Unbonded post-tensioned concrete differs from bonded post-tensioning by providing each individual cable permanent freedom of movement relative to the concrete. To achieve this, each individual tendon is coated with a grease (generally lithium based) and covered by a plastic sheathing formed in an extrusion process. The transfer of tension to the concrete is achieved by the steel cable acting against steel anchors embedded in the perimeter of the slab. The main disadvantage over bonded post-tensioning is the fact that a cable can destress itself and burst out of the slab if damaged (such as during repair on the slab). The advantages of this system over bonded post-tensioning are:
The ability to individually adjust cables based on poor field conditions (For example: shifting a group of 4 cables around an opening by placing 2 on each side).
The procedure of post-stress grouting is eliminated.
The ability to de-stress the tendons before attempting repair work.
Unbonded post-tensioning tendons are commonly used in parking garages as barrier cable. Also, due to its ability to be stressed and then de-stressed, it can be used to temporarily repair a damaged building by holding up a damaged wall or floor until permanent repairs can be made.
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We are PT Manufacturer from China, our full products range for post tensioning and pre-strssing construction:
1. Materials: pc strand, YJM anchor system(monostrand anchor, multistrands anchor), ducts(metal ducts, HDPE plastic ducts)
2. Equipment: Hydraulic Jack(QYC mono jack, YDC multi-strand tensioning jack), electric oil pump, YH30 embossing machie(onion jack), GYJ500 extrusion machine, ZG130 ducts making machine, grouting pump and mixer for post tensioning).
Contact Person: Jason Wang
Skype: PT Manufacturer
Email Address: sales@pt-concrete.com
Mobile ＆ Whattsapp(Viber) No.: +8613673713569
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