Well I guess it's my turn now to tackle Bushido's two points. Lol you don't have to withdraw though. My conditions if I am victorious is simply that we turn the page and do a little analysis on Bin Laden and the foreign actors involved in the attack which is in my opinion one of the biggest factors in 9/11 research, and yet is easily the most overlooked.
Kinda surprised Mitspa didn't take the easy way out with the passport. Yea they found the passport, it's feasible, tons of papers and debris was found in the 9/11 wreckage. Though I guess that's just too easy, so let's get back to the collapse.
Here is a pretty interesting article I read from a college source.
The Collapse of Buildings
Now a lot of the writer's points are theory with the author implying he leans moreso towards the buildings being poorly designed, but I'd like to mostly just cite his main headings to springboard off of.
-Bad Design
-Faulty Construction
-Foundation Failure
-Extraordinary Loads
-Unexpected Failure Modes
-Combination of Causes
The article focuses more on Bad Design, I could agree to that in part, it makes rational sense into why they fell but seems to me not to fully explain why they fell as they did. For that though you can chop it up on the Combination of Causes, (ie: the impacts severed some cables, the foundation was weakened, the fires weakened the steel, and a chain reaction occurred.)
My interest in the collapse theories has been in the little talked about foundation. The foundation damage, like the fires might only be a contributing factor, but it can provide a reasonable explanation why the buildings fell straight downwards. Here is an article about the construction of the foundation of the WTC.
The World Trade Center Bathtub - HowStuffWorks
Here is a lengthier, but more interesting report by one the guys that helped originally construct part of the foundation and was part of the investigation into it after the demise of the WTC. It mostly focuses on the effort to clean up and rebuild the "bathtub" as it is called. Nevertheless it indicates indeed that the foundational structure suffered damage in the attack which does mean it's quite plausible that foundational failure played a role in the collapse of the WTC, maybe not as a primary role, but in combination with the other factors (the building design, the initial impact, the fires) it is a possible explanation as to why they fell as they did.
http://www.pages.drexel.edu/~mitcheje/Mitchell_Courses/CAEE201/CAEE201_061/Documents/Slurry%20walls%20at%20the%20world%20trade%20center.pdf