Reply #26: DUH

[blackowl]

“"pull it' refers to pulling the NYFD back as the building was lost.”

So there’s no confusion about the context;)

<http://webfairy.911review.org/911/pullit/pull-it2_lo.wmv>

“it burned for 7 hours and was NOT a 'small fire'”



“The total collapse of Building 7 is officially blamed on fires.

This would be the first case in history in which fires alone were blamed for the total destruction of a steel-frame high-rise.

The fires in Building 7 were not severe:
· Limited to isolated regions of 2 floors
· No broken glass on north side
· Puny compared to other building fires

“apparently you don't live in NYC. it was fueled by diesel stored in the building.”

What Caused Building 7's Collapse?

This question would appear to be the greatest in engineering history. In over 100 years of experience with steel frame buildings, fires have never caused the collapse of a single one, even though many were ravaged by severe fires. Indeed, fires have never caused the total collapse of any permanent steel structure.

What was done to answer this most important question? The only official body that admits to having investigated the curious collapse of Building 7 is FEMA's Building Performance Assessment Team (BPAT), which blamed fires for the collapse but admitted to being clueless about how fires caused the collapse.

People who have seen buildings implode in controlled demolitions are unlikely to be as challenged as FEMA's team in understanding the cause of Building 7's collapse. They will notice, upon watching the videos, that Building 7's collapse showed all of the essential features of a controlled demolition.

Despite having the appearance of a controlled demolition, is it possible that Building 7 could have been destroyed by some combination of damage from tower debris, fuel tank explosions, and fires? Let's consider the possible scenarios.

The evidence does not support the idea that Building 7 was damaged by fallout from the tower collapses, nor that there were diesel fuel tank explosions. Fires were observed in Building 7 prior to its collapse, but they were isolated in small parts of the building, and were puny by comparison to other building fires. Let's imagine, contrary to the evidence, that debris from the tower collapses damaged Building 7's structure, that diesel fuel tanks exploded, and that incredibly intense fires raged through large parts of the building. Could such events have caused the building to collapse? Not in the manner observed. The reason is that simultaneous and symmetric damage is needed to produce a collapse with the precise symmetry of the vertical fall of building 7. This building had 58 perimeter columns and 25 core columns. In order to cause the building to sink into its footprint all of the core columns and all of the perimeter columns would have to be broken in the same split-second.

Any debris from the towers impacting Building 7 would have hit its south side, and any columns damaged by it would almost certainly be perimeter columns on its south side. Any fuel tank explosion would only be able to damage nearby structure. The rapid fall-off of blast pressures with distance from the source would preclude any such event from breaking all of the columns in the building.

Building 7 was about 5 times as tall as it was deep.

(Furthermore the very idea of a tank of diesel fuel exploding taxes the imagination, since diesel fuel does not even begin to boil below 320 degrees F. 1) Fires have never been known to damage steel columns in highrise buildings, but if they could, the damage would be produced gradually and would be localized to the areas where the fire was the most intense.

No combination of debris damage, fuel-tank explosions, and fires could inflict the kind of simultaneous damage to all the building's columns required to make the building implode. The precision of such damage required to bring Building 7 down into its footprint was especially great given the ratio of its height to its width and depth. Any asymmetry in the extent and timing of the damage would cause such a building to topple.

“Your characterization of the fires from jet aircraft, fully laden with fuel, exploding into buildings full of combustible materials as "small"
is breathtaking.”

I was referring to WTC7

“Wow, so the computer graphics aren't completely correct”

Not only are they not “completely correct”, they are highly deceptive.

Again:

o Omits cross-trusses, which would spoil zipper effect.
o Implies floors rested on trusses. In fact, trusses were bolted to steel floor pans every few inches.
· structural schematic:
o Core depicted as horizontal slabs instead of vertical columns.
o Spandrell plates linking perimeter columns are omitted.

“The official explanation that fires caused the collapse of Building 7 is incredible in light of the fact that fires have never caused a steel frame building to collapse, before or after September 11th.

Steel-frame highrises (buildings of fifteen stories or more) have been widespread for over 100 years. There have been hundreds of incidents involving severe fires in such buildings, and none have led to complete collapse, or even partial collapse of support columns.

The Interstate Bank Building fire consumed several floors but did not damage the steel superstructure.

Recent examples of highrise fires include the 1991 One Meridian Plaza fire in Philadelphia, which raged for 18 hours and gutted 8 floors of the 38 floor building; 1 and the 1988 First Interstate Bank Building fire in Los Angeles, which burned out of control for 3 1/2 hours and gutted 4 floors of the 64 floor tower. Both of these fires were far more severe than any fires seen in Building 7, but those buildings did not collapse. The Los Angeles fire was described as producing "no damage to the main structural members". 2

Research indicates that even if a steel frame building were subjected to an impossible superfire, hundreds of degrees hotter and far more extensive then any fire ever observed in a real building, it would still not collapse. Appendix A of The World Trade Center Building Perfomance Study contains the following:

In the mid-1990s British Steel and the Building Research Establishment performed a series of six experiments at Cardington to investigate the behavior of steel frame buildings. These experiments were conducted in a simulated, eight-story building. Secondary steel beams were not protected. Despite the temperature of the steel beams reaching 800-900 C (1,500-1,700 F) in three of the tests (well above the traditionally assumed critical temperature of 600 C (1,100 F), no collapse was observed in any of the six experiments).

In actual building fires, steel beams and columns probably never exceed 500 C. In extensive fire tests of steel frame carparks conducted by Chorus Construction in several countries, measured temperatures of the steel columns and beams, including in uninsulated structures, never exceeded 360 C. 3