Job Pile design-450 (R1).pdf

BORED CAST IN-SITU PILE 1.0. 1.0.0 0

DESI DESIGN GN OF PILE PILES S

1.1.0

STRUCTURAL DESIGN OF JOB PILE -450MM DIAMETER

1.1.1

Input Data Load factor 

FL

=

1.5

Diameter of pile Pile capacity in compression Pile capacity in Tension Pile capacity in Lateral

D P T H f ck

= = = =

450 750.00 120.00 45.00

Grade of concrete Grade of steel Clear cover Minimum % of steel required

f y

Diameter of helical reinforcement

φt φ1 φ2

Min. diameter main reinforcement Max diameter of main reinforcement

1.1.2

=

25 N/mm²

= = =

415 N/mm² 60 mm 0.4 %

=

8 mm

=

16 mm

=

25 mm 159043 mm 19000 mm

 Ac  Area of pile cross section = Length of pile below cut off level = Depth of Fixity calculation (As per Appendix C, Cl. C-1.2 C-1.2))

Coefficient of stiffness Length of pile above GL Modulus of Elasticity of Conc.

Moment of inertia of pile Pile Stiffness

 As Fixed head pile Length of Fixity 1.1.3

c pt,min

K1

= = = = = = =

L1 E

I T

mm kN kN kN

L1 / T

= = =

Lf  / T

=

Lf 

=

0.34 0 5 00 00 0 fc k 25000 254842 π D4 / 64

kg/cm² m

(From Table 1 of IS 2911, Part1 Sec.2)

N/ N/mm² k g/cm²

201289 cm 1/5 (E I /K 1 ) 172.1 cm 0.00

4

2.2

(From Fig 2 - IS 2911, Part1 Sec.2)

378.6 cm

Design of pile from cut off level to depth of fixity

1.1.3.1 Design for Tension with Bending Factored Lateral load

Hu

=

Factored Bending moment

Mu

=

Mu

= = =

127.77 kN kNm 0.83 106 kNm

d' d' / D  Tu

= = =

72.50 mm 0.16 180 kN

 Mu/f ck b*b

2

=

0.067

Tu / ( f ck b*b )

=

0.045

=

0.071

=  =

1.78 % 2823 mm

Reduction factor Design Bending moment Effective cover Factored Uplift load(Tension)

Refer Chart 80 & 81 of SP:16

p/f ck p

 Area of steel required

 Ast req

67.5 kN Hu(L1+Lf)/2

For fixed head pile (From Fig 3 - IS 2911, Part 1 Sec.2)

( b is the equivalent side of a square)

1.1.3.2 Design for Compression with Bending Slenderness ratio=(leff/D)=(3786x1.2/450)=10.096 < 12 ,hence considered & designed as short (ref. IS:456)

Minimum eccentricity =(Lf/500)+(D/30) =

(3786/500)+(450/30)

= 22.5mm < = 0.05D i.e. 22.5 mm.

Pu

Factored compressive load

Pu/f ckD

=

1125 kN

2

=

0.222

3

Mu/f ckD Refer Chart 57 & 58 of SP:16  Area of steel required

=

0.047

p/f ck

=

0.038

p  Ast req

=

0.95 % 1511 mm

=

1.1.3.4 Design for Bending only Pu

Factored compressive load

=

Pu/f ckD

=

0.000

3

Mu/f ckD Refer Chart 57 & 58 of SP:16  Area of steel required Provide

7 Nos

=

0.047

p/f ck

=

0.057

p  Ast req

= =

1.43 % 2266 mm

25 dia  Ast prov.

1.1.4

0 kN

2

+

0 Nos

0 dia 2 mm > 3436 O.K.

=

Design of pile below depth of fixity

1.1.4.1 Vertical Compression Factored compressive load  Axial capacity (As a plain conc section)

Pu

=

Pa,u

= =

1125 kN 0.4 f ck  Ac 1590 kN O.K.

1.1.4.2 Vertical Tension: Tu

Factored Tensile load

=

 Ast,req

 Area of steel required

=

180 kN Tu / 0.87 * f y

= Provide

7 Nos

16 dia  Ast prov.

+

499 mm

2

0 Nos

=

0 dia 1407 mm O.K.

HENCE PROVIDE 7-25 BARS TO A DEPTH OF 6000MM FROM CUT OFF LEVEL  AND PROVIDE 7-16 DIA. BARS FOR BALANCE DEPTH OF PILE. 1.1.5

LATERAL TIES Diameter of Circular ties Spacing of the circular ties : least of the following : i). Diameter of pile ii) 16 φ1

=

8 mm

= =

450 mm 256 mm

iii) 300 mm

=

300 mm

∴ provide

8 dia

@

200mm c/c

2823 mm2