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Single Pilecap 182

The document summarizes the design of a single pile cap to support a 600 kN axial load from a 400x600 mm column. Key details include: - The pile cap is 700 mm wide and 900 mm deep - Main reinforcement is 12 mm diameter bars at 110 mm c/c both ways - Shear reinforcement is 8 φ stirrups at 150 mm c/c - Punching shear and one-way shear checks are satisfied - Effective depth, bending moment, and shear force calculations are shown

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19K views2 pages

Single Pilecap 182

The document summarizes the design of a single pile cap to support a 600 kN axial load from a 400x600 mm column. Key details include: - The pile cap is 700 mm wide and 900 mm deep - Main reinforcement is 12 mm diameter bars at 110 mm c/c both ways - Shear reinforcement is 8 φ stirrups at 150 mm c/c - Punching shear and one-way shear checks are satisfied - Effective depth, bending moment, and shear force calculations are shown

Uploaded by

tanksaumil
Copyright
© Attribution Non-Commercial (BY-NC)
We take content rights seriously. If you suspect this is your content, claim it here.
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Download as DOC, PDF, TXT or read online on Scribd
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DESIGN OF SINGLE PILE CAP

DATA:-

Pile Diameter : 400 mm


Column Dimension B x D : 400 x 600 mm
Axial Load : 600 KN
Concrete Mix : M20
Steel Grade : Fe 415
DESIGN : -
1. Pile Cap Dimension :

Width of Pile Cap = ( hp + 2 x 150 ) = 400 + 150 + 150 = 700 mm

Depth of Pile cap = 2 hp + 100 = 2 x 400 + 100 = 900 mm.

2. Net Upward Pressure :

Pu = 1.5 x 600 = 900 KN


2
Upward Pressure = 900 = 1836.73 KN / m

0.7x 0.7
3. Bending Moment :-
Projection = 0.70 – 0.40 = 0.15 m
2
2
B.M. in Pile cap at section A – A Mu = 1836.73 x 0.15 /2 = 20.66 KN.m

4. Check for effective depth :


2 6
Mu = 0.138 fck b d = 20.66 x 10
6
d required = √ (20.66 x 10 ) / 2.76 x 700 = 103.40 mm

D provided = 900 mm
d available = 900 – 60 -12- 6 = 822 mm > d required i.e. 103.4 mm
5. Check for Punching Shear : -
As single Pile is provided, the cap has to be checked for punching shear.
Area resisting punching = (600 x 2 + 400x 2) x 822
=( 2000 x 822 ) mm
3 2 2
Punching stress = 900 x 10 = 0.550N/mm < 1.12 N/mm

2000 x 822
6. Main Reinforcement : -

Mu = 20.66 KN.m
2 6
K = Mu / bd = 20. 66 x 10 = 0.04 < Table value
2
700 x 822
2
Minimum Ast = 0.12 x 700 x 822 = 690.48 mm

100
Provide 12 mm Dia RTS @ 110 mm c/c both ways at bottom.
Provide same at top along perpendicular direction of main reinforcement.
7. Check for one way shear :-
Shear force at section A – A at a distance d/2 = 822 /2 = 411 mm from face of
column = 1836.73 x 0.15 x 0.70 = 275.51 KN
3 2
Shear stress = 275.51 x 10 = 0.48 N/mm

822 x 700
2
Ast provided = 113 x 700/110 = 719.71 mm

Pt = 719.71 x 100 = 0.13 % < Minimum Pt of Table value of shear stress

700 x 822
2
For Pt = 0.20% ζc from Table 61 of Design Aid to IS 456 -1978 = 0.33 N /mm
-3
Balance shear Vus =275.51 – (0.33 x 700 x 822 x 10 ) =85.628 KN.

Vus /d = 85.628 / 82.2 =1.042 KN/cm

Provide 8 Φ RTS 2 legged stirrups @ 150 mm c/c.

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