1 / 51

Dial 9/11 for Evidence

Dial 9/11 for Evidence. World Trade Center Building 7. The World Trade Center. The World Trade Center. FEMA: WTC 1 & 2 Debris. FEMA: South Tower Debris. FEMA: North Tower Debris. WTC7: before noon. WTC7: west side. WTC7 final damage. Pedestrian bridge, south side. WTC7 final damage.

ludwig
Download Presentation

Dial 9/11 for Evidence

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Dial 9/11 for Evidence World Trade Center Building 7

  2. The World Trade Center

  3. The World Trade Center

  4. FEMA: WTC 1 & 2 Debris

  5. FEMA: South Tower Debris

  6. FEMA: North Tower Debris

  7. WTC7: before noon

  8. WTC7: west side

  9. WTC7 final damage Pedestrian bridge, south side

  10. WTC7 final damage 1st floor, southeast

  11. WTC7 final damage Lobby, 1st floor (note atrium)

  12. WTC7 final damage Lobby, 3rd floor

  13. WTC7 final damage NIST schematic: south face 1-19

  14. FEMA: Building 7 Debris

  15. Building 7 Debris: 9/23

  16. FEMA: Building 7 Debris N W E S

  17. FEMA: Building 7 Debris E N S W

  18. Ground Zero Debris

  19. Larry’s New Toys

  20. NIST: WTC7 Structure Basic framing layout: floors 8-20, 24-45

  21. NIST: WTC7 Structure Columns and framing

  22. FEMA: WTC7 Structure 5th floor: 14” concrete w/embedded steel T-sections 7th floor, same, 8” concrete

  23. FEMA: WTC7 Structure Trusses: floors 5-7 (transfer weight from upper columns to foundation columns)

  24. FEMA: WTC7 Structure Weight transfer trusses & girders (floors 5-7)

  25. NIST: Collapse Mechanism Thermal expansion of floor beams against girder

  26. NIST: Collapse Mechanism Column 79 girder connection

  27. NIST: Collapse Mechanism Column 79

  28. NIST: Collapse Mechanism Columns 80 & 81

  29. NIST: Collapse Mechanism Unsupported east floors fall on Truss 2

  30. NIST: Collapse Mechanism Truss 2 fails

  31. NIST: Collapse Mechanism Columns 77-78-78A buckle

  32. NIST: Collapse Mechanism Core column collapse progression

  33. NIST: Collapse Mechanism Damage to south face, from south

  34. NIST: Collapse Mechanism Damage to south face, from west

  35. WTC7 Structure Multiple-floor atrium

  36. NIST: Collapse Mechanism Global collapse: part 1

  37. NIST: Collapse Mechanism Global collapse: part 2

  38. NIST: Collapse Mechanism Time comparison: model vs. observed

  39. NIST: Free Fall NOT Roof-center pixel change

  40. NIST: Free Fall NOT Roof-center fall distance

  41. NIST: Free Fall NOT Roof center fall velocity

  42. NIST: Fuel Fires NOT Fuel line rupture couldn’t create the problem: • Heat would have stopped the generators that powered the fuel pumps • Fire couldn’t have been hot/long enough to raise the concrete/steel temps to point of strength loss • Would have generated visible smoke through lourves, none was observed • Emergency generator “day” tanks on 5,7,9 floors • wouldn’t have added much to combustible load • safety measures in place would have prevented reloading • weren’t near probable collapse initiation points

  43. NIST: Fire Observations Diagrams based on photos (starting ch 5.6.5, vol 1, p. “290”)

  44. WTC7 Steel • Only one piece examined by FEMA (App C) • liquid iron/oxygen/sulfur eutectic moved along intergranular boundaries, weakening the beam • eutectic mixture evidenced only 1000C, much lower than expected for melting steel • Possibilities raised by FEMA • long-term heating in the ground • pre-collapse, accelerated steel weakening • Not examined further by NIST • Raises the larger question of WTC steel removal

  45. Removal of WTC SteelNot all bite-sized pieces Indicates not total dismemberment, but confuses issue of what melted prior to collapse

  46. Removal of WTC SteelWhy is it an important issue? • Largest crime in U.S. history • Law requires preservation of evidence • 350,000 tons removed (acc. to FEMA) • Bloomberg: looking at steel doesn’t tell anything, need computer models • Yet said to be “highly sensitive”

  47. Removal of WTC SteelReasons given • WTC1-2: Needed to find survivors • WTC7 • Needed to find survivors (but evacuated) • Putting pressure on Verizon building (but could have just moved that) • In any case, could have labeled, docu-mented location, and saved elsewhere

  48. Removal of WTC SteelWhat happened to it? • Thousands of pieces trucked to 4 landfills • Immediate result: • Most sent to Asia • Some used to build warship U.S.S. New York • 150 pieces saved (in off-limits hangar at JFK) • Only parts from underground and lobby area • Who decided? • Later (January 2007) found more • 2 columns, 3 connected perim columns(under road excavated for human remains) • 1 burned column at edge of site (city: cutoff)

  49. Removal of WTC SteelWhat did FEMA look for? • Exterior column trees & interior core columns from 1 & 2 above the impact zone or exposed to fire and/or aircraft-impacted • Badly burnt pieces from WTC 7. • Connections from WTC 1, 2, and 7, such as seat connections, single shear plates, and column splices. • Bolts from WTC 1, 2, and 7 that were exposed to fire, fractured, and/or that appeared undamaged. • Floor trusses, including stiffeners, seats, other components. • Any piece that, in the engineer's professional opinion, might be useful for evaluation. When there was any doubt about a particular piece, the piece was kept while more information was gathered. A conservative approach was taken to avoid having important pieces processed in salvage yard operations.

  50. Removal of WTC SteelWhat about FEMA? • 62 trips to landfills Oct-Feb • No access to Ground Zero • No permission to collect or store steel • No subpoena power to obtain building plans (to make intelligent choices) • Their observation of anomalies dropped

More Related