Originally posted by xmarksthespot
fearYes.
No, I occasionally venture into this cesspool of a thread to see what implausibilities and paranoia Deano has come up with recently. Apparently you've decided to be Deano for a day. It's really no substitute for the real thing.
ISo when deano says shape shifting aliens are taking over the world, you don't comment. but If I ask a question you drop in.
Originally posted by Grand_Moff_Gav
Ashtar, you said that the building was designed to survive an aearoplane attack, that is why it didn't topple, but, ofcourse, it had too collapse eventually didn't it.
Why would it collapse due to it's own weight, because the steel was weakened? since when has fire weakened steel to the point of collapse?
Oh egad, Ashtar, is all that you can do is parrot that? I have already explained!
Whenever there is a severe fire, the steel is ALWAYS weakened. That is not unique to the WTC. But there was a localised collapse caused by the plane impact, which preciptated the rest of the collapse!
If the upper floors on the other tower fires you may refer to had collapsed, then with their weakened steel structures, they would have gone down also. But their upper floors did not collapse. Why not? Because a whacking great metal object hadn't gone though them, explosively, at hundreds of miles an hour! Small difference, that.
Originally posted by Emperor Ashtar
Why would it collapse due to it's own weight, because the steel was weakened? since when has fire weakened steel to the point of collapse?
When a Jumbo Jet crashes into it, even just a small portion say, those girders will weaken and buckle, and guess what that does...those weakend girders will then support they weight of the entire building above it, then they pull the other girders down which buckle and then, break the top half collapses in on the bottm half. ( I left out the fire in that to make it easier for you, but the fire will have excelaerated the process)
Originally posted by Ushgarak
Oh egad, Ashtar, is all that you can do is parrot that? I have already explained!Whenever there is a severe fire, the steel is ALWAYS weakened. That is not unique to the WTC. But there was a localised collapse caused by the plane impact, which preciptated the rest of the collapse!
I never said steel doesnt weakened, I said when does it weaken to the point of collapse?
Originally posted by Ushgarak
If the upper floors on the other tower fires you may refer to had collapsed, then with their weakened steel structures, they would have gone down also. But their upper floors did not collapse. Why not? Because a whacking great metal object hadn't gone though them, explosively, at hundreds of miles an hour! Small difference, that.
<Sigh> again, the reason why the towers fell was because the steel allegdly weakened due to fire, again how is that possible?
Originally posted by Ushgarak
Again, read my posts above. Because you clearly have not. I have explained everything, in full. You are just ignoring it.
that buildings do not collapse in free fall by themselves. The TT did. They took just as long to collapse as a ball dropped from the top would have taken to fall. This means that no part of the structure was crashing into any other part on it's way down.
Originally posted by Emperor AshtarWow.. You're knowledge of structural engineering is astounding...
that buildings do not collapse in free fall by themselves. The TT did. They took just as long to collapse as a ball dropped from the top would have taken to fall. This means that no part of the structure was crashing into any other part on it's way down.
Originally posted by xmarksthespot
Sorry if I didn't make it clear. That was sarcasm on my part.
The wtc defies the laws of physics
The undamaged floors below the impact zone offered zero resistance to the collapse
The glass and concrete spontaneously disintegrated without any expenditure of energy
On 9/11, gravity was much stronger than gravity
On 9/11, energy was not conserved
How about an actual civil engineer's assessment instead of the incredulous statements of bored teenagers? 🙂
Tim Wilkinson. BSc BE (Hons) MA PhD. Lecturer in Civil Engineering, University of Sydney.
The structural integrity of the World Trade Center depends on the closely spaced columns around the perimeter. Lightweight steel trusses span between the central elevator core and the perimeter columns on each floor. These trusses support the concrete slab of each floor and tie the perimeter columns to the core, preventing the columns from buckling outwards.
After the initial plane impacts, it appeared to most observers that the structures had been severely damaged, but not necessarily fatally.
It appears likely that the impact of the plane crash destroyed a significant number of perimeter columns on several floors of the building, severely weakening the entire system. Initially this was not enough to cause collapse.
However, as fire raged in the upper floors, the heat would have been gradually affecting the behaviour of the remaining material. As the planes had only recently taken off, the fire would have been initially fuelled by large volumes of jet fuel, which then ignited any combustible material in the building. While the fire would not have been hot enough to melt any of the steel, the strength of the steel drops markedly with prolonged exposure to fire, while the elastic modulus of the steel reduces (stiffness drops), increasing deflections.
World Trade Center collapse
Modern structures are designed to resist fire for a specific length of time. Safety features such as fire retarding materials and sprinkler systems help to contain fires, help extinguish flames, or prevent steel from being exposed to excessively high temperatures. This gives occupants time to escape and allow fire fighters to extinguish blazes, before the building is catastrophically damaged.
It is possible that the blaze, started by jet fuel and then engulfing the contents of the offices, in a highly confined area, generated fire conditions significantly more severe than those anticipated in a typical office fire. These conditions may have overcome the building's fire defences considerably faster than expected. It is likely that the water pipes that supplied the fire sprinklers were severed by the plane impact, and much of the fire protective material, designed to stop the steel from being heated and losing strength, was blown off by the blast at impact.
Eventually, the loss of strength and stiffness of the materials resulting from the fire, combined with the initial impact damage, would have caused a failure of the truss system supporting a floor, or the remaining perimeter columns, or even the internal core, or some combination. Failure of the flooring system would have subsequently allowed the perimeter columns to buckle outwards. Regardless of which of these possibilities actually occurred, it would have resulted in the complete collapse of at least one complete storey at the level of impact.
Once one storey collapsed all floors above would have begun to fall. The huge mass of falling structure would gain momentum, crushing the structurally intact floors below, resulting in catastrophic failure of the entire structure. While the columns at say level 50 were designed to carry the static load of 50 floors above, once one floor collapsed and the floors above started to fall, the dynamic load of 50 storeys above is very much greater, and the columns were almost instantly destroyed as each floor progressively "pancaked" to the ground.
(US readers note: storey is the Australian/English spelling of story)
World Trade Center collapse
The only evidence so far are photographs and television footage. Whether failure was initiated at the perimeter columns or the core is unknown. The extent to which the internal parts were damaged during the collision may be evident in the rubble if any forensic investigation is conducted. Since the mass of the combined towers is close to 1000000 tons, finding evidence will be an enormous task.
World Trade Center collapse
This photograph shows the south tower just as it is collapsing. It is evident that the building is falling over to the left. The North Tower collapsed directly downwards, on top of itself. The same mechanism of failure, the combination of impact and subsequent fire damage, is the likely cause of failure of both towers. However, it is possible that a storey on only one side of the South Tower initially collapsed, resulting in the "skewed" failure of the entire tower.
While the ways the two towers fell were slightly different, the basic cause is similar for both - a large number of columns were destroyed on impact, and the remaining structure was gradually weakened by the heat of the fire. Not much significance should be taken from the fact that one tower fell in 45 minutes and the other in 90 minutes.
The gigantic dynamic impact forces caused by the huge mass of the falling structure landing on the floors below is very much greater than the static load they were designed to resist.
The fire wasn't hot enough to melt the steel
There has never been a claim that the steel melted in the fire before the buildings collapsed, however the fire would have been very hot. Even though the steel didnt melt, the type of temperatures in the fire would have roughly halved its strength.
There would have been variations in the distribution of the temperature both in place in time. There are photos that show people in the areas opened up by the impact, so it obviously wasnt too hot when those photos were taken, but this is not to say that other parts of the building, further inside were not hotter. In addition, to make a reasonable conclusion from these photos, it would be important to know when they were taken. It might be possible that just after the impact the area wasnt very hot, but as the fire took hold the area got hotter.
The way the building collapsed must have been caused by explosions
One demolition expert on the day of the collapse said it looked like implosion but this is not very strong evidence. Implosion firstly requires a lot of explosives placed in strategic areas all around the building. When and how was this explosive placed in the building without anyone knowing about it. Second, implosion required more than just explosives. Demolition experts spend weeks inside a derelict building planning an event. Many of the beams are cut through by about 90% so that the explosion only has to break a small bit of steel. In this state the building is highly dangerous, and there is no way such a prepared building could still be running day to day like WTC was.
Why did the building fall so quickly?
The buildings did fall quickly - almost (but not exactly) at the same speed as if there was no resistance. Shouldn't the floors below have slowed it down? The huge dynamic loads due to the very large momentum of the upper floors falling were so great that they smashed through the lower floors very quickly. The columns were not designed to carry these huge loads and they provided little resistance.
http://www.physics.byu.edu/research/energy/htm7.html
Why Indeed Did the WTC Buildings Collapse?
By Steven E. Jones
Department of Physics and Astronomy
Brigham Young University
Provo, UT 84602
ABSTRACT
In this paper, I call for a serious investigation of the hypothesis that WTC 7 and the Twin Towers were brought down, not just by impact damage and fires, but through the use of pre-positioned cutter-charges
Fireman: "bomb in the building start clearing out"
This is a clip from the CameraPlanet 9/11 Archive. A firefighter at ground zero clearly says that the building must be cleared because there is a bomb inside. This adds to the weight of testimony from firefighters that bombs were evident in the WTC.
http://prisonplanet.com/articles/may2006/220506bomb.htm
Thermite Identified As Culprit Of WTC Collapse
'A new branch of 9/11 research claims to have identified the cause of the collapse of the twin towers. The photographic and video evidence makes a very strong case for thermite being responsible for the unprecedented implosions of steel framed reinforced buildings on September 11.
This facet was first brought to light during a November 2005 appearance on The Alex Jones Show by Brigham Young University physicist Professor Steven Jones. Jones said that white phosphorous wasn't powerful enough to cause the implosion but that thermite was the likely culprit. Alex Jones's 2005 release Martial Law 9/11 Rise of the Police State highlighted the physical evidence that the towers and Building 7 were brought down with incendiary devices.
Brigham Young University physicist Professor Steven Jones told peers at a Utah meeting that, "while almost no fire, even one ignited by jet fuel, can cause structural steel to fail, the combination of thermite and sulfur "slices through steel like a hot knife through butter."'
http://prisonplanet.com/articles/april2006/240406thermiteidentified.htm
Dear Editor,
After reading in the Daily Herald the presentations made by Professor Steven E. Jones (BYU Physics) to students at UVSC and BYU, I feel obligated to reply to his "Conspiracy Theory" relating to the terrorist attacks on the World Trade Center (9/11/01).
I have studied the summary of the report by FEMA, The American Society of Civil Engineers and several other professional engineering organizations. These experts have given in detail the effects on the Towers by the impact of the commercial aircraft. I have also read Professor Jones' (referred to) 42 page unpublished report. In my understanding of structural design and the properties of structural steel I find Professor Jones' thesis that planted explosives (rather than fire from the planes) caused the collapse of the Towers, very unreliable.
The structural design of the towers was unique in that the supporting steel structure consisted of closely spaced columns in the walls of all four sides. The resulting structure was similar to a tube. When the aircraft impacted the towers at speeds of about 500 plus mph, many steel columns were immediately severed and others rendered weak by the following fires. The fires critically damaged the floors systems. Structural steel will begin to lose strength when heated to temperatures above 1000 degrees Fahrenheit. Steel bridge girders are bent to conform to the curved roadway by spot heating flanges between 800 and 1000 degrees Fahrenheit. It is easy to comprehend the loss of carrying capacity of all the structural steel due to the raging fires fed by the jet's fuel as well as aircraft and building contents.
Before one (especially students) supports such a conspiracy theory, they should investigate all details of the theory. To me a practicing structural engineer of 57 continuous years (1941-1998), Professor Jones' presentations are very disturbing.
D. Allan Firmage
Professor Emeritus, Civil Engineering, BYU
Isn't it remarkable? Other people also know how to copy and paste. 🙂
http://prisonplanet.com/articles/march2006/230306Sheen_CNN.htm
charlie sheen on 9/11
Comment: We are amazed and flabbergasted by how fair this piece is and it should help encourage other high profile figures in the public eye like Charlie Sheen to come forward.