# PARAM VISIONS

All about civil construction knowledge- PARAM VISIONS

### Bar bending schedule (BBS) of a pile cap.(Part-2) / Calculating the cutting length & weight of reinforcement in a pile cap.

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5. Side face or roundup bar:

Theoretically, the side face bars are the stirrups to hold the pile cap reinforcements as shown in the drawing.

But practically, if the size of the pile cap is large, the side face bars need lapping as the length exceeds 12m. So, in such cases, the side face bars are provided in two equal U-shape parts as shown below.

The cutting length of the side face bar

= [{2nos. × ( a +b )} +( 2nos. × hook length) - (3nos. × 90° bend) - (2nos. × 135° bend)]

Where,

a = [ pile width - ( 2 × cover) - (2nos. ×1/2 × dia. of bar)]

= [ 2500mm. - ( 2 × 50mm. ) - ( 2nos. × 1/2 × 12mm.)]

a  = 2388mm.

b= [ pile length - ( 2 × cover) - (2nos. ×1/2 × dia. of bar)]

= [ 3200mm. - ( 2 × 50mm. ) - ( 2nos. × 1/2 × 12mm.)]

b = 3088mm.

The cutting length of the side face bar

= [{2nos. × ( 2388mm. + 3088mm. )} +( 2nos. × 10d) - (3nos. × 2d) - (2nos. × 3d)]

= [{2nos. × ( 5476mm. )} + ( 2nos. × 10 × 12mm.) - (3nos. × 2 × 12mm.) - (2nos. × 3 × 12mm.)]

[{10958mm.} + ( 240mm.) - (72mm.) - (72mm.)]

= 11054mm.

= 11.054m. < 12m.

Hence no lapping is required.

B. No of rebars:

1. No. of bottom bar layer -1 required

= [{ length of pile cap - (2nos. × clear cover)} ÷ c/c distance ] + 1

=  [{ 3200mm. - (2nos. × 50mm.)} ÷ 125mm. ] + 1

=   [{ 3100mm.} ÷ 125mm. ] + 1

= 24.8 +1

= 25.8.

By rounding off = 26 nos.

2. No. of top bar layer -1 required

= [{ length of pile cap - (2nos. × clear cover)} ÷ c/c distance ] + 1

=  [{ 3200mm. - (2nos. × 50mm.)} ÷ 150mm. ] + 1

=   [{ 3100mm.} ÷ 150mm. ] + 1

= 20.66 +1

= 21.66

By rounding off = 22 nos.

3. No. of bottom bar layer -2 required

= [{ width of pile cap - (2nos. × clear cover)} ÷ c/c distance ] + 1

=  [{ 2500mm. - (2nos. × 50mm.)} ÷ 125mm. ] + 1

=   [{ 2400mm.} ÷ 125mm. ] + 1

= 19.2 +1

= 20.2

By rounding off = 21 nos.

4. No. of top bar layer -2 required

= [{ width of pile cap - (2nos. × clear cover)} ÷ c/c distance ] + 1

=  [{ 2500mm. - (2nos. × 50mm.)} ÷ 150mm. ] + 1

=   [{ 2400mm.} ÷ 150mm. ] + 1

= 16 +1

= 17 nos.

Now, let us prepare a BBS table for the pile cap.

 Sl. No. Type of Bar Dia. in mm. Nos. Length in m. Total length in m. Weight in Kg/m. Total  bar wt. in kg. 1. Bottom bar Layer-1 20 26 3.806 98.956 2.467 244.12 2. Bottom bar Layer-2 20 21 4.466 93.786 2.467 231.37 3. Top bar Layer-1 12 22 4.004 88.089 0.887 78.13 4. Top bar Layer-2 12 17 4.68 79.56 0.887 70.57 5. Side face bar 12 5 11.054 55.27 0.887 49.02 6. Total weight of steel bars = 673.21 7. Add 3% wastage = 20.20 8. The grand total wt. of rebar's in pile cap = 693.41

Thank you for going through these calculation steps. Have a good day ðŸ˜„.