econ41
Senior Member
@Goombah111 - the topic of this thread is 'Understanding the claim of "The top of the north tower fell at 65% or 2/3 of g"'
It is observed fact which should be agreed that the progression stage of Twin Towers colapses was at, in the order of, 2/3rds "G".
That is true whether or not there was any CD or even any need for CD. The question of "CD or not" has no effect on the OP topic. The reasons for the 2/3rds"g" are, or should be agreed as:
1) The falling debris fell down the spaces - the "Open Office Space" of the Tube in tube design plus the analogous spaces in the core.
2) Thus the debris missed the columns which offered no significant resistance to the falling debris;
3) The main source of structural force resisting the collapse(s) was from shearing of joist to columns connections as shown bt this graphic:
-- the same situation at the other end of the OOS joists and the analogous situation causing shearing of floor beams in the core area.
Those shearing forces were far less than the dominant "force" causing the "missing" 1/3rd "g". Which was the force involved in increasing momentum as additional debris was added as successive floors were disconnected from columns.
EDIT: I note that @Landru has drawn attention to the topic - we "crossed in posting".
It is observed fact which should be agreed that the progression stage of Twin Towers colapses was at, in the order of, 2/3rds "G".
That is true whether or not there was any CD or even any need for CD. The question of "CD or not" has no effect on the OP topic. The reasons for the 2/3rds"g" are, or should be agreed as:
1) The falling debris fell down the spaces - the "Open Office Space" of the Tube in tube design plus the analogous spaces in the core.
2) Thus the debris missed the columns which offered no significant resistance to the falling debris;
3) The main source of structural force resisting the collapse(s) was from shearing of joist to columns connections as shown bt this graphic:
-- the same situation at the other end of the OOS joists and the analogous situation causing shearing of floor beams in the core area.
Those shearing forces were far less than the dominant "force" causing the "missing" 1/3rd "g". Which was the force involved in increasing momentum as additional debris was added as successive floors were disconnected from columns.
EDIT: I note that @Landru has drawn attention to the topic - we "crossed in posting".