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