02C - Concrete - Post-Tension Cables Flashcards
(32 cards)
Reverse curvature of tendons in post-tensioned concrete construction can be avoided by _________________.
Providing additional support bars for the tendons (Training of Field Personnel for Unbonded Post-Tensioning Page 37)
A watertight cap should be installed on an encapsulated system for post-tensioned concrete within ______hours after stressing is complete.
24 hours (Training of Field Personnel for Unbonded Post-Tensioning Page 62)
Where two or more extensions of the stressing jack are required to achieve the required elongation for post-tensioned concrete, the final pull on the jack should not exceed _____________%.
60 (Training of Field Personnel for Unbonded Post-Tensioning Page 48)
Tendons in post-tensioned concrete should not be stressed until the concrete has reached about ________% of its full strength.
75 (Training of Field Personnel for Unbonded Post-Tensioning Page 8)
A minimum clearance of _________inches should be maintained around all block outs in post-tensioned construction.
6 inches (Training of Field Personnel for Unbonded Post-Tensioning Page 34)
If a tendon used in a post-tensioned concrete slab is to be stressed from both ends, at least ____ inches of tendon tail should be left outside the edge form at each end for stressing.
12 (Training of Field Personnel for Unbonded Post-Tensioning Page 32)
The back-stressing force applied to barrier cables should be equal to _____% of the ultimate strength of the cable.
80 (Training of Field Personnel for Unbonded Post-Tensioning Page 67)
Not more than _______ 0.5” diameter tendons should be banded together in a group in post-tensioned concrete.
5 (Training of Field Personnel for Unbonded Post-Tensioning Page 34)
What is the maximum that sheathing should be cut back on tendons?
1 inch (Training of Field Personnel for Unbonded Post-Tensioning Page 32 & 33)
Which of the below would be the best order to install post tension cables?
Forms set, install sleeves and embeds, cables, cable supports and install plumbing and electrical sleeves (Training of Field Personnel for Unbonded Post-Tensioning Page 30)
Which of the below would be proper way of unloading tendon coils?
Cradle coils by passing nylon straps through the center of coils (Training of Field Personnel for Unbonded Post-Tensioning Page 27)
What is the minimum spacing between bundles of tendons?
1 ½ inches (Training of Field Personnel for Unbonded Post-Tensioning Page 37)
What is the purpose for post-tensioning concrete?
To increase compressive strength in the bottom of a joist or girder to offset tensile stress (Training of Field Personnel for Unbonded Post-Tensioning Page 10)
Which of the below would be correct method of storing tendon coils?
Stored in a dry area on dunnage to keep the tendons off the ground (Training of Field Personnel for Unbonded Post-Tensioning Page 27)
In most field applications the amount of force that will actually be applied to the strand will be approximately what percentage of the MUTS (Minimum Ultimate Tensile Strength) of the strand?
80% (Training of Field Personnel for Unbonded Post-Tensioning Page 46)
What a method for strengthening reinforced concrete in which steel tendons are stretched through conduits and mechanically fastened is called what?
Post-tensioning (Training of Field Personnel for Unbonded Post-Tensioning Page 4 )
On concrete beams, what is the recommended distance between tendons/cables?
1 ½ inches (Training of Field Personnel for Unbonded Post-Tensioning Page 37)
Which of the following is not acceptable when grouting stressing pockets?
Having chlorides as an additive (Training of Field Personnel for Unbonded Post-Tensioning Page 62)
The maximum number of or .60 of an inch tendons / cables in a group is _____.
4 (Training of Field Personnel for Unbonded Post-Tensioning Page 34
Maximum number of .50 of an inch tendons / cables in a group is 5)
When installing post tension cables, you are allowed to have 1 inch of the cable exposed in the concrete at the end tying into the form without plastic sheathing. What procedures are required if more than 1 inch is exposed?
Grease cable and tape (Training of Field Personnel for Unbonded Post-Tensioning Page 33)
What does post tension cables have to have before concrete can be poured on them?
Covered in grease and plastic covering in place (Training of Field Personnel for Unbonded Post-Tensioning Page 13)
What is the definition of a post tension cable?
Reinforcing steel is housed in a plastic coating or sheath that prevents the concrete from bonding with the cable so it can be stressed after the concrete has hardened. (Training of Field Personnel for Unbonded Post-Tensioning Page 13 – 15 )
How are post tension cable / tendons installed?
Wrapped in plastic with PT applied (Training of Field Personnel for Unbonded Post-Tensioning Page 5 )
When performing the final operation where two extensions of the stressing jack are used, what is the percent of the final stroke of the jack?
60% (Training of Field Personnel for Unbonded Post-Tensioning Page 5 )
