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Originally posted by thedman
and "two huge jetliners" are not a legitimate destructive force to explain why all 3 towers collapsed
So 2 airliners weighing in at 350,000 lbs and hitting building at 500 + mph
are not destructive?
10,000 gallons of burning jet fuel cascading through the buildings not
destructive?
Top of skyscaper falls on adjacent building is not destructive enough?
What haven't accounted for is synergistic effect - aircraft impacts
damaged many of the supports columns and at same time set numerous
fires over multiple floors. Aircraft impact and associated secondary
debris knocked off fireproofing on the steel support columns exposing
them to fire. Impacts also knocked huge holes in building which allowed
air to feed fires .
The Banker's Trust building was half the distance from the collapsing south tower as WTC7 was from the north tower, yet sustained much less damage than NIST claims was sustained by the much more distant WTC7 - certainly nothing comparable to 1/3 of the WTC7 south face and 25% of the building gouged out, which would equate to 2/3 or more of the face of the Banker's Trust building. The photograph in Fig. 10a also shows a path of perimeter columns laid out leading to the face of the Bankers Trust, suggesting that a large, interconnected portion of the south face of WTC2 fell into it. Figures 13c and 13d below show that no such path of heavy interconnected perimeter debris leads to the critical portion of WTC7's south face, and indeed, a fragile pedestrian bridge in that region was still quite intact after the collapse of the north tower.
Originally posted by poet1b
I came to my own conclusion long ago. The Towers could not have collapsed the way they did from the 747 strikes. All the evidence supports this. Tower 7 simply should not have collapsed. This is not how buildings burn down. Many people still buy the official line of how Kennedy was assasinated, whe all the film footage, and thre reports of the witnesses say differently, as well as the evidence.
Originally posted by Lebowski achiever
The damage sustained at WTC 7 is largely anecdotal and little photographic evidence has surfaced. The photographic evidence existing today does not support the accounts from eyewitnesses. Which is not surprising as people's recollection is always shakey.
Originally posted by Lebowski achiever
I think firefighter's reports may be credible but is still annecdotal.
If they were, then what of the people who have heard explosions before the collapse of WTC 1 and 2? They are also discredited by nay sayers. Even some of those were firefighters, too.
This type of construction, with terra cotta tiles providing fire protection, was common in early 20th century construction. The style of construction resulted in a highly compartmentalized building, which may have helped slow the spread of fire. The Fire Department of New York was able to control the fires in this building. The fire damage observed in the building, with minimal structural damage from a normal fire load, is considered typical for this type of construction and fire protection; however, it has been suggested that the scaffolding that was in place for renovations contributed to the spread of fire between floors that may not have occurred otherwise. However, the only structural damage observed was buckling damage near the tops of two columns.
The east (Washington Street) side of the building was damaged from about the 9th floor down, primarily due to the impact of debris sliding out from the base of WTC 7 (Figures 7-6, 7-7, and 7-8). Some damage may have also been caused by WTC 1 debris. In addition to fairly extensive facade damage (bricks and windows), there was damage to two bays of slab and framing at the 1st, 4th, and 7th floors and to one bay of slab and framing (including spandrel beam) at the 1st floor mezzanine and at the 5th floor. Two exterior columns suffered major damage between the 1st and 2nd floors (Figure 7-9), one exterior column suffered minor damage between the 3rd and 5th floors, and two exterior columns suffered major damage between the 6th and 8th floors. In addition, one interior column suffered minor damage below the 7th floor.
Steel-frame construction from the 1900s through the 1980s, though different in many details, performed well under significant impact loads by limiting impact damage and progressive collapse to local areas.
Heavy unreinforced masonry facades were observed to absorb significant amounts of impact energy in the Verizon and 90 West Street buildings. Heavy masonry facades like those in the Verizon, 90 West Street, or even 130 Cedar Street buildings may also provide an alternative load path for a damaged structure.
Older, early-century fireproofing methods of concrete-, brick-, and terra cotta tile-encased steel frames performed well, even after 90+ years, and protected the 90 West Street building from extensive structural damage.
You said many of the buildings closer did not collapse - it depended on
what hit the building and type of construction. Older buildings fared
better than newer constuction. Older mod buildings were better using
heavier materials, fireproofing was concrete or terra cotta masonary
not light coating of mineral "mud".
Originally posted by exponent
Originally posted by poet1b
I came to my own conclusion long ago. The Towers could not have collapsed the way they did from the 747 strikes. All the evidence supports this. Tower 7 simply should not have collapsed. This is not how buildings burn down. Many people still buy the official line of how Kennedy was assasinated, whe all the film footage, and thre reports of the witnesses say differently, as well as the evidence.
If you came to your conclusion while believing the towers were hit by 747s you must have done no research at all.
Originally posted by Lebowski achiever
The damage sustained at WTC 7 is largely anecdotal and little photographic evidence has surfaced. The photographic evidence existing today does not support the accounts from eyewitnesses. Which is not surprising as people's recollection is always shakey.
Please read NISTs latest report, it includes firsthand accounts from firefighters of severe structural damage to WTC7. It also includes a detailed photo analysis and a map of suspected damage. None of this is 'largely anecdotal' and supersedes the link you posted.
The Bankers Trust building at 130 Liberty Street, also referred to as the Deutsche Bank building, withstood the impact of one or more pieces of column-tree debris raining down from the collapsing south tower (WTC 2). Although the debris sliced through the exterior facade, fracturing spandrel beam connections and exterior columns for a height of approximately 15 stories, the building sustained only localized damage in the immediate path of the debris from WTC 2 (hereafter referred to as the impact debris) (Figures 6-1 and 6-2). There were no fires in this building. The ability of this building to sustain significant structural damage yet arrest the progression of collapse is worthy of thorough study. Unlike WTC 1, 2, and 7, which collapsed completely, the Bankers Trust building provided an opportunity to analyze a structure that suffered a moderate level of damage, to explain the structural behavior, and to verify the analytical methods used. The following sections describe the building structure, the extent of damage, and the computational methods that were used to analyze the structure.
The structural steel sections were fireproofed with a spray-applied non-asbestos fireproofing material. The thickness on the beam flanges was observed to be on the order of 1/2 inch thick. Many of the rolled steel shapes appeared to be almost completely bare of fireproofing where directly impacted by debris; the remainder of the fireproofing appeared intact even in the damaged areas. Because fires were not ignited in combination with this structural damage, the damaged fireproofing did not affect the performance of the building.