As I said, you do have experience working with structures, but it does not sound like you have ever done design and analysis and may not be fully appreciative of some of the issues raised with the NIST WTC reports
I know the SR-71 airframe expands significantly in-flight and that is why its fuel tanks don't fully seal until after takeoff.
Then, you should have known why the WTC buildings collapsed. Remember, fire will expand and weaken an exposed steel structure to the point of failure.
Here is a case in point.
Kader Toy Factory Fire
At about 4pm on May 10th, 1993, a small fire was discovered on the first floor of part of the E-shaped building. Workers were instructed to keep working as the fire was thought to be minor. The fire alarm in this building did not sound.
The building was reinforced with un-insulated steel girders which quickly weakened and collapsed. This part of the building was dedicated to the storage of finished products and the fire spread quickly. Other parts of the factory were full of raw materials which also burnt very fast... Fire-fighters arrived at the factory at about 4:40pm, to find Building One about to collapse.
The Kader buildings,...collapsed relatively early in the fire because their structural steel supports lacked the fireproofing that would have allowed them to maintain their strength when exposed to high temperatures.
A post-fire review of the debris at the Kader site showed no indication that any of the steel members had been fireproofed.
https://en.wikipedia.org/wiki/Kader_Toy_Factory_fire
Not long ago, a small business jet rolled into a steel frame hangar in California, which stated a fire. The fire soon weakened the steel structure of the hangar which soon collapsed upon the aircraft.
Private jet crashes into hangar at California airport, sparks inferno
Santa Monica Fire Department Captain John Nevandro told NBC Los Angeles that the crash was "unsurvivable.” He added: "The building actually collapsed and wrapped itself around the plane."
http://www.nbcnews.com/news/other/p...california-airport-sparks-inferno-f8C11292403
In regard to the Windsor Building fire in Spain, the outer steel structure of the building collapsed due to fire leaving only the concrete core standing. Had the core been constructed of steel, the building would have suffered a total collapse.
Here's another account on WTC 7.
Chief Daniel Nigro's Report
Release date: September 23, 2007
Regarding WTC 7: The long-awaited US Government NIST (National Institute of Standards and Technology) report on the collapse of WTC 7 is due to be published at the end of this year (although it has been delayed already a few times [ adding fuel to the conspiracy theorists fires!]). That report should explain the cause and mechanics of the collapse in great detail. Early on the afternoon of September 11th 2001, following the collapse of WTC 1 & 2, I feared a collapse of WTC 7 (as did many on my staff).
The reasons are as follows:
1 - Although prior to that day high-rise structures had never collapsed, The collapse of WTC 1 & 2 showed that certain high-rise structures subjected to damage from impact and from fire will collapse.
2. The collapse of WTC 1 damaged portions of the lower floors of WTC 7.
3. WTC 7, we knew, was built on a small number of large columns providing an open Atrium on the lower levels.
4. numerous fires on many floors of WTC 7 burned without sufficient water supply to attack them.
For these reasons I made the decision (without consulting the owner, the mayor or anyone else - as ranking fire officer, that decision was my responsibility) to clear a collapse zone surrounding the building and to stop all activity within that zone. Approximately three hours after that order was given, WTC 7 collapsed.
Conspiracy theories abound and I believe firmly that all of them are without merit.
Regards, Dan Nigro
Chief of Department FDNY (retired)
