"It didn’t seem real… There are thousands of these steel beams that just fell like pickup sticks."
~ John Albanese, volunteer firefighter and amateur photographer
"What struck us – guys like Warren Jennings and myself, who have spent basically all our lives in the scrap business – we’d never seen steel this heavy, this huge, this massive. It was just unbelievable."
~ Michael Henderson (p. 93),
General Manager, Marine Terminals, Metal Management NE
To explain the unanticipated free-fall collapses of the twin towers at the World Trade Center on September 11, 2001, mainstream experts (also see The American Professional Constructor, October 2004, pp. 12–1Cool offer a three-stage argument: 1) an airplane impact weakened each structure, 2) an intense fire thermally weakened structural components that may have suffered damage to fireproofing materials, causing buckling failures, which, in turn, 3) allowed the upper floors to pancake onto the floors below.
Many will nod their head, OK, that does it and go back to watching the NBA finals or whatever, but I find this theory just about as satisfying as the fantastic conspiracy theory that "19 young Arabs acting at the behest of Islamist extremists headquartered in distant Afghanistan" caused 9/11. The government’s collapse theory is highly vulnerable on its own terms, but its blinkered narrowness and lack of breadth is the paramount defect unshared by its principal scientific rival – controlled demolition. Only professional demolition appears to account for the full range of facts associated with the collapses of WTC 1 (North Tower), WTC 2 (South Tower), and the much-overlooked collapse of the 47-story WTC building 7 at 5:21 pm on that fateful day.
The scientific controversy over the initial structural weakening has two parts: what caused the original tower damage and did that damage "severely" weaken the structures? Photos show a stable, motionless North Tower (WTC 1) after the damage suffered at 8:46 am and the South Tower after its 9:03 am impact. If we focus on the North Tower, close examination of photos reveals arguably "minor" rather than "severe" damage in the North Tower and its perimeter columns.
As many as 45 exterior columns between floors 94 and 98 on the northeast (impact) side of the North Tower were fractured – separated from each other – yet there is no direct evidence of "severe" structural weakening. None of the upper sections of the broken perimeter columns visibly sags or buckles toward its counterpart column below. We can infer this because of the aluminum covers on the columns: each seam uniformly aligns properly across the Tower, forming a horizontal "dashed line" in the façade from beveled end to end. Despite an impact hole, gaps in perimeter columns, and missing parts of floors 95–98 at the opening, the aluminum façade shows no evidence of vertical displacement in the columns, suggestive of little or no wider floor buckling at the perimeter.
The aluminum covers attached to the columns also aligned vertically after impact, that is, separated columns continued to visually remain "plumb" (true vertical), lining up top to bottom around the aperture, implying no perceptible horizontal displacement of the columns. Photographic evidence for the northeast side of the North Tower showed no wider secondary structural impact beyond the opening itself. Of course, there was smoke pouring out of the upper floors.
The fact that perimeter columns were not displaced suggests that the floors did not buckle or sag. Despite missing parts of floors 95–98, photos show no buckling or sag on other floors. If so, that boosts the likelihood that there was little damage to the core. Photos do not document what happened within the interior/core and no one was allowed to inspect and preserve relevant rubble before government authorities – primarily FEMA – had it quickly removed. Eyewitness testimony by those who escaped from inside the North Tower concerning core damage probably is unavailable.
Photos do not allow us to peer far into the interior of the building; in fact the hole is black, with no flames visible. We know that the structural core and its steel was incredibly strong (claimed 600% redundancy) making it unlikely that the core was "severely" damaged at impact. There were 47 core columns connected to each other by steel beams within an overall rectangular core floor area of approximately 87 feet x 137 feet (26.5 m x 41.8 m). Each column had a rectangular cross section of approximately 36" x 14" at the base (90 cm x 36 cm) with steel 4" thick all around (100 mm), tapering to ¼" (6 mm) thickness at the top. Each floor was also extremely strong (p. 26), a grid of steel, contrary to claims of a lightweight "truss" system.
Those who support the official account like Thomas Eagar (p. 14), professor of materials engineering and engineering systems at MIT, usually argue that the collapse must be explained by the heat from the fires because the loss of loading-bearing capacity from the holes in the Towers was too small. The transfer of load would have been within the capacity of the towers. Since steel used in buildings must be able to bear five times its normal load, Eagar points out, the steel in the towers could have collapsed only if heated to the point where it "lost 80 percent of its strength, " around 1,300oF. Eagar believes that this is what happened, though the fires did not appear to be extensive and intense enough, quickly billowing black smoke and relatively few flames.
While some experts claim that airliner impact severely weakened the entire structural system, evidence is lacking. The perimeters of floors 94–98 did not appear severely weakened, much less the entire structural system. The criminal code requires that crime scene evidence be saved for forensic analysis but FEMA had it destroyed before anyone could seriously investigate it. FEMA was in position to take command because it had arrived the day before the attacks at New York’s Pier 29 to conduct a war game exercise, "Tripod II," quite a coincidence. The authorities apparently considered the rubble quite valuable: New York City officials had every debris truck tracked on GPS and had one truck driver who took an unauthorized 1 ½ hour lunch fired.
The preliminary NIST Response claims that "the wall section above the impact zone moved downward" (pdf, p. 36) on WTC 1 but offers no evidence. It offers photographic evidence, however, for a "hanging floor slab" on the 82d floor of the South Tower at 9:55 a.m. This looks minor though because there is no sag on adjacent floors and the integrity of the structure looks very much intact. The fire looks weak too, yet the South Tower collapsed only four minutes later. This would be quite a puzzle without a demolition theory.
About a dozen of the fragmented ends of exterior columns in the North Tower hole were bent but the bends faced the "wrong way" because they pointed toward the outside of the Tower. This fact is troublesome for the official theory that a plane crash created the hole and subsequent explosion between floors 94 and 98. The laws of physics imply that a high-speed airplane with fuel-filled wings breaking through thin perimeter columns would deflect the shattered ends of the columns inward, if deflected in any direction, certainly not bend them outward toward the exterior.
A possible response would be that, well, yes, an airliner crash would bend a column inward rather than outward, if bent at all, but the subsequent force of a jet fuel blast would act in the opposite direction: any inward bends caused by plane impact would straighten toward vertical or even reverse the bent steel columns toward the exterior under blast pressure. However, such a proposed steel "reversal theory" (first bend inward by collision, then bend outward by explosion) suffers two major handicaps:
1.
No "inward-bending columns" were observed and it would be unlikely that each and every one would be reversed by subsequent explosion, and
2.
the hypothesis is ad hoc and lacks simplicity, both scientific negatives.
Occam’s razor would suggest that the outward bends in the perimeter columns were caused by explosions from inside the tower rather than bends caused by airliner impact from outside. Also supporting this theory is the fact that the uniformly neat ends of the blown perimeter columns are consistent with the linear shaped charges demolition experts use to slice steel as thick as 10 inches. The hypothesis of linear shaped charges also explains the perfectly formed crosses found in the rubble (crucifix-shaped fragments of core column structures), as well as the rather-neatly shorn steel everywhere.
