precast panels design, casting, iowa prestressed concrete, ordean johnson, craig brown, darrel...
TRANSCRIPT
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Precast Panels Design, Casting, Placement
January 25th, 2008Ames, Iowa
Presented by:Dean Bierwagen, Methods Engineer,
Office of Bridges and Structures, Iowa Department of Transportation
Acknowledgement
• Iowa DOT –Norm McDonald, Gary Novey, Ahmad Abu-Hawash, Thayne Sorenson., Mark Dunn, Wayne Sunday, Brian Worrel.
• FHWA -Curtis Monk, Max Grogg
• Bridge Engineering Center at ISU -Mike LaViolette, Doug Woods, Brent Phares
• The Transtec Group, Dave Merritt
• Iowa Prestressed Concrete, Ordean Johnson, Craig Brown, Darrel Olynick
• Dixon Construction
Overview
• Project
• Plans
• Precasting
• Construction
• Summary
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IA Highway 60 over Floyd River (O'Brien County)
Bridge Description
Panel Layout
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Panels
• 12 inches thick
• Skewed panel at abutment
• 14 ft x 20 ft
Properties
• fc = 7,000 psi (5000 psi required)
• Precast w/ mild reinforcing
• 1 inch diameter PT ducts ~ 2 ft spacing
• 0.6 in diameter strands, 75% of 270 ksi ~ 40 kips/strand
Post-tensioning Layout
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End Connection
Blockout Plan
Transverse Keyway
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Longitudinal Joint
Longitudinal Joint
Casting of Panels
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Panel Fit Up Test
• Check PT alignment
• Keyways
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Panel Field Placement
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Grouting PT and Underslab
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Summary
• Reinforcement around pocket
• Longer pocket (longitudinal)
• Keyway issues (Steel Forms)
• Detail between slab joints (neoprene doughnuts)
Summary (Cont.)
• Metal PT ducts
• Provided funds for mockup
• More / early involvement of precasters and post-tensioning industry
• Repair methods in place
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Future Work
• Under Traffic
• W/ precast approach slab support
• Pavement Projects