1. David Post v. Crane Rigging Corp.
Preliminary Reconstruction Presentation Drake Exhibits
DRAFT

2. Accident site overview
Revise roof lines on buildings per Morrell’s photos
DRAFT
Blevins Building Supply Co. - Site Plan

3. DRAFT Blevins Building Supply Co. - Site Plan US highway 21
new warehouse
construction
main office / store
Revise roof lines on buildings per Morrell’s photos
DRAFT
Blevins Building Supply Co. - Site Plan

4. DRAFT Plan View - Blevins Building Supply Co.
date of accident
US highway 21
new warehouse
construction
main office / store
DRAFT
Plan View - Blevins Building Supply Co.

5. DRAFT
New warehouse construction

6. DRAFT New warehouse construction roof trusses set
exterior wall framing
stack of
roof trusses
to be set
DRAFT
New warehouse construction

7. DRAFT New warehouse construction show crane
Add crane to image and all others following
Trusses are lifted by crane and
set on top of exterior wall frame
DRAFT
New warehouse construction

8. Accident Sequence
DRAFT

9. Add crane
DRAFT
Trusses are stacked in parking lot

10. DRAFT
Trusses are rigged to crane using a spreader bar approx. 20’ long

11. DRAFT Spreader bar is attached to truss with chains at each end
Check rigging detail with witnesses
DRAFT
Spreader bar is attached to truss with chains at each end

12. DRAFT
Truss is lifted to vertical from stack

13. DRAFT

14. DRAFT
Truss bends and tilts when lifted off stack

15. DRAFT A tag line is used to control movement of the truss
Add tag line and figure
DRAFT
A tag line is used to control movement of the truss

16. DRAFT
Truss bends and flops around while being moved to building

17. DRAFT
Truss is swung around to south end of building

18. DRAFT

19. DRAFT
Truss is moved to the north

20. DRAFT

21. DRAFT

22. DRAFT

23. DRAFT Worker positions on scissor lifts Randall ________ David Post &
Roger Billings
Add workers on scissor lifts
DRAFT
Worker positions on scissor lifts

24. DRAFT Truss is lowered toward final position Randall ________
David Post &
Roger Billings
Add workers on scissor lifts
DRAFT
Truss is lowered toward final position

25. DRAFT Truss breaks at attachment point severely injuring David Post
Roger Billings
Add workers on scissor lifts
DRAFT
Truss breaks at attachment point severely injuring David Post

26. Accident is Result of Improper Rigging of Truss
DRAFT

27. Rigging Trusses
DRAFT

28. DRAFT Accident rigging dangerously inadequate for 80 foot long truss
Chain angle more than 60º
Spreader bar
only attached
at ends
Spreader bar is too high on truss
Spreader bar
is too short
80 Feet
DRAFT
Accident rigging dangerously inadequate for 80 foot long truss

29. DRAFT Proper method for rigging an 80 Foot Long Truss
Chain angle 60º or less
Attachment points to truss at a maximum of 10 foot intervals
Locate spreader bar at or above mid-height
Spreader bar is 2/3 to 3/4 truss length
80 Feet
DRAFT
Proper method for rigging an 80 Foot Long Truss
From BCSI-B1 Guide for Handling, Installing, Restraining & Bracing of Trusses

30. 1. Calculation of Stress and Deformation of the Truss During Lifting Operations
ANSYS Finite Element Analysis computer software
used for all results
Actual incident truss geometry and material properties
incorporated in analysis
Truss lifting points obtained from witness statements
DRAFT

31. 1. Calculation of Stress and Deformation of the Truss During Lifting Operations
DRAFT

32. DRAFT 2. Animation of Truss Deformation During Lifting Operation
This movie will play automatically - click to stop

33. 3. Animation of Truss Deformation During Lifting Operation - close up of maximum stress location
DRAFT
Click this movie to play - click again to stop

34. 4. Truss Deformation as it Leaves the Truss Stack
DRAFT

35. DRAFT 5. Validation of the Computer Model of the Truss
Measure actual load-displacement response of an exemplar truss at Tru-Line Truss Company
Compare the measured values with that predicted by the computer model
DRAFT

36. 5. Validation of the Computer Model of the Truss
DRAFT

37. Modeling Stresses in Wooden Trusses During Lifting and Moving
DRAFT

38. Improper method of rigging
Show top truss with color coded stress in resting position
DRAFT
Trusses are improperly rigged using a spreader bar approx. 20’ long

39. DRAFT Stress shown in truss structure as truss is lifted off pile
Highest stress is at
the point of attachment
Colored stress model used through next 7 slides to show stresses during lifting and moving in both improperly rigged and properly rigged configurations
DRAFT
Stress shown in truss structure as truss is lifted off pile

40. DRAFT Truss bends and twists when lifted using inadequate rigging
Show truss with color coded stress values
DRAFT
Truss bends and twists when lifted using inadequate rigging

41. DRAFT Truss breaks at point of attachment to spreader bar
Show truss with color coded stress values
DRAFT
Truss breaks at point of attachment to spreader bar

42. Proper method of rigging
Show truss with color coded stress values
DRAFT
Trusses are rigged to crane using a spreader bar approx. 60’ long

43. Stress shown in truss structure as truss is lifted off pile
Show truss with color coded stress values
Stress shown in truss structure as truss is lifted off pile

44. DRAFT Stress shown in truss structure as truss is moved to building
Show truss with color coded stress values
DRAFT
Stress shown in truss structure as truss is moved to building

45. Show truss with color coded stress values
DRAFT

46. Show truss with color coded stress values
DRAFT
Stress shown in truss structure as truss is set and fastened to top plate

47. DRAFT END Drake Exhibits - Demonstrative Evidence Services
1275 Main Street
Brewster, MA 02631
DRAFT