Why Indeed Did the WTC Buildings Collapse?
- Thread starter kazakhan
- Start date
GeoffP said:
Qwerty mob said he studied the towers in the 80's so he might better answer this. But the building was ingeniously designed. To my understanding the outside structural steel was independent of the inside. The hollow steel cores in the center of the building had the loads of the floors above it, but not the steel from the outside structure. Those holes are on the outside, and I doubt the plane was solid enough to severely damage the central core once it "got in".
But not too many people would expect that a hole on the outside would have no effect on the load capacity of the building.
vincent28uk said:
That's interesting, so you're telling everyone that if there was no plane, just the jet fuel.. the building would have collapsed anyways? Where do you come up with these facts, it sounds like you're making shit up as you go along just so you don't expose the fact that you're actually retarded.
Hurricane Angel said:
http://www.boston.com/news/packages...ervers_say_fire_may_have_felled_towers+.shtml
ENGINEERS
Observers say fire may have felled towers
By Gareth Cook and Thomas C. Palmer Jr., Globe Staff, 9/12/2001
Even the impact of a passenger jet, a force one specialist estimated to be the equivalent of a half-ton of TNT, was not enough to demolish either tower.
But less than two hours after yesterday's initial collision, both of the buildings had almost totally collapsed, with terrible loss of life. And engineers were searching for an answer to the question everyone was asking: How could it have happened?
Although nobody knows exactly what took place on the planes or in the towers, specialists suggested the buildings may have fallen victim to the fire that followed the initial impact.
Once the planes hit the buildings, fires fed by jet fuel could have begun to melt the massive steel columns that held the building up and girders that support each floor. And then, engineers said yesterday, one floor probably gave way, slamming into the one below and setting off a chain reaction - a sickening process, driven by gravity, that engineers call ''progressive collapse.''
''You have a domino effect,'' said Mysore Ravindra, president of LeMessurier Consultants, a structural engineering firm in Cambridge that designs skyscrapers. ''I can't even watch it on television.''
For the engineers and architects charged with designing skyscrapers that hold thousands of people, yesterday's tragedy was especially potent.
But in this case, the crucial difference seems to have been the fire. The amount of fuel carried by the planes when they hit is not known, but a Boeing 767-200 can carry 16,700 gallons of fuel. When the planes hit, their fuel would have been spread by the impact. Fed by oxygen from the outside and fuel and other material inside, the building became a chimney.
At 1,200 degrees Fahrenheit, steel loses about half of its strength. The steel could buckle, bend, and eventually break, setting off a progressive collapse that would bring the building pancaking down in a column.
****************
http://architecture.about.com/library/weekly/aawtc-collapse.htm
Architecture
Why the Twin Towers Fell
Engineers who studied the World Trade Center after the September 11 attacks tell why the Twin Towers stood as long as they did, and why they eventually collapsed.
"Can we truly build an indestructible building? Let alone having it survive a fire being fed by jet fuel?" ~VORRATUS
New York's World Trade Center Twin Towers were designed to withstand fire and hurricane-force winds. Some engineers believed the Twin Towers could even survive impact from a Boeing 707. But no engineer or architect could have anticipated the terrorist attack that turned the Twin Towers to rubble, and experts often don't agree what steps might have been taken to make the buildings stronger. For the most recent findings and detailed technical information, be sure to visit the World Trade Center Coverage page at icivilengineer.
How did the Twin Towers fall?
1. Impact from the Terrorist Planes
When Boeing jets piloted by terrorists struck the Twin Towers, some 10,000 gallons (38 kiloliters) of jet fuel fed an enormous fireball. But, the impact of the planes and the burst of flames did not make the Towers collapse right away. Like most buildings, the Twin Towers had redundant design. The term redundant design means that when one system fails, another carries the load. Each of the Twin Towers had 244 columns around a central core that housed the elevators, stairwells, mechanical systems, and utilities. When some columns were damaged, others could still support the building.
2. Heat from the Fires
The sprinkler system was damaged by the impact of the planes. But even if the sprinklers had been working, they could not have maintained enough pressure to stop the fire. Fed by the remaining jet fuel, the heat became intense. Most fires don't get hotter than 900 to 1,100 degrees F. The World Trade Center fire may have reached 1,300 or 1,400 degrees F. Structural steel does not easily melt, but it will lose about half its strength at 1,200 degrees F. The steel structure of the Twin Towers was weakened by the extreme heat. The steel also became distorted because the heat was not a uniform temperature.
Could the World Trade Center have been made stronger?
In a report produced by the Federal Emergency Management Agency (FEMA), the American Society of Civil Engineers (ASCE), and other organizations, experts concluded that no skyscraper could have withstood the impact of the terrorist airplanes. Further, the experts warned that it would not be "technically feasible" to design a building that could survive this type of terrorist attack. Instead, engineers and architects are suggesting that we focus our efforts on designing better warning and evacuation systems so that we can save more people inside the buildings.
*************
"At 1,200 degrees Fahrenheit, steel loses about half of its strength. The steel could buckle, bend, and eventually break, setting off a progressive collapse"
"Once the planes hit the buildings, fires fed by jet fuel could have begun to melt the massive steel columns"
"Most fires don't get hotter than 900 to 1,100 degrees F. The World Trade Center fire may have reached 1,300 or 1,400 degrees F. Structural steel does not easily melt, but it will lose about half its strength at 1,200 degrees F. The steel structure of the Twin Towers was weakened by the extreme heat. The steel also became distorted because the heat was not a uniform temperature."
Now finally mr hurricane are we getting the pretty picture here Most fires don't get hotter than 900 to 1,100 degrees F. The World Trade Center fire may have reached 1,300 or 1,400 degrees, the steel melted.
How on earth does a building stay up when all the supports are melting, and jet fuel made them melt, no natural fire could have got so hot.
I rest my case, it was not the bloody impact but the bloody jet fuelled fire to blame.
First of all, you said 3000F now you're saying 1200F. I called you out on the 3000 so stop acting like you were right all along.
And second, stop using the word "melt". That did not happen to the WTC and the engineers in your article said that too.
More contradictions? "The steel also became distorted because the heat was not a uniform temperature" So I guess that means the towers will fall straight down right? That's the only obvious possibility when a non-uniform fire distorts steel.
Besides, this article was writtne one day after the attacks, do you think that's enough time for a decent investigation?
And second, stop using the word "melt". That did not happen to the WTC and the engineers in your article said that too.
More contradictions? "The steel also became distorted because the heat was not a uniform temperature" So I guess that means the towers will fall straight down right? That's the only obvious possibility when a non-uniform fire distorts steel.
Besides, this article was writtne one day after the attacks, do you think that's enough time for a decent investigation?
Hurricane Angel said:
the 3000 was aguess from what i heard on the news years ago, as you doubted the jet fuel was the reason i looked it up to get the accurate figure, i am not a library or calculator, sure i know the reasons but the numbers will always be vague unless this is my day to day job.
Besides, this article was writtne one day after the attacks, do you think that's enough time for a decent investigation?
The first story was, the second was not and engineers & architects around the world have all said the same thing, but in my view there just stating the bloody obvious, we all know the horrors of what jet fuel does, from other plane crashes.
"Besides, this article was written one day after the attacks"
That in its self should tell you how bloody obvious it was, it usually takes years of investigations before they stick there neck out.
"And second, stop using the word "melt". That did not happen to the WTC"
"Structural steel does not easily melt, but it will lose about half its strength at 1,200 degrees F., "
buckle, melt, the end result is the same collapse.
Hurricane Angel said:
Well, the pressure would have been all from directly above. If the supports gave, then the building would presumably come straight down as all the weight's coming from there. I don't know that it would necessarily tip, if that's what you're suggesting.
Still havent got to the video but I will.
Geoff
Anomalous said:
So i guess all the engineers & architects who say it was the jet fuel to blame for the collapse are wrong
http://education.jlab.org/qa/meltingpoint_01.html
What's the melting point of steel?
That depends on the alloy of steel you are talking about. The term alloy is almost always used incorrectly these days, especially amongst bicyclists. They use the term to mean aluminum. What the term alloy really means is a mixture of metals, any kind of metals. Almost all metal used today is a mixture and therefore an alloy.
Most steel has other metals added to tune its properties, like strength, corrosion resistance, or ease of fabrication. Steel is just the element iron that has been processed to control the amount of carbon. Iron, out of the ground, melts at around 1510 degrees C (2750°F). Steel often melts at around 1370 degrees C (2500°F).
******
Steel does not melt
"Steel often melts at around 1370 degrees C"
Do you want to say that again moron, are you talking about the man of steel here superman or what, please think before you type, you are looking more & more out of your depth, your drowning here pal..........
Maybe you could also tell us how a fire will reach those temperatures?
Remember the jet fuel burned within 4 minutes and the rest of the 50 minutes will be fuel from whatever the offices housed.
And vincent, he's talking about steel melting in a fire, we all know if you have a forge the steel will melt, but what about an office fire.. how hot do those get?
Remember the jet fuel burned within 4 minutes and the rest of the 50 minutes will be fuel from whatever the offices housed.
And vincent, he's talking about steel melting in a fire, we all know if you have a forge the steel will melt, but what about an office fire.. how hot do those get?
quoting what temperature the steel used in their construction melts?leopold99 said:
I did leopold
"Structural steel does not easily melt, but it will lose about half its strength at 1,200 degrees F.
"Steel often melts at around 1370 degrees C"
Official statistic
"The World Trade Center fire may have reached 1,300 or 1,400 degrees",
but the steel buckled on that there is no doubt, and in some case no doubt melted near the fire, as the fire was already hotter than 1370 degrees, which is beyond the melting point of steel.
Official statement
"Structural steel does not easily melt, but it will lose about half its strength at 1,200 degrees F. The steel structure of the Twin Towers was weakened by the extreme heat."
There is no doubt here that building would still be standing today, if there was no jet fuel involved here, the jet fuel made the intense heat that weakened the steel supports.
If you had read the report more carefully, you would have seen that the jet fuel had completely burned within 5 minutes, leaving only the office "stuff" to burn.
Oh yeah? There were several hundred tonnes of steel there, you'd need a fire as large as the building itself to heat all that metal.
You're basing all your ideas on what you saw on television, and what you think happens in a fire. You don't know science, and you don't know much about this discussion. I recommend you live your life 10 years, grow up, and then get back to me.
You're basing all your ideas on what you saw on television, and what you think happens in a fire. You don't know science, and you don't know much about this discussion. I recommend you live your life 10 years, grow up, and then get back to me.
http://en.wikipedia.org/wiki/Collapse_of_the_World_Trade_CenterHurricane Angel said:
After the airliners hit, it appeared to most ground observers that the buildings had been severely but not fatally damaged. However, intense heat from the burning jet fuel and combustibles near the cores of the towers was weakening the central steel columns, the longspan floor trusses and the joins connecting the floorplates to the external columns. The strength of the steel dropped markedly with exposure to fire, the steel losing its stiffness as its temperature rose.[4]
A combination of factors including the impact from aircraft flying at high speed was the cause of internal structural damage.[5] The resultant fires from the aviation fuel spread widely through the impact zone and ultimately led to the collapse of the Twin Towers.
*********
"You're basing all your ideas on what you saw on television?"
NO I AM BASING MY IDEAS ON WHAT ENGINEERS & ARCHITECTS HAVE ALL SAID SINCE THEN,
"The resultant fires from the aviation fuel spread widely through the impact zone and ultimately led to the collapse of the Twin Towers."
I did not say the above engineers did, you seem to have a talents for ignoring expert findings from the aftermath of the WTC collapse.
Do you also believe that earth is flat too, or do you believe the experts when they say it is round. LOL
Anomalous said:
If you tried reading peoples replies you would know, the steel supports were weekened by the jet fuel fire, i am not saying this the engineers are!!!!!!!!
You call me a ASS HOLE?
"Originally Posted by Anomalous
U stupid little moron, Beams and Steel Pilars never melt."
I see so steel cant melt, so when architects need steel girders for buildings, they go off to the steel orchid, & pick the shape & size of the girders from the trees.
LOL
Everthing melts including your brain.
Hey dont call me a ass, call all the engineers & architects, who stated jet fuel in the fire as the reason for the buildings collapse.
But you being a supreme mega engineer, dismiss all there findings & blame it all on what, star misalignment.
I suggest you finish off your kindergarden year, before typing again...