21-09-2012, 11:12 AM
(This post was last modified: 21-09-2012, 11:28 AM by Jeffrey Orling.)
First of all, wtc 7 DID collapse... it wasn't blown to bits. We can all see that it seems to come down, much like a Las Vagas CD where the lower columns are weakened or severed with explosives... then the mass above has no support and drops down crushing itself floor by floor. WTC 7 appears to match this sort of pattern.
But careful observation gives some clues to how the actual failure leading to the collapse happened. Those clues do NOT nail the cause of what weakened to destroyed the structure down at the bottom. THAT is speculation.
The official account has been demonstrated to be incorrect and not even supported by the observations of the buildings movement in the time frame just before the collapse.
On the other hand the most common explanation I have seen from AE911T's supporters is that 8 floors of 81 columns were destroyed in an instant leaving no structural support or resistance to a collapse for 100 feet. Sounds OK but what floors are they referring to? We can't see in the vids 8 floors of columns *blown out*. So were the more or less silently severed and pushed aside all at the same instant and all hidden by the glass curtain wall with no visable or audible signs of explosives or cutting devices? The failure to demonstrate how to destroy 81 x 4 (columns were 2 stories each) or 324 columns and find actual evidence of these destroyed or severed columns is what makes THAT explanation hard to swallow.
Further... the visuals DO show some sort of progression of *failure*... the building sways east to west beginning a minute before the naked eye observations of actual destruction of parts of the tower. A few seconds before the tower descends at FF for 100' the east penthouse collapses down through the building. Anyone can see it drop from the roof. But how far did it fall? It has been determined by careful analysis of the reflections on the north facade glass that there was a FF decent of *something*... and it appears to be the East penthouse... right through the entire visible stories. This process caused the glass facade to bulge out as some sort of event took place... a pressure wave perhaps... a pulling at the floor structure which was connect to the columns at the perimeter which in turn supported the glass curtain wall... perhaps. But the take away from these observations is that after the building swayed a bit the East penthouse dropped right down through the building. It appears that whatever supported it... way down was destroyed. The East penthouse was above the East side of the core atop the infamous column 79 which was supported by the massive transfer truss #3. Column 79 did not have a footing and no foundation.. it rested on the mid span of transfer truss #3. One could / should conclude that transfer truss #3 failed. This truss was located on floors 6&7 with the bottom being at about elevation (6x13)+78' above grade and the top of it at about (8x13) 104' above grade... the truss was supported by 2 columns.. a bridge between/one them. When the truss failed column 79 has no support and drop with no resistance 104' and everything above and connected to the column 79 came down with it... a sink hole inside the building!
Almost immediately the structure to the west failed... and the West penthouse which was about transfer trusses #1 and #2 likely failed. It too plunged down through the entire height of the tower. At this moment the building was without any core columns.. with the floors like trapezoid shaped donuts with a rectangular hole were supported by the 57 perimeter columns just inside the curtain wall.
The structural failure of the core region on floors 6&7 when the 3 transfer trusses appears to have broken apart might have pulled inward at the East and West perimeter supports from floors 1-7. The design had no columns on most of the east and west sides of the tower up to floor 8. Instead there were 8 story high trusses which carried the loads of the perimeter columns on the east and west sides. There were massive and very strong and the truss design created not separate columns but an integrated structure along each side to the 8th floor... connected at floors 6&7 to the aforementioned transfer trusses. What may have happened is that when the core collapsed from the transfer truss failures those trusses pulled the east and west trusses inward and this left the columns they supported with no support. At this moment there was nothing to support ANY of the columns above.. not the core nor the perimeter.... The 8 north side perimeter columns opposite the core were not resting on foundations either. Those 8 columns were perched on the ends of massive cantilever girders which ... were supported at their south end by the north columns which also supported the transfer trusses.
I believe the south side had a fewer columns to facilitate the loading dock and at least one of the columns above was supported mid span on a mass beam. The take away here is that the design had removed columns, used trusses and was vulnerable to the structure folding inwards if those trusses failed. If that happened there was essentially no columns below floor 8 and nothing to hold the tower up or resist its descent.
I am quite confident that this explains how the collapse progressed. But what caused the transfer trusses to fail? We don't know. It certainly could be placed devices. It might be loss of strength of one truss member or one truss connection. When a truss member fails or the connection of one of the struts.. the entire truss fails. This can be seen in truss bridge failures and has happened recently in MN and CT... where rust weakened bolts or pins or splices and the truss failed and the span dropped at free fall into the river.
It seems unlikely that fire could weaken a massive truss to the point of failure. But could a diesel or gas fueled flame burning on one small location for 7 hrs weaken it enough for it to lose strength and fail the truss? I can't say one way or the other. But we do know that steel normally had fire protection for 1 or 2 hrs and there are sprinklers to cool the steel as well. In bldg 7 the latter were inoperable in 9/11 as there was both a water main rupture and loss of power to pump water for the sprinkler system.
I discovered in my research that the building's structural engineer, Irwin Cantor stated that the building came down from a truss failure and he attributes the cause to diesel fueled flames. Maybe. He also stated that the emergency generator systems were retro fits which he had nothing to do with and which were fueled by 20,000 gal of diesel stored at the site. He appears to be saying his trusses failed but the cause was a Guiliani retro fit which he was not responsible for. NIST of course, tried to make the collapse the result of office fires at flr 13 column 79... which is pure nonsense. NIST also stated that there was nothing below floor 8 of interest to them in what could have caused the tower to collapse. WRONG completely and totally wrong.
If the collapse was the result of diesel fueled flames on the transfer truss... how did they get started? We don't know.
We can speculate that the explosion(s?) Jennings and Hess reported from a location below them when they were on floor 7 in the egress stairs which were inside the core region might have ruptured the diesel or gas risers and a sparks ignited the leaking fuels. The mech floors DID contain equipment which could explode.. transformers, switch gear etc. And the mech floors were above the Con Ed sub station which contained massive oil cooled (flammable) which can and have exploded in the past.... and in NYC. Power transformer explosions are common. They can occur as a result of shorts, or overloads and so forth. The circuit protection is often not fast enough in response to prevent these explosions... a sort of slow blow fuse.. simply because they can't make them fast enough.
Electrical failures in power grids can and do cascade. We all see a blackout spread from one power station failure to the entire north eastern US. It's certainly possible that this occurred on 9/11 started by a short in tower 1 associated with the plane strike. There is a Con Ed report of a series of 8 large 13.8kv feeds going offline beginning at the moment of the plane strike at 8:46am. So they admit their down town grid was under stress and failing. They DO have the ability to divert power to prevent the entire grid from going down and that's what they did on 9/11. But there was a partial grid meltdown and it likely involved the Con Ed sub station in bldg 7 which in turn supplied the 4 building sub stations for the tenants and equipment in the tower. There was no main power or elevator power at some time BEFORE 10 am as Jennings and Hess had to take the stairs down from flr 23.
These observations support the theory that there were electrical causes explosions and that in turn kicked off diesel and natural gas fires on the mech floors where the transfer trusses were located.
This theory needs further investigation. The cause of the transfer truss failure could be placed devices... or perhaps they could be from 7 hrs of diesel and natural gas flames. I would not rule out the latter.
Food for thought.
The call to *pull back*
We should have better information on this. We don't. The reason we don't may be because the authorities FDNY, NYC DOB expected a structural failure caused by the diesel and natural gas fires. If this was the cause it could make those who designed this tower negligent for the collapse.. much like a product liablity matter. In the Ford Pinto matter the death was triggered by a rear end collision... but the outcome (death) was nailed by the design which caused the gas tanks to catch fire or explode. Ford was held to be negligent. Same deal here. Silverstein was all about collecting his insurance and wante the cause to be terrorism which was covered by his policy. Apparently he checked with his insurers that day.
DOB and FDNY called for the evacuation because they feared a collapse and didn't want an persons killed or injurred if this happened which they believed it would. Two huge towers had collapsed even though it was common knowledge that they could withstand a plane strike. Numerous explosions were heard and it was believed that there was a terrorist attack. The explosions Jennings and Hess heard were of unknown origin and there was no determination if they were bombs or equipment exploding. Why take any risks with life. They were in a wait and see mode. What were they to do? They could not fight the fires with no water mains and perhaps they were out of control in the mech floors with some steel red hot. Who knows? The FDNY and DOB had every reason to believe that the tower might come down IF their surveys showed this sort of situation in the mech floors. The correctly and prudently called all personal out of the building and the area evacuated. This is routine. When they make such a call they go to the press. They use the press to reach all the people in the area of concern to evacuate and others to stay away. The BBC got this press release.. given verbally by the commisioner and went outside and did a stand up declaring that the building had collapsed... anticipating that it would. Someone needs to ask the BBC reporter and producer if this is what happened... or why they did that story when they did. Silverstein's remark about "pull it" might have referred to the personnel inthe building trying to asses the damage... not wanting them to get killed. Who knows. A despicable character for sure. Way too much speculation is being made about the BBC report and someone needs to get the actual answer from the horse's mouth. Maybe they will lie. But someone needs to ask.
But careful observation gives some clues to how the actual failure leading to the collapse happened. Those clues do NOT nail the cause of what weakened to destroyed the structure down at the bottom. THAT is speculation.
The official account has been demonstrated to be incorrect and not even supported by the observations of the buildings movement in the time frame just before the collapse.
On the other hand the most common explanation I have seen from AE911T's supporters is that 8 floors of 81 columns were destroyed in an instant leaving no structural support or resistance to a collapse for 100 feet. Sounds OK but what floors are they referring to? We can't see in the vids 8 floors of columns *blown out*. So were the more or less silently severed and pushed aside all at the same instant and all hidden by the glass curtain wall with no visable or audible signs of explosives or cutting devices? The failure to demonstrate how to destroy 81 x 4 (columns were 2 stories each) or 324 columns and find actual evidence of these destroyed or severed columns is what makes THAT explanation hard to swallow.
Further... the visuals DO show some sort of progression of *failure*... the building sways east to west beginning a minute before the naked eye observations of actual destruction of parts of the tower. A few seconds before the tower descends at FF for 100' the east penthouse collapses down through the building. Anyone can see it drop from the roof. But how far did it fall? It has been determined by careful analysis of the reflections on the north facade glass that there was a FF decent of *something*... and it appears to be the East penthouse... right through the entire visible stories. This process caused the glass facade to bulge out as some sort of event took place... a pressure wave perhaps... a pulling at the floor structure which was connect to the columns at the perimeter which in turn supported the glass curtain wall... perhaps. But the take away from these observations is that after the building swayed a bit the East penthouse dropped right down through the building. It appears that whatever supported it... way down was destroyed. The East penthouse was above the East side of the core atop the infamous column 79 which was supported by the massive transfer truss #3. Column 79 did not have a footing and no foundation.. it rested on the mid span of transfer truss #3. One could / should conclude that transfer truss #3 failed. This truss was located on floors 6&7 with the bottom being at about elevation (6x13)+78' above grade and the top of it at about (8x13) 104' above grade... the truss was supported by 2 columns.. a bridge between/one them. When the truss failed column 79 has no support and drop with no resistance 104' and everything above and connected to the column 79 came down with it... a sink hole inside the building!
Almost immediately the structure to the west failed... and the West penthouse which was about transfer trusses #1 and #2 likely failed. It too plunged down through the entire height of the tower. At this moment the building was without any core columns.. with the floors like trapezoid shaped donuts with a rectangular hole were supported by the 57 perimeter columns just inside the curtain wall.
The structural failure of the core region on floors 6&7 when the 3 transfer trusses appears to have broken apart might have pulled inward at the East and West perimeter supports from floors 1-7. The design had no columns on most of the east and west sides of the tower up to floor 8. Instead there were 8 story high trusses which carried the loads of the perimeter columns on the east and west sides. There were massive and very strong and the truss design created not separate columns but an integrated structure along each side to the 8th floor... connected at floors 6&7 to the aforementioned transfer trusses. What may have happened is that when the core collapsed from the transfer truss failures those trusses pulled the east and west trusses inward and this left the columns they supported with no support. At this moment there was nothing to support ANY of the columns above.. not the core nor the perimeter.... The 8 north side perimeter columns opposite the core were not resting on foundations either. Those 8 columns were perched on the ends of massive cantilever girders which ... were supported at their south end by the north columns which also supported the transfer trusses.
I believe the south side had a fewer columns to facilitate the loading dock and at least one of the columns above was supported mid span on a mass beam. The take away here is that the design had removed columns, used trusses and was vulnerable to the structure folding inwards if those trusses failed. If that happened there was essentially no columns below floor 8 and nothing to hold the tower up or resist its descent.
I am quite confident that this explains how the collapse progressed. But what caused the transfer trusses to fail? We don't know. It certainly could be placed devices. It might be loss of strength of one truss member or one truss connection. When a truss member fails or the connection of one of the struts.. the entire truss fails. This can be seen in truss bridge failures and has happened recently in MN and CT... where rust weakened bolts or pins or splices and the truss failed and the span dropped at free fall into the river.
It seems unlikely that fire could weaken a massive truss to the point of failure. But could a diesel or gas fueled flame burning on one small location for 7 hrs weaken it enough for it to lose strength and fail the truss? I can't say one way or the other. But we do know that steel normally had fire protection for 1 or 2 hrs and there are sprinklers to cool the steel as well. In bldg 7 the latter were inoperable in 9/11 as there was both a water main rupture and loss of power to pump water for the sprinkler system.
I discovered in my research that the building's structural engineer, Irwin Cantor stated that the building came down from a truss failure and he attributes the cause to diesel fueled flames. Maybe. He also stated that the emergency generator systems were retro fits which he had nothing to do with and which were fueled by 20,000 gal of diesel stored at the site. He appears to be saying his trusses failed but the cause was a Guiliani retro fit which he was not responsible for. NIST of course, tried to make the collapse the result of office fires at flr 13 column 79... which is pure nonsense. NIST also stated that there was nothing below floor 8 of interest to them in what could have caused the tower to collapse. WRONG completely and totally wrong.
If the collapse was the result of diesel fueled flames on the transfer truss... how did they get started? We don't know.
We can speculate that the explosion(s?) Jennings and Hess reported from a location below them when they were on floor 7 in the egress stairs which were inside the core region might have ruptured the diesel or gas risers and a sparks ignited the leaking fuels. The mech floors DID contain equipment which could explode.. transformers, switch gear etc. And the mech floors were above the Con Ed sub station which contained massive oil cooled (flammable) which can and have exploded in the past.... and in NYC. Power transformer explosions are common. They can occur as a result of shorts, or overloads and so forth. The circuit protection is often not fast enough in response to prevent these explosions... a sort of slow blow fuse.. simply because they can't make them fast enough.
Electrical failures in power grids can and do cascade. We all see a blackout spread from one power station failure to the entire north eastern US. It's certainly possible that this occurred on 9/11 started by a short in tower 1 associated with the plane strike. There is a Con Ed report of a series of 8 large 13.8kv feeds going offline beginning at the moment of the plane strike at 8:46am. So they admit their down town grid was under stress and failing. They DO have the ability to divert power to prevent the entire grid from going down and that's what they did on 9/11. But there was a partial grid meltdown and it likely involved the Con Ed sub station in bldg 7 which in turn supplied the 4 building sub stations for the tenants and equipment in the tower. There was no main power or elevator power at some time BEFORE 10 am as Jennings and Hess had to take the stairs down from flr 23.
These observations support the theory that there were electrical causes explosions and that in turn kicked off diesel and natural gas fires on the mech floors where the transfer trusses were located.
This theory needs further investigation. The cause of the transfer truss failure could be placed devices... or perhaps they could be from 7 hrs of diesel and natural gas flames. I would not rule out the latter.
Food for thought.
The call to *pull back*
We should have better information on this. We don't. The reason we don't may be because the authorities FDNY, NYC DOB expected a structural failure caused by the diesel and natural gas fires. If this was the cause it could make those who designed this tower negligent for the collapse.. much like a product liablity matter. In the Ford Pinto matter the death was triggered by a rear end collision... but the outcome (death) was nailed by the design which caused the gas tanks to catch fire or explode. Ford was held to be negligent. Same deal here. Silverstein was all about collecting his insurance and wante the cause to be terrorism which was covered by his policy. Apparently he checked with his insurers that day.
DOB and FDNY called for the evacuation because they feared a collapse and didn't want an persons killed or injurred if this happened which they believed it would. Two huge towers had collapsed even though it was common knowledge that they could withstand a plane strike. Numerous explosions were heard and it was believed that there was a terrorist attack. The explosions Jennings and Hess heard were of unknown origin and there was no determination if they were bombs or equipment exploding. Why take any risks with life. They were in a wait and see mode. What were they to do? They could not fight the fires with no water mains and perhaps they were out of control in the mech floors with some steel red hot. Who knows? The FDNY and DOB had every reason to believe that the tower might come down IF their surveys showed this sort of situation in the mech floors. The correctly and prudently called all personal out of the building and the area evacuated. This is routine. When they make such a call they go to the press. They use the press to reach all the people in the area of concern to evacuate and others to stay away. The BBC got this press release.. given verbally by the commisioner and went outside and did a stand up declaring that the building had collapsed... anticipating that it would. Someone needs to ask the BBC reporter and producer if this is what happened... or why they did that story when they did. Silverstein's remark about "pull it" might have referred to the personnel inthe building trying to asses the damage... not wanting them to get killed. Who knows. A despicable character for sure. Way too much speculation is being made about the BBC report and someone needs to get the actual answer from the horse's mouth. Maybe they will lie. But someone needs to ask.