Tag Archives: BBS

What is Bar Bending Schedule ?

Hello Friends ,

The Blog has recently achieved a status of having 850 Followers .

Various Initiatives are regularly planned for the engagement and enlightment of the readers.

One such initiative is ” On Line courses for Civil Engineers ” which have been commenced from Sept 2016.

Many students have benefitted through the Basic Module for construction .

” The On line courses “ is an appropriate medium for learning new concepts or for honing the skills without disturbing the routine activities .

Now presenting the On line course on “BAR BENDING SCHEDULE ” which was requested by many students for some time.
This article explains the course Objectives and other details you would like to know.

Hope you get registered for this course by 15th April 2017 .

Course begins from 20th April 2017.

All the best !

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You can also directly apply through this form below :

 

 

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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BOX FOOTING…SO MANY BARS ?

Dear Friends ,

Now let us do one exercise on Box footing.

This is the exercise for you !

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This is the sketch for your reference :

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Now try to calculate the Cutting length for each of the bars and calculate the weight of the re-bars.

After you have done your work , just verify your answer with the solution given below.

All the best !

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RCC footing : Reinforcement

Exercise :

There is a sketch of a RCC footing.on which we need to work today.

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This is a hand drawn sketch of a trapezoidal footing.

The dimensions and the reinforcement details have been given in the sketch.

First thing is to ask several questions and seek the answers :

  1. What is the size of the footing in plan ? { 4 m x 3 M }
  2. What is the depth of the raft ? { 300 mm }
  3. What is the vertical depth of the sloping portion of the footing ? { 900 mm }
  4. What is the size of the column in plan ? { 1000 mm x 1000 mm }
  5. What is the main steel of the footing ? {16 mm Tor @ 200 mm c/c both ways }
  6. What is the reinf. in column ? { 8 bars of 25 mm dia Tor }
  7. Column stirrups ? {10mm bars @ 200 mm c/c }
  8. Height of the column { 5000 mm }.
  9. Cover for  the footing bars : 50mm
  10. Cover for the column bars : 40 mm
  11. Weight of 16 mm bars : 1.58 Kg/M
  12. Weight of 25 mm bars : 3.86 kg/M
  13. Weight of 10 mm bars : 0.62 Kg /M.

Thus we know the basic details.

Now let us calculate the weight of the reinforcement .

}1.MAIN BARS OF THE COLUMN: NOS X 25TOR

}TOTAL HEIGHT:

Vertical height + sloping height + Raft height 

5000 + 900 + 300 = 6200

}CUTTING LENGTH:

}TOTAL HEIGHT (6200) – BOTTOM COVER (50) -TOP COVER (40) + development length ’’L’’(300)

6200-50-40 + 300 = 6410= 6.41M

WEIGHT:

}25TOR : 8NOS X 6.41M* 3.85KG/M=  197.43KG

}2.STIRRUPS:  10 TOR@200 C/C

}CUTTING LENGTH:

}920*4 = 3680+ Hook length 120 = 3800 = 3.8M

NO OF STIRRUPS: 6110/200+1=32NOS

WEIGHT: 10 TOR:  32 NOS*3.8M*0.62=75.39KG

}

}

}3.RAFT BARS: 16TOR@200C/C BOTH WAYS

}A. LONG SIDE ( 4M):

}CUTTING LENGTH:

}4000-50-50+ development length ( 200+200) =4300= 4.3M

}NO OF BARS:

}(3000/200) +1= 16NOS

WEIGHT:

}16TOR:16NOS*4.3M@1.58KG/M=108.7KG

}

}

}3.RAFT BARS: 16TOR@200C/C BOTH WAYS

}B.SHORT SIDE( 3M):

}CUTTING LENGTH:

}3000-50-50+development length ( 200+200) =3300= 3.3M

}NO OF BARS:

}4000/200+1= 21NOS

}WEIGHT:

}16TOR:21NOS*3.3M @1.58KG/M=109.49KG

}16TOR:TOTAL:108.7KG+109.49KG=218KG

}

}

}

}10 TOR:    76   KG

}16TOR:   218   KG

}25TOR :  198   KG

}

}TOTAL WEIGHT:       492 KG

}