Sfobb Dec08

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New San Francisco - Oakland Bay Bridge Surveying Presentation

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Sfobb Dec08

  1. 1. The Survey for the New San Francisco Oakland Bay Bridge December 1 st , 2008 ASCE Dallas Branch Meeting
  2. 2. Presentation Topics <ul><li>An Introduction to the Project </li></ul><ul><li>Key Bridge Components </li></ul><ul><li>Geodetic Surveying and Tectonic Considerations </li></ul><ul><li>Transition Span OBG’s </li></ul><ul><li>Footings (T1 & E2) </li></ul><ul><li>SAS Tower </li></ul><ul><li>SAS OBG’s </li></ul>
  3. 3. Project Limits San Francisco Oakland Treasure Island Yerba Buena Island
  4. 4. Introduction <ul><li>The New Bridge </li></ul><ul><ul><li>Designed by Ty Lin and Moffett Nichol JV </li></ul></ul><ul><ul><li>Constructors - American Bridge/Flour JV </li></ul></ul>
  5. 5. SAS Components
  6. 6. Surveying Challenges <ul><li>Unique single tower design requires extreme survey accuracy </li></ul><ul><li>Complex OBG Deck Geometry (e.g., pre-camber) </li></ul><ul><ul><li>Primary geodetic control network (Order B) </li></ul></ul><ul><ul><li>Steel component fabrication tolerances (1 mm  3 mm depending on specific dimensional criteria) </li></ul></ul><ul><ul><li>Thus survey accuracies must be 5 x to 10 x better than the tolerances </li></ul></ul>
  7. 7. <ul><ul><li>Project Area sits on a single tectonic plate </li></ul></ul><ul><ul><li>No discernable scale or rotation seen in the HTDP output </li></ul></ul><ul><ul><li>Presented Results to Client </li></ul></ul>Primary Geodetic Control and Related Issues, e.g., Tectonic Motion
  8. 8. Transition Span Survey For Caltrans <ul><li>USA Steel Fabrication Verification - Portland </li></ul><ul><ul><li>Transition Spans </li></ul></ul><ul><ul><li>First Survey Attempt by Others Failed </li></ul></ul><ul><ul><li>Original Fabricator went out of Business </li></ul></ul>
  9. 9. Conventional Precision Survey Methods
  10. 10. Conventional Network 95% confidence regions exceed project tolerance (3 mm)
  11. 11. State of the Art Technology <ul><li>Laser Tracker </li></ul>
  12. 12. Primary Control <ul><li>Applied Technology </li></ul><ul><ul><li>Precision prisms </li></ul></ul><ul><ul><li>Drift nest tools </li></ul></ul><ul><ul><li>Circle tools </li></ul></ul><ul><ul><li>Edge tools </li></ul></ul><ul><ul><li>Hidden point tools </li></ul></ul><ul><ul><li>Etc. </li></ul></ul>
  13. 13. Leica Laser Tracker and 1.5″ Precise Sphere
  14. 14. Laser Tracker Survey of the Transition Span OBG’s
  15. 15. T1 Footing Survey – Corpus Christi <ul><li>Five Elements </li></ul><ul><ul><li>Dimensions </li></ul></ul><ul><ul><li>Pile Sleeve Radii and Orientation </li></ul></ul><ul><ul><li>Dowel Locations </li></ul></ul><ul><ul><li>Location and Axis of 438 Bolt Holes </li></ul></ul><ul><ul><li>Dowel and Bolt Hole Template </li></ul></ul>
  16. 16. Pile Sleeve Analysis
  17. 17. T1 Footing Pile Sleeve Alignment and Key Dimensions
  18. 18. T1 Footing Organized Chaos
  19. 25. T1 Footing Survey – Corpus Christi <ul><li>Use a Laser Tracker </li></ul><ul><li>Work at Night </li></ul><ul><ul><li>Minimize ambient conditions flux </li></ul></ul><ul><ul><li>Easier access with minimal other work </li></ul></ul><ul><ul><li>Network based on 63 surveyed dowel locations </li></ul></ul>
  20. 26. Dowel Survey Results
  21. 27. Template Survey Results
  22. 28. T1 Footing at KOS
  23. 29. T1 Footing Delivery
  24. 30. Driving the Piles
  25. 31. T1 Footing in Place
  26. 32. T1 Footing Installed
  27. 33. ZPMC Fabrication Facility Shanghai
  28. 34. ZPMC
  29. 35. Tower Survey - China Tower Fabrication <ul><li>Getting Oriented (no pun intended) </li></ul>
  30. 36. The Basic Tower Design
  31. 37. Tower Mock-up Surveys <ul><li>China Tower/Deck Fabrication – First Survey </li></ul><ul><ul><li>The Project Site </li></ul></ul><ul><ul><li>Steel Fabricator in Shanghai </li></ul></ul><ul><ul><li>Mock up Survey </li></ul></ul><ul><ul><ul><li>3 Elevations of the Tower </li></ul></ul></ul><ul><ul><ul><li>To Prove Capability </li></ul></ul></ul><ul><ul><ul><li>Actual Sections 40 M </li></ul></ul></ul><ul><ul><ul><li>Survey for </li></ul></ul></ul><ul><ul><ul><ul><li>Dimensions </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Flatness </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Orthogonality </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Torsion </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Alignment </li></ul></ul></ul></ul>
  32. 38. Tower Survey <ul><li>China Tower Fabrication </li></ul><ul><ul><li>Survey Using Laser Tracker </li></ul></ul>
  33. 39. Tower Shaft Survey <ul><li>China Tower Fabrication </li></ul><ul><ul><li>Performing the Survey </li></ul></ul>
  34. 40. Tower Shaft Survey <ul><li>China Tower Fabrication </li></ul><ul><ul><li>Performing the Survey </li></ul></ul>
  35. 41. Control Network and Object Observations <ul><li>Network Design </li></ul><ul><li>Point Cloud </li></ul><ul><ul><li>Maximum Residual found was 0.023mm (0.0009’) </li></ul></ul>
  36. 42. Survey Report (Shaft Dimensions)
  37. 43. Survey Report (Shaft Skin Analysis) <ul><li>Results </li></ul><ul><ul><li>Flatness </li></ul></ul><ul><ul><li>CI = 0.5 mm </li></ul></ul><ul><ul><li>(1/50 th inch) </li></ul></ul>
  38. 44. Survey Report (Stiffener Locations and Orthogonality)
  39. 45. Survey Report (Shaft Torsion Analysis)
  40. 46. Alignment at Shaft Splice
  41. 47. OBG Jig Survey <ul><li>Use of jigs to maintain OBG fabrication geometry </li></ul>
  42. 48. Jig Under Construction
  43. 49. OBG Survey
  44. 50. Ice Cream Break
  45. 51. Shanghai Surveys <ul><li>Towill Engineer with Buddy from Shanghai Hash House Harriers </li></ul>
  46. 52. Thank You

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