PTI M-50/ASBI JOINT TASK GROUP

Specification for Grouted Post-Tensioning

2011 Update Presented By

David Martin

The Group

The Mission & Goals

Why

The Process

Support & Reference Documents

History

Sticking Points – Tough Subjects

Where we go from here

OVERVIEW

• David Martin – Co-Chair (PTI M-50 Chair)

• Guido Schwager – Co-Chair (ASBI)

• Miroslav Vejvoda – Secretary

• Ted Neff – ex-officio (PTI)

• Randy Cox – ex-officio (ASBI)

• 31 Voting Members

• 3 Associate Members

.

THE JOINT TASK GROUP

Suppliers Contractors, Engineers, Research Consultants, Owners

THE JOINT TASK GROUP – OUR INDUSTRY

Develop and report on post-tensioned concrete structures with

bonded tendons.

MISSION

GOAL

Develop a national standard specification for bonded tendons

Set a minimum standard for all grouted post-tensioning

Define the design and testing requirements before a post-tensioning

systems can be used.

Give the owner/engineer a choice of performance levels in a post-

tensioning system.

Ensure the installed systems meet the approved system description.

Ensure the system is installed in a technically sound manner.

Ensure the durability goals will be achieved.

Give the suppliers an avenue for innovation beyond current best

practices.

Ensure that post-tensioned construction methods remain competitive.

Keep the specification as brief as possible.

GOAL IN DETAIL

WHY DOES THE INDUSTRY NEED A BONDED

POST-TENSIONING SPECIFICATION?

ENDLESS APPLICATIONS AND OPTIONS

APPLICATIONS from A..Z

Buildings, Concert Halls, & Dams

APPLICATIONS from A..Z

Bridges

APPLICATIONS from A..Z

Towers, Tanks & Silos

APPLICATIONS from A..Z

Pavement & Runways

APPLICATIONS from A..Z

Viaducts & Walls

SYSTEM OPTIONS – Multi-Strand

SYSTEM OPTIONS – Single-Strand Bonded

SYSTEM OPTIONS – Threadbar

SYSTEM OPTIONS – Materials

Plastic Duct

Metal Duct

THE PROCESS

Collect input from committee members.

Collect and evaluate industry documents for consideration.

Prepare draft specification.

Collect comments from committee after initial review period.

Prepare and distribute 2nd draft.

Work through balloting process.

Publish and distribute specification.

Promote specification to industry.

DOCUMENTS UTILIZED IN THE PROCESS

PTI – Acceptance Standards for Post-Tensioning Systems

PTI – Specifications for Grouting of Post-tensioned Structures

AASHTO LRFD Bridge Construction Specification

FDOT Standard Provisions

MnDOT Standard Provisions

Caltrans Standard Provisions

Fib Bulletin 33 – Durability of Post-Tensioning Tendons

2007 M-50 Committee formed

2008 First meeting to discuss the base document for

specification development.

8/ 2009 M-50 established an ad-hoc joint task group with ASBI

with the joint interest of the standard specification

10/ 2009 Draft #1 of the specification

4/ 2010 Draft #2 of the specification

5-7/ 2010 Draft was balloted

May 1, 2011 Resolution of negative votes

HISTORY OF THE TASK GROUP

STICKING POINTS – TOUGH SUBJECTS

AIR PRESSURE TESTING OF TENDONS

Ideas of purpose were questioned.

Value gained in testing vs. cost

questioned.

Amount of pressure questioned.

STICKING POINTS – TOUGH SUBJECTS

SEGMENTAL COUPLERS

Industry wants the latest technology for increased durability.

Intent of specification is not to preclude any current systems available.

Future Goals

Establish a PTI Recommendations Document with commentary.

Focus on industry acceptance and promotion of specification.

Consider developing mechanism for national acceptance and

certification of individual proprietary systems.

Ensure the document always remains current with consideration for

the latest technologies.

WHERE TO GO FROM HERE

THE FUTURE IS POST-TENSIONED CONCRETE

NOT STEEL

Thank You