Williamsburg Bridge Presentation

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Waldo-Hancock Bridge
Cable Retrofit
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Existing Bridge - Elevation
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7 m
8.6 m
Cross Section Main Spans
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Wood Fillers
37 1 3/8 Dia. Pre-stressed Helical Strands
9 5/8 Diameter
Cross Section Main Cable
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Main Cable Deterioration
Inspection
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Wedging Operation
Wedging Operation
PARSONS
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Stage 1 Surface shiny, some white areas
(zinc corrosion)
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Stage 4 corrosion where strands touch (typ.)
Section Thru Main Cable
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37 Wire Strand
Typical Wire Corrosion Patterns at Worst Location
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Multiple Wire Breaks
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Wire and Strand Testing
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Stage 4 Pitting
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Severe Stage 4 Section Loss
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Legend
Stage 4
Stage 3
Stage 2
Assumptions at PP12E 14E North Cable
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PARSONS
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Strand Testing
Three Strand Specimens Tested 83 to 67 of
Original UTS
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Acoustic Monitoring
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Supplementary Strands
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Sequence of Construction
Tower and Bent Saddles, Anchorages Pulling of
Structural Strands Installing Strongbacks Cable
Bands Load Transfer
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CONSTRUCTION TIMELINE Mid-July Decision to
strengthen cables August 25 Mobilization on
site September 2 Start on-site work September
12 Placed first saddle concrete October
17 Started Load Transfer October 26 Completed
Final Steps Complete - 11 weeks after
first meeting
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Free Cable Geometry
4.2 m
1.3 m
.36 m
.36 m
1.3 m
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Strand Pulling Operation
Rollers Crane
Rollers
Winch
Reel Tensioner
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Load Transfer Sequence - First Stage
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Strongback Tie Rod
New Strands
Existing Cable
Threaded Tie Rod
Strong Back
Existing Suspenders
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Inclined Tie Rod
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Original Tower Saddle
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Tower Saddle
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Tower Saddle Offset
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Installed tower extension
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Cable Bent
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Installed Cable Bent extension
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West Anchorage
Bed Rock
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East Anchorage
New Anchorage
Existing Anchorage
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East Anchorage
Bridge Bowl
Dywidag Rod
Steel Tube
Strand
Dowels
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Tensioner Position (For Strand Pulling Operation)
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High Tension Power Cable Tensioner Modified to
Accommodate Cable End (Bridge Bowl) Maintained
10-15 Kips of Tension During Strand Pulling
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Loading New Strand Spool onto Spool Stand / Brake
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Spool Stand/Brake
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Threading Bridge Bowl Onto Tensioner
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Overview of Entire Strand Tensioning Equipment
Set-Up
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Pulling Device to Guide Bridge Bowl Over the
Saddle Rollers
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Hydraulic Winch for Pulling Strand
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Installing Cable Clamps on Existing Suspender
Cables
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Installation of New Suspender Hanger Blocks
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