Tag Archives: re-bars

This is BBS ..dear !

Friends ,

The Structure of a building is in Reinforced Cement Concrete.

The steel bars provided in the concrete make it strong to carry the tensile forces.

Thses bars are called as REINFORCEMENT.

The detailing of these bars [ Diameter ,spacing,covers, laps , dowel lengths, development lengths and shapes } are provided by RCC designer and are specified in the RCC drawing.

The extract of the steel reinforcement in the form of a table is known as Bar bending Schedule. The tabulation of the reinforcement details can be conviniently done using the MS Excel.

Professional contracting firms have got printed formats for BBS ready for the use of their staff. The BBS is prepared by the Qauntity Surveyors during estimation . The BBS is also prepared by the Site Engineers for controlling the quality of the Reinforcement Bars at site. The BBS is also an excellent tool for recording the measurements of the Reinforcement bars at site and the BBS can also be used to submit the Bills for the Reinf..bars.

This is a chart which basically gives the micro details about the various bars. This gives the dia, shape of bar , cutting length of the various bars in a RCC element such as Footing, column , beam ,slab etc.

The site engineer prepares the BBS based on the drawing and after due verification , hands it over to the reinforcement fitter.

By the use of BBS , the weight of the Re-bars can be easily calculated.

Let me explain you this popular tool with an example.

Imagine , there is a beam of the following cross section.

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CROSS SECTION OF A RCC BEAM

The details of the reinforcement have been tabulated in the following table :

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The cutting lengths of each bar is calculated and tabulated as follows :

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But you can see that many details are missing from this abstract. Hence , a better tabulation , known as the BBS has been prepared which gives each details of the Re-bar in a crystal clear method :

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The bar bending gives a very clear picture of the reinforcement.

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What kind of concrete mix and dia of steel bars are used in high rise structures?

Answer by Arafat Basheer:

Differs from level to level and type of member. I worked in a project of G+27 and we used concrete mixes ranging from M50 to M30 in columns and beams, and  M35 to M25 in slabs higher mixes in lower levels and lower mixes in upper levels. Column reinforcements ranged from 32mm to 12mm depending again on location and level of structure. Shear walls had dense and higher dia bars, so did outer skeltal columns. Inner skeltal columns had lower dia as compared to outer columns.

What kind of concrete mix and dia of steel bars are used in high rise structures?