editor said:
Jazz, can you provide a remotely sane explanation as to how every single person in an entire office complex housing tens of thousands of people all failed to notice mysterious workmen installing explosives, drilling holes and running wires all over the place yet please?
Jazz, I've had some fun with explosives (being ex-army), I'm an engineer (not structural though!) I've looked at a lot of things to do with CD because I'm interested in a wide range of engineering topics. It ranges from Fred Dibnah using his burning wood supports to demolish chimneys to very complex demolitions on large high rises (20 odd floors). The larger the job the more complex it becomes.
For the larger structures you have to demolish partition walls (not a problem with the WTC), then use steel hawser to tie the outer structure to the inner. Then explosives ranging from several hundred pounds to several tonnes are applied to strategic points throughout the structure. The detonators of which have to be wired to a pretty complex timing device to set them off in the correct sequence. The order is to start at the bottom of the core and work its way up, a short delay for the collapse to start, then the charges in the outer structure are detonated, from bottom to top. The hawsers ensure that the outer structure receives forces to pull them towards the centre so that the structure collapses within it's own footprint. One key indicator of CD is multiple fracture points in the structure as it collapses.
So, where is the evidence for CD in the collapse of WTC1 or 2? There were no multiple fracture events, there were no hawsers (admittedly the floor trusses could have acted in the same way), but there was no large scale detonation at the lower levels (please try and find one witness that says there were any low level explosions, believe me they would realise when a few hundred pounds of HE goes off next to their ear drums, they could only have been less than 30m from them!
Next problem is timing - You have mentioned thermite in this discussion. there is absolutely no way that anyone can predict how quickly thermite would attack structural steel of that thickness! Then to say that they must have done it to enough columns to overcome what you say was overwhelming safety factors. If you were going to use thermite you would use it from one side to another at an angle so that you would topple a tower, clearly that didn't happen.
In terms of timing of the event and the collapse in it's own footprint ( pretty much) the only thing that could cause the collapse of the tower is the failure of the structure in a vertical plane. The simplest solution (so likeliest to be correct by Occam's Razor) is the same as the NIST report. The impact compromised the structure as a whole, though not enough to immedately cause the collapse. The fires applied >1GW of heat to the metalwork that reduced the strength of the steelwork in the damaged areas to <50% of the normal values. The perimeter columns started to deform because of the lack of support, bowing inwards (as observed in the video images). The upper structures were no longer supported and collapsed, once this started the loadings for the lower structures were exceeeded by up to 64 times. This caused failure of the joints and lower assemblies as the impulse wave propagated through the structure.
Whether the core could have stood as an individual stucture or not is really immaterial. My thought is that, over that height and area that it occupied it could have survived as a self supporting structure. There is cetainly not a hope in hell that it could have supported the entire the dead weight of the entire structure. Your post about supporting the perimeter wall if one complete side and some of the structre of the adjacent walls were removed at level 1 belied that suggestion. If it were able to do so then cutting all four walls would not have been a problem.
Not only have you failed to show that TA and Crispy's arguements have been in any way false, but you have not provided any evidence to show that CD is a viable alternative.
Please give up, you are out gunned (not by me, but by TA, Crispy, NIST, and every other rational agency involved)
