Much respect for digging up this information, however, you have not answered my question.
I asked..."Where did NIST explain the RAMIFICATIONS of free fall"
What ramifications? I wasn't aware there were any.
As for detailed explanation (a different matter I think) here is what they wrote under 'Global Collapse', Chapter 12, pp 586, 587, 588 NCSTAR 1-9 Vol 2
It explains the 'why'. I haven't seen any detailed, engineering-based refutation of this model and analysis - lots of blanket denials and hand-waving, of course, but anybody can say 'it couldn't have happened' without the burden of actually refuting the details.
In much the same way, a child can say 'rocket flew up into the sky' without having the foggiest idea of the details; a truther can say 'freefall = controlled demolition with the same deficit of facts and knowledge.
'Global Collapse
After the horizontal progression of column buckling in the core of WTC 7, the exterior columns buckled
at the lower floors, completing the global collapse sequence as follows:
• As the interior columns failed, the exterior columns on the west face buckled inward at the
lower floors as a result of floor pull-in forces due to the downward movement of the building
core. The floor connections to the columns had not failed in this region because there were no
fires observed on the west side on Floors 10 through 14 at any time during the day, and the
intact floors were able to pull the exterior columns inward.
• Exterior column buckling began at Column 14, adjacent to the debris impact zone near the
southwest corner, between Floors 10 and 12. The exterior columns adjacent to the seven
columns severed in the southwest region due to the collapse of WTC 1 were the first to
buckle because additional load was distributed to them following the debris impact damage.
• The south and west exterior columns buckled first, followed by the north and east face
columns.
• All exterior columns buckled between approximately Floors 7 and 14.
• Once column support was lost in the lower floors, the remaining exterior structure above
began to fall vertically as a single unit.
The buckling of the interior columns in the global collapse analysis was followed by the buckling of the
exterior columns.
Figure 12–60 shows a schematic view of Floor 8 that highlights the exterior columns that were used to
track the column load history for each face. Also noted on the figure is the debris impact zone from the
collapse of WTC 1, which shows the southwest columns that were severed. Loads were extracted just
above Floor 8 for three columns per face and were averaged to generate the loads shown in Figure 12–61.
Figure 12–61 shows that selected exterior column forces increased as gravity loads were applied
(compressive loads are negative). As indicated at 4.5 s (LS-DYNA calculation time), there was an
increase in compressive forces on the west and south faces of the building after debris impact damage was
applied. As Columns 79, 80, and 81 buckled and the floor systems failed on the east side of the building
(at 15 s to 16 s), column forces reduced in the north and east faces. The west face column forces were
dominated by the forces in Column 14, which was adjacent to the severed columns in the southwest
corner. At 21.5 s, exterior column buckling began at Column 14, between Floors 10 and 12. The exterior
columns adjacent to the (seven) columns severed in the southwest region due to the collapse of WTC 1
were the first to buckle due to the increased forces in these columns following the debris impact damage.
The south and west face columns buckled first, followed by the north and east face columns.
The floor connections to the west face columns had not failed above Floor 9 because no fires were
observed on the west side of Floors 10 through 14.
The intact floor framing pulled the exterior columns
inward as the interior columns fell downward during the horizontal progression of failure stage and the
floors pulled on the exterior columns. As the interior columns buckled across the building, the exterior
columns were left laterally unsupported normal to the east, south, and north faces.
Exterior column
buckling spread from column to column, as loads were redistributed, until all the exterior columns had
buckled between Floors 7 and 14 within approximately 2 s.
When all the exterior columns had buckled, as shown in Figure 12–62, the entire building above the
buckled-column region moved downward as a single unit, resulting in the global collapse of WTC 7.
Detailed views of the lower exterior column buckling are shown in Figure 12–63. '
