thedude953
Member
If it was planned IF They tried to help it come down big ifs here they would only need to help take out one or two floors not some crazy rig every floor type deal here
The collapsing floors allowed the buckling to occur. Not the other way round.The buckling argument does not explain simultaneous synchronized collapse of the floors to allow the freefall or close to freefall speed during the first few seconds. we all understand it explains the collapse just not in the way It actually happened
Well this is good thanks for clarifying this makes it easier for people to understand how impossible a synchronized collapse would beThe collapsing floors allowed the buckling to occur. Not the other way round.
The floors depended on their trusses to remain flat, but the trusses were exposed to the fire. Once the bar work of the trusses was up to fire temperature, and under constant load, it crept, and the floors began to hang like curtains. They then exerted considerable side forces on the columns which supported them, and once they were pulled far enough off their vertical centerlines, they buckled en masse.
The collapse wasn't "synchronized". Your use of the word implies someone's overall control and is misleading.Well this is good thanks for clarifying this makes it easier for people to understand how impossible a synchronized collapse would be
Just started reading this thread but I see a fundamental error in this response. The way to think of a collapse is in terms of kinetic energy and equal and opposite reactions. The falling object strikes the entire structure bellow it. That structure is designed to resist this force, plus some safety margin, typically about 100% including wind, snow and occupancy loads. The week point will be at the buildings highest intact point due to the tapering of columns towards the top. So a large amount of energy is absorbed by any flex that occurs in the remaining intact areas. That expenditure of energy will result in a loss of speed in the falling mass, or masses as the collapsing segment will not all strike the area bellow at the same time. Simultaneously there will be some deflection in the falling mass as it attempt to follow the path of least resistance, there will also be some deflection at the weakest points in the remaining structure which will/may lead to catastrophic failure of individual members. These members, in the case of WTC towers can be seen to eject horizontally from the structure. An equal and opposite energy must be considered to both the falling mass above and the remaining structure bellow. There's a collision, the structure fails but the but the acceleration of the falling mass is deflected and diminished by the act of expending energy to damage otherwise intact components bellow it. The energy of the falling mass should have been either deflected laterally into the path of least resistance or gradually halted as the kinetic energy of it originally having only collapsed one or two stories was gradually expended on a building designed to handle likely 2x its expected loading. The collapse should have decelerated and/or destabilized into the path of least resistance.
Another fundamental flaw is the structural steel doesn't like to shatter, it bends, it actually bends a lot before it even begins to reach any critical point. This bending absorbs energy, which again must be subtracted from the kinetic energy of the falling debris. This fundamental error can be found in a huge number of arguments about the falling block hypothesis.
If we modify Jazzy's hypothesis with his Newtons swing we find that energies are dissipated in many directions but only under manufactured conditions does it travel through the path of most resistance. In Jazzy's model he'd have the energy going straight down through the structural steel and melting the base of each column. Not likely. But there is some truth to the principal he's misunderstanding. The energy does transfer, but not all of it goes into breaking a single bond at a time, just as not all of it would go in a single direction. Its transferred to the entire remaining structure, which will respond as its designed and spread that load out as much as possible and bending when the loads get to some critical stage. Somewhere in there something breaks. But what broke isn't the only resistive force involved. Shock loading and bending strain must also be considered along with the individual elements of catastrophic failure. IE each beam that gets broken away from the remaining structure and its energy of ejection (IE acceleration ) from a position of resistance to a position of less resistance.
In the end, no I'm not going to calculate out the exact numbers, I'd need a free month or two and a set of print which we all know aren't available. But the towers should never have reacted the way they did and completely collapsed. At worst some significant portion of the towers should have survived and at best I don't think fire or the damage they received should have been sufficient to cause any major collapse.
I wouldn't want to overstate things. What this does prove is that the theory proffered by NIST is flawed, and that the gravitational loading and subsequent momentum that it would transfer would cause enough of a reduction in velocity for the perceived collapse to be arrested at quite an early stage. It should be considered more of a critique of NISTs lack of explanation, after all, they did not address the actual collapse itself in their report. Only the events leading up to it. Bazant did do an analysis early on and then revised it but did not take the shortening of the bottom block into account. Also, it is worth remembering that we are presuming that a whole floor (3.7m) of the tower just disappears and allows the block to drop at g.
It proves that there should be a more thorough investigation into the whole event. The fact that controlled demolition was not considered in the report is counter intuitive as this is the only cause ever of high rise steel framed building collapses like these. Fire does not have form for dong this to buildings made of steel, so the fact that NIST discarded the most likely cause, but clung to the least likely historically speaking should be a red flag to anyone. The implication that every highrise on the planet is now liable to collapse from fire should be disturbing to us all, whether it is true or not.
Incorrect. You are confusing static and dynamic loads.Let's do some maths: The outer collumns of the twin tower bore 40% of the load and they were designed to hold 5 times the load which they bore. The core collumns bore 60% of the load and they were designed to hold 3 times the load which they bore.
During the "collapse" the towers fell at roughly 0.6G. Using Newtons 3rd law we can derive that the upward force must have been 0.4 times the weight of the towers. Let's assume that due to the weakening of the trusses the outer collumns literally turned into spaghetti and lost all their supporting force. In this case The core collumns below the plane crash which do not rely on any tension from the trusses to maintain their supporting force and being below the plane crash had not undergone any weakening (using 0.6 x 3) would still be able to support 1.8 times the weight of the towers. However we know that the upward force was only 0.4 times the weight of the towers so the core collumns must have literally turned into spaghetti also.
The truth is that anyone with a background in newtonian physics and structural engineering that has researched 9/11 either knows that it is incontrovertible that all 3 towers under went a controlled demolition or they are lying to themselves. Tower 7 fell at freefall acceleration for almost half of it's descent. Freefall is impossible during a building collapse and can only be acheived via controlled demolition
Incorrect. In order for collumn to completely fail the load must exceed it's maximum load capacity. So during the collapse the uprward supporting force of the collumns would have been at their maximum. Freefall is not possible during a building collapse. Mick West you are a deluded chronic debunker who works from preconceived conclusions to use any and all evidence to support your notion and try to downplay all the incontrovertible proof that shows otherwise.
Let's do some maths: The outer collumns of the twin tower bore 40% of the load and they were designed to hold 5 times the load which they bore. The core collumns bore 60% of the load and they were designed to hold 3 times the load which they bore.
During the "collapse" the towers fell at roughly 0.6G. Using Newtons 3rd law we can derive that the upward force must have been 0.4 times the weight of the towers. Let's assume that due to the weakening of the trusses the outer collumns literally turned into spaghetti and lost all their supporting force. In this case The core collumns below the plane crash which do not rely on any tension from the trusses to maintain their supporting force and being below the plane crash had not undergone any weakening (using 0.6 x 3) would still be able to support 1.8 times the weight of the towers. However we know that the upward force was only 0.4 times the weight of the towers so the core collumns must have literally turned into spaghetti also.
The truth is that anyone with a background in newtonian physics and structural engineering that has researched 9/11 either knows that it is incontrovertible that all 3 towers under went a controlled demolition or they are lying to themselves. Tower 7 fell at freefall acceleration for almost half of it's descent. Freefall is impossible during a building collapse and can only be acheived via controlled demolition
There is a difference between a weight resting on something and a weight falling on something as far as calculating kinetic energy. Kinetic energy is a function of speed. Force is a function of acceleration. Force is not a function of speed.
It is wrong to assume that an object traveling at a high speed will exert a bigger force onto the object it hits. It will have higher kinetic energy so if the object it hits brings it to rest then it will have transfered more momentum. However if the first object continues to accelerate while it crushes through the 2nd object then the force on the first object is greater than the force of the 2nd object pushing against the 2nd object. During a building collapse or during the verinage technique as the top half of the building drives into the bottom half, the bottom half exerts a greater force onto the top half than the weight of the top half driving it into the bottom half. This results in a deceleration. You can observe a deceleration in the videos you posted in the earlier part of this thread on the verinage technique, it has also been measured by phycisist David Chandler. The fact is that during every observed collapse and in coordinance with Newtons universal laws of motion when the top section of a building drives into the bottom section of a building it decelereates. The twin towers accelerated all the way to the ground meaning that there was another force present other than gravity to weaken the structure during the collapse.
Also in the video of the collapse of wtc 1 you can see the spire of the building start to fall a fraction of a second before the outer structure starts to fall showing that it was the core collumns that failed first and not the precise point where the plane hit or the trusses holding the floors in place.
Yeah... like no one has done that before...To which I must assume that you have been carefully analysing different slow motion clips of the onset of collapse of wtc 1 for the last 3 hours.
The analogy of someone jumping on the ground with their knees bent and their knees straight is a bit of an obfuscation. When the person is standing stationary on the ground, the ground is applying an equal force upwards as the weight of the person pushing down. When the person jumps and bends their knees the ground applies a force greater than the persons weight to cause a deceleration and bring them to rest. When the person lands with straight legs the ground exerts a greater force still to bring them to rest quicker. If we take this analogy and apply it to the twin towers, the person stands on the ground and the ground can hold their weight then the person jumps up and accelerates through the ground, the force that the ground was exerting on the person before they jumped has miraculously disapeared when they land back on the ground. "Same weight. Different forces." It's actually different weight and different forces as weight is a force. If the person jumped on a scale with straight legs the scale would measure higher than if the person jumped on the scale with bent legs as the net force is constantly being balanced by the rate of acceleration/deceleration.
Just as well, then, as it didn't.I never stated that the bottom structure should stop the top structure
You have already obfuscated enough for the rest of us."The key is what effect should upward force that is capable of holding the objects weight have on it's rate of acceleration." Would you like to answer this question instead of more obfuscation.
It never took up loads where it was expected to. Instead, individual parts of the intact tower were individually and separately subjected to the impact of the entire mass of the falling tower top. They failed uniquely and separately from each other.However it would still have taken up the load or it would still have been standing after the collapse.
The top was out of alignment and fell through the core. The same rules as above applied. Individually and separately the core elements met the full force of the falling tower top and failed instantly. As, of course, did parts of the tower top.The core structure of the towers were a tower in their own right which did not rely on the floors or the outer structure to support them. If the core structure was not taking up the load then it should still be standing.
Pardon me, but you show a "W". That represents the total downward loading. My point is that the impact loading at the collision speed was at least TEN TIMES "W" (rising to a HUNDRED TIMES "W"). You shouldn't argue in a language whose lexicon you aren't yet familiar with. Your diagram is wrong. False. A mistake.How can something that doesn't have any numbers be wrong by at least an order of magnitude. That is totally retarded.
The fact remains that the reduction of downward acceleration (30%) exactly conforms with what you might expect with random collisions with the intact structure slowing the tower top's free fall. There is every justification in what I have written to you, and I haven't yet felt the need to be impolite.The fact remains that in every single case of the top section of a building collapsing onto the bottom section, the top section undergoes deceleration as it crushes through the rest of the building. You are trying to justify something that has no basis in scientific theory or experimental data.
Who says it didn't decelerate compared to acceleration due to gravity?There is not 1 example you could point to of a building collapsing and not decelerating as it crushes through it's structure. There is no justification for what you have written and it is not supported by any experimental evidence.