Some Misunderstandings Related to WTC Collapse Analysis

[Tony Szamboti]

Video analysis shows that WTC 7 was in free fall acceleration for the first 100 feet of its vertical drop. This is impossible in a natural collapse.

Is there video of a natural collapse of a sky scraper for comparison purposes?

A few points here.

The most detailed analysis done shows that the 100 foot descent of the curtain wall was neither completely smooth and has periods of above and below G.

There was movement which began about 7 - 10 seconds (don't recall) BEFORE the clocked 100' 2.25 second descent... indicating that the so called "collapse of the entire building" did not begin with the motion of the curtain wall and was in fact not at FF. The take away is the FF doesn't "mean" anything.

There are no "natural collapses" ever. That is unless you consider that forces of nature including erosion as natural causes. The Miamus River bridge and the Takoma narrows collapses were from corrosion weakening a pin in the CT collapse and wind pressure causing the structure to vibrate at its harmonic frequency and break apart.

In the case of the WTC we are asked to believe that mechanical damage from the planes hitting the two tower and fire which heated parts of the frame and weakened them below their design load capacity such that they failed leading to a (natural) load redistribution... which caused other nodes to fail leading a further redistribution of loads leading to more failures until there was insufficient axial capacity to support the loads and the tops came down and apart as they did and this drove the destruction of the floor systems which robbed both the facade and the core of the bracing required to stay erect and they too buckled. The progress WAS "natural" in that it's what engineering and physics predicts and describes.
But the plane damage and fires are not natural, or typical either in scope or magnitude and so they became the proximate causes initiating the collapses. Gravity was the main driving force.

7WTC was a bit different in that it had massive load transfer structures which redirected the column loads from above to bedrock. It appears that these massive structures located between flrs 5&7 may have failed a victim of the fact that they were constructed of massive steel will less massive connections and splices. These connections may have been the undoing of the massive structures which again weakened the nodes to below their design load capacity such that they failed leading to a (natural) load redistribution... which caused other nodes to fail leading a further redistribution of loads leading to more failures until there was insufficient axial capacity to support the loads. This is not the NIST explanation or theory. It is mine and I refer to it as TTF - transfer truss failure. The amount of heat down in the region in question has not been determined... hence the need for further investigation. But if the connections failed, the trusses would and that would lead to the visuals we have of the collapse. The fires were not fought. We don't know the fuel source and there is much to be determined. NIST refused to examine anything below flr 8. That seems odd to me.

But in conclusion... once axial load capacity has been eroded to below the design capacity of a node, it fails and this can and apparently lead to eventually global collapse. The progressive failure is a natural and predicted process. Whether one wants to call un fought fires natural or not as a cause... is another thing.

And true... we have no other visuals of large buildings collapsing without the INTENT to bring them down. In nature we have things like avalanches and rock slides... which are gravity driven natural collapses.

Your theory cannot produce a symmetric free fall of the entire building for eight stories, so it is nonsense and you shouldn't even be saying it.

People should use their common sense and ask themselves if a truss failing due to fire here and then one due to overload over there and another one would produce a symmetric free fall like that observed with WTC 7. In case everyone doesn't understand

symmetric means all at the same time

free fall acceleration is the full rate of gravity which is only possible with no resistance. This occurred for eight stories or just over 100 feet at the beginning of the collapse.

The symmetric free fall was due to eight stories of the core being removed simultaneously via controlled demolition.