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Showing posts with label Steel Building Prices. Show all posts
Showing posts with label Steel Building Prices. Show all posts

Wednesday, January 17, 2018

Post Tension Slab and its benefits

Generally, post-tensioned (PT) slabs belong to flat slabs, band beam and slabs or ribbed slabs. PT slabs provide the leaner slab type, as concrete functions to its strengths, mostly being maintained in compression. Longer spans are obtained because of pre-stress, which are also utilized to resist deflections.

Post-tensioned slabs employ high-strength tensioned steel strands to compress the slabs to retain most of the concrete in compression. Reinforcement is arranged to control the compression.

In Post tension slab, the cables/steel tendons are applied to replace the reinforcement. It develops a very well-organized structure to reduce material usages as well as economic span range with regard to reinforced concrete.

Post-tensioning is very useful to defeat the natural weakness of concrete in tension and to optimize its strength in compression. In concrete structures, high-tensile steel tendons/cables are placed in the element prior to casting.

If the concrete attains the preferred strength the special hydraulic jacks are used to drag tendons and retain them in tension with specially designed anchorages fixed at each end of the tendon. It offers compression at the edge of the structural member that enhances the strength of the concrete for withstanding tension stresses.

If tendons are properly curved to a specific profile, they will employ, besides compression at the perimeter, a beneficial upward set of forces (load balancing forces) that will resist applied loads, alleviating the structure from a portion of gravity effects.
In this type of slab, cables are attached in spite of reinforcement. In Steel reinforcement the gapping among bars is 4 inch to 6 inch while in Post tension slab the gapping is over 2m.
Benefits:
• It facilitates slabs and other structural members to be slimmer
• It facilitates us to develop slabs on expansive or soft soils
• The produced Cracks are retained firmly mutually
• Post tension slabs are useful for building up stronger structures economically.
• It minimizes or removes shrinkage cracking. So, no joints, or fewer joints, are essential
• It allows us to design longer spans in elevated members, like floors or beams
Drawbacks:
• Only experienced professionals can construct post tension slabs.
• If precaution is not undertaken at the time of making it, it can cause future mishaps. In various situations, untaught workers become unable fill the gaps of the tendons and wiring entirely. These gaps lead to decay of the wires which become breakable quickly and unexpected collapsing may occur.
Post Tension Slab and its benefits

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Published By
Rajib Dey
www.constructioncost.co
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Wednesday, January 10, 2018

The process of concrete by weight and volume

atching is defined as the method for computing & combining the various components (cement, fine aggregate, coarse aggregate and water) for the formation of concrete prior to mixing following the mix design.

If this calculation is accomplished based on the volume, it is known as volume batching. Batching is categorized as follow :-

1) Volume batching
2) Weigh batching


Volume batching: In volume batching, the mass of each component is not calculated before batching, rather than there are some fabricated boxes(generally wooden) which are calculated in volume to retain the concrete components.

• This method is normally suitable for small jobs.
• Gauge boxes are applied for estimating the fine and coarse aggregate.
• The volume of gauge box has the similarity with the volume of one bag of cement.
• Gauge bow are also titled as FARMAS.
• They are formed with timbers or steel.

• Normally, they are created as deep and narrow.
• Normally, bottomless gauge boxes are not recommended for application.
• At the time of filling the gauge boxes the material should be filled loosely, no compaction is permissible.


Weigh batching: Weigh batching is the proper and most recognized method of estimating concrete ingredients. Weigh batching is performed in very vital modern concrete batching and mixing plants.

• Batching by weight is better than volume batching in terms of perfectness. Besides, it offers more consistent proportioning. It is always recommended professionally.
• It does not contain uncertainties related to bulking.
• Its equipment’s are divided into 3 general categories.
• Manual
• Semi-automatic
• Fully automatic.
• If batching is done by hand all weighing and batching of concrete are performed by hand. It is suitably for small jobs.

• For semi-automatic batching the aggregate bin gates are opened by operating switches with hand and gates are closed automatically when the material is delivered. This system also comprises of interlock that resists charging and discharging.

The process of concrete by weight and volume

Read more

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Published By
Rajib Dey
www.constructioncost.co
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Tuesday, May 2, 2017

Joint Detailing of Steel Hollow Sections

Likewise detailing of main structural members, detailing of joints in steel structure is also very vital. Joints mainly bear the loads which are transmitted from structures to various structural members. Therefore, the detailing work of joints in steel structure should be performed efficiently to make the structure secure for the specified loads.
Given below, the detailed information concerning the types of joints generally applied for structural steel hollow sections. There are different types of hollow sections which range from Rectangular Hollow Sections (RHS) and Square Hollow Sections (SHS) and Circular Hollow Sections (CHS).
Given below, the joint details for structural steel hollow sections (RHS and SHS) which are generally applied:
1. K – Type Joints: K – Type joints in steel structures develop as soon as the centroidal axis of horizontal member and two lateral bracings touch with the central axis of top chord.
Make sure that the ends of hollow sections should be closed. If any ends of a hollow section does not come nearer because of more width, then a plate is welded on that end so that the ends come to the nearer as well as the connection with other members remain effective with the sealing of the members. It resists inner corrosion of the hollow sections.
K-type of joints in structural steel members is easiest and most cost effective.
2. Knee – Type Joint: Knee-type joint is ideal for enhancing the strength of connection among vertical and horizontal members of structure.
In welded knee-joint, the chord situated at top is directly welded to the primary column and then an appropriately cut haunch is welded to the vertical and the chord member for making stiffening superior.
3. N – Type Joint: By following the implemented configuration, N-type joint is developed for relating web members to top and bottom chords.

To get more information, go through the following link theconstructor.org

Joint Detailing of Steel Hollow Sections

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Published By
Rajib Dey
www.constructioncost.co
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