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Thread: Building a Case Against Controlled Demolition, Inc.

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    There were no planes. The fires were minimal and localized and
    mostly smoke, few flames.

    Quit quoting the Official Conspiracy Theory.

    Jack

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    Jack,

    I am not quoting anything. Could you elaborate on your last post kindly?

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    Hello.
    Just bringing this back up to see if anyone has any new input.
    Regards,
    Bruce
    "If you're looking for something that isn't there, you're wasting your time and the taxpayers' money."

    -Michael Neuman, U.S. Government bureaucrat, on why NIST didn't address explosives in its report on the WTC collapses

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    I've recently turned my attention from the destruction of the twin towers to that of bldg 7. If the twins can be shown to not be a controlled demolition (I think there is a good case that this is so)... then it makes little sense that B7 was a CD. On the other hand... if the twins were CD it seems to suggest B7 was but not necessarily so.

    Whatever the actual cause which *kicked off* the collapse of the twins, there is no evidence that once it began explosives were involved. What many see as explosive ejections of materials as the collapse progresses downward are actually materials ON the floors.. walls, ceiling tiles, office contents and people if they were still on those floors ... forced outward through and breaking the windows... by a massive over pressure created when 18,000 cu yards of air on each floor was forced out of the way of the collapsing debris from above. The path of least resistance was through the windows and so with winds approaching 400 miles/hr a storm of enormous power hit each floor and evacuated everything on it in .1 second destroying it in the process.

    The floors collapsed because when the tops lost their support at the zone of the plane impacts tens of thousands of tons of materials (floors and contents above) rained down and brcame the violent avalanche of broken and eventually crushed to dust to the bottom.

    Physics and engineering can account for the collapse phase. But what caused the impact zone to collapse?

    The columns could have been blasted or cut with incendiary devices. But we know from some of recovered steel that many of the columns at the plane strike/collapse zone buckled. One is the famous horse shoe column. That sort of buckling means that the column was seeing way more load than its yield strength... so it buckles.

    What would make a column acquire loads exceeding its yield strength? If anything the building was getting lighter from the plane damage and fire. The answer is there were several possible factors.

    1. Heat does weaken and lower the yield strength of steel. More heat lowers it more. We don't know how much heat and so how much yield strength was lost, but heat lowered the strength of the columns.

    2. Load redistribution. When the planes struck the towers they destroyed a number of columns. This meant that the remaining ones had to carry all the weight of the floors above them. If the remaining columns held it meant that they had sufficient strength to carry the redistributed loads.

    3. Increased its unbraced length. The effective length of the twins columns were just under 12' the floor to floor dimension. The column segments were 36' long and stacked to the full height of the tower. But the floor beams/truss which supported the floors also provided the bracing for the columns.. reducing the unbraced length to about 12'. If the bracing is removed... the yield strength of a given column section is reduced. A steel column cannot even support its own weight when the ratio of the shortest plan dimensions is less than 1/150 its length. So a steel column of say... 150 feet tall by 12"x12" would not stand on its own... it would be unstable and actually buckle just as if too much load were placed on the top. But buckling from extra loads likely didn't occur... but a reduction in yield strength when some of the floors with the bracing collapsed effectively doubling or perhaps tripling the unbraced length from 12 to 24 to 36'.

    So there are few mechanisms in play... lowering the yield strength by heating (or cutting away at its cross section), taking on additional load from redistribution of the loads from the failed columns.... and lowering of the yield strength from loss of bracing.

    Here we need to consider some additional aspects of the structural design. That is columns size, placement and the designed in factor of safety. If the factor of safety was 2 a column is only carrying half the load it is capable of. However, extra weight and therefore extra strenght and increased FOS is expensive and it's cumulative as you progress down the tower. If you add 1000 pound per floor for whatever reason... the bottom floor needs to support an additional 110 x 1000 or 110,000 pounds and so on. Saving weight meant saving money and small columns - more usable floor space.

    Most steel framed skyscrapers have an FOS of about 1.5. It appears that the twins average FOS was somewhere between 1.65 and 1.85 perhaps some columns had and FOS of 2. FOS is of course related to the actual loads. So practically speaking... when the tower is occupied by 20 thousand people... their weight lowers the FOS. But the live load contribution/variations is so small as to not be a real factor for the FOS.

    The design of the core columns meant that some columns were supporting more floor loads than others. The 23 central core columns carried only the corridors within the core and some space used by tenants above elevator shafts. The 24 columns around the perimeter of the core were not equally spaced and the 4 corners carried half the 35' x 60' corners of the floors... an area more than 2x larger than any other column supported. So the columns were not equal in strength... because they were not carrying equal loads. Accordingly if a small column were destroyed it would *offload* for redistribution a smaller load than if one of the larger columns were destroyed.

    6.84% 4.17% 5.03% 3.67% 3.27% 4.96% 4.17% 6.84%
    2.32% 2.32%
    2.67% % of axial floor loads carried 2.46%
    2.32% 2.48%
    2.32% 2.32%
    7.02% 4.32% 5.72% 5.16% 3.06% 5.23% 4.32% 7.02%


    The above is the approximate load carrying distribution/percentages of the perimeter of the core. Each of the 236 facade columns essentially carried (though again not precisely) 1/236 x .54 of the perimeter columns of core's total load. The facade actually supported about 54% of the floor load and the core 46%.

    When a column fails its load shifts to the adjacent columns. You can see the implication of the failure of the corner columns... it would immediately also fail the column on the short side of the core adjacent to it...and so on.

    Columns will stand as long as the FOS remains above 1... The weakening process is eroding FOS. When FOS drops below 1 the last remaining columns buckle the structure above come crashing down. This is the *rapid onset* seen in structural failures... it is the moment the FOS has gone below 1.

    Back to Bldg 7.

    Rather than critique NIST's mistaken explanation... observation shows that B7 also had a core failure.. again the precise cause is indeterminate because we can't see the what was going on. But we do know that the structure and design of B7 had some unusual features, to say the least.

    1. Part of the core in the office tower part... was supported in 3 massive transfer trusses... because the columns could not extend straight down directly to the foundations... the Con Edison sub station was in the way. This was essentially like building the core for the tower on a bridge span. Bridge goes core aboce drops... drops 8 floors to the ground. Sub station is structurally transparent... no alignment with the core columns to resist their descent.

    2. Whatever failed the trusses.. also failed 8 huge girders which supported the columns opposite the north side of the core at the perimeter just inside the curtain wall.

    3. Failure of the trusses and the girders will cause the north columns AND the core to fall with little to nothing in the way to resist... hello free fall.

    4. A possible scenario is that the truss and girder failure collapse the lowest 8 floors just before the upper 41 stories drop down.

    5. While the cause of this failure could be CD devices... consider the following:
    a. the B7 sub station might have exploded. Upon impact of the plane in tower 1 the sub station in B7 lost power instantly ... published in a Con Ed after report. This could have been a short, a voltage spike and caused the transformers to overheat and release flammable oil and explosive gas - POW... Jennings and Hess encounter explosions from BELOW the 8th floor BEFORE tower 1 descends to tjhe ground when they were at level 6/7 in B7. Transformer explosions?

    b. flrs 4,5, 6&7 in B7 contained diesel tanks and HVAC equipment, emergency diesel fueled power generators and high voltage electrical switch gear. When Jennings and Hess descended there was no power to the elevators (emergency power is not the DC used for elevator motors). But the emergency generator power ran the pumps to replenish the day tanks on 6&7. Is it possible that the fuel was leaking and burning all day... consuming thousands of gallons of diesel and slowly cooking the transfer trusses and cantilever girders? I think it's a good possibility. Slowly the trusses' steel was growing weaker. One truss chord or panel fails.. and the whole truss immediately collapses. Truss collapses core above falls... tower *implodes* inward no structure remains below floor 8.

    What caused the trusses and transfer girders to fail? Heat from 8-10 hrs of diesel fires? Damage from from exploding transformers from the sub station just below? Planted bombs or devices?

    Careful study of the movement of B7 indicates a core failure and below floor 8... where there were no office contents to be burning.

    Why put a tower above a sub station? Why support part of a tower's core on 3 transfer trusses? in proximately to diesel tanks with a 20,000 gal supply?

    Whether or not there was a CD initiation... there were some boneheaded decisions made when the towers were designed and built.

    Boneheaded is not a legal term... negligence is.
    Last edited by Jeffrey Orling; 05-16-2012 at 09:39 AM.

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