Oh here we go
My point was they could have placed those explosives throughout the building. I only mentioned the basement incident because they had gained access once before as it was.)
Did I say that "ALL" buildings are designed to come straight down? Or that "NO" high rises ever topple? No. Doing some more reading however I think I may have been a bit off. The main reason it fell straight down was weight and inertia.
You had a few critical damage points, which it could withstand, but then when the heavily damaged floors collapsed, the outer "box" structure bowed outward, resulting in the floors directly above falling on top of the collapsed floors. That whole mess then slammed downward onto the floor below, well above its limit. It then fails, dropping everything down to the next floor, which then also collapses, etc, resulting in the domino effect that we saw. The only way for it to topple instead of come straight down was to either blow one side of the building completely away and a lot further down to get that sideways motion going. That wasn't going to happen easily, not with the building design. And with the aircraft impacts pretty far up the buildings the chances of it going sideways was next to none. There were no notable lateral forces involved when it started to come down. Simply one floor smashing into the next floor below it.
There is simply no way this would have happened in a perfectly uniform way due to the plane. The damage from the impact was all on one side, the fire was on that side, yet the collapse of both buildings was perfectly symmetrical.
BTW, the building took about 10 seconds to fall at a final impact speed about about 125 mph. Free fall would have been under 8 seconds at over 180 mph.
Good reading about the structural design of the buildings, its strengths that allowed it to withstand such a massive initial impact, and the physics behind the buildings' collapse.
http://www.tms.org/pubs/journals/jom/0112/eagar/eagar-0112.html
An interesting read. Pretty much all his key points are in the section "The collapse".
"This started the domino effect that caused the buildings to collapse within ten seconds, hitting bottom with an estimated speed of 200 km per hour. If it had been free fall, with no restraint, the collapse would have only taken eight seconds and would have impacted at 300 km/h"
The WTC towers were 417m tall. Using an acceleration due to gravity calculator, they would have taken 9.22 seconds to completely collapse, not 8 seconds, never mind the fact that he's clearly rounding to exaggerate his point. I would expect a collapse from a controlled demolition to be slightly slower than a pure free fall.
" First, the building is not solid; it is 95 percent air and, hence, can implode onto itself. "
Well, yes. That's why controlled demolitions are possible.
"Second, there is no lateral load, even the impact of a speeding aircraft, which is sufficient to move the center of gravity one hundred feet to the side such that it is not within the base footprint of the structure. Third, given the near free-fall collapse, there was insufficient time for portions to attain significant lateral velocity. To summarize all of these points, a 500,000 t structure has too much inertia to fall in any direction other than nearly straight down."
Pretty much all of this is proven false by the fact that some high rise buildings do topple over. The laws of physics don't change because the towers were larger than other high rises.
He doesn't address WTC 7 at all.