Just because it 'looked like' something does not mean its cause must be the same. That is among the most important rules in scientific investigation. In other words, the same behaviors can have different causes.
The Windsor was not of the same construct as the WTC towers. The Windsor was of concrete construction below the 17th floor and similar steel construction to the WTC towers above the 17th floor.
Case Studies: Historical Fires: Windsor Tower Fire
Above the 17th floor, the Windsor's steel columns collapsed, just as how the WTC towers' steel columns failed. In effect, above the 17th floor, we had a smaller version of the WTC towers.
I like it when you stick to engineering which I know nothing about. But it sounds good. lol