Elastic-inelastic analysis alone is taking momentum transfer out of context according to Gordon Ross.
Then it's a good thing that neither Bazant, Greening nor I limited ourselves only to that.
You have no calculations for energy sinks. There is no energy costing for deformations.
Please reread my calculations more carefully. I explicitly mention the energy required to demolish one floor of the WTC towers.
And you divide total mass by just 110 floors for an average. What about the five basements? Slip-shod!
The five basements have a decidedly different construction, being made almost entirely of reinforced concrete, therefore throwing off the average. Moreover, unless their mass has been added into the total mass,(which I do not believe is the case), it would be even more slip-shod to include them.
Here is [url=http://journalof911studies.com/articles/Journal_5_PTransferRoss.pdf]Gordon Ross, mechanical engineer[/url](pdf) with his summary of energy requirements for initial collapse:Quote:Energy Summary:
The energy balance can be summarised as
Kinetic energy 2105MJ
Potential energy Additional downward movement 95MJ
Compression of impacting section 32MJ
Compression of impacted section 24MJ
Total Energy available 2256MJ
Momentum losses 1389MJ
Plastic strain energy in lower impacted storey 244MJ
Plastic strain energy in upper impacted storey 215MJ
Elastic strain energy in lower storeys 64MJ
Elastic strain energy in upper storeys 126MJ
Pulverisation of concrete on impacting floor 304MJ
Pulverisation of concrete on impacted floor 304MJ
Total Energy required 2646MJ
Minimum Energy Deficit -390MJ
The energy balance of the collapse moves into deficit during the plastic shortening phase of the first impacted columns showing that there would be insufficient energy available from the released potential energy of the upper section to satisfy all of the energy demands of the collision. [...]
And Ross goes on to say that he hasn't even considered all of the probably energy sinks likely to have extinguished the "pile driver" effect at a number points during collapse.
Ross is incorrectly assuming that the structure stays together long enough to transfer the loads in the same way that the structure was designed to do.
To clarify: Ross is making the incorrect assumption that the stresses imparted to the structure on impact would transfer themselves effectively through the structure without significantly weakening the structure. This is incorrect because the upper block of storeys did not land squarely on the lower structure, but instead landed at an angle due to tilting. This meant that the weight of the upper block landed on parts of the lower structure that were never designed to transmit such a heavy load to the lower floors. These elements would have failed before passing the stresses onto the rest of the structure.
My logical reason for believing that the structure failed is that some of the columns of upper block must have fallen onto the floor structure (i.e. the composite floor deck, open web steel joists, and the beams supporting the joists), which was not designed to hold the weight of the upper block of storeys. The only parts of the structure on the lower block of storeys that were designed to carry the loads of the upper block were the columns. Since the columns of the upper block did not land exactly on the columns of the lower block, the loads were not capable of being transferred in the way that they were designed to.
Consequently, the energy requirements that Ross estimates for demolishing the structure of the lower floors are far higher than what they actually were.
And furthermore, if Szamboti's experience in structural engineering doesn't apply, then why should we care what Frank Greening, with all his degrees in chemistry, has to say about structural engineering? And if this is going to descend into a my father can beat up your father tiff, then Kevin Ryan has something to say about that.
[url=http://www.globalresearch.ca/index.php?context=va&aid=5071]9/11: Looking for Truth in Credentials: The Peculiar WTC "Experts"[/url]
I couldn't care less about anyone's credentials. Joe the Plumber could start posting here, and if his math was correct and was consistent with the empirical data, I would concede that he was correct. Szamboti could be a Nobel Prize winning structural engineer for all I care. The trouble is that Szamboti does not show his calculations.