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Spliced Precast Girders

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Presentation on theme: "Spliced Precast Girders"— Presentation transcript:

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
Detailing issues Fabrication details Erection details Splice details Post-tensioning and grouting

35 Detailing Issues Girder geometry End blocks and anchorages
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”, ”, ”) Duct size and type (plastic or metal) Anchorage type Anchorage zone reinforcement Anchorage protection Grouting

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

44 Types of Post-Tensioning Tendons

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

46 Anchorage Types

47 Multistrand Anchorage Sizes
Anchor head Trumpet Bearing plate Duct and coupler Permanent grout cap Inspectability The VSLAB+TM System was developed for use in slabs. If your project has beams, VSL will combine our ES multistrand grouted system for beams with our VSLAB+TM System for slabs. 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 The VSLAB+TM System was developed for use in slabs. If your project has beams, VSL will combine our CS multistrand grouted system for beams with our VSLAB+TM System for slabs.

50 Protection of Anchorages
Non metallic permanent grout caps We see here the stress and components, both assembled and disassembled. Looking at the line of disassembled components from left to right we see the recess former, the grout cap, the end anchor head, the bearing plate, the 2 half shells, the wedge clamps and the duct. When assembled, the system is mechanically locked together, providing the strand with reliable encapsulation. . Galvanized Bearing plates Anchorheads Spiral reinforcement

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

52 PT Grouting Details Procedures QC Specifications Inspection

53 Practice Recommended by ASBI and PTI Specifications
Grouting Materials Testing, Q/A, Q/C Construction VSL decided few years ago to carry out an extensive R & D program on grout to review the Grout Mix Design, Procedures, Equipment and Personnel on the impact of grout We will show you selected results of the R&D program

54 Grout Vents

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

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

57 Grouted Duct VSL decided few years ago to carry out an extensive R & D program on grout to review the Grout Mix Design, Procedures, Equipment and Personnel on the impact of grout We will show you selected results of the R&D program

58 Completed Girder

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

60 Project Status Phase I: Concept design
Complete Phase II: Standard drawings & details Phase III: Design examples 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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