Melting steel?

a reply to: wildb

It is all very simple.

I've posted WTC videos that do not depict demolition explosions and I have posted actual demolition explosions that do. The differences other than the loud noise that demolition explosions are well-known for, is that real demolition explosions generate seismic signals that are detected by seismic monitors and yet, not only is there no sound of demolition explosions in the WTC videos, but that not one seismic monitor had detected demolition explosions as WTC 1, WTC 2,and WTC 7 collapsed.

That's two strikes against demolition explosives (no sound of demolition explosions and no seismic data signals) and strike three came after the RJ Lee Group found no evidence of demolition explosives in their dust samples, which is backed by the fact no demolition hardware was ever found within the rubble of the WTC buildings.

To sum it up once again, there is no case for explosives at ground zero.

Debunking the 9/11 Myths: Special Report

"Melted" Steel

Claim: "We have been lied to," announces the Web site AttackOnAmerica.net. "The first lie was that the load of fuel from the aircraft was the cause of structural failure. No kerosene fire can burn hot enough to melt steel." The posting is entitled "Proof Of Controlled Demolition At The WTC."

FACT: Jet fuel burns at 800° to 1500°F, not hot enough to melt steel (2750°F). However, experts agree that for the towers to collapse, their steel frames didn't need to melt, they just had to lose some of their structural strength—and that required exposure to much less heat. "I have never seen melted steel in a building fire," says retired New York deputy fire chief Vincent Dunn, author of The Collapse Of Burning Buildings: A Guide To Fireground Safety. "But I've seen a lot of twisted, warped, bent and sagging steel. What happens is that the steel tries to expand at both ends, but when it can no longer expand, it sags and the surrounding concrete cracks."

"Steel loses about 50 percent of its strength at 1100°F," notes senior engineer Farid Alfawak-hiri of the American Institute of Steel Construction. "And at 1800° it is probably at less than 10 percent." NIST also believes that a great deal of the spray-on fireproofing insulation was likely knocked off the steel beams that were in the path of the crashing jets, leaving the metal more vulnerable to the heat.

But jet fuel wasn't the only thing burning, notes Forman Williams, a professor of engineering at the University of California, San Diego, and one of seven structural engineers and fire experts that PM consulted. He says that while the jet fuel was the catalyst for the WTC fires, the resulting inferno was intensified by the combustible material inside the buildings, including rugs, curtains, furniture and paper. NIST reports that pockets of fire hit 1832°F.

"The jet fuel was the ignition source," Williams tells PM. "It burned for maybe 10 minutes, and [the towers] were still standing in 10 minutes. It was the rest of the stuff burning afterward that was responsible for the heat transfer that eventually brought them down."

www.popularmechanics.com...

a reply to: wildb

How the WTC buildings collapsed.

Mechanics of Progressive Collapse: Learning from World Trade Center and Building Demolitions

Review of Causes of WTC Collapse

Although the structural damage inflicted by aircraft was severe, it was only local. Without stripping of a significant portion of the steel insulation during impact, the subsequent fire would likely not have led to overall collapse
Bažant and Zhou 2002a; NIST 2005. As generally accepted by the community of specialists in structural mechanics and structural engineering
though not by a few outsiders claiming a conspiracy with planted explosives, the failure scenario was as follows:

1. About 60% of the 60 columns of the impacted face of framed tube
and about 13% of the total of 287 columns were severed, and many more were significantly deflected. This caused stress redistribution, which significantly increased the
load of some columns, attaining or nearing the load capacity for some of them.

2. Because a significant amount of steel insulation was stripped, many structural steel members heated up to 600°C, as confirmed by annealing studies of steel debris
NIST 2005 the structural steel used loses about 20% of its yield strength already at 300°C, and about 85% at 600°C
NIST 2005; and exhibits significant viscoplasticity, or creep, above 450°C
e.g., Cottrell 1964, p. 299, especially in the columns overstressed due to load redistribution; the press reports right after September 11, 2001 indicating temperature in excess of 800°C, turned out to be groundless, but Bažant and Zhou’sanalysis did not depend on that.

3. Differential thermal expansion, combined with heat-induced viscoplastic deformation, caused the floor trusses to sag. The catenary action of the sagging trusses pulled many perimeter columns inward
by about 1 m, NIST 2005. The bowing of these columns served as a huge imperfection inducing multistory out-of-plane buckling of framed tube wall. The lateraldeflections of some columns due to aircraft impact, the differentialthermal expansion, and overstress due to load redistribution also diminished buckling strength.

4. The combination of seven effects—
1 Overstress of some columns due to initial load redistribution;
2 overheating due to loss of steel insulation;
3 drastic lowering of yield limit and creep threshold by heat;
4 lateral deflections of many columns due to thermal strains and sagging floor trusses;
5 weakened lateral support due to reduced in-plane stiffness of sagging floors;
6 multistory bowing of some columns
for which the critical load is an order of magnitude less than it less than it is for one-story buckling; and
7 local plastic buckling of heated column webs—finally led to buckling of columns Fig. 1
b. As a result, the upper part of the tower fell, with little resistance, through at least one floor height, impacting the lower part of the tower. This triggered progressive collapse because the kinetic energy of the falling upper part exceeded
by an order of magnitude the energy that could be absorbed by limited plastic deformations and fracturingin the lower part of the tower.

web.archive.org...://www.civil.northwestern.edu/people/bazant/PDFs/Papers/466.pdf

Nothing there about explosives as responsible for the collapse of the WTC buildings nor pools of molten steel.

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a reply to: wildb

WTC structures were weakened to the point of collapse by fire and impact damage.

The Collapse of World Trade Center Buildings 1 & 2

The unique structure of the WTC towers exaggerated the problems caused by the weakened steel. The towers had a lightweight “perimeter tube” design consisting of 244 exterior columns of 36 cm square steel box section on 100 cm centers, with 95% of the structure’s interior consisting of nothing but air (see Figure 1).6 Within this perimeter tube design there was a 27m by 40m core, designed to provide additional support to the tower. Steel trusses, or joists, connected the outer beams to the core at each story, and provided much of the overall support to the weight of each floor.

The impact and explosion of the airplane crashes probably knocked off most of the insulating material intended to fireproof the steel beams, considerably increasing their vulnerability to flames. The heat of the flames reduced the steel to a fraction of its initial strength, while also causing the steel trusses to expand at each end until they no longer supported the weight of the building’s floors, triggering the collapse. The expansion and warping of the steel would have been particularly significant due to temperature differences within the burning structure.

web.archive.org...://www.civil.northwestern.edu/people/bazant/PDFs/Papers/466.pdf

Nothing there about demolition explosions nor pools of molten steel.

.

a reply to: DeceptioVisus

Read your post and I'm asking the wife to get'm for christmas.

I have seen videos that confirm explosive sequences in real time and loads of eyewitness testimony. For example you can find compilations of people who were there that say it was like a controlled demolition or sounded like a bunch of explosions. There are multiple witnesses to explosions in the basement, they were not severed elevators. There are videos of the lobby being blown out by something 80 floors below the impact area. I believe one firefighter even explains it as "boom... boom.. boom. boom. boom. boom, and then the building started to collapse." But I guess we can just say debunked on that fool.

I would post links but they have been repeatedly "debunked" by conspiracy theorist who believe the OS like it's some kind of dogmatic religion. I don't even know what debunked means anymore. I guess you just throw it out there and you automatically win a participation award.

a reply to: DeceptioVisus

have seen videos that confirm explosive sequences in real time and loads of eyewitness testimony.

Nothing to do with explosives. No explosive evidence of any kind was ever found at ground zero. That is not one single valid video that depicts the sound of demolition explosions as the WTC buildings collapsed.

The Collapse of World Trade Center Buildings 1 & 2

The unique structure of the WTC towers exaggerated the problems caused by the weakened steel. The towers had a lightweight “perimeter tube” design consisting of 244 exterior columns of 36 cm square steel box section on 100 cm centers, with 95% of the structure’s interior consisting of nothing but air (see Figure 1).6 Within this perimeter tube design there was a 27m by 40m core, designed to provide additional support to the tower.

Steel trusses, or joists, connected the outer beams to the core at each story, and provided much of the overall support to the weight of each floor. The impact and explosion of the airplane crashes probably knocked off most of the insulating material intended to fireproof the steel beams, considerably increasing their vulnerability to flames.

The heat of the flames reduced the steel to a fraction of its initial strength, while also causing the steel trusses to expand at each end until they no longer supported the weight of the building’s floors, triggering the collapse.

The expansion and warping of the steel would have been particularly significant due to temperature differences within the burning structure.

www.civil.northwestern.edu...

In other words, fire, in conjunction with impact damage, was responsible.

There are multiple witnesses to explosions in the basement, they were not severed elevators.

No one in the basement heard anything that depicted the sound of demolition explosions and there was no evidence that supported such a claim.

There are videos of the lobby being blown out by something 80 floors below the impact area.

That falling elevators were determined to have caused the explosive-like sound and hurricane-forced winds.

The Elevator Man's Tale

We heard the explosion and within a matter of seconds after that impact, I heard – and as well as everybody else heard – this noise, this increasing sound of wind. And it was getting louder and louder. It was like a bomb, not quite the sound of a bomb coming down from a bomber. It was a sound of wind increasing, a whistling sound, increasing in sound.

What we heard was 6 and 7 car free-falling from the 107th floor and they impacted the basement at B-2 Level. And that’s the explosion that filled the lobby within a matter of two or three seconds, engulfed the lobby in dust, smoke.

www.thrnewmedia.com...

In other words, no case for explosives in the basement.

I believe one firefighter even explains it as "boom... boom.. boom. boom. boom. boom, and then the building started to collapse." But I guess we can just say debunked on that fool.

Now, for the rest of the story.

Craig Carlsen

...there were about ten explosions...At the time I didn't realize what it was. We realized later after talking and finding out that it was the floors collapsing to where the plane had hit.

graphics8.nytimes.com...

I would post links but they have been repeatedly "debunked"..

Of course they have been debunked because if explosives were truly used to bring down the WTC buildings, many people would have had ringing in their ears from explosions that could have been heard many miles away and the explosions would have been detected on seismic monitors in the area and yet, not one seismic monitor detected a single demolition explosion - not one!

In addition, demolition explosions leave behind physical evidence everywhere and yet, not one single piece of demolition hardware was found and do you know why? Because the claim that demolition explosives to bring down the WTC buildings was a fabrication and that claim has been used to discredit the truth movement because anyone who has heard real demolition explosions would have known that at no time were demolition explosions heard and I have heard many. many bomb explosions in war to know that at no time such explosions were heard on the WTC video.

In other words, there are folks whose goal was to discredit the truth movement have been highly successful in duping 9/11 conspiracy theorist into thinking that demolition explosives were used to bring down the WTC buildings when no such evidence exist. Add to the fact that New York City is a place where well over 2000 explosions occur each year that have nothing to do with explosives. Check it out.

Metropolitan Engineering Consulting & Forensics - Expert Engineers

THERE ARE OVER 2,000 MANHOLE FIRES/EXPLOSIONS EACH YEAR IN NYC. UNDERGROUND CABLES BECOME FRAYED FROM SNOW/ICE MELTING CHEMICALS, AGING, CORROSIVE CHEMICALS, OVERLOAD OR RATS BITING THEM.

metroforensics.blogspot.com...

originally posted by: charolais
The thing is... the steel beams don't need to melt in order to lose a lot of their strength.

If you look at a stress vs strain chart for carbon steel at elevated temperatures you will see that the tensile strength and ultimate strength plummets over 1500F.

Since part of the building may have been damaged due to the collision with the plane, some of the beams will be put under elevated stress. Then take into account the increase in temp and bad things can happen.



But when it comes to WTC 7... it's anyones guess

And ultimately wasn't it rivets at question?

a reply to: DeceptioVisus

There are videos of the lobby being blown out by something 80 floors below the impact area

Correct, and this happened before the plane hit....

a reply to: wildb

Unsupported hearsay is not evidence.

Fire, Not Extra Explosives, Doomed Buildings, Expert Says

"Certainly the fire is what caused the building to fail," said Van Romero, a vice president at the New Mexico Institute of Mining and Technology.

Romero supports other experts, who have said the intense heat of the jet fuel fires weakened the skyscrapers' steel structural beams to the point that they gave way under the weight of the floors above. That set off a chain reaction, as upper floors pancaked onto lower ones.

911research.wtc7.net...

originally posted by: skyeagle409
a reply to: wildb

Unsupported hearsay is not evidence.

You are deeply in denial Skyeagle, and therefore impossible to reason with.

a reply to: wildb

That won't fly. You have yet to refute my presentations with evidence.

whenever anyone tested the dust; tried to "investigate" the compounds...it was refuted by a book that wasn't even written yet...??? ....written while the tube-in-tube steel structure gets carted-off to be investigated by the chinese? no, they melted it down so as to build with it!!! just trading partners is all.
we already know concrete needs a 'miraculous act of god' to happen for it to fail-to change it's face...why build with it then if it just crumbles to dust at the mere site of aeroplanes!!!

will a simple brick dustify like the concrete that fell the same distance (13 to 15 vertical feet) as any one of the floors in any of the 3 buildings that fell to the ground that day?

a reply to: loveguy

The fact that everything in the building was pulverized is pretty telling.

a reply to: Chadwickus

I saw this video that day and thought I'd share in the hopes that maybe it will dissuade the silly notion that the steel in the World Trade buildings melted from jet fuel.

Well it seems something melted steel..

From the RJ Lee report page 17


Various metals (most notably iron and lead) were melted during the WTC
Event, producing spherical metallic part
icles. Exposure of phases to high
heat results in the formation of sphe
rical particles due to surface tension
show a spherical iron particle resulting from the
melting of iron (or steel)

911research.wtc7.net...

originally posted by: loveguy
whenever anyone tested the dust; tried to "investigate" the compounds...it was refuted by a book that wasn't even written yet...??? ....written while the tube-in-tube steel structure gets carted-off to be investigated by the chinese? no, they melted it down so as to build with it!!! just trading partners is all.
we already know concrete needs a 'miraculous act of god' to happen for it to fail-to change it's face...why build with it then if it just crumbles to dust at the mere site of aeroplanes!!!

will a simple brick dustify like the concrete that fell the same distance (13 to 15 vertical feet) as any one of the floors in any of the 3 buildings that fell to the ground that day?

I thought you would like to see this, start at 5:15 into the video..

a reply to: loveguy

we already know concrete needs a 'miraculous act of god' to happen for it to fail-to change it's face...why build with it then if it just crumbles to dust at the mere site of aeroplanes!!!

You forget that the only concrete in WTC was the floor slabs.
And it was light weight concrete using added fillers instead of your driveway mix.

So yes a lot of it was pulverized.
But how many truck loads of sheet rock (drywall) were pulverized too?

a reply to: wildb

Various metals (most notably iron and lead) were melted during the WTC
Event, producing spherical metallic part
icles. Exposure of phases to high
heat results in the formation of sphe
rical particles due to surface tension
show a spherical iron particle resulting from the
melting of iron (or steel)

They are referring to iron flakes that melt at much lower temperatures than bulk iron and lead melts at temperatures that are typical of house fires.

originally posted by: skyeagle409
a reply to: wildb

Various metals (most notably iron and lead) were melted during the WTC
Event, producing spherical metallic part
icles. Exposure of phases to high
heat results in the formation of sphe
rical particles due to surface tension
show a spherical iron particle resulting from the
melting of iron (or steel)

They are referring to iron flakes that melt at much lower temperatures than bulk iron and lead melts at temperatures that are typical of house fires.

Debunked..

a reply to: loveguy

we already know concrete needs a 'miraculous act of god' to happen for it to fail-to change it's face...why build with it then if it just crumbles to dust at the mere site of aeroplanes!!!

The floors were of concrete supported by steel structures that failed when fire weakened those structures.

...will a simple brick dustify like the concrete that fell the same distance (13 to 15 vertical feet) as any one of the floors in any of the 3 buildings that fell to the ground that day?

With that much mass slamming against one another during the collapse of the WTC builikdngs, it would have been expected for concrete to have been pulverized.