Why Did the EXTERIOR of WTC 1 & 2 Fail?

Fet Juel Man't Celt Bteel Seams!

a reply to: Kromlech

Not on its own, no, but there were other, hotter fires burning as a result of the explosion.

Not only that, but the steel doesn't have to melt....just get hot enough to lose some of its strength.

I would assume the exterior of the building failed in large part by the failure of the internal skeleton like structure. Most buildings including the World Trade centers are built with a framework first, if that goes, then the remaining weight has nothing to rely on, and fails also. I manufacture a lot of highrise glass, And their are many cases were a prefab panel is used, its easier for installation, and their can be an inspection of the entire panel done before its taken up to those heights. It just makes more sense to have all your fabricating done before your 100 stories in the air. then they would either use the new way, which uses a spider like design of bolts, which creates a very clean looking face of the building. because everything is hidden behind the curtain wall. Some curtain walls are a non see thru glass, and others are of completely different building materials. Its a very strict building code. Very tight tolerances, and actually is amazing that the buildings lasted as long as they did. That was an engineering masterpiece, and still is when designing buildings. If an entire section of the building did fail the way they said it did, then really it would have only taken a few floors to dislodge the entire structure

a reply to: woogleuk

No, they were designed to collapse in a certain way if needed, ie during controlled demolition when they were no longer needed, I'm sure I heard / read that somewhere.

Alright, just check'n and I know this isn't the first time I've heard something
like that either. But I'm most likely a lot more skeptical of the notion.

Any building is a number of structural elements designed to transfer loads down to its foundation.

Significantly weakening, or breaking those structural elements causes loading to increase on whatever structural elemts are left. If the load cannot be transferred in its entirety then structural failure will occur, usually at weak points such as bad welds, fatigued sections or poorly fixed joints.

While a degree of redundancy can be built in, the force of the impacts themselves will have weakened the structure and removed key supports. As the load spreads, catastrophic chain failures will occur across the rest of the building. With subsequent fires causing more damage/weakening supports as well the integrity of the building will fail, and it will collapse.

a reply to: neformore

points such as bad welds,

No, doesn't happen, especially on two high profilers. Every weld
on every building I've ever been on is inspected and has to be certified
by the inspector. And his name goes on it. No ironworker, no welder,
no inspector on the planet will accept that as even remotely true. And
if they do? They're a G-D liar. Iron workers aren't on any job ever, try'n
to get by without do'in this or, cross'n their fingers hope'n the inspector
doesn't test the torque on a certain bolt, because the snap off gun
wasn't dialed in quite right. Sh#t don't happen.

Everything is a team effort all the way around, everyones included and
if something can't be done right, because of whatever or any
circumstance? It's just to easy to go to something else and wait until
the task can be performed ABOVE PAR. I can not stress enough the
performance of ironworkers and any other trade involved with the iron
in those structures. And the reason is beyond simple Nef! Everyones life
depends on it. And the last building I remember hearing about to fail
structurally not involving the crane? Downtown L.A. right next to the 110
fwy in the early 80s. And as I remember the only reason it failed?

They were loading the iron up on the iron joists from a
truck. With no space left on the ground, two apprentice riggers loaded
to much iron up on the iron joists. But I'm just go'n by memory as far as
that incident. However I believe it was four guys that didn't make it home
that night. Anyway always keep in mind, when you're talk'n about structural
iron. Nothing like that happens anywhere in the U.S. that doesn't effect the
whole trade nation wide. Every accident, every little mishap, has
consequences that burden both trade and journeyman with more safety
equipment, more regulations and more bigass bureaucracy look'n over your
shoulder, making the task that much tuffer. So when I see someone even
mention bad welds, loose rivets, shoddy workmanship on the part of my
trade? I just lose it. Hen peck my key board like it's chicken feed.

But here's a thought, if it's so easy to get buildings to fall like that? Why
do they ever need some highly trained demo crew with expertise in
explosives?

a reply to: randyvs

Just because you don't think it could happen, doesn't mean it didn't.

And in these terms a bad weld could simply be on that's 0.5% weaker (maybe even less than that) than others that surround it, and would never - ever - have posed a problem if someone hadn't slammed a fully fuelled jet liner at speed into the side of the building, causing the entire loading of the structure to change. And when that one gives, the load changes again and another goes.

Your pride is irrelevant to the mechanism of structural collapse.

a reply to: neformore

Just because you don't think it could happen, doesn't mean it didn't.

How sad, you must feel for some reason that you have to believe
that crap! I've never said I don't think it could happen. But I do
know it couldn't happen, so w/e.

Your pride is irrelevant to the mechanism of structural collapse.

And that's not information.

a reply to: randyvs

Unless you are some form of divine entity, you don't know anything for sure.

That's one of the the problems with 9/11 truth. Painting conjecture as absolutes. I've explained how things could have happened and the potential mechanism of collapse, but I'm not saying it happened exactly that way.

If you choose to ignore or dismiss that information, thats your prerogative.

a reply to: Informer1958

I had no idea office fires could melt steel but according to the NIST Report they can.

NIST made no such claim. Here is what NIST said.

Answers to Frequently Asked Questions

In no instance did NIST report that steel in the WTC towers melted due to the fires. The melting point of steel is about 1,500 degrees Celsius (2,800 degrees Fahrenheit). Normal building fires and hydrocarbon (e.g., jet fuel) fires generate temperatures up to about 1,100 degrees Celsius (2,000 degrees Fahrenheit). NIST reported maximum upper layer air temperatures of about 1,000 degrees Celsius (1,800 degrees Fahrenheit) in the WTC towers (for example, see NCSTAR 1, Figure 6-36).

However, when bare steel reaches temperatures of 1,000 degrees Celsius, it softens and its strength reduces to roughly 10 percent of its room temperature value. Steel that is unprotected (e.g., if the fireproofing is dislodged) can reach the air temperature within the time period that the fires burned within the towers. Thus, yielding and buckling of the steel members (floor trusses, beams, and both core and exterior columns) with missing fireproofing were expected under the fire intensity and duration determined by NIST for the WTC towers.

UL did not certify any steel as suggested. In fact, in U.S. practice, steel is not certified at all; rather structural assemblies are tested for their fire resistance rating in accordance with a standard procedure such as ASTM E 119 (see NCSTAR 1-6B). That the steel was “certified ... to 2000 degrees Fahrenheit for six hours” is simply not true.

www.nist.gov...

I will take your misstep as a mistake.

If anyone believes something else brought down the WTC they better be careful, or they will be labeled a "conspiracy theorist". or anti-government.

You must remember that non-government experts concluded that fire, in conjunction with impact damage, was responsible for the destruction of the WTC buildings. We have evidence of fire and impact damage, but absolutely no evidence for thermite, nano-thermite nor explosives.

a reply to: randyvs

But here's a thought, if it's so easy to get buildings to fall like that? Why
do they ever need some highly trained demo crew with expertise in
explosives?

That is a very good question. I have always wonder that to. Why not pour jet fuel on the top floors of any building and watch it burn for an hour and the whole building should fall down in it's own foot print, just like the Trade Centers.

a reply to: neformore

Alright nef,

I don't understand why I would be guilty by reason of mortality. Or how,
only divinity is privledged to enough world class knowledge to be in the know?
When all I have to do is consider the alternative.

I agree to disagree.

a reply to: Informer1958

That is a very good question. I have always wonder that to. Why not pour jet fuel on the top floors of any building and watch it burn for an hour and the whole building should fall down in it's own foot print, just like the Trade

Jet fuel got the ball rolling whereas, combustible materials inside the WTC buildings took over. Here is what jet fuel can do to steel.



Let's take a look at WTC 5, which suffered an internal collapse due to fire alone.

World Trade Center 5 Failure Analysis

World Trade Center 5 (WTC 5) was a 9-story office and retail building at the World Trade Center complex in New York City, NY. On September 11, 2001, flaming debris from the collapse of the World Trade Center Towers penetrated the roof of WTC 5, causing a fire that burned unchecked until the fuel from building contents was consumed (FEMA, 2002, p. 4-4). While impact damage over a portion of the building and an intense fire throughout are not surprising given the assault this building received, engineers inspecting the building after the event were not expecting to see an interior collapse, due entirely to the influence of the fire. The floors collapsed between the 8th and the 4th levels in the eastern section of the building, where there was no initial impact damage (Figure 1).

Photo: WTC 5 Internal Collapse

The major fire-induced collapse that occurred in WTC 5 involved the portion of the building that had Gerber framing (girder stubs welded to columns, and simply supported central girder spans with shear connections to the ends of the stubs (Figure 2)), but not other areas of the building where girders spanned the full distance between columns. This fact, and observations at the site suggesting that the failure was early in the fire, raised the possibility that this structure had a vulnerability that led to premature failure, perhaps during the heating phase of the fire.

Just what caused all those panels to fail at the same time?



Still no answers from the truth movement as to why the walls pulled in before collapse.

Just think,
All that prep work all that explosive to bring a tall building down safely.
And all they had to do is set a fire near the top.
I hope they start using It on All new demolitions now.

a reply to: buddha

The fact the building is buckling is evidence that fire was responsible. You could place 1 ton of explosives on every floor in the WTC Tower and detonate them all at once and the WTC building would still have remained standing minus its walls and windows because the blast waves will simply flow around steel beams like wind flowing around a flag pole and to further add, there was no way to place those explosives in an occupied building and not be detected.

Even with explosives, the steel structures must be pre-weakened, a process that no doubt will attract a lot of attention in an occupied building.

Ever wonder what a ton of JDAM will do to a thin-skinned building -- like a hangar? Check it out.

JDAM Bomb Leaves Steel Structure of Hangar Intact.

.

a reply to: Informer1958

Not one of your claims are right.
Office & house fires can reach a 1000c
The steel did not need to melt only weaken at the area of aircraft impacts.
The government did not say the ground floor steel had melted.
The fire protection was poorly applied that is documented.
When a large mass is moving/ falling it produces a dynamic load on imoact that is greater than the stationary load when at rest.

originally posted by: waypastvne
Just what caused all those panels to fail at the same

Still no answers from the truth movement as to why the walls pulled in before collapse.

They failed at about the same time because they are attached to the building. It's the other way around which doesn't require a high level of mechanical insight. The core failed first therefore the perimeter columns had to follow because they are not designed for vertical loads. For some people that seems to be hard to understand.

originally posted by: drommelsboef
the perimeter columns had to follow because they are not designed for vertical loads.

This is what makes the truth movement so entertaining.

a reply to: wmd_2008

When a large mass is moving/ falling it produces a dynamic load on imoact that is greater than the stationary load when at rest.

Here's an easy way for the conspiracy believers to test out what you are saying.

1. Rest a baseball on your head.
No problem. No pain.

2. Drop the same baseball 6 inches above your head.
Hurts doesn't it.

Care to drop it from 10 feet and then say your head should resist it without any problems?
I didn't think so.
Now imagine what hundreds of tons of steel and concrete would do to the floor below.