All about civil construction knowledge- PARAM VISIONS

What are the points to be checked before buying TMT bars?/ Check list to purchase steel bars for construction.

 Following are the 11 points, that should be observed before buying a TMT bar, without doing any tests over the bars.


1. Brand :

Always go for the top brand while buying the TMT bars from the market. They may cost 5 to 10% more when compared to the other locally manufactured steel bars. My suggestion is, don't compromise in quality to save a little money in your budget. 

Some of the top brands in India are 1. Tata steel.  2. JSW steel.  3. Jindal steel.  4. ESSAR steel etc.


2. Grade of steel :

As you can observe in the above drawing, you will find the grade of steel embossed over the bars. Select the right one, to suit the design of your structure.


3. Bar diameter:

Check the diameter of the bars to purchase the right amount of steel bars of needed size & weight. You will find the diameter on every bar, as shown in the above drawing.


4. Type of bar:

Different types of bars are available in the market having different mechanical & chemical properties. Among them, TMT bars are the widely used ones, in the construction of residential buildings.

Note: Go through the article Different types of steel bars used in construction.   to understand the rebar classification.


5. Surface ribs:


The ribs over the rebars should be uniform & clear, placed at an equidistant from each other (as shown above). These ribs play a major role in developing a good bond strength with the concrete to provide the required stability to the structure.


6. Rusted rebar:


The fresh rebars are grey in color. When the steel bars are exposed to atmospheric moisture for a longer duration, they get rusted due to oxidation. As you can observe in the above image, the rusted bar turned orange-brown in color. 

At any cost, you should not buy the rusted bars. They create a decreased bond strength & affect the life span of the structure. 


7. Rebar test certificate:




When you deal with the trader, ask for the rebar test certificate to know the specification & strength of the bar of different diameters. All the branded manufacturers have these test certificates, to maintain the standard & quality of rebars.


8. ISI mark:



The Industrial Standards Compliance ( ISI ) is set for the steel bars to ensure quality while manufacturing them. Check for the ISI mark before buying the bars. 


9. National certification :

While manufacturing the steel bars, different types of codes or standard certifications are followed to meet the required properties & specifications of rebars. 

The general codes or certifications that are used are IS 1786, IS 432 (MS ), ASTM A706, BS 449, ASTM A615, JIS G3112, etc. Check the manufacturer's certification, to know the characteristic properties & bar quality.


10. Steel brochure:




Go through the steel bar brochure, to know the chemical composition like percentage of carbon content in steel, mechanical & chemical properties, rebar weight tolerance, etc.



11. Bundle weight:

The manufactured bars may be underweight, theoretical weight, or overweight, depending upon the dye used while casting the bars. If the weight of the bars is above the tolerance limit, then you will pay more money for that extra weight. 

The weight of the bundle should be within the purchase range, according to the tolerance given in IS-1786.

So, check the weight of each bundle of TMT bars and compare them with the purchase range table of that particular diameter bar.

To know the theoretical weight & purchase range of the steel bundle, go through the table in the article,

Tolerance or rolling margin for the steel bundle as per IS-1786.






Share:

No comments:

Post a Comment

Please do not enter any spam link in the comment box

Translate

Blog Archive

popular posts

Google search

Recent Posts

Pages