|
 |
![Diagram of the composite WTC floor system [from National Institute of Standards and Technology (NIST)]](thumbnails/s62.jpg) |
 |
 |
 |
|
| ANSYS finite element model of the 96th floor of WTC1, showing the short and long trusses that support the floor above |
|
| Diagram of the composite WTC floor system [from National Institute of Standards and Technology (NIST)] |
|
| Detailed 2005 analysis of the collapse of the World Trade Center Buildings 1 and 2 (WTC1 & WTC2) by the National Institute of Standards and Technology (NIST) |
|
| Multi-level "local-to-global" analyses of the collapse of WTC1 and WTC2 (from the same 2005 NIST report as the previous slide) |
|
| Multiple trusses supported each floor of the WTC buildings 1 & 2. See the diagrams 3 and 4 slides ago. (from the same 2005 NIST report as the previous 2 slides) |
|
|
|
 |
 |
 |
 |
 |
|
| Two models of failure of the floor trusses (from the same 2005 NIST report as the previous 3 slides) |
|
| Sagging and perhaps buckling of the very hot floor joists on the floors of one of the WTC buildings nearest the site of initial impact |
|
| ANSYS model of inward bowing of the south face of WTC 1 at 6000 seconds after initial impact: Floors 101 - 93 |
|
| ANSYS model of inward bowing of the east face of WTC 2 in the neighborhood of the 80th floor at 2540 seconds after initial impact (This image is from the same source as that for the previous slide.) |
|
| (1) Region of initial impact; (2) Sagging of hot floor trusses causing inward deflection of columns of the perimeter wall; (3) collapse of one of the hot floors giving rise to impact of upper "rigid" mass giving rise to column plastic hinge collapse; (4) progressive downward collapse |
|
|
|
 |
 |
 |
 |
 |
|
| Collapse of World Trade Center (WTC) Building 7 (WTC7) on September 11, 2001. WTC7, on fire, collapsed about 6 hours after the collapse of WTC1 and WTC2. |
|
| Terminal 2E of the Charles de Gaulle International Airport in Paris, France under construction. This and the next 7 slides show collapse of part of this huge shell-like building 30 months after construction. |
|
| Interior view of part of Terminal 2E of the Charles de Gaulle International Airport after completion |
|
| Terminal 2E of the Charles de Gaulle International Airport after completion and before local collapse |
|
| A schematic of Terminal 2E (opposite view from that in the previous slide), showing in red the portion that collapsed on May 23, 2004 |
|
|
