WTC7 and the girder walk-off between column 79 and 44

[triforcharity]

Link?

http://en.wikipedia.org/wiki/Hyatt_Regency_walkway_collapse

http://www.engineering.com/Library/...cleId/175/Hyatt-Regency-Walkway-Collapse.aspx

You get the idea. I remember this very vividly.

 

[jaydeehess]

The Hyatt, yes thats it, thanks to all

unfortunately the book Tezro refers to is not available on the KOBO. I'll have to wait until I can order a hard copy

 

[000063]

Hmm. Any chance of a collapse if the builders had followed the original design?

 

[DGM]

Hmm. Any chance of a collapse if the builders had followed the original design?

I would tend to doubt it. Each walkway connection would only have to hold it's own loads, not that of any others.

The design as originally drawn was good. Revisions did this design in.

 

[ozeco41]

I would tend to doubt it. Each walkway connection would only have to hold it's own loads, not that of any others.

The design as originally drawn was good. Revisions did this design in.

It was a classic case of someone losing the plot when they made what looked like simple changes.

I gathered a few "war stories" of real world errors over the years ... none relevant to here.

 

[DGM]

It was a classic case of someone losing the plot when they made what looked like simple changes.

I gathered a few "war stories" of real world errors over the years ... none relevant to here.

I can't tell you how many times I've gone to an old house that has had many "remodels" and said, "isn't there supposed to be a load bearing wall here"?

 

[000063]

According to Wikipedia, the investigation found that the original design could've only supported 60% of the minimum load it was supposed to, by law. Supporting the second walkway dropped it to 30%.

http://www.eng.uab.edu/cee/faculty/ndelatte/case_studies_project/Hyatt Regency/hyatt.htm#Causes

Analysis of these two details revealed that the original design of the rod hanger connection would have supported 90 kN, only 60% of the 151 kN required by the Kansas City building code. Even if the details had not been modified the rod hanger connection would have violated building standards.

Though that link also answers my earlier question, but I'm not sure if it's a statement of fact or opinion.

Neither the original nor the as-built design for the hanger rod satisfied the Kansas City building code making the connection failure inevitable.

 

[tfk]

Strawman!
The drawings said 1 feet 0 inches and NIST said 11 inches. It's not a matter of mind reading, it's obvious that NIST lied.

Petulent children, angry young boys & conspiracy theorists claim all those big, mean authority figures lie regularly. You're too old to be in the first two categories ...

And you're looking at the Installation drawing instead of the Parts Fabrication drawing.

In an ideal world, every time a change happens at the part level, those changes will get updated in all related assemblies.

Guess what. Sometimes that just doesn't happen. Just like the conflicting callouts in the shear stud drawings.

Go find the part fab drawing.

There is some basis for NIST saying that the part was 11". And in the entire report, I've not found one single thing that they've lied about.

That was the failure that started the collapse. Without it, there was no collapse. It could not have collapsed if the seat was 12 inches wide.

And you possess not one iota of the skills, training or experience to make this statement.

Bare assertions are valueless.

That's why NIST lied about it. They did lie about it and there is no other reason for them to lie about it.

Petulent children, angry young boys & conspiracy theorist...

 

[Christopher7]

Ok, so your saying that the column would have held with 0.5" left to go on the bearing seat?

NIST [not me] said:
NCSTAR 1-9 Vol.2 pg 527 [pdf pg189]
"A girder was considered to have lost vertical support when its web was no longer supported by the bearing seat. The bearing seat at Column 79 was 11 in. wide. Thus, when the girder end at Column 79 had been pushed laterally at least 5.5 in., it was no longer supported by the bearing seat."

But there is another fraudulent representation in addition to the "11 inch" seat. NIST omitted the stiffeners which would have prevented the bottom flange from buckling even if it could be pushed sideways 6 inches, which could not happen because the beam would sag before it could expand that much.

The girder would have to be pushed well beyond the mid point before the bottom flange flange buckled. Also note that the girder is over the 2 inch thick plate so the seat would not buckle either.

It would be physically impossible for the beams to push the girder off its seat. This is not an opinion but a physical fact confirmed by the data.


These are the drawings that NIST used for the data that they used in their models and they falsified that data.

 

[tfk]

C7,

And where exactly did you come up with this sketch for the locations of the "stiffener plates"?

 

[ozeco41]

I note that you are still treating it as a "one single factor" exercise C7 despite my cautionary post at http://www.internationalskeptics.com/forums/showthread.php?postid=8118276#post8118276 and your untruthful response at http://www.internationalskeptics.com/forums/showthread.php?postid=8118299#post8118299

.... which could not happen because the beam would sag before it could expand that much.

...Also note that the girder is over the 2 inch thick plate so the seat would not buckle either.

...It would be physically impossible for the beams to push the girder off its seat. ⁽¹⁾
... This is not an opinion but a physical fact confirmed by the data. ⁽²⁾

All four of those clips presume that there is only a "single factor" in play and, for the last two:
⁽¹⁾ Why?
⁽²⁾ What data?

 

[Christopher7]

C7,

And where exactly did you come up with this sketch for the locations of the "stiffener plates"?

It's from the same FoIA release as in post#8. Here is the full drawing:
http://img21.imageshack.us/img21/7438/9114.png

 

[Christopher7]

I note that you are still treating it as a "one single factor" exercise C7 despite my cautionary post at http://www.internationalskeptics.com/forums/showthread.php?postid=8118276#post8118276 and your untruthful response at http://www.internationalskeptics.com/forums/showthread.php?postid=8118299#post8118299
All four of those clips presume that there is only a "single factor" in play and, for the last two:
⁽¹⁾ Why?
⁽²⁾ What data?

The single factor is the crux of the NIST hypothesis and I have listed the data. Go back and read it again, it's all there.

I am refuting the failure that NIST says started the collapse using the info in the NIST reports and the drawings. Without that initial girder failure, there is no collapse.

The NIST hypothesis is that a fire that had burned out pushed a girder off its seat and that led to the total collapse of the building. The data shows that that did not happen.

 

[MarkLindeman]

Again you resort to repetition in lieu of argument.

I am refuting the failure that NIST says started the collapse using the info in the NIST reports and the drawings. Without that initial girder failure, there is no collapse.

How do you think you know this? That's just one of several missing links in your logic.

 

[tfk]

It's from the same FoIA release as in post#8. Here is the full drawing:
http://img21.imageshack.us/img21/7438/9114.png

Got it.

Now, why don't you re-read NCSTAR1-9, Section 8.8, where NIST describes exactly the failure mode that their model predicts.

If you were able to read & comprehend, you'd immediately see that it doesn't matter one iota to the failure if that seat is 11", 12" or 35" wide.

If you were able to read & comprehend, you'd immediately see that it doesn't matter one iota to the failure if the stiffener plates were present or absent, 1/2 the central web height or full web height, 1" thick or 6" thick.

The failure mode would STILL have occurred.

Because the ultimate failure mode - the rotation of the W33 girder off of its seat - was not a failure "simply" due to gravity acting on the girder & the girder just "dropping off" or "rotating & dropping off" of the seat.

The failure mode was a sequence of events, ending up with:

1. both ends of the W33 girder being free to slide & rotate on their seats due to the fracture of all erection bolts (& the fact that the girder was not welded in place)

2. the girder expanding due to increased temps, & ultimately coming to be wedged into the NE corner of Col 79 & NW corner of Col 44, restraining from further movement in the N direction. (See fig 8-23)

3. the buckling of W24 x 55 floor beams, starting near Col 44, because of the new lateral constraint of the W33 girder.

When the beams buckled, they dragged down the W33 girder at the top (where they were attached to it), FORCING the W33 girder to rotate southward at the top, while staying fixed at both bottom north corner ends of the W33 girder against the Col 79 & Col 44 internal flanges.

It was not a passive drop of the girder.

The rotation buckled the W33 girder & rotated it off of its seats.

The seats & stiffeners could have been any thickness or width you want to specify, because the failure didn't happen at the seat.

The seats & stiffeners could have been made out of infinitely strong unobtainium.

The failure mode would have occurred in the identical fashion.

Prattle away.

 

[Christopher7]

Got it.

No you don't.

You have not been reading this thread - or the final report for that matter. Someone here pointed out that the "rock to the east" was just a preliminary test. The final conclusion was that the expanding beams pushed the girder off its seat to the west.

The final word on "rock off"
1-9 pg 353
This analysis demonstrated possible failure mechanisms that were used to develop the leading collapse hypothesis further. The failure modes in this model were incorporated into the 16 story ANSYS and 47story LS-DYNA analyses.

This is from the Technical briefing 8-26-08

 

[Christopher7]

How do you think you know this? That's just one of several missing links in your logic.

If you knew what the NIST hypothesis was you would know what I am talking about.

 

[ozeco41]

The single factor is the crux of the NIST hypothesis...

Quite possibly -- but the single factor which may be the crux is not the whole of the hypothesis.

And you merely repeat the following without answering my two brief questions which were spot on target.

I am refuting the failure that NIST says started the collapse using the info in the NIST reports and the drawings. Without that initial girder failure, there is no collapse.

The NIST hypothesis is that a fire that had burned out pushed a girder off its seat and that led to the total collapse of the building. The data shows that that did not happen.

It appears that your mindset is locked on partial truth, partial understanding. You keep missing the point I make when I refer to "single factor".

 

[MarkLindeman]

If you knew what the NIST hypothesis was you would know what I am talking about.

What makes you think that I don't know what you're talking about? Goodness, you have a knack (or at least a penchant) for deflection.

Can you point me to a demonstration that the only way in which Column 79 could have failed as a consequence of the fires is if this beam pushed this girder off its seat?

 

[GlennB]

You have not been reading this thread - or the final report for that matter.

The final word on "rock off"
1-9 pg 353
......

Just for clarification - The NIST document titled "Final Report .... 7" only runs to 80-odd pages.

Whereas NCSTAR 1-9 (Nov 2008, labelled "Final report..." on the NIST website, but not in the doc itself)) does, indeed, talk about the girder being rocked off its seat by a collapsing floor.

Which document are you referring to as "the final report". Obviously I might be looking at the wrong one or an old version.