16-05-2011, 03:44 PM
Mr. Lewis.
There are very few buildings which share the structural attributes of the Twin Towers. And this certainly applies to all previous towers which experienced raging fires such as the one cited in your post. Totally different animal.
Of course all towers have columns and so this is a shared attribute. But what I have described did not involve column failure but FLOOR failures... between the columns which help them "in place".
But more importantly, I am not claiming that FIRES caused the weakening which led to the floor destruction. While intense heat DOES weaken steel and hence fireproofing is applied to give a two hour margin typically for steel, I don't believe office fires burning for the time intervals at the twin towers had much to do with the floor collapse... if anything. I've made that clear many times.
I am not a scientist and do not make such representations. I am architect for over 40 years and actually worked for the firm which did the construction drawings for the twin towers as my first post graduate job. I simply look at the failure by examine the structure which is precisely what anyone who would take them down would do - study the structure and figure out the most efficient way to take them down. And that is part of what I have done.
Obviously you fail to understand that a floor can collapse... any floor... in any building (not slab on grade of course) if there is too much imposed load placed on it. In the case of the twin tower floor failure/destruction this began AFTER the section above the plane strikes (in tower 1 from floor 96 or so up and in tower 2 from floor 80 or so up) were dissociated from the columns which supported them. We don't know the mechanism for this and as stated above office fires don't seem to cut it here so something else was a play.
But one masses of those magnitudes was no longer supported by columns these masses began to drop, pulled by gravity of course. And these masses... 30,000 tons or more in for wtc 1 and perhaps 60 or 70 thousand tons for tower two dropped they came crashing onto the top floors of the intact section below. It doesn't much matter whether this mass was rubblised entirely or partially or acted a single mass.... if it descended on a typical WTC floor that floor would immediately fracture and fail... turn to rubble and the driving mass would continue on down also breaking apart with each collision.
ROOSD is the explanation for the collapse... not what began the collapse. We don't know what BEGAN the collapse... explosives, cutter charges, even DEW which might have turned to tops to disorganized mass as opposed to mass organized as office floors and equipment and so forth.
This is a forensic engineering explanation which IS supported by the observations... and to most engineers who study this it looks like a duck and quacks like a duck so it IS a duck and that duck is a progressive floor failure from over loading.
Try this though experiment. Place an German made Landkreuzer P. 1500 Monster tank weighing 1500 tons and gently lower it onto floor 98. Observe what happens. I'll tell you what happens. The tank will crash through every single floor right to the ground.
And that is essentially what happened to the twin tower floors. Burning contents by fire is not going to free the mass of the floors themselves and the contents to become the destructive driver. Fire protection of steel is there to prevent the FRAME itself from buckling and collapsing. What happened at the twin towers is the FRAME basically was INTACT, but the floors were destroyed. And then the frame collapsed without lateral support.
Get it?
There are very few buildings which share the structural attributes of the Twin Towers. And this certainly applies to all previous towers which experienced raging fires such as the one cited in your post. Totally different animal.
Of course all towers have columns and so this is a shared attribute. But what I have described did not involve column failure but FLOOR failures... between the columns which help them "in place".
But more importantly, I am not claiming that FIRES caused the weakening which led to the floor destruction. While intense heat DOES weaken steel and hence fireproofing is applied to give a two hour margin typically for steel, I don't believe office fires burning for the time intervals at the twin towers had much to do with the floor collapse... if anything. I've made that clear many times.
I am not a scientist and do not make such representations. I am architect for over 40 years and actually worked for the firm which did the construction drawings for the twin towers as my first post graduate job. I simply look at the failure by examine the structure which is precisely what anyone who would take them down would do - study the structure and figure out the most efficient way to take them down. And that is part of what I have done.
Obviously you fail to understand that a floor can collapse... any floor... in any building (not slab on grade of course) if there is too much imposed load placed on it. In the case of the twin tower floor failure/destruction this began AFTER the section above the plane strikes (in tower 1 from floor 96 or so up and in tower 2 from floor 80 or so up) were dissociated from the columns which supported them. We don't know the mechanism for this and as stated above office fires don't seem to cut it here so something else was a play.
But one masses of those magnitudes was no longer supported by columns these masses began to drop, pulled by gravity of course. And these masses... 30,000 tons or more in for wtc 1 and perhaps 60 or 70 thousand tons for tower two dropped they came crashing onto the top floors of the intact section below. It doesn't much matter whether this mass was rubblised entirely or partially or acted a single mass.... if it descended on a typical WTC floor that floor would immediately fracture and fail... turn to rubble and the driving mass would continue on down also breaking apart with each collision.
ROOSD is the explanation for the collapse... not what began the collapse. We don't know what BEGAN the collapse... explosives, cutter charges, even DEW which might have turned to tops to disorganized mass as opposed to mass organized as office floors and equipment and so forth.
This is a forensic engineering explanation which IS supported by the observations... and to most engineers who study this it looks like a duck and quacks like a duck so it IS a duck and that duck is a progressive floor failure from over loading.
Try this though experiment. Place an German made Landkreuzer P. 1500 Monster tank weighing 1500 tons and gently lower it onto floor 98. Observe what happens. I'll tell you what happens. The tank will crash through every single floor right to the ground.
And that is essentially what happened to the twin tower floors. Burning contents by fire is not going to free the mass of the floors themselves and the contents to become the destructive driver. Fire protection of steel is there to prevent the FRAME itself from buckling and collapsing. What happened at the twin towers is the FRAME basically was INTACT, but the floors were destroyed. And then the frame collapsed without lateral support.
Get it?