Design of Micropile
GEOPROFOUND ENGINEERING SDN BHD
Pile Geotechnical Design using SPT Values
Site: Round Pile
=
1000 mm
Skin Area per
3.142
Base Area, Ab =
Factor of Safety (FoS) =
Depth Interval (m)
1 2 3 4 5 6 7 8 9 10 11 12 13.5 15 16.5 18 19.5 21 23 24
Avg SPT Value, N
11 11 2 2 2 13 26 21 21 1 12 5 6 6 1 3 1 2 2 2
Unit Skin Skin Cumulative Fric, fs Fric, Fs Skin Fric, Fs = 2N (kN) (kN) 2 (kN/m ) 22 69.1 69.1 22 69.1 138.2 4 12.6 150.8 4 12.6 163.4 4 12.6 175.9 26 81.7 257.6 52 163.4 421.0 42 131.9 552.9 42 131.9 684.9 2 6.3 691.2 24 75.4 766.5 10 31.4 798.0 12 56.5 854.5 12 56.5 911.1 2 9.4 920.5 6 28.3 948.8 2 9.4 958.2 4 17.0 975.2 4 22.6 997.8 2464.8 7743.2 8741.0
0.785
m
2
2.000
End Bear at Pile Allowable depth, End Bear at Pile Ultimate qb=min(400N/ depth, Qb Capacity, Qult = Capacity, Qall = 3, 10000) Qult /FoS (kN) (kN) Fs+Qb (kN)
Pile Capacity (kN)
0
2
(kN/m )
1466.7 1466.7 266.7 266.7 266.7 1733.3 3466.7 2800.0 2800.0 133.3 1600.0 666.7 800.0 800.0 133.3 400.0 133.3 240.0 240.0 10000.0
2000
4000
0
1151.9 1151.9 209.4 209.4 209.4 1361.4 2722.7 2199.1 2199.1 104.7 1256.6 523.6 628.3 628.3 104.7 314.2 104.7 188.5 188.5 7854.0
1221.0 1290.1 360.2 372.8 385.4 1619.0 3143.7 2752.0 2884.0 795.9 2023.2 1321.6 1482.8 1539.4 1025.2 1262.9 1062.9 1163.6 1186.3 16595.0
610.5 645.1 180.1 186.4 192.7 809.5 1571.8 1376.0 1442.0 397.9 1011.6 660.8 741.4 769.7 512.6 631.5 531.5 581.8 593.1 8297.5
5
10
) m ( h t 15 p e D
20
25
Specified Working Load =
8000 kN
Depth required =
13
m
30
(Based on given BH/MKT Report & above FoS)
3/9/2014
Design of Micropile
GEOPROFOUND ENGINEERING SDN BHD (707134-T)
Micropile Structural Capacity Calculation Pile Diameter, f = Grade, f cu
35
1000 mm
cement grout (w/c ratio = 0.45)
Use API Pipe,
88.9 mm 6.45 mm thk 2 500 N/mm (min)
f
f y = Area of Steel & Concrete As (provided) = 2prt As = 1670.707 mm
2
785500 mm
2
2
Ac = p*d /4 Ac = Ultimate Axial Load, f u = 0.4f cu*Ac + 0.75f y*As f u = 11623515 N f u =
11623.5151 kN
Taking Factor of Safety (FoS) = f all = f u/FoS
2
f all =
5811.8 kN Based on the structural capacity above, the micropile is able to take the given working load of 5811.8 kN Micropile Details 1000 mm
Micropile, Dia
API Pipe inside
f
88.9 6.45
Clear spacing/Cover =
Cement grout, G
35
mm thk
455.6
mm
N
W/C Ratio 0.45 min
3/9/2014
Design of Micropile
GEOPROFOUND ENGINEERING SDN BHD (707134-T)
Micropile Structural Capacity Calculation Pile Diameter, f = Grade, f cu
35
1000 mm
cement grout (w/c ratio = 0.45)
Use Rebar,
32 mm 25 Nos 2 460 N/mm (min)
f
f y = Area of Steel & Concrete 2 As (provided) = Spr bars As = 20106.19 mm
2
785500 mm
2
2
Ac = p*d /4 Ac = Ultimate Axial Load, f u = 0.4f cu*Ac + 0.75f y*As f u = 17933637 N f u =
17933.6366 kN
Taking Factor of Safety (FoS) = f all = f u/FoS
2
f all =
8966.8 kN Based on the structural capacity above, the micropile is able to take the given working load of 8966.8 kN Micropile Details 1000 mm
Micropile, Dia
R6 Spiral Link
Rebar
Cement grout, G
35
4Y12
N
3/9/2014
Design of Micropile
GEOPROFOUND ENGINEERING SDN BHD (707134-T)
W/C Ratio 0.45 min
3/9/2014
