What is the difference between bonded and unbonded tendons?
Bonded tendons (Figure 1) are seven-wires strands inserted inside a plastic or steel duct, and after stressing the strands, grout is injected to fill the duct. Unbonded tendons (Figure 1) are made up of greased seven-wires strands covered with plastic sheathing [2].
What equipment is used for post tensioning?
Stressing Equipments is an essential part of post tensioning / prestressed concrete work. TMG has a range of stressing equipments that includes Mono Jack, Stressing Jack, Bond Head Machine, Compression Fitting Machine etc, and accessories, to economically and efficiently stress its tendons.
What is wedges in post tensioning?
Post-tensioning wedges are normally used in the production of post-tensioned concrete elements. These anchor grips remain in the concrete unit. Apart from the need for good quality, economy also plays a role.
What are the stages of post tensioning?
1) Casting of concrete. 2) Placement of the tendons. 3) Placement of the anchorage block and jack. 4) Applying tension to the tendons.
What is grouting in post tensioning?
The grouting of the ducts surrounding post-tensioning tendons provides the necessary mechanical connection to transfer the stresses between the tendons and the concrete and also protects the tendons from corrosion.
Can you anchor into post tension slab?
Decorative Post-Tensioned Concrete PT slabs on ground can be placed and stamped just like with any other concrete slab. Surfaces can be stained or overlaid. The only concern is to always remember not to cut or drill into post-tensioned concrete slabs, since once a tendon has been cut, it is very difficult to repair.
What is unbonded post tensioning?
Unbonded post tensioning is a way to reinforce concrete with high-strength steel strands known as tendons. An unbonded tendon is one in which the pre-stressing steel is bonded to the concrete at the anchorages.
What is the difference between post tensioning and pre stressing?
Pretension is the technique in which we are imparting tension in strands before placing the concrete. Post tensioning is done by forming a duct in which strands are pulled (tensioned) after the concrete gains it’s full strength. 2.
What happens if you cut into a post-tension slab?
Cutting a tensioned cable, or tendon, can endanger the contractor and compromise the structural integrity of the slab. Building professionals frequently use ground-penetrating radar (GPR) to locate cables within concrete slabs and reinforce the slab during and after cutting operations.
Can you fix a post-tension slab?
Post-Tension Foundation slabs can be efficiently repaired and retro-fitted. While most of our calls are after someone has already broken a PT cable, we can help eliminate major damage to the slab and tendons with locating tendons and a review of the repair conditions, prior to cutting into the PT slab.
How do I make post tensioned beams?
The load balancing method is the most widely used technique to design post-tensioned concrete beams and slabs. This method will be used exclusively in this course. In the load balancing method, a portion of the design load is selected to be “balanced”, or carried, by the action of the tendons.