POST TENSIONINGReview Session

Review Session

Objective: Performance through product quality, as well as effective installation, supervision and inspection to achieve a successful completion of a project.

Note: This review session will not replace the training that an installation/ inspection agency receives. AMSYSCO, Inc. is not responsible for the training of the installation crew or individual associated with the field installation of the post tensioning material.

I. Change in ACI Code

• To use an encapsulated system at all locations on a commercial structure.

II. Upgrade of AMSYSCO’s Encapsulated System

• No grease at “dead ends” and stressing ends• Grease to be filled in sleeves of intermediate

anchors• Plastic sheathing remains intact within the

extended sleeve of the anchor– Field labor savings

III. Post Tensioning Field OperationsA. Storage & Handling

• Store PT bundles off ground• Cover with tarp• If bundle is shrink wrapped, punch holes in wrapping to

allow air circulation• Use nylon slings for handling• Do not drag by “dead end”• All material (PT tendons, anchors, wedges) to be stored

in dry environment• Mill certification• Calibration chart of stressing equipment

III. Post Tensioning Field OperationsB. Installation

• Attach stressing anchors and intermediate anchors to bulkhead

• Position of anchor with regards to bulkhead• Tendons installed in a curve• Anchor/ pocket former• Pocket former and grease – What type of

grease• Use WD-40

Installation (cont.)

• Overlapping anchors• Reverse curvature• Position of support and backup bars• Wobble• Standard friction loss

• Can tendon be moved vertically or horizontally?• Can anchor (position) be moved vertically or

horizontally?

III. Post Tensioning Field OperationsC. Stressing

• Wedge orientation• Gage pressure – What does it mean?• Position of stressing jack• Location and positioning of pump• Eye contact by pump operator• One-way stressing• Two-way stressing• Multiple pulls (stressing) on the same tendon

Stressing (cont.)

• Paint marking (benchmark)• Scale and guide for paint marker• Measurement of elongation• Recording of elongation• Recording of gage pressure• Recording notes in the Elongation Report

Stressing (cont.)

• Elongation tolerances• Under elongation• Over elongation• Instant comparison of field elongations vs.

mathematical elongations• Decision making if there is deviation and

resultant action• Submitting elongation report to the Structural

Engineer of Record

III. Post Tensioning Field OperationsD. Stressing Equipment

• Keep equipment dry at all times• Service and maintenance of the stressing

equipment• Calibration chart• Safety• Log of service by the operator or contractor’s

appointed person

III. Post Tensioning Field OperationsE. Miscellaneous

• Hairline cracks in wedges• Strand break

– Why strand can break at a lower pressure/ force below the ultimate breaking level

• Unraveled strand• Kink in strand• Length of electric cord from stressing pump• Stressing equipment and rain• Lift off• Detensioning• When to detension• Overstressing (5%)