- 1 How does post-tensioned concrete work?
- 2 What is the purpose of post tensioning?
- 3 What is post-tensioned concrete slab?
- 4 Where is post-tensioned concrete used?
- 5 Is post tension better than rebar?
- 6 What happens if you hit a post tension cable?
- 7 What does post-tensioning mean?
- 8 Can you drill into a post tension slab?
- 9 What are the advantages and disadvantages of prestressed concrete?
- 10 Do post tension slabs have rebar?
- 11 Can a post tension slab be repaired?
- 12 Do I have a post tension slab?
- 13 Why do engineers need prestressed concrete?
- 14 How far apart are post tension cables?
How does post-tensioned concrete work?
Post tensioning is a technique for reinforcing concrete. Post–tensioned concrete means that the concrete is poured and then the tension is applied-but it is still stressed before the loads are applied so it is still prestressed. For an excellent overview of PT, visit the Post–Tensioning Institute.
What is the purpose of post tensioning?
The function of post–tensioning is to place the concrete structure under compression in those regions where load causes tensile stress. Post–tensioning applies a compressive stress on the material, which offsets the tensile stress the concrete might face under loading.
What is post-tensioned concrete slab?
Post tension slab is a combination of conventional slab reinforcement and additional protruding high-strength steel tendons, which are consequently subjected to tension after the concrete has set. This hybridisation helps achieve the formation of a much thinner slab with a longer span devoid of any column-free spaces.
Where is post-tensioned concrete used?
Post–tensioning now is used extensively in bridges, elevated slabs (parking structures and residential or commercial buildings), residential foundations, walls, and columns. Jim Rogers Bending and flexing creates high tensile forces that can cause the concrete floor slab to crack.
Is post tension better than rebar?
Post–tensioning, which is a form of prestressing, has several advantages over standard reinforcing steel (rebars): It reduces or eliminates shrinkage cracking-therefore no joints, or fewer joints, are needed. Cracks that do form are held tightly together. It allows slabs and other structural members to be thinner.
What happens if you hit a post tension cable?
Cables typically run East to West or North to South. Do NOT cut into a post tensioned slab if there is a chance you will rupture a cable. People have been dismembered and killed when cables are cut and burst out of the concrete.
What does post-tensioning mean?
OVERVIEW. Post–tensioning is a method of reinforcing (strengthening) concrete or other materials with high-strength steel strands or bars, typically referred to as tendons.
Can you drill into a post tension slab?
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 are the advantages and disadvantages of prestressed concrete?
It requires high strength concrete and high tensile strength steel wires. The main disadvantage is construction requires additional special equipment like jacks, anchorage, etc. It requires highly skilled workers under skilled supervision. Construction cost is little higher than RCC structures.
Do post tension slabs have rebar?
Post–tension slabs are created with concrete trenches around the perimeter of the house where the external walls will be placed. The top slab of concrete is thinner than with concrete & rebar.
Can a post tension slab be repaired?
Post tension (PT) tendon systems are primarily used for large slab construction projects. Since the early 1950’s, post tension tendons have been used in the design of concrete structures. For such critical structural element, the repair should only be completed using a certified, experienced repair contractor.
Do I have a post tension slab?
Most homes that have post tension slabs have a sign that is stamped into a concrete garage floor, often near the edge of the garage door in plain sight. They may be able to look at the building plans and tell you if the home has a post tension slab, it’s thickness and location of the cables.
Why do engineers need prestressed concrete?
The aim in the use of prestressed concrete is to increase the tensile strength of concrete by introducing an internal compressive stress, counteracting in part the tensile stresses caused by these loads on the structural element.
How far apart are post tension cables?
The cables (steel bands wrapped together) are set up within the concrete in a grid pattern (usually about 48 inches apart) and are called tendons when they are covered by a plastic outer shell and held by an anchorage.