How To Make BBS Of Pile Foundation & Pile Cap - LCETED -lceted LCETED INSTITUTE FOR CIVIL ENGINEERS

## Jan 30, 2022

In this article, we explained How to make a bar bending schedule of pile foundation

PILE FOUNDATION DIAGRAM

GIVEN DATA:

Pile cap length = 4000mm

Pile diameter = 1.2m or 1200mm

Pile radius = 0.5m or 500mm

Number of Vertical rod in piles = 16nos

Length of the pile driven = 32.5m

Clear cover of the pile= 75mm

Vertical Rods Diameter and Numbers of Piles

 Length No of vertical rods are used in piles Diameter of steel 0 to -12 m 16nos 25Ã˜ -12 to -21m 16nos 20Ã˜ -21 to -32.5m 16nos 16Ã˜

The length of the vertical rods, divided by 12meter of rod length and diameter of the rod changes on each segment, which will be decided by the structural consultant. The above table is for calculation purpose

Master Ring Calculation

Dia. Of master ring = 16 mm @ 1500 mm c/c

No. of master ring = (Length of pile / Spacing) + 1 = 32.5/1.5 = 21.67 = 22nos

Helical Ring Calculation

No. of spirals = (Length of pile / Pitch of pile) + 1 = 32.5/0.15 = 216.67 = 217nos

MASTER RING CALCULATION

Details Given for Master Ring

Length of pile = 32.5 m or 32500 mm

Diameter Of master ring = 16 mm @ 1500 mm c/c

Length of 1 master ring = Circumference of ring/circle = 2 Ï€r

r = R = Radius = diameter/2

Diameter of The Master Ring = Diameter of pile – (2 x clear cover) – (2 x spiral ring diameter) – (2 x Vertical bar diameter) – (Master ring dia)

Vertical bar diameter varies in each segment as 16, 20 and 25. We will take 25mm dia for the vertical bar diameter because it is the highest dia

Dia = 1200 – (2x75) – (2x8) – (2x25) – (16)

Dia = 968mm

r = dia/2 = 968/2 = 484mm = 0.484m

Length of 1 master ring = Circumference of circle = 2 Ï€r

Length of 1 master ring = 2 x 3.14 x 0.484 = 3.039m

Total number of master ring (Nr)= (Length of pile / Spacing) + 1 = (32500 / 1500) + 1 = 22.67 - 23nos.

For 23 nos. of master ring = 3.039 x 23 = 69.897m of 16mm dia

SPIRAL OR HELICAL RING CALCULATION

Details Given For Spiral or Helical Ring:

Dia. of pile = 1200 mm or 1.2 m

Length of pile = 32.5 m or 32500 mm

Pitch or Spacing = 150 mm

Clear cover = 75 mm

Dia. of spiral bar = 8 mm Ã˜

Length of 1 helical ring = Circumference of ring/circle= 2 Ï€r

r = R = Radius = diameter/2

Diameter of the helical Ring = Diameter of the pile – (2 x clear cover) – (Spiral bar dia)

Diameter of the helical Ring = 1200 – (2x75) – (8) = 1042mm

Diameter = r/2 = 1042mm

r = dia/2 = 1042/2 = 521mm

r = 521mm or 0.521mm

Length of 1 spiral or helical ring = 2Ï€r = 2 x Ï€ x 0.521 = 3.27mm

No. of helical or spirals ring (Nr) = (Length of pile / Pitch of pile) + 1

= (32500 / 150) + 1

= 217.666666667 – 218 nos.

Total length of spiral or helical ring = 3.27 x 218 = 712.86m

We know that the length of a full-length bar is 12 m. so, we should find the total length of lap

To find, Lap considered 50 d

As we know diameter of spiral ring 8mm = 50 x 8 = 400 mm = 0.4 m

Number of lap needed = [Total no. of bar / One full length bar] – 1

= (712.86 / 12) – 1 = 58.405 – 59nos

Total length of lap = 0.4 x 59 = 23.6 m

Total Length of Spiral Ring = 712.86m + 23.6m = 736.46 meters of 8mm dia

VERTICAL BAR CALCULATION

Details Given on Vertical Bar Calculation

Length of one bar 25 Ñ„ – 12m

 Length No vertical rods used in piles Diameter of steel 0 to -12 m 16nos 25Ã˜

= 50 d +12000 + 50d = (50 x 25) + 12000 + (50 x 25) = 14.5 m - 14500 mm

Therefore,

Length for 16 no. bar = 14.5 x 16 = 232m

Length of one bar 20 Ñ„ – 12m

 Length No of vertical rods are used in piles Diameter of steel -12 to -21m 16nos 20Ã˜

= 50 d +12000 = (50 x 25) + 12000 = 13.25 m - 13250 mm

Therefore,

Length for 16 no. bar = 13.25 x 16 = 212m

Length of one bar 16 Ñ„ – 8.5m

 Length No of vertical rods are used in piles Diameter of steel -21 to -32.5m 16nos 16Ã˜

= 8500 + 300 – (bend) = 8500 + 300 – (2d) = 8500 + 300 – (2x16) = 8.768m - 8768mm

Therefore,

Length for 16 no. bar = 13.25 x 8.768 = 116.176m

 Dia. of bar in mm Spiral ring Master ring Vertical rod Total length in m Unit weight of steel in kg/m Total weight in kg 8 mm 736.46 m - - 736.46 m 0.395 kg/m 290.90 kg 16 mm - 69.897m 116.176m 186.07m 1.58 kg/m 293.99 kg 20 mm - - 212m 212 m 2.47 kg/m 523.64 kg 25 mm - - 232m 232 m 3.86 kg/m 895.52 kg Total Weight in Kg 2004.05

How to Make BBS of Pile Cap - Pile Cap Steel Bar Calculation

Given Details

Pile Cap size = 4.0m x 4.0m

Bottom Reinforcement 1st layer

Pile Cap Size = 4000 X 4000

Clear cover = 50 mm

Bottom reinforcement dia = 25 Ñ„

Length of the Bottom reinforcement 1st layer = Length of pile cap – (2 x clear cover) – (2 x half of dia bar) + (2 x development length (x)) – (2 x bend)

As we know,

Clear cover = 50mm

Diameter = 25mm

Bend = 2d = 2 x 25 = 50mm

Development length x = 750 – 75 – 50 (clear cover) – 12.5 (half dia) + 150 = 762.5mm – 0.762m

Therefore,

Length of the Bottom reinforcement 1st layer = 4000 – (2 x 50) – (2 x 25/2) + (2 x 762.5) – (2 x 50) = 5300 mm = 5.3m

Number of bar (25 Ñ„ @ 100c/c) = [Length of bar / Spacing] + 1 = [4000 / 100] + 1 = 41 nos.

For 41 nos,

Total length of bar required = 5.3 x 41 = 217.3m

Top Reinforcement 1st layer

Length of the Top reinforcement 1st layer = Length of pile cap – (2 x clear cover) – (2 x half of dia bar) + (2 x development length (x)) – (2 x bend)

As we know,

Clear cover = 50mm

Diameter = 12mm

Bend = 2d = 2 x 12 = 24mm

Development length Y = 750 – 50 (clear cover) – 6 (half dia) + 150 = 844mm – 0.844m

Therefore,

Length of the Top reinforcement 1st layer = 4000 – (2 x 50) – (2 x 12/2) + (2 x 844) – (2 x 24) = 5528mm = 5.5m

Number of bar (12 Ñ„ @ 125 c/c) = [Length of bar / Spacing] + 1 = [4000 / 125] + 1 = 33 nos.

For 33 nos,

Total length of bar required = 5.5 x 33 = 181.5m

Bottom Reinforcement 2nd layer

Length of the Bottom reinforcement 2nd layer 25 Ñ„ = Length of pile cap – (2 x clear cover) – (2 x half of dia bar) + (2 x development length (x1)) – (2 x bend)

As we know,

Clear cover = 50mm

Diameter = 25mm

Bend = 2d = 2 x 25 = 50mm

Development length X1 = 750 – 75 – 50 (clear cover) – 12.5 (half dia) – 25 (1st reinforcement dia) + 150 = 737.5mm – 0.737m

Therefore,

Bottom reinforcement 2nd layer 25 Ñ„ = 4000 – (2 x 50) – (2 x 25/2) + (2 x 737.5) – (2 x 50) = 5250mm – 5.2m

Number of bar (25 @ 100 c/c) = [Length of bar / Spacing] + 1 = [4000 / 100] + 1 = 41 nos.

For 41 nos,

Total length of bar required = 5.2 x 41 = 213.2m

Top Reinforcement 2nd layer

Length of the Top reinforcement 2nd layer 12 Ñ„ = Length of pile cap – (2 x clear cover) – (2 x half of dia bar) + (2 x development length (Y1)) – (2 x bend)

As we know,

Clear cover = 50mm

Diameter = 12mm

Bend = 2d = 2 x 12 = 24mm

Development length Y1 = 750 – 50 (clear cover) – 6 (half dia) – 12 (1st reinforcement dia) + 150 = 832mm – 0.832m

Therefore,

Top reinforcement 2nd layer 12 Ñ„ = 4000 – (2 x 50) – (2 x 12/2) + (2 x 832) – (2 x 24) = 5504mm – 5.5m

Number of bar (12 Ñ„ @ 125 c/c) = [Length of bar / Spacing] + 1 = [4000 / 125] + 1 = 33 nos.

For 33 nos,

Total length of bar required = 5.5 x 33 = 181.5m

Side Face Reinforcement

Length of the Side reinforcement 12 Ñ„ = (Length of pile cap – (2 x clear cover) – (2 x half of dia bar) + (2 x development length) – (2 x bend)) x 2 (sides)

As we know,

Clear cover = 50mm

Diameter = 12mm

Bend = 2d = 2 x 12 = 24mm

Development length Y1 = 2000 – 50 (clear cover) – 6 (half dia) –+ 150 = 2094mm – 2.094m

Therefore,

Length of the Side reinforcement 12 Ñ„ = (4000 – (2 x50) – (2 x 6) + (2 x 2094) – (2 x 24)) x 2 = 16056mm - 16m

Number of bar (12 @ 125 c/c) = [Length of bar / Spacing] + 1 = [2000 / 125] + 1 = 17 nos.

For 17 nos,

Total length of bar required = 16 x 17 = 272m

 Dia. of bar in mm Spiral ring Master ring Vertical rod Side reinforcement Top reinforcement Total length in m Unit weight of steel in kg/m Total weight in kg 8 mm 736.46 m - - - - 736.46 m 0.395 kg/m 290.90 kg 12 mm - - - 272m 363m 635 m 0.889 kg/m 564.51 kg 16 mm - 69.897m 116.176m - - 186.07m 1.58 kg/m 293.99 kg 20 mm - - 212m - - 212 m 2.47 kg/m 523.64 kg 25 mm - - 232m - 430.5m 662.5 m 3.86 kg/m 2557.25 kg

Total weight of steel required = 4230.29/kg - 4.2ton

If you find

Tags: #pilefoundations #pilefoundaitonbbs #foundationpiles #foundationdrilling #deepfoundation #pilefoundation #piling #corebarrel #bulletteeth #rollerbits #boredpiling #drillrig #drillingbucket #boredpiles #boredpile #foundationcontractor #rockdrilling #pilingrig #drillingtools #rockbucket #pilings #deepfoundationdrilling #foundationdrillingtools #corebarreldrilling #hardrockdrilling #pilingequipment #rockdrillingtools #pilingrigs #pilingworks #deepfoundations #pilingwork