post tensioning review session for installers
Post on 08-Dec-2014
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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%)
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