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Spliced Precast Girders Solving Transportation and Handling Problems.

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Presentation on theme: "Spliced Precast Girders Solving Transportation and Handling Problems."— Presentation transcript:

1 Spliced Precast Girders Solving Transportation and Handling Problems

2 Project Genesis n 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 n 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 n Fuller Warren Bridge, Jacksonville, Florida n Moore Haven Bridge, Florida n Highland View Bridge, Florida n 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

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

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

13 KLICKITAT COUNTY, WA

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

15 HARBOUR ISLAND PEOPLE MOVER

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

21 ROCK CUT BRIDGE, WA

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

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

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

27 Standard Drawings

28 Based on PA Bulb Tee

29 Single-Span Spliced Girder

30 End Block

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32 Reinforcing

33 Reinforcing

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

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

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

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

38 Erection Scheme

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40 Splice Details n Shear keys n Rebar splicing n Duct splicing n Wet joints

41 Closure Pour

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

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

44 Types of Post-Tensioning Tendons

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

46 Anchorage Types

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

48 Anchorage Zone Reinforcement

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

50 Protection of Anchorages n Non metallic permanent grout caps n Galvanized - Bearing plates - Anchorheads - Spiral reinforcement n Galvanized - Bearing plates - Anchorheads - Spiral reinforcement

51 Multistrand Stressing Equipment n Stress 20% then 100% n Elongation measured during stressing n Stress 20% then 100% n Elongation measured during stressing

52 PT Grouting n Details n Procedures n QC n Specifications n Inspection

53 Practice Recommended by ASBI and PTI Specifications n Grouting Materials n Testing, Q/A, Q/C n Construction n Grouting Materials n Testing, Q/A, Q/C n Construction

54 Grout Vents

55 Materials - Anchorages n Permanent Cap - Positive Seal - Integral Vent n Positive Duct Connections

56 Materials - Vents & Drains n Positive Shut-Off n Reopen & Close n Grouting Pressure

57 Grouted Duct

58 Completed Girder

59 Summary n Extend practical span range of precast/prestressed girders to 225’ n Solve handling problem with segmentation: Spliced Girders n Final girder is erected as ordinary precast/pretensioned girder n No additional complexity for contactor

60 Project Status n Phase I: Concept design - Complete n Phase II: Standard drawings & details - Complete n Phase III: Design examples - Complete Awaiting release by PennDOT

61 Questions? Developer of Standards and Design Examples Roy L. Eriksson, P.E. Eriksson Technologies, Inc. Tampa, FL LRFD.com


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