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BBS for RCC Column

Bar Bending Schedule for R.C.C Column

Bar Bending Schedule for R.C.C Column

This article is about How to prepare B.B.S for Column With Complete Details.

To preparing B.B.S for a column. there are some criteria and assumptions that require to be met Let’s get started.

Bar Bending Schedule for R.C.C Column

Forces on Column

U should know the normal forces action on a column.

Just look at the diagram that is given below:

If you see the shear force and bending moment diagram, the column has less moments at center & more at bottom and top.

When bending moment is maximum not at any time tie a column at top and bottom every rime tie the column at center.

At site tie the bars at the height of 4 to 5 feet. The height of roof should not be more than 11 feet.

  • Use less cutting of steel and provide desirable lapping.
  • Lap another steels at same time.
  • Overlap the top steels with bottom steels.
  • Between the laps end to end spacing should be provided.

Learn More

Bar Bending Schedule ( B.B.S ) Estimate of The Steel in Building Constructions

Bar Bending Schedule (B.B.S) used by

B.B.S is used by different kind of peoples and officials on construction site which is given below:

  • Quantity surveyor
  • Steel fixer
  • Contractor
  • Project manager
  • Inspectors
  • Clerks of construction

In construction site all Estimation & Costing operation is the responsibilities of Quantity Surveyor. The B.B.S gives the details to Quantity Surveyor for finding out the number of steel its type, size and shape. Contractor are using (B.B.S) for ordering the steel bar for proceeding the construction.

Learn More

  1. Bar Bending Schedule for RCC Beam In Full Detail

  2. How to Calculate Staircase Concrete & Bar Bending Schedule And Staircase Reinforcement Details

Steel fixer using  (B.B.S) for doing their work or installing the bar in column, beam or slab according to the (B.B.S) that how much cut length or bending of bar will be needed and which size of steel should be use. The inspector and clerks of construction refers to the B.B.S to make are that the reinforcement work in the field is in proper with the design reinforcement as per drawing.

Bar Bending Schedule for Column

Bar Bending Schedule for RCC Column

Details from the diagram

  • Thickness of slab is150 mm
  • Floor height is 3 m or 3000 mm
  • Footing depth is 400 mm
  • Development Length is 50d
  • Column has 4 numbers of 16 mm dia bars
  • Stirrup spacing is 8mm @ 150 mm C/C
  • Concrete Cover of Footing is 40 mm
  • Concrete Cover of slab is 20 mm

Learn More

  1. How To Calculate The Cutting Length Of Circular Stirrup

  2. Estimating Of Steel Bar Quantity for Construction

 

Steps for B.B.S of Column

Generally, there are five steps for preparing the B.B.S of column these five is given below:

  • Find the length of Vertical Bar
  • Find out lapping
  • Cutting Length of Stirrups
  • Number of Stirrups
  • B.B.S

Find the length of  Vertical Bar

Length of Vertical bar = Development length (Ld) + footing depth + Floor Heights + Slab Thicknesses + Overlap Length

= (12×16) +400+ (3000) +(150) +(50×16)

= 4734 mm or 4.73 m

Learn More

  1. Calculation Method For Find Out The Overlapping Length Of Beam, Column And Slab
  2. Bar Bending Schedule For Slab And Estimation Of Steel Reinforcement In Slab

Now We Will find the length of the One Vertical bar

The total length of the vertical bar = 4732 x number of steels in column

The total length of the vertical bar = 4732 x 4

The total length of the vertical bar = 18928 mm

Find out lapping:

length of lapping is 50d

Lapping length = 50 x Dia of steel

Length of lapping = 50×16 = 1000 mm.

We know that the length of typical steel is 12.25 m or 40 feet length

Total Length of Vertical Bar = 18.9 m that is more than 12.25 m or 40 feet so lapping should be provided.

Length of lapping is 1000 mm the result will be 18.928 + 1 = 19.928 m

It is mentioned already in this article, consider the points while lapping the bar. There is no one right process we can use. Just remember the lines.

  1. Don’t tie a column at bottom and also at top
  2. Lap at another bars every time
  3. Overlap top bars with bottom bars always

Learn More

  1. How To Calculate The Cutting Length Of Stirrups In Beam And Column

  2. How to Calculate Staircase Concrete & Bar Bending Schedule And Staircase Reinforcement Details

  3. Cutting length Determination Of a Spiral Or Helix Bar

Cutting Length of Stirrups

We already discussed cut length of stirrup in B.B.S for beam article.

Length of One Hook = 9d

Cutting length of Stirrup = (Perimeter of stirrup – concrete cover) + Number of Hooks

Cutting length of stirrup = 2(a- cc) + 2(b-cc) + 2 hooks

Cutting length of stirrup = 2(500- 25) + 2 (200-25) +(2x9d)

= (2×475) +(2×175) + (2×9×16)

Cutting length of Stirrup = 1588 mm

Number of Stirrups:

Number of stirrups = (Total length of Column ÷ spacing of stirrups) +1

Number of stirrups = 4773 ÷ 125 + 1

Number of stirrups = 39 numbers

Learn More

How do you take off a Staircase

B.B.S=

The B.B.S of column is shown below in table

S. NO Bar Mark Bar dia No of bars Length (m) unit weight(m/kg) weight of steel (Kg)
1 Vertical Bar 16 4 4.773 1.57 29.97
2 Stirrups Bar 8 39 1.588 0.395 24.46
Total Weight of Reinforced Concrete Column 54.43

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Other Post

  1. How To Calculate The weight of Steel With Formula

  2. How to calculate the cutting length of reinforcement bars in circular R.C.C slab

  3. Calculation Of Staircase Concrete And Bar Bending Schedule (BBS) | Staircase Reinforcement Details

  4. How To Calculate The Cutting Length Of Chair-bar In Footings

 

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About Raja Junaid Iqbal

Hi My name is Raja Junaid Iqbal and i am Land Surveyor by Profession but I've specialized in the field of Q,S and land development. As Professional Surveyor I engaged my self in all over the Gulf since 14 years.

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