WTC Collapses

[John99]

you trained as a police forensics expert?

i dont believe i said forensics expert. maybe i did, dont remember that though. I sat in on lectures given by experts.

 

[John99]

experience in iron working, personally witnessed steel beams exactly like the wtc beams snapping, breaking and bending, worked with large turbines the size of houses that sound exactly like explosives, worked as a manager of incinerator plant, trained as a a police forensics expert.

And that is wrong. I said that i worked on a project lifting the top of a turbine that was the size of a small house of which there were three such turbines side by side. Using an apparatus involving an i-beam (http://en.wikipedia.org/wiki/I-beam) the same type found in wtc construction. in the process the beam was forced and bent in such a way that it went flying approx 50 feet and could have been mistaken as an explosion. which was a response to the oft quoted misleading straw man - 'i hear explosions'.

all related to my work as a certified licensed ENGINEER.

 

[John99]

worked as a manager of incinerator plant,

and i never said manager...did i? this was one of the biggest plants in the world too.

 

[leopold]

well are there any conclusions?

 

[leopold]

How much expertise does it take to know that every level of a skyscraper must support the combined weights of all levels above?


So why isn't everyone demanding to know the TONS of STEEL on every level?

Doesn't it take more energy to heat more steel? So isn't that information relevant to analyzing the fire? How much steel can get how hot in less than TWO HOURS?

Talking about expertise in a problem this simple when people aren't DEMANDING the obviously relevant but simple information is ridiculous. People that want to BELIEVE stupid bullshit have to make it seem much more complicated than it is.

psik

this entire post is a strawman.

i can diagnose illnesses too but that by no means says i'm a doctor.

 

[Buffalo Roam]

LiteSteel was developed in 2004.
you must be confusing the cosmetic aluminium cladding with the structural steel.
your comparison with LiteSteel box beam is ridiculous.
here is steel from the wtc:

No that is a peace of steel from the WTC center, from what part is unknown, and it appears to be a Hollow Box Beam, Litesteel, from the end holes that are readily visabe, now again look up the construction of the WTC towers, it was one of the largest if not the largest Litesteel construction in the world at that time.

Now just because it was a lite steel construction doesn't mean that there were not Heavy Red Steel materials used there is always a certian ammount of Heavy Iron in any building construction.

http://www.history.com/minisite.do?...lay_order=3&sub_display_order=2&mini_id=60026

SIGHTS SET ON RECORD-BREAKING HEIGHT
By this time, the Port Authority had decided that the trade center should replace the 1,250-foot-high Empire State Building, built in 1931, as the world's tallest building. To fulfill the Port Authority's requirement, architect Minoru Yamasaki designed two towers of 110 stories each. Instead of the traditional stacked glass-and-steel box construction of many New York skyscrapers, Yamasaki worked with structural engineers to come up with a revolutionary design: two hollow tubes, supported by closely spaced steel columns encased in aluminum. Floor trusses connected this exterior steel lattice to the central steel core of the building.

In this way, the "skin" of the building would be much stronger, so that internal columns wouldn't be necessary to hold it together.

Construction began in February 1967, after the Port Authority faced down criticism about the towers' safety and viability from many powerful quarters, including real estate tycoon (and Empire State Building owner) Lawrence Wien. Wien even ran an ad in the New York Times in May 1968 predicting that a commercial airliner was likely to fly into the towers. Plans had already been made to guard against such an accident – which had happened in July 1945 with a smaller plane at the Empire State –and the towers were designed to be safe in a collision with a fully loaded 707 plane (the largest existing plane at the time). It was assumed such a plane would have to be lost in fog for such an event to occur; a terrorist attack was never envisioned.

And as in all litesteel constructions once the outer skin is compromised, the strength of the outer shell is gone, and the failure is certain, the loads bearing transfers to the floors under the damaged section, and as they collapse, it becomes progressive, till total catastrophic failure.

The impact of the two planes that hit the World Trade Center towers on September 11, 2001, was more devastating than any of the building's designers and engineers had ever imagined. The first plane ripped a hole in the north tower from the 94th to the 98th floors, causing massive structural damage and igniting some 3,000 of the 10,000 gallons of jet fuel the plane was carrying. The second plane hit the south tower at an even faster speed, striking the corner and gashing the building from the 84th to the 78th floors.

The heroic efforts of the city's fire and police departments and other emergency services helped 25,000 people escape from the site before the unthinkable occurred. The damage done at each point of impact forced the physical weight of the towers to be redistributed, and the undamaged part below the hole had to support the floors above. At the same time, the fires raging in both buildings weakened the steel trusses holding up each floor. With damage to a greater number of floors lower down on the building, the south tower gave way first, crumbling to the ground at 9:59 a.m., only 56 minutes after being hit. The north tower collapsed less than a half hour later, at 10:28 a.m.

It is a remarkable point that the Towers lasted as long as they did, which allowed for the rescue of most of the people who were working and visiting them.

 

[leopold]

It is a remarkable point that the Towers lasted as long as they did, which allowed for the rescue of most of the people who were working and visiting them.

from my understanding there were few, if any, people "rescued" from WTC 1 and 2. all survivors evacuated under their own power.

 

[Stryder]

from my understanding there were few, if any, people "rescued" from WTC 1 and 2. all survivors evacuated under their own power.

From memory it was due to the time of Day. If it had occur 1/2 hour later there would of been larger numbers of people trying to escape.

 

[Headspin]

From memory it was due to the time of Day. If it had occur 1/2 hour later there would of been larger numbers of people trying to escape.

a big al quaeda screw up if the intention was to maximise the number of deaths.

 

[Buffalo Roam]

from my understanding there were few, if any, people "rescued" from WTC 1 and 2. all survivors evacuated under their own power.

Rescue, escape what ever, it was remarkable the the Towers lasted long enough to allow all those people to make it out.

The fact is that in that type of construction, the Outer Walls need the Inner Columns for their structural integrity, and the Inner Columns need the Outer Walls to keep it's structural integrity.

Compromise either one and the system fails and you get a catastrophic collapse, and both outer wall and column in the WTCs were compromised, and the damage spread out from their like dominos causing more and more lose of structural integrity to the wall systems and inner columns, till total catastrophic collapse initiated.

 

[scott3x]

The Windsor Tower in Madrid, Round 2, Part 2

This post is in response to the 1st part of shaman_'s post 640 from this thread.

Alright, since you won't go to the link, I guess the link must come to you. Here's a good chunk of it:
**********************************
Because the Windsor fire produced a partial collapse, some have argued that it validates the official account of the collapses of WTC Buildings 1, 2, and 7. Because the same fire was so massive and did not produce total collapse, others have cited it as evidence disproving that account.

Compare these photographs of the Windsor building fire to photographs of the Twin Towers' fires and Building 7's fires:

Windsor fire

Windsor fire close-up

Twin Tower fires

As has been pointed out once or twice the construction of these two buildings was quite different.

Have I ever disagreed with that assertion?

The WTC relied on fireproofing which was not intact after the full speed collision of the 767s.

From what I've seen, the only evidence that fireproofing wasn't intact -before- the collapse (whereupon the explosives did a very good job of removing it and pulverizing the concrete to boot) is at the entrance to the building. Kevin Ryan has also described how the tests NIST did in order to ascertain that the fireproofing was removed from the planes was weak to put it mildly. FInally, from tests that Kevin Ryan describes, however, it seems apparent that even without fireproofing the buildings shouldn't have collapsed.

The Windsor Tower was not hit by any large planes, and the fires still caused the steel to weaken and collapse.

Much weaker steeler and it only reinforced the concrete frame. The twin towers, by contrast, had a 100% steel frame.

That only a small percentage of the WTC is visibly on fire is irrelevant. It was one of the tallest buildings in the world. Only one floor had to fail for the collapse to start.

Do you have any evidence that (a) the fires could have caused even one floor to collapse and (b) that one floor collapsing would make any other floors collapse, let alone the whole building at near free fall speeds?

Steel Versus Steel-Reinforced Concrete [framed buildings]

In fact, comparisons between the Windsor tower and the WTC Towers are limited because of the very different structures of these buildings. The Twin Towers and Building 7 were both 100% steel-framed, with large wide-flange columns and box columns, some measuring over four feet wide and fabricated of steel up to five inches thick. Severe fires in other skyscrapers which, like the WTC Towers, were 100% steel-framed, have not produced even partial collapses.

In contrast to the WTC Towers, the Windsor building was framed primarily in steel-reinforced concrete, with columns of concrete reinforced by thin sections of rebar. 4 The concrete pillars in the Windsor building are clearly visible in the photographs showing the intact core exposed by the collapsed facade. The very light construction of the perimeter, described [at their site], makes it clear that the core was the main load-bearing component of the building.


Before examining the partial collapse of the Windsor building more closely, we note that steel-framed and steel-reinforced-concrete-framed structures behave very differently in fires.

* Steel is a good conductor and concrete is a poor conductor of heat. Thus in a fire, a steel frame will conduct heat away from the hotspots into the larger structure. As long as the fire does not consume the larger structure, this heat conductivity will keep the temperatures of the frame well below the fire temperatures. The same is not true of steel-reinforced-concrete structures, since concrete is not a good thermal conductor, and the thermal conductivity of the rebar inside the concrete is limited by its small mass and the embedding matrix of concrete.

* Fires can cause spalling of concrete, but not of steel[Emphasis mine]. This is because concrete has a small percentage of latent moisture, which is converted to steam by heat. Thus, a large fire can gradually erode a concrete structure to the point of collapse, whereas a fire can only threaten a steel-framed structure if it elevates steel temperatures to such an extent that it causes failures.[/b]

Clearly the spalling at the Madrid tower was not a problem was it Scott? The concrete core held firm while the steel collapsed.

The concrete core was the strongest element. However, the top part of the steel reinforced concrete frame gradually collapsed. You seem to think that the weak link was the steel, when in fact it was the concrete. 9/11 Research makes that clear, but for some reason you seem to have missed it...

Thus, a large fire can gradually erode a concrete structure to the point of collapse, whereas a fire can only threaten a steel-framed structure if it elevates steel temperatures to such an extent that it causes failures.

That's right, just as with the steel at the Madrid Tower, the steel at the WTC reached temperatures when the steel was sufficiently weakened so that it could no longer bear the load.

If by 'weakened' you mean 'sliced through by explosives', I couldn't agree with you more. The jet initiated office fires had no chance of doing it though.

It's really not complicated.

That's what it seems like to me as well. And yet here we are disagreeing..

The problem you have is that the behavior of the Madrid tower supports the official story and you are still trying to say otherwise but you are unable to.

Actually, 9/11 Research is the one making it clear that the behaviour of the Madrid tower doesn't, in fact, support the official story. I've simply followed its train of logic and found it to be valid.

 

[scott3x]

The Structure of the World Trade Center, Round 2, Part 1

This post is in response to the 1st part of shaman_'s post 643 from this thread.

I agree. So does 911review.org, even including a diagram of this belief and stating that it is mistaken. It states the reverse; that the core columns reinforced the concrete core.

.. and I am saying that is not correct. The information I have regarding the towers states that the floors were concrete but it was the steel box columns providing the support in the core. There was no support provided by any concrete walls.

Alright, you've seen my source, let's see yours; perhaps others here can weigh in as well.

Even your own 911 article says “In contrast to the WTC Towers, the Windsor building was framed primarily in steel-reinforced concrete, with columns of concrete reinforced by thin sections of rebar. 4"

To be sure. You are aware that the 9/11 research article in question was referring to the frames of the buildings, not the cores, right?

The framing of the building does not exclude the cores.

Perhaps Tony, Headspin or psikey can weigh in on that. All I know is that the article in question definitely does distinguish between the perimeter walls, interior core colums and core when it comes to gravity loads. Quoting:
"Distribution of gravity loads was; perimeter walls 50%, interior core columns 30% core 20%."

And that a steel frame is much stronger and more resistant to fire than a (lightly) steel reinforced frame?

What are you talking about?

I'm talking about the Madrid Tower's lightly steel reinforced concrete frame, which was susceptible to spalling when subjected to fires, vs. the Twin Towers strong 100% steel frame, which wasn't.

The Madrid Tower had steel-reinforced concrete while the WTC had steel with fireproofing. The concrete, which is extremely fire resistant, is the reason the Madrid Tower stayed up.

I haven't seen any evidence that steel can't resist fires quite well. And steel doesn't spall.

Ok, the 911review.org article in question is stating that the inner core, which bore 20% of the load, was surrounded by the interior steel core columns, which bore 30% of the load. The remaining 50% of the load was borne by the perimeter columns. If you disagree with any of this, then I can certainly attempt to seek more confirmation as at present, the only source I have for those precise distributions is the above linked article from 911review.org (not to be confused with 911review.com, an official story supporter).

9/11 Research elaborates:
******************
"The Twin Towers and Building 7 were both 100% steel-framed, with large wide-flange columns and box columns, some measuring over four feet wide and fabricated of steel up to five inches thick... In contrast to the WTC Towers, the Windsor building was framed primarily in steel-reinforced concrete, with columns of concrete reinforced by thin sections of rebar. 4 The concrete pillars in the Windsor building are clearly visible in the photographs showing the intact core exposed by the collapsed facade. The very light construction of the perimeter, described below, makes it clear that the core was the main load-bearing component of the building."
******************
Only the Windsor Tower's relatively weak perimeter collapsed; the core remained intact.

Weak because it was steel? While the core was concrete?

No, no no. I originally just quoted what I had just quoted above but then realized it was the same thing I'd quoted before. So I'll phrase it as an answer to your question this time.

The Windsor tower -frame- (as opposed to the core) was weak because it was primarily framed in steel-reinforced concrete, with columns of concrete reinforced by thin sections of rebar. The concrete pillars in the Windsor building are clearly visible in the photographs showing the intact core exposed by the collapsed facade. The very light construction of the perimeter, described here, makes it clear that the core was the main load-bearing component of the building.

The Twin Towers and Building 7 were both 100% steel-framed, with large wide-flange columns and box columns, some measuring over four feet wide and fabricated of steel up to five inches thick. Severe fires in other skyscrapers which, like the WTC Towers, were 100% steel-framed, have not produced even partial collapses.

To sum up- the Windsor Tower had a concrete frame that was only reinforced by a bit of relatively thin steel (for a building that size, that is). The twin towers' frames were 100% steel framed. Stronger, and no spalling possible.

 

[Headspin]

the perimeter columns of the windsor tower were not a major structural component.

the ratio of steel to window space on the perimeter was massively lower than that for the twin towers. most of the structure was supported by the core. its bogus to conclude that fire will weaken to the point of collapse a steel structure.

the windsor tower did not collapse catastrophically, despite being fully involved in flame (which would have reduced conduction of the heat). the flimsy steel perimeter sections deformed and collapsed over a period of hours as you'd expect. the twin towers collapsed catastrophically in seconds.

 

[Headspin]

perhaps others here can weigh in as well.

I have seen no evidence that the core of the twin towers was concrete. the towers had to flex in the wind, i don't see how a concrete core could survive 50 years of flexing.

 

[scott3x]

the perimeter columns of the windsor tower were not a major structural component.

the ratio of steel to window space on the perimeter was massively lower than that for the twin towers. most of the structure was supported by the core. its bogus to conclude that fire will weaken to the point of collapse a steel structure.

the windsor tower did not collapse catastrophically, despite being fully involved in flame (which would have reduced conduction of the heat). the flimsy steel perimeter sections deformed and collapsed over a period of hours as you'd expect. the twin towers collapsed catastrophically in seconds.

Amen

 

[scott3x]

perhaps others here can weigh in as well.

I have seen no evidence that the core of the twin towers was concrete. the towers had to flex in the wind, i don't see how a concrete core could survive 50 years of flexing.

My source says the following on the subject:
Yamasaki's design for a torsion resistant core structure made from non flexible material, steel reinforced cast concrete, won a competition in strength with several others. All steel towers failed high winds because the steel perimeter columns could take the weight but were prone to flexing and the twisting.

 

[Headspin]

My source says the following on the subject:
Yamasaki's design for a torsion resistant core structure made from non flexible material, steel reinforced cast concrete, won a competition in strength with several others. All steel towers failed high winds because the steel perimeter columns could take the weight but were prone to flexing and the twisting.

there is a lot on that website that doesn't pass the bullshit test, for example what exactly is he communicating here:

 

[leopold]

I have seen no evidence that the core of the twin towers was concrete. the towers had to flex in the wind, i don't see how a concrete core could survive 50 years of flexing.

i have not been able to confirm scotts assertion that the box columns was surrounded by concrete. all construction videos i've seen of WTC 1 and 2 shows no such concrete.

 

[Headspin]

i have not been able to confirm scotts assertion that the box columns was surrounded by concrete. all construction videos i've seen of WTC 1 and 2 shows no such concrete.

I would agree.

 

[MacGyver1968]

Yes..there was no concrete surrounding the core columns.. just look at the picture i posted with the wtc under constuction. You only see steel beams...if concrete was used..You see the forms for the concrete.