Published by: Harga Besi Beton
Post-tensioning can be process of reinforcing and prestressing concrete. Stresses are delivered into the concrete applying bars or strands of steel while is it being conscructed. The strands of steel are usually utilized in horizontal construction for example foundations and beams. Steel bars are utilized for vertical purposes for instance columns and walls.
Standard steel strands used in post-tensioning use a tensile strength of 270,000 pounds/in². In contrast, an average non-prestressed piece of reinforcing includes a tensile strength of 60,000 psi. Strands typically have a diameter of 1/2 in. and therefore are stressed to a force of 33,000 pounds. The stresses delivered into the concrete offset the expected external loads the concrete will experience.
In post-tensioning the steel is held in a duct, which halts the steel and concrete from binding after the concrete solidifies. The steel are able to be stressed after concrete sets. Normally, this is accomplished in two phases. The first prestress used is up to 50% of the last force and this is completed when the compressive strength reaches 12-15N/mm².
Then 2nd phase is once the last stressing takes place and this is conducted when te concrete meets its design strength. The strands and bars are tensioned by stretching all of them with a hydraulic jack. They're then fixed in place by having an anchoring element, which holds the force in them for the life of the building. Post-tensioning permits te engineer to have all the advantages of using prestressed concrete while maintaining the freedom of constructing on site.
Concrete is extremely strong in compression and weak in tension. Steel on the other hand is quite strong in tension. By mixing the two materials we make a component, which is strong in both tension and compression. Additional advantages are available by using the steel to put the concrete into compression. This increases it's tensile strength, that allows for longer spans and thinner parts. It also helps to stop the formation of shrinkage cracks, which often stops moisture passing through the material.
The more the concrete is compressed, the more unlikely it's that cracking will happen. Using post-tensioned concrete permits flexible column spacing as well as structural depth.
Thursday 13 November 2014
Details about the Reinforced Concrete Process
Published by: Harga Besi Beton
You will find various material that are used for the reinforcement of concrete, to create reinforced concrete. Mos popular material that's utilized in the reinforcement of concrete is steel. This is due to the fact steel is hard and therefore tension forces won't affect it a lot and also it could very easily be coated to make it stainless.
Using steel in reinforcement of concrete is performed in various methods, depending on the wanted end result. You can find reinforced concretes, where the steel reinforcement are just applied to support the concrete to resist the forces. This kind of steel is known as tension steel. The reinforced concrete where the forces which are guarded against are bot tension and compression are referred to compression steel. This process referred to as double reinforcement is where the points that are tensile, meaning that tension forces will probably act are correctly reinforced.
Another points that are reinforced in additional are the compressive points, where the compression forces are likely to act on. In having these precautions, the constructors also take special care not over reinforce the building and to neither under reinforce the building. The effects of under reinforced concrete tend to be that the tension steel reinforcement can give in to the pressure and finally failure. It is because, the mixed compression force, which is the overall compression force of the concrete and the force exerted at the compression steel could be more than the tensile force. The reinforced concrete can therefore fail. In the situations of over reinforcement, the tension capability has become higher than the mixed compression force of the concrete and the force at the compression steel. This has an impact that the reinforced concrete building merely collapses. Another element that could trigger the reinforced concrete structure to be volatile and in severe cases disintegrate is carbonation. This is where the calcium silicate in the concrete responds with the CO2 in the air.
This mostly occurs when there are cracks in the concrete or when the cover layer wasn't properly applied. Fresh holes are often drilled in the surface to test how the building is dealing with carbonation. The drilled is added an indicator to exhibit weather carbonation has taken place in the concrete. If in becomes pink, then carbonation has taken place ad one may also figure out deep the extent of the carbonation is.
You will find various material that are used for the reinforcement of concrete, to create reinforced concrete. Mos popular material that's utilized in the reinforcement of concrete is steel. This is due to the fact steel is hard and therefore tension forces won't affect it a lot and also it could very easily be coated to make it stainless.
Using steel in reinforcement of concrete is performed in various methods, depending on the wanted end result. You can find reinforced concretes, where the steel reinforcement are just applied to support the concrete to resist the forces. This kind of steel is known as tension steel. The reinforced concrete where the forces which are guarded against are bot tension and compression are referred to compression steel. This process referred to as double reinforcement is where the points that are tensile, meaning that tension forces will probably act are correctly reinforced.
Another points that are reinforced in additional are the compressive points, where the compression forces are likely to act on. In having these precautions, the constructors also take special care not over reinforce the building and to neither under reinforce the building. The effects of under reinforced concrete tend to be that the tension steel reinforcement can give in to the pressure and finally failure. It is because, the mixed compression force, which is the overall compression force of the concrete and the force exerted at the compression steel could be more than the tensile force. The reinforced concrete can therefore fail. In the situations of over reinforcement, the tension capability has become higher than the mixed compression force of the concrete and the force at the compression steel. This has an impact that the reinforced concrete building merely collapses. Another element that could trigger the reinforced concrete structure to be volatile and in severe cases disintegrate is carbonation. This is where the calcium silicate in the concrete responds with the CO2 in the air.
This mostly occurs when there are cracks in the concrete or when the cover layer wasn't properly applied. Fresh holes are often drilled in the surface to test how the building is dealing with carbonation. The drilled is added an indicator to exhibit weather carbonation has taken place in the concrete. If in becomes pink, then carbonation has taken place ad one may also figure out deep the extent of the carbonation is.
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