Merged New video! Architects and Engineers - Solving the Mystery of Building 7

[Dave Rogers]

During Stage 1, for 1.75 seconds at least 8 storeys worth of lower supporting columns, across the complete WTC7 floor area, were simultaneously demolished.

I was going to make a sarcastic reply to this, but it might be more constructive to point out that "for 1.75 seconds" and "simultaneously" so obviously contradict each other as to make this sentence patently absurd. Conspiracy theorists have been claiming for years that the sudden onset of collapse of WTC7 indicates that controlled demolition, and only controlled demolition, must have been responsible. Miragememories is now advancing the contradictory claim that controlled demolition is demonstrated by the presence of an initiation phase of 1.75 seconds duration, with no vestige of an explanation as to why this is the case. In fact, 1.75 seconds is a particularly inconvenient time frame for the conspiracy theorist; it's too short for thermite, which takes several seconds to produce significant quantities of molten iron, and far too long for explosives, which act over very much shorter times than a second. It's significant that Miragememories has not advanced, and will not advance, any justification as to why a CD must exhibit an initial 1.75 second period of increasing acceleration; at best, he'll just claim something along the lines of the perpetrators being able to control the demolition any way they liked, in which case he's simply resorting to the time-honoured fallacy of the conspiracy theorist, that absence of evidence of a conspiracy is evidence of a conspiracy.

Dave

 

[Miragememories]

"How many ways must you hear it?

NIST's Stage 1, was the period before the global collapse of WTC7 reached freefall acceleration (Stage 2). During Stage 1, for 1.75 seconds at least 8 storeys worth of lower supporting columns, across the complete WTC7 floor area, were simultaneously demolished..."

"I was going to make a sarcastic reply to this, but it might be more constructive to point out that "for 1.75 seconds" and "simultaneously" so obviously contradict each other as to make this sentence patently absurd. Conspiracy theorists have been claiming for years that the sudden onset of collapse of WTC7 indicates that controlled demolition, and only controlled demolition, must have been responsible. Miragememories is now advancing the contradictory claim that controlled demolition is demonstrated by the presence of an initiation phase of 1.75 seconds duration, with no vestige of an explanation as to why this is the case. In fact, 1.75 seconds is a particularly inconvenient time frame for the conspiracy theorist; it's too short for thermite, which takes several seconds to produce significant quantities of molten iron, and far too long for explosives, which act over very much shorter times than a second. It's significant that Miragememories has not advanced, and will not advance, any justification as to why a CD must exhibit an initial 1.75 second period of increasing acceleration; at best, he'll just claim something along the lines of the perpetrators being able to control the demolition any way they liked, in which case he's simply resorting to the time-honoured fallacy of the conspiracy theorist, that absence of evidence of a conspiracy is evidence of a conspiracy."

I do not see a contradiction Dave.

Simultaneously in the context I used, means that the same or similar action (demolition) was occurring against 8 storeys worth of lower supporting columns, across the complete WTC7 floor area for a period of 1.75 seconds.

It means all at the same time, which is not the same as saying it took zero time to complete.

You have to allow a small portion of time to clear (demolish) a path for the ensuing freefall.

Please learn the nuances of the english language Dave.

MM

 

[NoahFence]

Simultaneously in the context I used,

 

[Dave Rogers]

I do not see a contradiction Dave.

Simultaneously in the context I used, means that the same or similar action (demolition) was occurring against 8 storeys worth of lower supporting columns, across the complete WTC7 floor area for a period of 1.75 seconds.

It means all at the same time, which is not the same as saying it took zero time to complete.

I addressed that, as you may have noticed. The time is too long for explosives and too short for thermite.

You have to allow a small portion of time to clear (demolish) a path for the ensuing freefall.

And here is a slightly different version of the bare assertion fallacy to the one I predicted. No explanation as to why it takes 1.75 seconds for the structural elements to be removed from the path of freefall, when all that's required is for the columns to be severed and moved laterally by a few inches, something explosives could do in very much less than a second and thermite could not do at all; just the simple assertion that this was what happened. This is pure fantasy, unsupported by any explanation of the mechanics of the proposed process; as such, it's not even worth the briefest consideration.

Dave

 

[sylvan8798]

I do not see a contradiction Dave.

Simultaneously in the context I used, means that the same or similar action (demolition) was occurring against 8 storeys worth of lower supporting columns, across the complete WTC7 floor area for a period of 1.75 seconds.

It means all at the same time, which is not the same as saying it took zero time to complete.

You have to allow a small portion of time to clear (demolish) a path for the ensuing freefall.

Please learn the nuances of the english language Dave.

MM

So, then, enough of the columns are removed that somehow the entire top starts sinking slowly? Wouldn't the columns that are still intact at this instant either break or continue holding up THEIR part of the building so that we would see the building fall from the outset into clearly distinguishable parts?

 

[A W Smith]

How many ways must you hear it?

NIST's Stage 1, was the period before the global collapse of WTC7 reached freefall acceleration (Stage 2). During Stage 1, for 1.75 seconds at least 8 storeys worth of lower supporting columns, across the complete WTC7 floor area, were simultaneously demolished.

Stage 1 was followed by Stage 2, a period of freefall for 2.25 seconds, clearly meaning an unobstructed global drop through those column-removed 8 storeys. A 100 foot free fall, unobstructed and unresisted.

From the videos you can see for yourself that the north face and the west face were free-falling in unity.

http://img263.imageshack.us/img263/9872/set3sccompositeua1.png

Vertical structural supports from the northeast corner all the way around to the southwest corner were proven by the video to have been instantly removed.

Not even a left to right progressive collapse which might have supported the NIST fantasy.

When global collapse started, the left side dropped in time with the right.

MM

Funny how truthers only use the video that is obstructing the portion that they allege is a cd. Lets look at it from a different angle.
Can you point out the columns being cut in this screen grab as seen almost unobstructed from the north but further east? before and after alleged CD event.

 

[GlennB]

Vertical structural supports from the northeast corner all the way around to the southwest corner were proven by the video to have been instantly removed.

Taking "instantly" to mean very quickly indeed (for example, by shaped-charges or similar) then your "8 storeys-worth of support removed simultaneously" theory would lead to freefall in as long as it took the charges to cut the columns and for the columns to get out of the way enough to be offering unmeasurably small resistance.

The 'slug' of a cutter charge travels at ~ 1km/sec and will cut a few cms of steel in the kind of time it would require high-speed photography to measure.

If the weight of the building on bevelled cuts is what is removing the severed columns from the collapse path, then this clearly will succeed in the first few cms of fall. If additional charges were used, then it might be even quicker.

So the question remains unaswered by you - what was happening during the 1.75 secs during which acceleration was gradually approaching g?

 

[GlennB]

But when you start calculating how many charges it would take to remove all columns over 8 floors, then it gets hilarious. And that's before considering that flange (I-shaped) columns need pre-cutting to get the charges flush with the flanges and that it typically takes 4 cutter charges to take out one end of an I column.

Some 80 columns over each of 8 floors, cut only top+bottom by mystery devices that work stand-alone ....

That conservative scenario comes to 1280 devices.

It really is "too funny", but it's exactly what certain flavours of Truther are obliged to believe.

 

[Seymour Butz]

But when you start calculating how many charges it would take to remove all columns over 8 floors, then it gets hilarious. And that's before considering that flange (I-shaped) columns need pre-cutting to get the charges flush with the flanges and that it typically takes 4 cutter charges to take out one end of an I column.

Some 80 columns over each of 8 floors, cut only top+bottom by mystery devices that work stand-alone ....

That conservative scenario comes to 1280 devices.

It really is "too funny", but it's exactly what certain flavours of Truther are obliged to believe.

Forget about the core columns.

Twoofers are saying that either thermite or explosives were used on the ext columns when they make their claim that ALL of the columns MUST have been removed over an 8 story distance. On the EXT columns too...... And STILL not be noticed or recorded or spoken about.....

Anybody making this claim is not worth responding too, for they are nothing more than a troll. Pointing out what I just did is enough. Yo do more just gives them satisfaction that you rose to their troll bait.

If just one twoof could come up with a reasonable scenario that matches up with logic and reality, it would an interesting discussion. I could imagine it to be something like:

The fires couldn't have heated the floor beams enough to thermally expand enough to push the girder off its seat. Even at the elevated steel temp of 200C that NIST shows, the beam would have only been able to produce x force, which would have been resisted by y force from the shear studs and z force from the girder itself, and w force from the connections. Therefore, an accelerant such as thermite must have been used on the floor beams to weaken them. this was done in the partially unoccupied 13 floor....... etc.

Never gonna see it...

 

[Miragememories]

"I do not see a contradiction Dave.

Simultaneously in the context I used, means that the same or similar action (demolition) was occurring against 8 storeys worth of lower supporting columns, across the complete WTC7 floor area for a period of 1.75 seconds.

It means all at the same time, which is not the same as saying it took zero time to complete.

[Added note, simultaneous also does not mean instantaneous)"

"I addressed that, as you may have noticed. The time is too long for explosives and too short for thermite."

The NIST's Stage 1 does not suggest that WTC7 was standing still. It was falling but its acceleration had not yet reached that of gravity. I have read much debate regarding the legitimacy of the NIST's Stage 1 calculation, but I include it because they still acknowledge freefall in their Stage 2.

"You have to allow a small portion of time to clear (demolish) a path for the ensuing freefall."

"And here is a slightly different version of the bare assertion fallacy to the one I predicted. No explanation as to why it takes 1.75 seconds for the structural elements to be removed from the path of freefall, when all that's required is for the columns to be severed and moved laterally by a few inches, something explosives could do in very much less than a second and thermite could not do at all; just the simple assertion that this was what happened. This is pure fantasy, unsupported by any explanation of the mechanics of the proposed process; as such, it's not even worth the briefest consideration."

The simultaneous demolition occurring on the lower structural columns was not represented by 8 storeys of instantly vaporized steel. The NIST's Stage 1 <g acceleration, indicates their belief that the WTC7 collapse had not reached freefall for the first 1.75 seconds into its global collapse.

Clearly during that first 1.75 second period, there was a uniform removal of support across the complete WTC7 cross-section but structural resistance was not quite zero. After 1.75 of near freefall acceleration, zero resistance was achieved and WTC7 achieved the NIST's Stage 2, freefall acceleration for their estimated 2.25 seconds, followed by a Stage 3 de-acceleration less than freefall for 1.4 seconds (resistance from the growing debris pile).

MM

 

[NoahFence]

There was no demolition.

Please join us here in reality. The water's nice!

 

[Dave Rogers]

The simultaneous demolition occurring on the lower structural columns was not represented by 8 storeys of instantly vaporized steel. The NIST's Stage 1 <g acceleration, indicates their belief that the WTC7 collapse had not reached freefall for the first 1.75 seconds into its global collapse.

It is not a belief, but a measurement. WTC7 did not reach freefall until 1.75 seconds after the starting point NIST chose for their measurement, and at the time its acceleration reached freefall it had already fallen a significant distance.

Clearly during that first 1.75 second period, there was a uniform removal of support across the complete WTC7 cross-section but structural resistance was not quite zero.

This is completely incorrect. Firstly, we know from the deformation of the building as it fell - in particular, the kink in the north face clearly visible in the photographs posted in this thread - that the removal of support was not uniform, but rather that it occurred significantly sooner near the centre of the face and significantly later near the east and west ends. The kink alone proves conclusively that the removal of support was not, in fact, simultaneous; rather, it was sequential across the face, exactly as would be expected from a laterally progressing structural failure due to overloading. Secondly, the structural resistance can be determined directly from the rate of acceleration, and it is entirely misleading to describe its value as "not quite zero" over this entire period. It decreased smoothly, and more or less monotonically, from a value equal to the weight of the structure above it to a value insignificantly different from zero over the 1.75 seconds of phase 1.

After 1.75 of near freefall acceleration, zero resistance was achieved and WTC7 achieved the NIST's Stage 2, freefall acceleration for their estimated 2.25 seconds, followed by a Stage 3 de-acceleration less than freefall for 1.4 seconds (resistance from the growing debris pile).

And this is both incorrect and, in places, close to scientific illiteracy. The initial 1.75 seconds was not at near freefall acceleration, but at a varying acceleration increasing steadily from zero to freefall. The duration of the final stage of the collapse is not accurately known, as far as I'm aware, but I've seen no indication that the building decelerated in its final stages; in fact, if it had decelerated, it would have been the most extraordinary event observed at any point in the day. I presume you mean that its acceleration decreased to a value less than 1G; clearly you're confusing your second and third derivatives, as I would expect from someone with not even the most basic understanding of Newtonian dynamics.

Since your beliefs about the collapse progression of WTC7 are so extraordinarily inaccurate, it would of course be no surprise that your conclusions were similarly inaccurate even if they proceeded from your premises. But, of course, they don't; you're just making up fantasies, without any basis in fact whatsoever.

Dave

 

[sylvan8798]

Clearly during that first 1.75 second period, there was a uniform removal of support across the complete WTC7 cross-section but structural resistance was not quite zero. After 1.75 of near freefall acceleration, zero resistance was achieved and WTC7 achieved the NIST's Stage 2, freefall acceleration for their estimated 2.25 seconds, followed by a Stage 3 de-acceleration less than freefall for 1.4 seconds (resistance from the growing debris pile).

MM

If there was no support, what was providing the structural resistance during that 1.75 seconds?

 

[tsig]

The NIST's Stage 1 does not suggest that WTC7 was standing still. It was falling but its acceleration had not yet reached that of gravity. I have read much debate regarding the legitimacy of the NIST's Stage 1 calculation, but I include it because they still acknowledge freefall in their Stage 2.




The simultaneous demolition occurring on the lower structural columns was not represented by 8 storeys of instantly vaporized steel. The NIST's Stage 1 <g acceleration, indicates their belief that the WTC7 collapse had not reached freefall for the first 1.75 seconds into its global collapse.

Clearly during that first 1.75 second period, there was a uniform removal of support across the complete WTC7 cross-section but structural resistance was not quite zero. After 1.75 of near freefall acceleration, zero resistance was achieved and WTC7 achieved the NIST's Stage 2, freefall acceleration for their estimated 2.25 seconds, followed by a Stage 3 de-acceleration less than freefall for 1.4 seconds (resistance from the growing debris pile).

MM

Then every single column must be removed before the building will fall?

 

[Oystein]

It is not a belief, but a measurement. WTC7 did not reach freefall until 1.75 seconds after the starting point NIST chose for their measurement, and at the time its acceleration reached freefall it had already fallen a significant distance.



This is completely incorrect. Firstly, we know from the deformation of the building as it fell - in particular, the kink in the north face clearly visible in the photographs posted in this thread - that the removal of support was not uniform, but rather that it occurred significantly sooner near the centre of the face and significantly later near the east and west ends. The kink alone proves conclusively that the removal of support was not, in fact, simultaneous; rather, it was sequential across the face, exactly as would be expected from a laterally progressing structural failure due to overloading. Secondly, the structural resistance can be determined directly from the rate of acceleration, and it is entirely misleading to describe its value as "not quite zero" over this entire period. It decreased smoothly, and more or less monotonically, from a value equal to the weight of the structure above it to a value insignificantly different from zero over the 1.75 seconds of phase 1.



And this is both incorrect and, in places, close to scientific illiteracy. The initial 1.75 seconds was not at near freefall acceleration, but at a varying acceleration increasing steadily from zero to freefall. The duration of the final stage of the collapse is not accurately known, as far as I'm aware, but I've seen no indication that the building decelerated in its final stages; in fact, if it had decelerated, it would have been the most extraordinary event observed at any point in the day. I presume you mean that its acceleration decreased to a value less than 1G; clearly you're confusing your second and third derivatives, as I would expect from someone with not even the most basic understanding of Newtonian dynamics.

Since your beliefs about the collapse progression of WTC7 are so extraordinarily inaccurate, it would of course be no surprise that your conclusions were similarly inaccurate even if they proceeded from your premises. But, of course, they don't; you're just making up fantasies, without any basis in fact whatsoever.

Dave

Excellent and lucid explanation, Dave.

Allow me to expand on the highlighted sentence to drive the point even further into MM's home territory where he will hopefully finally pick it up:

Acceleration increased more or less smoothly from 0 to g. This means that

• For the first 0.85s or so, acceleration was closer to 0 than it was to g.
• For about 90% of that 1.75s secomnd interval, acceleration differed from g by more than 10%

Contrast that with MM's assertion of "1.75 of near freefall acceleration", and we see now how wrong he was:
For half of that time interval, it would be more accurate to describe the fall as "... near zero acceleration".
For most of that time, or 1.5-1,6s, it would be more accurate to observe "...acceleration not near g".

MM, please acknowledge!

 

[Clayton Moore]

Funny how truthers only use the video that is obstructing the portion that they allege is a cd. Lets look at it from a different angle.
Can you point out the columns being cut in this screen grab as seen almost unobstructed from the north but further east? before and after alleged CD event.

[qimg]http://i294.photobucket.com/albums/mm89/AWSmith1955/wtc7fromnorth9plusseconds.jpg[/qimg]



[qimg]http://i294.photobucket.com/albums/mm89/AWSmith1955/wtc7northafterfreefall.jpg[/qimg]

The entire building was C'd.

 

[twinstead]

The entire building was C'd.

Shhhh. The grownups are trying to have a conversation

 

[Miragememories]

"How many ways must you hear it?

NIST's Stage 1, was the period before the global collapse of WTC7 reached freefall acceleration (Stage 2). During Stage 1, for 1.75 seconds at least 8 storeys worth of lower supporting columns, across the complete WTC7 floor area, were simultaneously demolished.

Stage 1 was followed by Stage 2, a period of freefall for 2.25 seconds, clearly meaning an unobstructed global drop through those column-removed 8 storeys. A 100 foot free fall, unobstructed and unresisted.

From the videos you can see for yourself that the north face and the west face were free-falling in unity.

Vertical structural supports from the northeast corner all the way around to the southwest corner were proven by the video to have been instantly removed.

Not even a left to right progressive collapse which might have supported the NIST fantasy.

When global collapse started, the left side dropped in time with the right."

"Funny how truthers only use the video that is obstructing the portion that they allege is a cd. Lets look at it from a different angle.
Can you point out the columns being cut in this screen grab as seen almost unobstructed from the north but further east? before and after alleged CD event."

Well A W Smith I see a great deal of the smoke and debris cloud at the lower levels of WTC7.

What I do not see in your favored screen grab is NIST's critical floor 13?

Unfortunately, the image you provided does not show the lower floors where the primary demolition occurred.

It would appear that your reference picture shows the roofline down to maybe floor 17.

The smoke and debris cloud is too intense to observe any detail below the 25th floor.

MM

 

[NoahFence]

Unfortunately, the image you provided does not show the lower floors where the primary demolition occurred.

Indeed. This is because there is no "primary demolition".

 

[LSSBB]

[qimg]http://i294.photobucket.com/albums/mm89/AWSmith1955/wtc7fromnorth9plusseconds.jpg[/qimg]

Well A W Smith I see a great deal of the smoke and debris cloud at the lower levels of WTC7.

What I do not see in your favored screen grab is NIST's critical floor 13?

Unfortunately, the image you provided does not show the lower floors where the primary demolition occurred.

It would appear that your reference picture shows the roofline down to maybe floor 17.

The smoke and debris cloud is too intense to observe any detail below the 25th floor.

MM

MM, you have yet to provide proof of this "primary demolition". Where do you think all the debris from the interior went when it collapsed first (the penthouse and what was below it, remember)? What do you think that debris did when it hit the bottom?