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Spliced Precast Girders

Spliced Precast Girders. Solving Transportation and Handling Problems. Project Genesis. Problem: Girder Weight and/or Length Haul weight limitations Haul size limitations Permitting costs and scheduling Terrain and access Precast limited to spans < 160’. Pennsylvania Permit Vehicles.

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Spliced Precast Girders

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  1. Spliced Precast Girders Solving Transportation and Handling Problems

  2. Project Genesis • Problem: Girder Weight and/or Length • Haul weight limitations • Haul size limitations • Permitting costs and scheduling • Terrain and access • Precast limited to spans < 160’

  3. Pennsylvania Permit Vehicles 33X95.5 PABT

  4. Project Genesis • Solution: Spliced Girder Design • Segment girder into 2 or more pieces • Pretension for handling • Haul segments to jobsite • Assemble segments using post-tensioning • Erect girder as “pretensioned” girder

  5. Drop-In Span Projects Fuller Warren Bridge, Jacksonville, Florida Moore Haven Bridge, Florida Highland View Bridge, Florida Main Street Viaduct, Pueblo, CO

  6. FULLER WARREN BRIDGE, JACKSONVILLE, FL

  7. MOORE HAVEN BRIDGE, FLORIDA

  8. HIGHLAND VIEW BRIDGE, FL

  9. MAIN STREET VIADUCT, PUEBLO, CO

  10. MAIN STREET VIADUCT, PUEBLO, CO

  11. Simple-Span Projects • Harbour Island People Mover, Tampa, FL • Klickitat County, WA • Rock Cut Bridge, WA • I-15 Reconstruction, Salt Lake City, UT

  12. Klickitat County, WA • Built 1954 • 90 ft total length • 3 – 30 ft segments • Erected on falsework • Spliced because of contractor’s equipment

  13. KLICKITAT COUNTY, WA

  14. Harbour Island People Mover • Built 1984 • Single box beam elevated guideway • 140 ft total length • 2 – 70 ft segments • Erected on falsework

  15. HARBOUR ISLAND PEOPLE MOVER

  16. HARBOUR ISLAND PEOPLE MOVER

  17. HARBOUR ISLAND PEOPLE MOVER

  18. HARBOUR ISLAND PEOPLE MOVER

  19. HARBOUR ISLAND PEOPLE MOVER

  20. Rock Cut Bridge, WA • Built in 1995 • 190 ft total length • 3 segments • Spliced near site, then launched • Access required splicing • Owners wanted concrete bridge • Very tight schedule and budget

  21. ROCK CUT BRIDGE, WA

  22. ROCK CUT BRIDGE, WA

  23. ROCK CUT BRIDGE, WA

  24. Project Objectives • Extend current span limit • Provide a concrete alternative for the 150’ – 225’ span range • Provide pretensioned girder equivalency • Utilize PennDOT detailing to degree possible • No additional complexity for contractor

  25. PA Spliced Girder Standards • Based on PA Bulb Tee • Single-span splicing • 2- or 3-piece segmentation • Span Limit: 225 ft

  26. Project Scope • Phase I: Concept design • Phase II: Standard drawings & details • Phase III: Design examples

  27. Standard Drawings

  28. Based on PA Bulb Tee

  29. Single-Span Spliced Girder

  30. End Block

  31. End Block

  32. Reinforcing

  33. Reinforcing

  34. Concepts & Design Issues • Design issues • Detailing issues • Fabrication details • Erection details • Splice details • Post-tensioning and grouting

  35. Detailing Issues • Girder geometry • Flange • Bulb • End blocks and anchorages • Joints – Girder end treatments • Post-tensioning ducts • Rebar placement • Bearings

  36. Fabrication Issues • Post-tensioning • End blocks and anchorages • Haunched pier segments • More intensive fabrication effort

  37. Erection Issues • Splicing before erection • In-place splicing • Girder stability • Crane pick

  38. Erection Scheme

  39. Erection Scheme

  40. Splice Details • Shear keys • Rebar splicing • Duct splicing • Wet joints

  41. Closure Pour

  42. Post-Tensioning Issues • Tendon size (7-0.6”, 12-0.6”, 19-0.6”) • Duct size and type (plastic or metal) • Anchorage type • Anchorage zone reinforcement • Anchorage protection • Grouting

  43. Material PT Strand Strength (ksi) 250/270/300 Prestressing Materials

  44. Types of Post-Tensioning Tendons

  45. Metal More widely used Less costly Unlimited sizes Stiffer Better grout flow Plastic More durable Non-corrosive Lower coefficient of friction Plastic vs. Metal Ducts

  46. Anchorage Types

  47. Inspectability Anchor head Trumpet Duct and coupler Bearing plate Permanent grout cap Multistrand Anchorage Sizes • 0.5” Strand - 12,19,31,43,55 • 0.6” Strand - 7,12,19,22,31,37,55

  48. Anchorage Zone Reinforcement

  49. Corrosion Protection of Strand • Corrugated plastic duct • Galvanized corrugated metal duct • Smooth HPDE duct

  50. Protection of Anchorages • Non metallic permanent grout caps • Galvanized • Bearing plates • Anchorheads • Spiral reinforcement

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