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By
Guido Schwager, P.E.Schwager Davis, Inc.
Presented at the
2010 PTI ConferenceFort Worth, Texas
National GroutedPost-Tensioning Specification
Eugene Freyssinet applies prestressedconcrete to bridges:Plougastel Bridge (1925-30)
History of Post-Tensioning
Post-Tensioning in North America
Unbonded Single Strand Tendons
Grouted Post-Tensioning
Galvanized Corrugated Metal Duct
Corrugated Plastic Duct
• Freeway Interchanges• Freeway Overpasses• Pedestrian Bridges
Typical Applications of Grouted Post-Tensioning
• Segmental
ConcreteBridges
Typical Applications of Grouted Post-Tensioning
Storage Structures including
• Water Tanks• Grain Storage Facilities• LNG Storage Tanks
Typical Applications of Grouted Post-Tensioning
• Pontoons• Floating LNG
Terminals• Oil & Gas
ProductionFacilities
Typical Applications of Grouted Post-Tensioning
WHY DO WE NEED AGROUTED POST-TENSIONING
SPECIFICATION
PTI M-50/ASBI JOINT COMMITTEE
EXISTING DOCUMENTS REVIEWED FOR CONSIDERATION
• PTI – Acceptance Standards for Post-Tensioning Systems• PTI – Specifications for Grouting of Post-Tensioned Structures• AASHTO LRFD Bridge Construction Specification• FDOT Standard Provisions• Caltrans Standard Provisions• Fib Bulletin 33 – Durability of Post-Tensioning Tendons
GOALS• Set a minimum standard for all grouted post-tensioning• Define the design and testing requirements before a post-tensioning system
can be used• Give the owner/designer a choice of performance levels in a post-tensioning
system• Ensure the installed components meet the approved system description• Ensure the system is installed in a technically sound manner• Ensure the durability goals will be achieved• Create a safety-conscious culture for all phases of post-tensioning• Give the suppliers an avenue for innovation beyond current best practices• Ensure post-tensioned construction remains competitive• Keep the specification as brief as possible
THE PROCESS
• Collect input from committee members• Prepare first draft document• Collect comments from committee members• Prepare second draft• Ballot process• Publish specification• Promote specification