@files_walQer
Ce n’est pas "un truc sur le toit" qui tombe en premier. C’est toute la structure interne. Vous répétez sans arrêt la même chose, en ne visionnant pas les réponses qu’on vous fait : VIDEO ou simulation (et discussion) sur cette page. Et l’explication en anglais : "The fires burned out of control during the afternoon, causing floor beams near column 79 to expand and push a key girder off its seat, triggering the floors to fail around column 79 on Floors 8 to 14. With a loss of lateral support across nine floors, column 79 buckled [la colonne 79 céda] – pulling the east penthouse and nearby columns down with it. With the buckling of these critical columns, the collapse then progressed east-to-west across the core, ultimately overloading the perimeter support, which buckled between Floors 7 and 17, causing the remaining portion of the building above to fall downward as a single unit."

Dans la description de la vidéo sur YouTube, l’auteur a répondu a tout un tas d’objections récurrentes, comme au sujet de la symétrie : "WTC7 underwent a slow, internal progressive collapse. There was nothing symmetrical about it, except superficially, the last part of the collapse."

Je vous laisse aussi méditer cette remarque de Mick West sur Metabunk (avec des liens vidéo) :

The biggest challenge in debunking 9/11 myths is that the physics is a bit complicated, and yet the believers think they understand it. There’s several concepts that are difficult to convey, but the biggest two are :

1) scale and square-cube law
2) static vs. dynamic loading