Total Building Collapse from a Single Column Failure

[JSanderO]

Have not read the entire thread, not enough time as yet. However it should be noted that WTC 7 was a very complex structure, from foundation to 8th floor especially.
I said in the other thread that I believe that its quite possible that the single failure of col 79 led to debris damage to TT1 that then caused further failures including that of col 80 & 81.
Load redistribution was not the primary cause of failure progression, imho. It was debris impacts that caused caused the first progressions beyond col 79.
col 79 fails, debris is raining down on TT1. col 80 is pulling in as col 79 fails AND col 80's base at TT1 is under attack by debris. Col 80 fails at TT1, TT1 fails under increasing debris falls, col 81 falls with TT1, TT1failure means the eastern extent of the western core has also failed compromising TT2 TT3 and the lateral support of the core columns under the cantilever trusses.

The girder walk off itself was aided by the design of the structure that had no symmetric beam placements to counter the movement of the girder, as would have been the case in a more classic post and beam structure.

So, does this single point of failure in 7WTC mean potential disaster for all other steel framed buildings, no , of course not.

I feel that question was a bit of hyperbole on the part of Mr.JSO

No? Explain why not? Why was 7 so different?

And no... I don't support the idea that 7wtc came down because of CD.

And no... I am not a NIST fan boy

I speak for me and me only and what makes sense to me. I find the single column failure a bridge too far.

 

[jaydeehess]

No? Explain why not? Why was 7 so different?

NIST makes quite a bit out of the uniqueness of the construction of WTC 7, you are aware of the oddities I am sure, the assymetric beam placements , the construction above an existing structure, the transfer and cantilever trussses, the long span open floor concept.

And no... I don't support the idea that 7wtc came down because of CD.

I knew that and was basically stating so in my post above.

And no... I am not a NIST fan boy

I would not put myself in such a category either.

I speak for me and me only and what makes sense to me. I find the single column failure a bridge too far.

Which is again what I stated in the post above.
We t'ain't so different JS

 

[jaydeehess]

Problem for your analysis is that it does not match the movements. TT#1 failed BEFORE column 79... 79 did NOT destroy TT1 as it was not under it.

You got the sequence backwards but yes the complexity below 8 likely caused the floors etc north of the core to collapse pull the braced wind frames below 8 in and that allowed the curtain wall to drop.

79,80&81 are all on top of TT1, or am I incorrect on that?

I also believe that the columns at the south end of the cantilever trusses failed first rather than those at the north end and that this caused the c'lever trusses to tilt down at their south end thus pushing the curtain wall at the eigth floor level, northward as the columns within the Con-Ed building were crushed starting at the core and moving northward through the Con-Ed. Once that progression reached the northernmost columns there was nothing at all holding up the curtain wall and nothing between curtain wall and core either. FFA ensues.

 

[JSanderO]

NIST makes quite a bit out of the uniqueness of the construction of WTC 7, you are aware of the oddities I am sure, the assymetric beam placements , the construction above an existing structure, the transfer and cantilever trussses, the long span open floor concept.

I knew that and was basically stating so in my post above.

I would not put myself in such a category either.

Which is again what I stated in the post above.
We t'ain't so different JS

I am well aware of the unusual structure of 7WTC and it is used to drive my transfer truss failure theory.

Above the load transfer region, aside from the open office space where the spans were not exceedingly large, it was a pretty generic steel frame. The funny business and where the failure likely occurred was in the load transfer region and likely not in the generic region such as where they claimed the failure of column 79 was... floor 13.

Why are you giving NIST a pass on a bogus location for the initiation?

 

[JSanderO]

79,80&81 are all on top of TT1, or am I incorrect on that?

I also believe that the columns at the south end of the cantilever trusses failed first rather than those at the north end and that this caused the c'lever trusses to tilt down at their south end thus pushing the curtain wall at the eigth floor level, northward as the columns within the Con-Ed building were crushed starting at the core and moving northward through the Con-Ed. Once that progression reached the northernmost columns there was nothing at all holding up the curtain wall and nothing between curtain wall and core either. FFA ensues.

No they are not... ON TOP OF TT#1. see the attached which I posted previously. TT#1 is supported on girder MG53 which is supported by E3 and E4. 79,80 and 81 are positioned to the east.

 

[JSanderO]

79,80&81 are all on top of TT1, or am I incorrect on that?

I also believe that the columns at the south end of the cantilever trusses failed first rather than those at the north end and that this caused the c'lever trusses to tilt down at their south end thus pushing the curtain wall at the eigth floor level, northward as the columns within the Con-Ed building were crushed starting at the core and moving northward through the Con-Ed. Once that progression reached the northernmost columns there was nothing at all holding up the curtain wall and nothing between curtain wall and core either. FFA ensues.

TT#1 and TT#2 were oriented east west. TT#3 was oriented north south.

The failure of TT#1 pulled the north end of TT3 over via the connecting girder bolted to beam stubs which were welded to the north core columns.

Dat's what happened.

 

[JSanderO]

A sketch of the key columns, trusses and girders which failed causing the collapse of 7WTC.

 

[jaydeehess]

I am well aware of the unusual structure of 7WTC and it is used to drive my transfer truss failure theory.

You asked what was so unique about 7WTC so I answered.

Above the load transfer region, aside from the open office space where the spans were not exceedingly large, it was a pretty generic steel frame. The funny business and where the failure likely occurred was in the load transfer region and likely not in the generic region such as where they claimed the failure of column 79 was... floor 13.

Aside from the assymettry of beam placements, which was one major point that NIST made in their theory.

Why are you giving NIST a pass on a bogus location for the initiation?

yeah, and why did you stop beating your dog

I see that 79 is next to TT1 not on it. So you are saying that col 76 & 73 came down and pulled EPH with them? What was all that about 80 & 81 then?

IIRC you are saying that the diesel fuel was contributory to failure of TT1 but NIST found no evidence of a Diesel fuel fire. Do you have evidence that there was other than the apparently missing fuel from the tanks?

 

[JSanderO]

I am well aware of the unusual structure of 7WTC and it is used to drive my transfer truss failure theory.

You asked what was so unique about 7WTC so i answered.

Aside from the assymettry of beam placements, which was one major point that NIST made in their theory.

yeah, and why did you stop beating your dog

I see that 79 is next to TT1 not on it. So you are saying that col 76 & 73 came down and pulled EPH with them? What was all that about 80 & 81 then?

TTF is not about load redistribution and sequential column failure. TTF is about the failure of TT1, then TT2 pulling the girder along the north of the core east taking TT3 down and all the MG27s. TT1 and TT2 collapse pulls the columns 79, 80 and 81 and the girders attached to it to the 8 story East wind shear braced from to the West and the collapse of TT3 pulls the 8 story West wind shear braced from to the East.

The "pulling" above along with the pulling of the 8-MG27s off column support removes virtually all support (W,N & E) for the perimeter moment frame and it collapses taking the curtain wall with it.

 

[JSanderO]

yeah, and why did you stop beating your dog

I never beat my dog.

 

[jaydeehess]

I never beat my dog.

Then since I, afaiac, am not giving NIST a pass we are even

 

[jaydeehess]

NIST did show the results of their computer analysis for each of several column failures, what it would have looked like at the rooftop level. They deduced that the best fit to observables was a col 79 failure. I recall that as I read the report I agreed that the results they showed best fit a col 79 failure. I do not recall if they showed a TT1 first failure analysis.


I used to have the final wtc 7 report saved on my computer but had not used it for so long that I deleted it. Of course now that I want it again I am having a lot of trouble downloading the pdf of it again. Download fails on several devices and on at least two network connections.

What I do recall with certainty is that they found no evidence to support the theory of diesel fuel fed fires on the floors in question. No smoke billowing out the generator room vents for instance. When FFs were on the floors where this would have been occuring (fifth?) they reported no fires or diesel spills or smells(iirc).

That is why I have been getting mixed up as the where the columns are. JSO has his diagrams but I was looking for both the NIST report analyses and the column location diagram looking down on the building.

 

[jaydeehess]

TTF is not about load redistribution and sequential column failure. TTF is about the failure of TT1, then TT2 pulling the girder along the north of the core east taking TT3 down and all the MG27s. TT1 and TT2 collapse pulls the columns 79, 80 and 81 and the girders attached to it to the 8 story East wind shear braced from to the West and the collapse of TT3 pulls the 8 story West wind shear braced from to the East.

The "pulling" above along with the pulling of the 8-MG27s off column support removes virtually all support (W,N & E) for the perimeter moment frame and it collapses taking the curtain wall with it.

I understandall that but if TT1 failed first it would have drawn down col 73 & 76 FIRST, before column 79 fails as a result of TT1 failure. Would that not have had the opening at the rooftop occur further west than was observed?

 

[JSanderO]

Then since I, afaiac, am not giving NIST a pass then we are even

Excellent! They made some decent sized boners.

Now why would anyone comment on the unusual nature of the structure if that uniqueness was not contributory to the collapse?

Surely the girder walk off scenario or the connections and so forth at column 79 floor 13 are not unique or unusual. They look pretty run of the mill.

The weirdness of the design was the transfer trusses, and the assorted transfer girders especially the 8 - MG27s supporting the more than half the floor area north of the core on the end of cantilevers.

The weirdness was how all these transfer structures were actually INTERCONNECTED and this might lead to a cascading catastrophic failure. Hahahaha It did. It wasn't the walk off of a girder on floor 13 which initiated the catastrophic collapse. Anyone who believes that is hardly more rational that a truther in my opinion.

Actually I think NIST knows it but figured they could get away with it because at the time of their report the plans were unavailable. But with the report and FOIA's we can see what they avoided. The truth.... Jeez I hate to even use the tainted word.

 

[Seymour Butz]

I have no idea where he's going with this. If these "hanging" floors are no longer there the column is no longer braced. It's going to fail under it's own weight.

Exactly

The floors have two actions on the columns. They impose axial loads while at the same time providing lateral stability.

Those clever engineers, eh?

 

[JSanderO]

I understandall that but if TT1 failed first it would have drawn down col 73 & 76 FIRST, before column 79 fails as a result of TT1 failure. Would that not have had the opening at the rooftop occur further west than was observed?

Mr. Hess.

I am not an engineer. Just a dumb architect who has the distinction of having worked for the architects of the twin towers when the designs were being completed in 1970. Of course being just out of architecture school I was assigned to draft granite patterns for elevator lobbies and such. I don't design steel framed hi rise buildings and I don't have access to evidence.

I also don't trust anyone who issues a report and controls the evidence and the data... and releases conveniently that which supports their conclusion. Jeez that sounds like Szamboti and Chandler. Don't it?

NIST maybe have determined nothing of interest below 8. But I like to see how they did that?

Further I don't think you would need massive fires to destroy one of those trusses. They were field erected and had splice plates bolting the heaving panels and chords together. Fail the connections and the members can't work and the truss folds like a cheap card table.

I picked up a comment by ASCE who felt the connections were suspect in the collapses. They made the statement in 2002. Not only that FEMA seemed to suggest a truss failure. And Cantor the building's engineer thought the trusses failed too.

Cantor of course blamed the failure on diesel fires because there were day tanks adjacent to TT#1 and TT#2.

There were also at least 2 large explosions BEFORE 10 am which most likely were electrical caused. The first came when AA11 hit 1WTC and shorted the 13.8kv riser to the 108th floor. This short caused the William Rodriguez explosion... the explosion in the sub station at 7WTC which knocked the power out. You do know that tenants reported an explosion at around or before 9am in 7 WTC? That was from overheated electrical equipment in the sub station. Con Ed issued an after report that at 8:46am the moment of the AA11 collision with 1WTC they LOST 13 (if I recall correctly) 13.8 kv feeders... which the grid was able to take over.

What could those explosions have done? The 10 am Jennings-Hess one was between TT1 and TT2 where the east egress stair was located. It blew the stair down there on 5,6 nd perhaps 7 to kingdom come. And it probably blasted off a bit of fire protection of them there trusses... and causes a breach/break in the diesel fuel delivery system or some sort of diesel fire. I am not talking thousands of gallons either. A localized uncontrolled diesel fire would screw those truss connections nicely warping and shearing off bolts. Maybe. I don't expect to see 5" plates bent like pretzels from heat softening.

In fact why DON'T we get to see the components of the massive trusses? Did they break apart at their connections? Or did they just fall over? If the connections failed what did they look like? Why is that not interesting? it is to me.

I suspect the reason we don't see this incriminating evidence is because it reveals how vulnerable the design was as a result of placing diesel fuel in close proximity to the trusses AND THEIR FIELD ERECTED CONNECTIONS. And whose dumb idea was that?

If the connections were exposed to fires for 7 hrs.... not massive huge conflagrations... but more like a steady burn for a sufficient leak... there would be no visible evidence of smoke and not much to smell either considering the entire place wreaked from stink from the collapse of the towers and the fires in WTC 4, 5 and 6. not to mention 7. Report that they didn't smell diesel? Gimme a break.

And how WAS all the diesel recovered? Was the main tank just peachy keen after 250,000 tons of building came down on top of it? It didn't get crushed? or fracture? Inquiring minds want to know.

But the easy way out was to just blame it on office fires cos they have nothing to do with engineering and place the fire on floor 13 where the office fire was pretty hot. Bait and switch.

The visual evidence.. and the structural design.. and the Con Ed report and the two large explosions in the load transfer region and the diesel day tanks there and the building's engineer stating that his trusses failed puts a lie to the NIST 7 WTC report. It's all distraction from the real cause... bad decisions and gross incompetence.... exposed by shorts in the 1WTC risers.

The knee bone connected to the thigh bone and the thigh bone connected to the hip bone.

79 failed... but it was NOT the cause of the global collapse. You can take my dumb word for it.

 

[JSanderO]

Exactly

The floors have two actions on the columns. They impose axial loads while at the same time providing lateral stability.

Those clever engineers, eh?

Surely that doesn't include you?

 

[ozeco41]

I have no idea where he's going with this. ...

If you follow Sanders posts on three forums you will be clear where he is going. Most of his thinking is here on JREF - but even clearer if like me you engage in discussion with him elsewhere.

There are two aspects which dominate his thinking and those are:

ASPECT ONE - He disagrees with NIST on one detail of WTC7 collapse mechanism. (And builds a house of cards logic on that one detail)

He disagrees with the NIST girder walk off explanation as the initiator of Col79 failure >>> EPH falling >>> therefore remainder of EPH support must also have failed.

He proposes an alternate initiation mechanism due to failure of transfer trusses. Both explanations. Sander's and NIST's, are prima facie plausible initiator causes. Note that they are both merely initiators of a cascade failure. Both led to failure of Col79 and associated structures supporting EPH. Note also that the language of "caused" is unfortunate - I can explain more fully but the whole event was a cascade and without doubt other events preceded Col 79 failure. So Col 79 failure may have been the central feature of the mechanism. Hardly the "Cause". However Col 79 MUST have failed and that failure MUST have been part of the cause of EPH falling. Sander actually is not denying that and his hypothesis is on common ground with NIST - he is not proposing something vastly different other than the "initiator".

ASPECT TWO - He hasn't said this so far in this thread BUT he considers that there should be accountability for the design vulnerabilities which were revealed in hindsight.

He and a colleague go as far as advocating criminal liability for those design vulnerabilities which raises two main areas of objection:
1) The legally and ethically obnoxious concept of changing laws or design codes with retrospective application. Thus advocating sanctions, criminal or civil, against people whose conduct was correct at the time - in this case 1970's; AND
2) The reality that design standards are an evolutionary process as we push the frontiers. AND have to be risk managed against foreseeable likely events. Deliberate aircraft impact attacks were outside the envelop of reasonable risk in 1970's. (BTW Probably still are - but that could be a hot sideline derail The buildings didn't fall from structural failure directly caused by the impacts. Future buildings are likely to have multiply redundant fire systems AND better protected egress - maybe improved resistance to progressive collapse BUT otherwise not "stronger")

So with that as the context/scenario some comments:

Are you worried he may be proposing CD as the cause of the collapses?

He is not and has many times explained his disaffection with the Truth Movement esp AE911.

.
So, does this single point of failure in 7WTC mean potential disaster for all other steel framed buildings, no , of course not.

I feel that question was a bit of hyperbole on the part of Mr.JSO

Yes - that ambiguity in the OP is characteristic of Sanders style. Best if "we" keep the two claims separate. Whatever lack of clarity there may be over the specific explanations for WTC7 it goes several grades more complex trying to turn it into a generic model of claim. Even Bazant ballsed up that one. Let's not go there.

Finally Sander makes it explicitly clear what his hypothesis is:

Chris,...My theory is that column 79 failure was NOT the initial failure but TT#1 which cause 79 to drop alone with the floors around it... AND pulled the girder running north attached to the core columns which yanked TT#3 and dislodged the 8 MG17 girders which supported the columns of the north curtain wall opposite the core on cantilevers.

BUT we will never know and why should it interest anyone?

It doesn't change anything in the two bigger picture scenarios:
A) The professional technical understanding that WTC7 fell as the result of a fire induced cascade failure. NIST has put forward a plausible hypothesis after extensive studies. Nothing of significance hinges on that hypothesis being correct. Sander adds in another plausible factor. It doesn't detract from NIST other than the detail of the initiator. In fact it reinforces NIST on all aspects other than that initiator.

B) In the pseudo debate over CD - the real issue for CD proponents is their failure to prove CD. Nothing changes - they have never put forward a plausible hypothesis to prima facie standard. There is no legitimate debate.

As I have said to Sander many times both here and on two other forums - Sanders hypothesis is a plausible hypothesis to prima facie standard. Worthy of discussion. Good thinking IMO. But ultimately it has no where to go. Even for those whose focus of interest is knowing the details - the details of WTC7 were hidden - they will not by miracle be revealed.

And on the other agenda - possible use as prosecution evidence as someone chases the ghosts of those 1970's responsible parties - how will anyone ever raise speculations to "beyond reasonable doubt"? So we can argue all we want. It ain't going nowhere.

 

[jaydeehess]

Excellent! They made some decent sized boners.

no assigning of blame for design flaws, or for special fire codes for PANYNJ
No analysis of cooling phase pull on heat deformed structural members.

Now why would anyone comment on the unusual nature of the structure if that uniqueness was not contributory to the collapse?

Surely the girder walk off scenario or the connections and so forth at column 79 floor 13 are not unique or unusual. They look pretty run of the mill.

No symmetric beams on both sides of the girder was contributory to girder walk off. That is rather unique.

The weirdness of the design was the transfer trusses, and the assorted transfer girders especially the 8 - MG27s supporting the more than half the floor area north of the core on the end of cantilevers.

Which was the weirdness that allowed progression to global collapse.

The weirdness was how all these transfer structures were actually INTERCONNECTED and this might lead to a cascading catastrophic failure. Hahahaha It did. It wasn't the walk off of a girder on floor 13 which initiated the catastrophic collapse. Anyone who believes that is hardly more rational that a truther in my opinion.

Something had to happen to the lower portions of the core to cause global collapse but the initiating event need not have occured in that region.

Actually I think NIST knows it but figured they could get away with it because at the time of their report the plans were unavailable. But with the report and FOIA's we can see what they avoided. The truth.... Jeez I hate to even use the tainted word.

Now its you who sounds like a truther. Assigning unsubstantiated malfeasance to NIST.

 

[ozeco41]

...Now its you who sounds like a truther. Assigning unsubstantiated malfeasance to NIST.

A sad aspect that detracts from his message.