BORED CAST IN-SITU PILE DESIGN OF PILES

STRUCTURAL DESIGN OF BORED CAST IN-SITU PILE

HFL

SCOUR DEPTH

RBL

L1

Input Data

Load factor FL FL 1.5

Diameter of pile D D 500 mm

Pile capacity in compression P P 740 kN

Pile capacity in Tension T Tc 480 kN

Pile capacity in Lateral H Hc 100 kN

Grade of concrete fck fck 25 N/mm^2

Grade of steel fy fy 500 N/mm^2

Clear cover c c 60 mm

Minimum % of steel required pt,min pt 0.4 %

Diameter of circular tie reinforcement φt φt 8 mm

Min. diameter main reinforcement φ1 φ1 16 mm

Max diameter of main reinforcement φ2 φ2 25 mm

Area of pile cross section Ac Ac 196349.5 mm^2

( b is the equivalent side of a square) b 443.1 mm

Length of pile below cut off level L1 20000 mm

Depth of Fixity calculation (As per Appendix C, Cl. C-1.2)

Coe. of stiffness K1 inkg/cm² (From Table 1 of IS 2911, Part1) K1 0.26 kg/mm²

Length of pile above GL, L1 L1 0

Modulus of Elasticity of Conc. E = 5000√fck Ec 25000 N/mm²

254842.0

Moment of inertia of pile I = π D4 / 64 I 306796.2 cm⁴

Pile Stiffness T = (E I /K1 )^1/5 T 197.5 cm

L1 / T = 0.00 L1/T 0

As Fixed head pile Lf / T (From Fig 2 of IS 2911, Part1 Sec.2) Lf/T 2.2

Length of Fixity Lf Lf 434.6 cm

Design of pile from cut off level to depth of fixity

Factored Lateral load Hu Hu 111 kN

Factored Bending moment Mu = Hu(L1+Lf)/2 For fixed head pile Mu 241.2 kNm

Reduction factor = 0.83 (From Fig 3 - IS 2911, Part 1 Sec.2) Rf 0.83

Design Bending moment Mu Mu(d) 200.2 kNm

Effective cover d' d' 72.5 mm

d' / D = d'/D 0.145

Design for Compression with Bending

Slenderness ratio=(leff/D) Leff/D 10.43

<12 short col.

Minimum eccentricity =(Lf/500)+(D/30) 25.36 mm

0.05D 25 mm

Factored compressive load Pu Pu 1110 kN

Pu/fck*D*D Pu/fck*D^2 0.1776

Mu/fckD^3 Mu/fck*D^3 0.064

Refer Chart 57 of SP:16 pt/fck 0.025

percentage of steel, pt pt 0.63 %

Area of steel required Ast required Ast 1227.2 mm^2

Design for Bending only

Factored compressive load Pu Pu 0 kN

Pu/fckD2 = 0 Pu/fck*D^2 0

Mu/fckD^3 Mu/fck*D^3 0.064

Refer Chart 57 of SP:16 for pt/fck pt/fck 0.065

pt pt 1.625

Area of steel required Ast Ast 3190.7 mm²

Provide 7 Nos 25 dia 7 25 mm

Ast provided Ast provided 3436 OK

Design of pile below depth of fixity

Vertical Compression

Factored compressive load Pu = 1500 kN Pu 1110 kN

Axial capacity Pa,u = 0.4 fck Ac Pa 1963.5 kN

OK

Vertical Uplift (Tension):

Factored Tensile load Tu = Tu 0 kN

Area of steel required Ast,req = Tu / 0.87 * fy Ast 0.0 mm^2

Provide 7 Nos 16 dia + 0 Nos 0 dia 7 16 mm

Ast provided 1407 OK

HENCE PROVIDE 7 No. - Y25 Dia REBARS TO A DEPTH OF 6250MM FROM CUT OFF LEVEL

AND PROVIDE 7 No. - Y16 DIA. BARS FOR BALANCE DEPTH OF PILE.

LATERAL TIES

Diameter of Circular ties = 8 mm

Spacing of the circular ties :

least of the following :

i). Diameter of pile = 500 mm

ii) 16 φ1 = 256 mm

iii) 300 mm = 300 mm

∴ Provide Y8 Dia @ 200mm c/c