About the concrete destruction into dust; F.R. Greening did a paper called Energy Transfer in the WTC Collapse in which he says “the energy required to crush concrete to 100 μm particles is 1.9 × 1011 J, which is well within the crushing capacity of the available energy. Hence it is theoretically possible for the WTC collapse events to have crushed more than 90 % of the floor concrete to particles well within the observed particle size range.” http://nistreview.org/WTC-REPORT-GREENING.pdf I would also investigate the possibility that the concrete was sub par due to freezing during curing or too much air or water having been added during construction.
The windows broken out and marble wall panels detached on the interior of the first floor lobby were probably because of torque forces experienced on the lower floor columns from the plane impacts many floors above. The reports of “explosions” in the cellars were also probably from such column displacements or from jet fuel ignitions in the elevator shafts. There were reports of split walls and ceiling collapses on many floors after the planes hit. Much damage was done on many floors by the planes impact deforming the structure.
In conclusion I think the reports of controlled demolition can be explained by sounds or sights produced by the plane impacts and jet fuel and air explosions; the sounds of the Towers collapses, - remember most of the people in Tower 1 did not know Tower 2 had collapsed and attributed the sounds of that collapse to be happening in the building they were in. When the interior of building 7 collapsed it would have produced explosive sounds before the exterior walls began collapsing.
(Note: You can view every article as one long page if you sign up as an Advocate Member, or higher).
