Tweaking the Damage Scenarios
NIST created two sets of cases:
-
Original: North Tower case A and South Tower case C
-
Adjusted: North Tower case B and South Tower case D
Adjustments:
|
North Tower
case A->B |
South Tower
case C->D |
| increase in impact speed |
29 mph |
28 mph |
| decrease in approach angles |
3º |
1º |
| increase in aircraft weight |
5 percent |
5 percent |
| increase in aircraft strength |
25 percent |
15 percent |
| decrease in Tower strength |
20 percent |
15 percent |
| decrease in Tower live load |
20 percent |
20 percent |
| increase in Tower fuel load |
25 percent |
25 percent |
NIST's disclosure of contrived cases that weaken the buildings
invite the criticism that they adjusted their models to achieve collapse.
But NIST provides no evidence that models showed any collapse behavior.
Did NIST add scenarios B and D to hide its failure to model any collapse event?