so. I think there was a failure in the load transfer region near TT#1. I think it was HEAT weakening or destroying the connections. I have no proof. Neither does NIST dispute this.

 

[JSanderO]

I don't believe it was NIST that reported all the diesel was recovered. I also know they looked into fires and cause on all floors. They found no interest below 8. Big difference, right?

So the collapse on floor 13 destroyed the massive structure on 5, 6 & 7? You believe that?

Seriously?

 

[DGM]

So the collapse on floor 13 destroyed the massive structure on 5, 6 & 7? You believe that?

Seriously?

Not all by itself.

Wasn't it you that talked about cause vs consequence?

 

[jaydeehess]

Not all by itself.

Wasn't it you that talked about cause vs consequence?

'Zactly, IMHO

I do not see that cols 79, 80, & 81 all must fail at once in order to cause EPH to begin falling.
Col 79 fails pulling down all flooring attached to it. By the time this affects the rooftop, debris from dozens of floors has rained down upon TT1, cols 80 & 81 have also been pulled by the 40+ storeys of failed flooring at col 79.

So, as the EPH is affected by 79 going down, 80 & 81 have tilted and are in the process of losing their base, TT1.

Evidence? EPH begins its fall by tilting into a hole that opens first at the location of col 79.

WPH & screen wall are under cols not directly affected by TT1 but cols further west are affected quickly because falling debris has destroyed their base, including the other TTs. Note that the western progression of rooftop failure begins at about the time that the heavy mechanicals in the EPH would have reached the 5th-7th floor possibly ensuring the destruction of the other TTs.(40 floor free fall of an air conditioning unit, elevator motor, or similar)

With the eastern extent of the core system destroyed, all north core columns are no longer properly restrained laterally, and under assault from falling debris. Each north side core column fails in quick sequence from east to west.

These columns support the south end of all cantilever trusses, thus as they fail they cause increasing load on the columns of the older Con-Ed building. This increased load is greater on columns more on the south of the cantilever trusses than the north.

Cantilever truss support fails first on their south ends, tilting the trusses and thus increasing lateral loading on remaining columns to the north. These columns snap their base connection or simply fold over to the north.
At this point there is effectively no support for the 40+ storeys above the cantilever trusses. By this time most of the floor structure above the eight level has fallen in to the core , destroying the rest of the core.
The south side of the building already has tension pulling to the south and west due to loss of perimeter columns at 1WTC debris impact. South core destruction removes the structure that is keeping the south half of the building upright.
This half falls mostly straight down , with slight southern tilt. North half rotates into core area, pivoting at first about a point near the north side of the core. However the cantilever trusses on which the north half rests have moved north keeping thst pivot somewhat north of the core. When north perimeter columns fail the north half CoM falls straight down and conservation of angular momentum requires that it now be rotating about the CoM. It is doing so while the CoM is essentially at FFA.


That is my humble, somewhat physics savvy, opinion.

 

[JSanderO]

Given the wealth of information accumulated by the NIST, would they have not given more credence to the stored diesel fuel if they had found justification?

You make a poor case for your primary failure point.

MM

Not if they wanted to not find the design, the planners, the agencies which approved the design at least partially negligent for the collapse and loss of property.

My case is better than girder walk off... by a country mile.

 

[JSanderO]

'Zactly, IMHO

That is my humble, somewhat physics savvy, opinion.

Please explain the sequence from the lengthening of the beams from heat which pushed the girder shearing the shear studs which may of may not have been composite with the slab.

Then what??? you have the floor. You're on flr 13 and the girder took a walk westwards as the story goes...

 

[ozeco41]

That is my humble, somewhat physics savvy, opinion.

And, BTW, the topic was "What exactly does NIST say about collpase[sic] times" and that means WTC1 and WTC2 NOT WTC7.

But seeing as we are at least three orders of derail off topic - what's one more - except if I write a brilliant analysis of the drift off topic process OR the current topic if I can work out what it is OR of the OP - which I can remember --- the whole lot risks AAH.

 

[ozeco41]

Ozzie,
My problem with your logic is not that col 79 failure was contributory to the collapse of the EPH, but it wasn't the ONLY column supporting the EPH which would have had to have failed fore the ENTIRE EPH to drop.

My logic was in response to your specific question which was:

Does anyone aside from NIST accept the column 79 floor 13 scenario leading to the global collapse we witnessed?

So you said "Column 79" and I responded. Sure other components were involved BUT my response was quite tightly focussed on BOTH your question AND what I consider "proved" (using lay person language ["LPL"])

my position on Col 79 published many times.
1) Column 79 must have failed; AND
2) Column 79 failure must be CAUSAL of EPH falling NOT consequential.

I then added two alternate explanations which to me seem to be "plausible" i.e. NOT "proven^LPL". Those two are:

3a) NIST's hypothesis is plausible...;
3b) Your thoughts also plausible.....;AND
3c) There could well be other plausible hypotheses.

I then stated the two bounding conditions which IMO are:

4a) I doubt we will ever prove anything....; AND
4b) [Why does it matter?] [Will it ever happen?]

You agreed on Col 79 involvement as CAUSAL and agreed with the final point:

"Do those persons to whom it matters have sufficient political pull to require that Government should expend additional public funds researching further?"

Who knows? Probably not.

your "probably" is IMO too generous - 12 years on and no further investigation?

So nothing new added to the framework of my statement.

HOWEVER you now introduce the theme of retrospective liability for negligence or exposure to judicial sanction for criminal negligence.

But the reason I raise this topic is that the authorities in my opinion failed to find an negligence on the part of those who made engineering, planning and approval decision with respect to the WTC buildings.

Who or what got blamed? Hijackers and fires.

That strikes me as an avoidance of some accountability much like we saw in Katrina, BP Deep Water Horizon, Fukushima and Sandy. The authorities are just getting around to some wrist slapping of BP and it looks like no one will face criminal penalties.

That's why.

The discussion is about WTC7 - those others are irrelevant UNLESS you explain a principle applicable to WTC7 which the other examples illustrate. (BTW I won't go further off-topic and comment on Sander's "multiple cars collision" but it is a poor analogy. The point he tries to make is not the way it would be interpreted in AU law - probably the same in US law but I am not qualified in US law.)

So a move to go even further off topic? However for benefit of other members it is a topic which Sander and and I have discussed several times on another forum.

It has both practical barriers and ethical objections.

Even at the softest level of a civil claim in negligence the acts or failures to act are no more than contributory negligence in a scenario where the events could not have been "foreseen" by the "reasonable person" which is the standard test in a civil case for alleged negligence. Both "quoted" words subject to proper legal interpretation in this setting.

And, even if somehow it was judged to have been foreseeable the share of damages attached to contributory negligence is usually much less than those allocated to the primary respondent. Put simplistically if someone lights a fire using matches that some other person left lying unsecured and the fire causes damage. (Accidentally - I want the example in civil jurisdiction for ordinary negligence NOT Criminal Negligence in criminal jurisdiction). The part played by the leaver of unsecured matches is merely contributory. Primary responsibility rests with the person who caused the fire. And the "damages" assessed for contributory negligence are always minor.

Criminal negligence carries the burden of additional elements of proof.

Both have the barrier that use of aircraft as offensive military weapons was not "reasonably foreseeable" at the time.^#

And your whole plot carries the odious unethical suggestion that blame should be assigned in hindsight - highly unlikely for different reasons in either of the legal jurisdictions.

And, if anyone wants to chase this derail further - start a thread in the proper forum.


Edit - PS:
# For the legal types - yes there are two aspects at least viz:
1) Use of aircraft in that manner; AND
2) The consequence of collapse which was the proximate cause of most damage both human and property.

...and both of those would have to be judged "foreseeable by the reasonable person". A tough call and near impossible^LPL to satisfy IMO.

 

[JSanderO]

Typical thread creep. I plead guilty. Apparently NIST did find the collapse time of significance. Wasn't it Chandler who brought up the 2.25 sec period of FF and set off the whole thing based on the his assertion that FF could only occur if the structure was made to disappear for the height of the FF descent?

I don't recall the way the entire debate about FF unfolded.... but I don't have a sense that the meaning of the collapse speed was explored. The truther position seems to have been that collapses take place slowly as it takes an observable measurable longer than FF period to destroy the structure by the falling mass. A good portion of the fog was due to the notion that for a building to collapse columns had to be crushed or "gotten out of the way". But this clearly ignores the notion of column misalignment and the notion that a descending building misaligned column would penetrate through slabs *lickity split" and slow down the descent hardly at all. That's a fair explanation for 7wtc.

With respect to the twins... once the top sections' columns went out of alignment with the lower section up at the plane crash zones... the descending floor mass of the upper sections was able to destroy the floors in sequence top to bottom at what amounts to a rate of about 65mph or about 1 floor per .01 seconds (10 seconds for 90 floors or so). Is this an unreasonable time for multiple tens of thousands of tons of debris to crash through a typical twin tower slab? I don't think so.

Apparently others don't either... that is except Chandler's friends.

 

[dafydd]

You make a poor case for your primary failure point.

MM

And you truthers just make a poor case.

 

[ozeco41]

Typical thread creep. I plead guilty.

Plea accepted - you do get the opportunity to put a case for mitigation of sentence. Two acceptable bases are:
a) Promise never to do it again; AND
b) (In "LayPersonLanguage") Agree to not mix with bad company - which includes me.

Apparently NIST did find the collapse time of significance.

They were right - it isn't.

Wasn't it Chandler who brought up the 2.25 sec period of FF and set off the whole thing based on the his assertion that FF could only occur if the structure was made to disappear for the height of the FF descent?

Ignore any comment made by Chandler or which includes his name - safest tactic. (yup - my comment is re-entrant )

That's a fair explanation for 7wtc.

(Or, for those who know the code

- you mentioned WTC7. Do it again and you risk

)

...With respect to the twins... once the top sections' columns went out of alignment with the lower section up at the plane crash zones...

The frustrating thing IMNSHO is the thousands of words wasted debating whether columns would impact or misalign.

We know that the top blocks fell. So we know that the column ends misaligned.

It is that bleedingly simple. The top blocks fell so the columns were not aligned...or even if they tried to align they got smashed sideways again so go back to "they were not aligned".

But the number of our colleagues who cannot grasp that simple point is astonishing. Many debunkers as bad as the truthers/trolls.

Remember the fatal error with T Sz's "Missing Jolt' - he went looking for a big jolt when the time for the jolt was already past at the starting point of his explanation. Too late. Opportunity gone. And a hell of a lot of debunkers don't get that point. (and that factor is "Twin Towers" topic ) (And related to the reasoning behind the OP.)

AND the same principle shows the false arguments from both sides about whether "tilt" causes misalignment of columns. Another error of misunderstood "sequence". The mechanism which causes tilt has already caused the affected columns to misalign. To late yet again. More wasted thousands of words. The cue is "think before you engage maths, think before you measure". Think before you post explanations which have missed the obvious key point. More generically stated as "get your premises and assumptions right"

Multiple examples scattered across this sub-forum - and all the ones from cascade failure explanations are WTC1 and WTC2 relevant - and set the starting line for global descent of the Twins THEREFORE are on-topic.

[/endrant

 

[jaydeehess]

Please explain the sequence from the lengthening of the beams from heat which pushed the girder shearing the shear studs which may of may not have been composite with the slab.

Then what??? you have the floor. You're on flr 13 and the girder took a walk westwards as the story goes...

That is somewhat irrelevant to whether or not the visual evidence supports the sequence I put out.

It is also a further derail from the thread title. I won't push the derail any further than I already have.

 

[JSanderO]

That is somewhat irrelevant to whether or not the visual evidence supports the sequence I put out.

It is also a further derail from the thread title. I won't push the derail any further than I already have.

Seems to me that speed/time/interval of collapse has to be related to the process of undoing.

It's not really thread creep to discuss the mechanics of the collapse. The fall of the EPH was not included in the FF period.

So what was fall at FF and why? How much of the insides was already gone? And what undermined the last bit where we see the curtain wall and whatever may have been attached to it go down?