How were WTC core columns separated at the weld planes?

[R.Mackey]

Also recall that not all welds are created equal. The mechanical floors had full welds and bolts, too. This also holds true low in the structure (the biggest columns) where the core structure was required to have lateral stability -- making up for the 2/3 fewer perimeter columns on the lowest seven floors -- and was heavily cross-braced. Away from these places, not so much.

What's important is that the majority of welds were substantially weaker, particularly with respect to moment, than the columns themselves. It isn't significant that a few lucky welds survived. What's significant, albeit totally contrary to Major Tom's still-semi-secret-for-some-reason explosives hypothesis, is that weld failure without significant column bending is exactly what one expects in a gravity-driven collapse... and not what we expect if explosives were used.

It'll be interesting to see if Major Tom ever completes his thought.

 

[BenBurch]

With all total welds in the core and human nature being what it is. What percentage of all those welds would be good and what percentage would be not so good?

Impossible to say now. But I strongly suspect that not all welds in that building were as good as they could have been. ESPECIALLY where two different alloys were joined.

 

[Sunstealer]

Around Here, We often usethe phrase "Thermal stress", which is well-known as shorthand for "Stress due to differential expansion and contraction under various thermal transition conditions" which is a bit of a mouthful...

Yes I agree that's how I understand it, however the OP seems to use thermal (heat) stress as way of describing steel that has degraded strength due to heat or am I reading it wrong and he is suggesting that thermal stress (expansion in this case) was significantly high enough to cause failure rather than load plus reduced yield point due to heat?

R.Mackey has hit the nail on the head when he says

What's important is that the majority of welds were substantially weaker, particularly with respect to moment, than the columns themselves. It isn't significant that a few lucky welds survived. What's significant, albeit totally contrary to Major Tom's still-semi-secret-for-some-reason explosives hypothesis, is that weld failure without significant column bending is exactly what one expects in a gravity-driven collapse... and not what we expect if explosives were used.

Whilst no two welds will ever share exactly the same characteristics it's safe to assume that welding was of a high enough quality across the entire structure, otherwise there would have been significant problems during the life of the building(s).

 

[Apollo20]

Smoking Columns

Major Tom:

You ask about those falling columns "trailing smoke"...

Ace Baker likes to ask questions about those columns too....

I have suggested the "smoke" was thermal insulation and/or or gypsum.

I believe AB thinks it was "dustified steel"

What do you think!

 

[A W Smith]

We need to answer:

How strong were the welds?


Max


* * *

not very strong at all compared to the column cross section itself. Show me evidence of a weld at the end of this column, Note the one inch chamfer at the end.
http://911research.wtc7.net/wtc/arch/docs/corebase1.jpg
also show how to weld completely to the root of this column cross section through steel two or even three inches thick.

 

[Belz...]

We need to answer:

How strong were the welds?

And here it is:


Weaker than the columns themselves


*****


Belz...

 

[Max Photon]

Weld failure without significant column bending is exactly what one expects

[snip] ...the majority of welds were substantially weaker, particularly with respect to moment, than the columns themselves. It isn't significant that a few lucky welds survived. What's significant, albeit totally contrary to Major Tom's still-semi-secret-for-some-reason explosives hypothesis, is that weld failure without significant column bending is exactly what one expects in a gravity-driven collapse... and not what we expect if explosives were used.

(bold mine)


I agree.


While is it certainly true that welds can be stronger than the surrounding metal, my very cursory study of welds in the FEMA photos shows that the welds on the core box columns are relatively superficial, and sometimes just on two sides.


If one thinks about it, the column-to-column splice is not the only weld plane!

The entire box column is welded together from flat plates, so there are several weld planes. The column splice is just the short one.


There are not only the continuous bending moments from dynamic loads, but also sharp impulses from collisions - impulses that will statistically tend to have lateral components (relative to the long axis of the columns).


I suspect lateral impulses from collisions (which were well distributed in all directions - not just downward) played a large role in separating core columns at the weld planes.


Major Tom, a section at your site, dedicated to zoom-ins on core column welds, would probably be very useful for those who want to examine the welds themselves.


Cheers

Max

* * *

 

[Max Photon]

MAX-MIHOP says: The "smoke trails" from falling columns is aluminum-oxide.

Major Tom:

You ask about those falling columns "trailing smoke"...

Ace Baker likes to ask questions about those columns too....

I have suggested the "smoke" was thermal insulation and/or or gypsum.

I believe AB thinks it was "dustified steel"

What do you think!

Apollo20,

I think that thermal insulation and/or gypsum is an excellent hypothesis to explain the "trailing smoke" seen on the falling columns.

MAX-MIHOP proposes a second hypothesis:

The "trailing smoke" seen on falling WTC core columns is from a combination of:

• thermal insulation and/or gypsum;
• aluminum-oxide from thermite planted at the seats connecting core columns to horizontal members. (The thermite heat-weakened the connections, in effect partially unshoring the core columns.)

I believe additional evidence to support this hypothesis is seen in the FEMA photos of core columns, in particular, the heavy, continuous, yellow-orange to red-orange oxidation layers at the core columns' seats.

The rust is a bust.

(HI MILDEC!)


Max Oxidation

* * *

 

[rwguinn]

(bold mine)


I agree.


While is it certainly true that welds can be stronger than the surrounding metal, my very cursory study of welds in the FEMA photos shows that the welds on the core box columns are relatively superficial, and sometimes just on two sides.


If one thinks about it, the column-to-column splice is not the only weld plane!

The entire box column is welded together from flat plates, so there are several weld planes. The column splice is just the short one.


There are not only the continuous bending moments from dynamic loads, but also sharp impulses from collisions - impulses that will statistically tend to have lateral components (relative to the long axis of the columns).


I suspect lateral impulses from collisions (which were well distributed in all directions - not just downward) played a large role in separating core columns at the weld planes.


Major Tom, a section at your site, dedicated to zoom-ins on core column welds, would probably be very useful for those who want to examine the welds themselves.


Cheers

Max

* * *

Who are you and what have you done with Max Photon?


That was actually a coherent, and almost correct posting.


"Dynamic" and "Continuous" are not always mutually exclusive, but I think "continuous bending moments from Quasi-static Loads, as well as moments from Dynamic loading" would have been a better fit[/nit-pick]

 

[Apollo20]

How to make white smoke

Max:

I trust you know that the military formulation for WHITE SMOKE is based on AMMONIUM PERCHLORATE with additives such as cellulose acetate, hexachloroethane, hydroxy, or carboxy-terminated polybutadiene, ammonium chloride and zinc oxide?

What, no thermite!?!

 

[cmcaulif]

We need to answer:

How strong were the welds?


Max


* * *

That is a good question max but I can tell you that the weakest of the WTC core columns (W14X61, A36 steel) has a moment capacity of 3672kip in. The rest of the columns get stronger from there, in fact much stronger, the next largest as build section listed in NCSTAR1-1(W14X219, I had to use a W14X211 in the AISC manual) has a capacity of 14040kip in.

for comparison, FEMA calculated in appx b that the moment capacity of the bolt groups connecting the perimeter columns at 1468kip in. I think this can give you some idea as to what might fail first under the type of extreme loading conditions the towers were subjected to.

 

[Max Photon]

What caused the "white smoke" trails from the WTC falling steel members?

Max:

I trust you know that the military formulation for WHITE SMOKE is based on AMMONIUM PERCHLORATE with additives such as cellulose acetate, hexachloroethane, hydroxy, or carboxy-terminated polybutadiene, ammonium chloride and zinc oxide?

What, no thermite!?!

Apollo,

Thanks for the military formulation for white smoke. I did not know that.

(What is the military formulation for white smoke in the intellectual domain?)


So possible explanations for the light grey smoke trails are any or a combination of the following:

1. Fire protection material and/or gypsum
2. Spicy ammonium perchlorate
3. Aluminum-oxide from thermite
4. Residue from high-explosives
5. Water droplets, or "steam" - (just thought I'd throw that in)
6. Dustified steel - (I don't even know what that is)

I can handle 1-3.

I don't see 4 because there are no signs - the sharp bright flashes - of explosives near the "smoke sources".

I don't see any mechanism for #5.

I'll punt on 6.


That leaves:

1. Fire protection material and/or gypsum
2. Spicy ammonium perchlorate
3. Aluminum-oxide from thermite

When I look at photos of falling steel members and the "white smoke trails", it seems to me that the spiraling trails emerge from connections between orthogonal members.

Do others see the same? Or is it the nature of the eddies in the lee of the falling members that they are stable near calm zones near junctions?

Anyway, to rephrase:

Could the "white smoke" be aluminum-oxide ash from thermite reactions that were ignited right before or at collapse initiation, to make the core connections ductile, thereby effectively partially unshoring the core columns? Is this hypothesis at least consistent with the smoke trails?


Apollo,

How would the AP be ignited at all "white smoke" sources?

Didn't your AP model call for migrating fires igniting the AP?


Cheers everyone!

Max

* * *

 

[Crazy Chainsaw]

Max:

I trust you know that the military formulation for WHITE SMOKE is based on AMMONIUM PERCHLORATE with additives such as cellulose acetate, hexachloroethane, hydroxy, or carboxy-terminated polybutadiene, ammonium chloride and zinc oxide?

What, no thermite!?!

The best place to place Ammonium perchlorate is in the thermal insulation, or in the drywall itself, it would produce white smoke, as the drywall or insulation was heated.
IT would work by destroying the Insulation, as well as heating the structure, however an electrical short could ignite the whole structure in a matter of seconds and a fire would do the same. It is to ignitable to be used unless put in place in a relatively short time frame.
Gypsum and insulation would be more highly more likely.

 

[rwguinn]

Apollo,

<<SNIP>>
Could the "white smoke" be aluminum-oxide ash from thermite reactions that were ignited right before or at collapse initiation, to make the core connections ductile, thereby effectively partially unshoring the core columns? Is this hypothesis at least consistent with the smoke trails?


Apollo,

How would the AP be ignited at all "white smoke" sources?

Didn't your AP model call for migrating fires igniting the AP?


Cheers everyone!

Max

* * *

Ah.. He's back, and barkingly incoherent as ever...

 

[uruk]

{snip}

That leaves:

1. Fire protection material and/or gypsum
2. Spicy ammonium perchlorate
3. Aluminum-oxide from thermite

1. Plenty of documented evidence for the existance and use of on WTC
2. Not so much.
3. Not so much.

And judicius use of Occam sez?.............


That is, of course, if there is more than just speculation provided for two and three.

MILDEC or not.

 

[BenBurch]

When concrete decomposes in a fire it gives off water vapor.

 

[Max Photon]

Water wapor is probably not a good explanation for the "white smoke" trails.

When concrete decomposes in a fire it gives off water vapor.

The core wasn't on fire at the floors where many of the "white smoke" trails were seen.

ETA: Although, come to think of it, you are correct if thermite is the heat source that caused the concrete to decompose and give off water vapor.

* * *

 

[Max Photon]

Weaponizing Ockham's Razor - For Dullards

* * *

I listed the following explanations for the "white smoke" trails:

1. Fire protection material and/or gypsum
2. Spicy ammonium perchlorate
3. Aluminum-oxide from thermite

1. Plenty of documented evidence for the existance and use of on WTC
2. Not so much.
3. Not so much.

And judicius use of Occam sez?.............


That is, of course, if there is more than just speculation provided for two and three.

MILDEC or not.

See Ben, right there!

Are not positions #2 and #3 the perfect place to hide the catalyzed controlled-demolitions in plain view?

Then, MILDEC does not even need to bother with dynamic stabilization to maintain the deception.

Instead, pseudo-gangs of (well-intentions) people such as yourself provide the dynamic stabilization, as you and others try to damp my attempts to illuminate the true collapse initiation mechanisms (which I understand, and don't mind - in fact, MAX-MIHOP predicts it).


MILDEC knew how to weaponize Ockham's Razor, and use it as a cloaking device with robust, real-time dynamic stabilization.

The energy requirements?

Zero.


You do all the work for them!


MAXDEC

* * *

 

[TerryUK]

Who are you and what have you done with Max Photon?

LOL That is too funny!

 

[pomeroo]

* * *

I listed the following explanations for the "white smoke" trails:

1. Fire protection material and/or gypsum
2. Spicy ammonium perchlorate
3. Aluminum-oxide from thermite

See Ben, right there!

Are not positions #2 and #3 the perfect place to hide the catalyzed controlled-demolitions in plain view?

Then, MILDEC does not even need to bother with dynamic stabilization to maintain the deception.

Instead, pseudo-gangs of (well-intentions) people such as yourself provide the dynamic stabilization, as you and others try to damp my attempts to illuminate the true collapse initiation mechanisms (which I understand, and don't mind - in fact, MAX-MIHOP predicts it).


MILDEC knew how to weaponize Ockham's Razor, and use it as a cloaking device with robust, real-time dynamic stabilization.

The energy requirements?

Zero.


You do all the work for them!


MAXDEC

* * *

How about a little oil and vinegar on that word salad, Doc?