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Outline
Capabilities and Benefits
Design Examples Pretensioned (Threaded-Rod) Alternative
Post-Tensioned Alternative Future Innovations
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Up to 70 strands
WWR Long span capability Can be P/T
Super Girder
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CA Wide Flange
4Pretensioned Post Tensioned
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WF Bottom
Flange #5 Stirrup
WWR
3 5/8 diameterducts
54 Straight strand
14 Harped strand
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Non-Composite Section
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Composite Section
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Girder Spacing = 10 ft
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WF Span Capabilities 0.6 Strand
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Simple SpanGirder Spacing = 10 ft
045.0=S D
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Design Examples
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WF Girder Alternatives
Threaded Rod Alternative:
Pretensioned Girders Continuous for deck weight
Post Tensioned Alternative 2-stage P/T Pretensioned for girder self weight
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Threaded Rod Continuity
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Threaded Rod Continuity
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Threaded Rod Continuity
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Post-tensioned Alternative
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Analysis Considerations
Elastic behavior no redistribution
Lump-sum losses Deflections superimposed from each stage
Sag soffit profile not allowed
CT Bridge used for live load and P/T
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Threaded Rod Alternative
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P/T Alternative Girder Details
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Girder Post-tensioning
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Midspan Deflections (in)
Girder + pretension 0.4 in.
Stage 1 P/T 2.5 in. Deck weight -2.6 in.
Stage 2 P/T 0.5 in. SDL -0.5 in.
Total 0.5 in.Note: Positive is upward
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Girder Shear
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MCFT Shear Capacity
vvc pscn d b f V V V V ++= 25.0
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Girder Shear NCHRP 579
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Abutments
Post-tensioned Alternative Threaded Rod Alternative
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Bent Cap
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Future Innovations
0.7 in. Strand
Full-depth precast deckpanels
Railroad applications
Prefabricated substructureconnections
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Pacific Street Bridge over I-680
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10 NU900 girders spaced 10 ft -8 in 30-0.7 in straight strands spaced 2 in horizontally and 2.5 in
vertically Two spans 98 ft each with TR continuity Opened to traffic in August 2008
D/S = 0.038
Omaha, NE
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Acknowledgements