Some Misunderstandings Related to WTC Collapse Analysis

[Tony Szamboti]

Lateral translation requires a lateral load, and lateral movement of large things, like the upper 12 stories of the North Tower, would require a very large lateral load. From where I sit the only significant load acting on the upper section is due to gravity and that is a vertical load. Where does your lateral load to shift the upper section columns out of alignment with those of the lower section come from?

Come on Jeffrey, provide a scientific basis for what you are saying here. Let us see how you came to these conclusions.

You know that the small degree of rotation caused the columns to mis align and they were unrestrained connections 4' above the slab. You were shown this... but ignored it. Also the column ends were 8' below the lateral restraint and the splice connection to the column below was little more than some welded plates to align them for erection purposes. These connection failed and you had the misalignment.

I asked for a scientific basis. That isn't what you provide here.

The 1 degree tilt only causes an offset of 3/8" on the complete opposite side of the building, so no it won't cause misalignment.

So now it sounds like you are saying the splices of the core column sections which were 4 feet above the slab on the 98th floor are what failed and that they just slipped to the side and missed each other. This would still require a lateral load. So how would they do that Jeffrey? Are you actually serious that the core column splices on the 98th floor are what you think failed? If so, why would they fail? How hot would they have needed to get? And why would the columns move even if the splices did fail? The columns were in vertical compression and there was little to no lateral load such as wind or seismic forces that day.