The cable may still be live if only one strand has broken. The cable should be de-tensioned (which can be very dangerous) and removed. Cable failures can be as uneventful as a “pop,” or as catastrophic as “exploding concrete,” capable of severe damage and bodily injury.Beside this, how deep are post tension cables?
Cables are arranged as indicated by the engineer and chaired to run through the center of the slab. For residential construction, tendons at 48 inches on center are common.
One may also ask, how do you know if you 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. Older home's with post tension slabs may have a plastic or paper sign fastened to the wall.
Also to know is, can you cut a post tension slab?
Small penetrations are cut into a slab without affecting any of the existing PT tendons. Large openings require the cutting of existing tendons. Small penetrations. Prior to cutting small penetrations in a PT slab, existing tendons should be located using nondestructive testing (NDT) equipment.
How do post tension cables work?
Post-Tensioned Concrete Post tensioning is a technique for reinforcing concrete. Afterwards, once the concrete has gained strength but before the service loads are applied, the cables are pulled tight, or tensioned, and anchored against the outer edges of the concrete. Post-tensioning is a form of prestressing.
When should you stress post tension cables?
Post tensioned slabs should be stressed when the concrete strength designated by the engineer's plan is reached. The practice of MLAW has been to apply stress when the concrete reaches 2000 psi.Do post tension slabs have rebar?
Post-tensioned slab construction uses a combination of common rebar and high-strength tendon reinforcing, which is stressed after the concrete is poured. Rebar slabs work well for odd column layouts or geometries. Rebar placement tolerances are not as strict as would be required for PT tendons.Is post tension better than rebar?
Post tension foundations are what tract home and apartment builders use so therefore they are lower quality. Post tension foundations don't work for our soils. Rebar works better here. Those post tension cables can break one day and go flying out and might kill someone.Why Post Tensioning is done?
Common uses and advantages 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.How deep can you drill into a post tension slab?
In the absence of any other info, most PT applications are fairly standard. The field (the whole interior area) of a 4" slab has tendons at mid depth or below. If you drill no more one inch and set a 1" anchor, and select your bolt length for max 3/4" embed, you'll be secure. Drill 1/8" at a time and inspect the hole.What is the difference between pretension and post tension concrete?
In pre-tensioning the stressing wires or tendons are stressed prior to placing concrete as shown below. In post-tensioning the wires or tendons are stressed and each end is anchored to concrete section after has been cast and has attained sufficient strength to safely withstand the prestressing force, as shown below.What is a post tension Foundation?
A post-tensioned foundation is a concrete slab foundation that is reinforced with stranded steel cables that are tensioned after the. concrete hardens. The stranded cables are slid inside of plastic-sheathing, which prevents the stranded steel tendons from touching the concrete.What is post tensioning system?
Post-tensioning is a method of reinforcing (strengthening) concrete or other materials with high-strength steel strands or bars, typically referred to as tendons. Although post-tensioning systems require specialized knowledge and expertise to fabricate, assemble and install, the concept is easy to explain.Can post tension slabs crack?
Post-tensioned concrete slabs are typically expected to crack less than other slabs because post-tensioning produces a compressive stress that must be exceeded before enough tensile stress develops to cause cracking. For a 100,000 ft2 post-tensioned slab, this would result in an estimated 900 lineal ft of cracks.What is the benefit of a post tension slab?
Strength. Post-tensioned concrete is stronger and more flexible than conventional steel-reinforced concrete. According to the Concrete Network, post-tensioning helps reduce cracking from shrinkage as the concrete dries, and holds together any cracks that do form.How much does a post tension slab cost?
The cost of the post-tensioned slab is $30.52 per square foot which is approximately the average cost of the four floor systems.When did they start using post tension slabs?
When did we start using Post Tension Slabs ? The use of post tension cables has been around for many years. Back in the 1960 there was limited use in concrete foundations in residential construction, but very little.What are post tension cables?
Post–tension cables are used in concrete construction to allow thinner slabs and greater span lengths between support columns. These cables, composed of steel wires inserted into a plastic sheath, are subsequently "tensioned" and grouted after the concrete is poured.Can I cut into a post tension slab?
Post-tensioned (PT) slabs have the added complexity in that PT strands may have to be cut. Small penetrations are those that can be cut into a slab without affecting any of the existing PT tendons; conversely, large openings are those that require the cutting of existing tendons.How do you make a post tension slab?
To create a slab using this method, plastic sleeve-covered steel cables are laid in a grid running in both directions. Then concrete is poured and allowed to harden to 75% of its design strength. The cables are then post-tensioned or pulled by a hydraulic jack and the concrete is allowed to cure completely.How can you tell if concrete is reinforced?
To find whether the concrete contains rebar is simple, you can just use a metal detector. You can get a pretty good idea whether it's reinforced or not. To find the sizes or the depth of rebar is more complicated and you need more professional tools. Generally you can use a covermeter/rebar locator/pachometer.Which is better raised foundation or slab?
If the building site has problematic soil, such as expansive clays, a raised floor foundation would perform much better than slab, as slab would most likely crack on this type of soil. A raised floor is also used to raise the building above a floodplain. 
