yah, watching it right now... in the purdue simulation, i didn't see any cement columns in the core... they are going to light some jet fuel on fire soon.
just lit a pool of 700 gal of jet fuel and in a few min it collapsed... but it wasn't vaporized like in WTC what a croc.
Their Perdue example is totally flawed as that building is a "box frame" sort of steel "skyscraper". The spread-out support columns of a box frame (Empire State Building example) structure do usually need to be covered with concrete or wallboard and are equidistantly spaced throughout the floors intruding into all occupied floor areas. This sort of a building design system only works in small buildings or in a tall structure, if the outside and most inner columns are cross-braced (to prevent box-racking) in an very huge and heavy rigid outer concrete and masonry core like the Empire State Building.
To demolish such a primitive structure as this one must go into occupied areas and break out column-encasements to place explosives all over the place on every floor.
If you are unfamiliar with architecture, "racking" is the tendency any upper platform supported on any stick-frame assembly has to twist or bend sideways, due to torsional-twist or angular lateral stresses on the sticks supporting it. This racking tendency can only be fully cured in any one wall plane by adding "X" angular cross braces, which is anathema to the placement of windows. The alternative is massive column encasing concrete sleeves throughout and on the outside like on the old Empire State Building.
The WTC "space frame" tower design was different. It was two towers (a massive central core concrete/steel space "framed column trunk spine" and an outer steel "frame can exoskeleton") held together by the floors laterally contained within! In this design the horizontally contained solid floor-planes are the flexible spinal cross bracing!
This column-less revolution in tower design was a magnificent engineering achievement, that has won many awards and is the basis for all high tower designs now today.
Nonetheless any taller steel box frame structure must have its central elevator core which is the "spine" of the building encased in and reinforced with a hollow core-containing hollow concrete central column reinforced with rebar steel, and that was the only similarity to the WTC in the Perdue example. But it was not similar in fact, since the WTC cores outer rebar and concrete elevator core and floor support container was 5X the size and strength of what would be needed to reinforce a box frame structures hollow elevator core, since in the WTC the massive space frame column container core sleeve held both the floors and half of all their weights and loads up AND prevented much of the higher torsional (twist) and lateral (bend) racking!The tall mega-skyscraper engineering of the WTC towers was completely different than the primitive simplicity of the Perdue office building. Nobody had to go into an occupied area to expose a beam and attach explosives to it in WTC 1 or 2!
In order to provide tenants with flexible open spaces on each floor devoid of equidistant box frame support columns like the old Empire State Building (Perdue office building) system, the WTC Towers were designed as revolutionary new "space frame" structures instead. This meant that the building was supported by lighter, stronger yet more rigid floors anchored to densely powerful "outer and inner cores" only. The 2 WTC towers (not building 7) had and needed no (immovable) columns within their floor spaces other than the buildings densely reinforced central "trunk core" and the outer exoskeletal "Window Columns"!
The inner cores incredibly powerful, rigid, yet flexibly compact cross ("I beam") braced steel box "0 beam" central core frame system decreased in steel-mass density (5" thick to 2" thick) with height, while it's "trunk" and "trunk to floor" was given added "floor branch" support by a massive steel rebar reinforced concrete core column "bark tube" container. In other words the floor to core joints were totally encased in a solid massive reinforced concrete "sleeve" which held the cross-braced steel box frame core columns assembly, and the weights and loads of all floors up and resisted torsional (twist) racking.
The outer exoskeletal 'core" was a giant steel can-container approximately 5X stronger than it had to be consisting of massive equidistant steel girders. As an external "can frame" it's well distributed weight alone also held up the outer half of the floors weights and loads while innately resisting lateral "slide" racking, by virtues of both it's rigidity and its own weights!Unlike the box frame WTC7 which housed mostly political racketeers and lawless military industrial criminal spooks, WTC towers 1 and 2 could easily be pre-demolished by simply having access to it's hidden inner core alone!
The corollary to their defective "Daniel Chapter 8" asbestos liability escaping demolition plan however was the massive design strength of the WTC cores!
Simply diagonally melt-cutting the massive steel into vertically cut sections with advanced "thermate®
" heat incendiaries wouldn't cause or allow the cut core sections to "slide-over" and fall down on one another ANYWHERE because the core frames were POWERFULLY held in place horizontally by the concrete/steel rebar outer elevator-shaft floor brace anti-torque core! It had to be blown out in at least 20 heights to allow the cut steel and floor "hammers" to fall!And these twenty timed concrete-core opening explosions travelling downwards at the moment of demolition (after the early morning basement core-weight loading explosions that pre-hung the core from the can by the floors, designed to look like/coincide with the plane hits but botched) are exactly what we hear!http://www.youtube.com/watch?v=Iya_s7J7K6Y