Bar Bending Schedule for Column – Detailed Practical Guide

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In this post, we are going to explain “How to make bar bending schedule for Column?”

This article will be quite long. Brace Yourself.

First of all, there are some criteria & assumptions that need to be met while making bar bending schedule for a column. Let’s get started.

Loads Acting on Column

We hope that you know the typical load action on a column.

Just take a look at the below diagram.

Load acting on column

If you see the internal forces and moment diagram, the column has maximum moments at top and bottom and less at centre.

Never tie a column at top & bottom where the critical moment is high. Always tie the column at centre.

For practical always tie the bars at 5 feet height. Since every roof should not be more than 10 feet.

  • Minimise the cutting of bar and lapping as often as possible.
  • Always lap alternate bars at a time.
  • Always overlap top bars with bottom bars.
  • Maintain sufficient end to end spacing between the laps.

Bar Bending Schedule for Column

Reinforcement Details of Column

From the diagram,

  • Slab Thickness – 125 mm & 100 mm
  • Floor height – 3000 mm or 3 m
  • Ground Floor Level – 3300 mm
  • Footing Height – 300 mm
  • Development Length – 50d
  • Column has 6 numbers of 20 mm dia bars
  • 8mm stirrups @ 150 mm C/C
  • Footing Clear Cover – 40 mm
  • Slab Clear Cover – 25 mm

Step 1 – Find the length of Vertical Bar

Length of Vertical bar = Development length (Ld) + Height of Ground Level + Floor Heights (1,2,3)+ Slab Thicknesses + Overlap Length (Det.B)

= (50×20)+3300+ (3×3000)+(3×125)+100 +(50×20)

= 14775 mm or 14.78 m

Now we know the length of one vertical bar. Normally column reinforcement drawings won’t come with lapping details.

Step 2 – Find out lapping

As we know that lapping length required is 50d = 50 * Diameter of the bar = 50×20 = 1000 mm.

We know that each bar is 12.25 m or 40 feet length (approx).

Total Length of Vertical Bar = 14.2 m which is more than 12.25 m so each rod will be lapped at least once to attain the required length.

So we have added the lapping length with the total length = 14775+1000 = 15775 mm or 15.78 m

As we mentioned earlier in this post, consider the points while lapping the bar. There is no one correct method we can use. Just remember the lines.

  • Never tie a column at top & bottom
  • Always lap at alternate bars
  • Always overlap top bars with bottom bars

Step 3 – Cutting Length of Stirrups

As we already discussed in Bar Bending Schedule for Beam post,

Cross Section of Column Reinforcement

Length of One Hook = 9d (As per Estimating and Costing in Civil Engineering P.No.214)

Cutting length of Stirrup = Perimeter of stirrup + Number of Bends + Number of Hooks

= 2(a+b) + 3 numbers of 90 degree bends + 2 numbers of hooks

= 2(500+200)+(3 x2d)+(2x9d)= 2×700+3x2x20+2x9x20

Cutting length of Stirrup = 1880 mm

Step 4 – Number of Stirrups

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

      = (3300+125+3000+125+3000+125+3000+100)/150 + 1

Number of stirrups                = 85 no.s

Step 5 – Bar Bending Schedule

Diameter of Bar Numbers Cutting Length Total Length
Vertical bar 20 mm 6 14.2 m 85.2 m
Stirrups Bar 8 mm 85 1.88 m 159.8 m

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