Bored Pile

1. Prepared By
Mohamad Shakri bin Mohmad Shariff
2009106705

2.  Proposed by Kementerian Pengajian Tinggi
Malaysia to construct a Kompleks IPPP and
Makmal Penyelidikan Berpusat (Research
Laboratory Center) at University Malaya,
Kuala Lumpur.
 A soil investigation programme consists of 7
boreholes have been sunk with all the
associated disturbed and undisturbed
samplings and associated laboratory tests
 5 mackintosh probing and 5 hand auger holes
been carried out by Messrs Kumpulan Ikram
Sdb Bhd (IKRAM).

3. Geological Map of the Project
Proposed Site

4.  From the Geological map, the site may be in
3 geological formations, which are granite,
phyllite and limestone.
 The phyllite formation may consist of state,
shale and sandstone.
 By site visit, the area most likely within the
carboniferous age phyllite, slate, shale and
sandstone area.

5.  The ground level at project site range
from RL 41.8 to RL 52.3.
 The purposed level is around RL 41.8 .
The slope will cut to standardize of level.
 For the drainage, perimeter drainage
exist around the area and also inside the
boundary according the staggered stages
of the existing car park.

6. FIGURE A1 : SOIL PROFILE ACROSS BOREHOLE BH1-BH4

7. FIGURE A2 : SOIL PROFILE ACROSS BOREHOLE BH5-BH7

8. FIGURE A3 : SOIL PROFILE ACROSS BOREHOLE BH1-BH4

9.  The drilling of boreholes was terminated after a minimum of
3.0m of continuous rock coring or 5 time SPT ‘N’ values = 50
blows
 Based on borehole results, the subsoil mainly consist of sandy
SILT.
 The standard Penetration test had been plot based on 5
boreholes (BH 1 – BH 5) which are about the same level.
 The soil layer and parameters had been analysis and design based
on SI result.
 Chemical Test, Atterberg Limit Test Hydrometer Analysis are
example tests that had been conducted.
 The silt basically have liquid limit around 25 to 62. silt in BH 5
indicated very high liquid limit as high as 62.
 There was no rock encountered in all the boreholes which were
terminated within depth of 30 meter from the existing ground
level.

10. Groundwater level (m-BGL)
Borehole
Date
BH1 BH2 BH3 BH4 BH5 BH6 BH7
23 April 2008 1.74 0.40 0.98 1.30 0.80
24 April 2008 1.75 0.46 0.95 1.00 0.72
25 April 2008 1.80 0.50 0.98 1.00 0.80
26 April 2008 1.81 0.75 1.15 1.10 1.00
27 April 2008 1.83 1.00 1.15 1.10 1.00
28 April 2008 1.84 1.00 1.18 1.15 1.00
29 April 2008 1.90 1.18 1.20 1.30 1.10
30 April 2008 1.98 1.19 1.20 1.51 1.12
02 Mei 2008 2.05 1.20 1.21 1.60 1.15 6.70
03 Mei 2008 2.18 1.25 1.21 1.84 1.20 6.70
05 Mei 2008 2.20 1.30 1.28 2.00 1.28 6.75
06 Mei 2008 2.25 1.39 1.20 2.10 1.28 6.85
07 Mei 2008 2.35 1.39 1.20 2.10 1.30 6.85
08 Mei 2008 2.48 1.43 1.25 2.25 1.33 6.88
09 Mei 2008 2.69 1.55 1.25 2.45 1.33 6.90
12 Mei 2008 2.76 1.65 1.30 2.48 1.49 6.92
14 Mei 2008 2.90 1.87 1.35 2.55 1.62 7.05 6.55
15 Mei 2008 2.92 1.94 1.41 2.58 1.70 7.38 6.60

11. Borehole
ID
Ground
Level
(m, RL)
Soft Layer
(m, bgl)
Hard Layer
(m, bgl)
Rock Depth
(m, bgl)
G.Water
Level
(m, bgl)
BH1 42.0 N.A 7.5 N.A 3.1
BH2 41.8 N.A 6.0 N.A 3.9
BH3 42.6 N.A 7.5 N.A 4.1
BH4 43.3 N.A 7.5 N.A 3.7
BH5 44.6 N.A 9.0 N.A 3.9
BH6 52.3 N.A 12.0 N.A 4.7
BH7 49.2 N.A 10.5 N.A 4.9

12. Prepared By
Teh Maisara Binti Mohd Hassan
2009762251
Nor Aziyatimah Binti Abdul Mutalib
2009905993

13.  Large Diameter Cast-In In-Situ Piles (Bored
Piles)
 Size : 450mm to 2m
(Up to 3.0m for special case)
 Lengths : Varies
 Structural Capacity : 80Ton to 2,300Tons (Tall
buildings or massive industrial complexes)
 Concrete Grade : 20MPa to 35MPa (Tremie)
 Joints : None
 Installation Method : Drill then Cast-In-Situ

14. Axial Load Capacity
Concrete, Cc : 0.25 x fcu x
Ac
Steel , Sc : 175 x As
Total: Cc + Ac
where,
Concrete strength, fcu : 35
N/mm²
Concrete area, Ac : (h x h) – As
Pile size : h x h
Pile NOS
No of Pile, N : Applied Load, Papp
Single Pile Capacity,
Qall
Skin Friction
( kN/m² )
Clay / Silt / Sand : 2.5 x Average
SPT, N
Frictional Resistance
( kN/m² )
Qs : ∑ p ∆L f
where,
Perimeter, p : Π D
Depth, L
Skin friction, f
Point Bearing Capacity
( kN/m² )
Qp : Ap x qp
where,
Cross-section Area, Ap
qp : 50 x Average SPT, N
Allowable Load-Bearing
Capacity ( kN )
Qall : (Qs + Qp )/ FOS
where,
Factor of safety, FOS

15. Example
Size of
pile
(mm)
Column
No.
Column
Load
(kN)
Column
Load
/FOS
(kN)
Proposed
No. of
Piles
Depth of
Piles
(m)
600 C6 2490 830 1 18
** Refer Soil Profile for BH7
Pile Data
Soil Profile
for BH7

19. Cross-section of
bored pile
Plan
view

21. Bored piling is
used to remove
the soil and
rock.

22. For cohesionless
soils such as sands,
gravels, silts, pile
bore hole must be
supported using
steel casing or
stabilizing muds
such as bentonite
suspension

24. Reinforcement bar
will be put into
the bore hole

26. Concrete will be
poured into the
bore hole

28. Prepared By
Wan Mohd Azri Bin Wan Mohd Zubir
2009919835
Khairul Amri Bin Sanusi
2009106705

29.  Pile cap defined as a concrete block cast on
the head of a pile, or a group of piles to
transmit load from structure to the pile.

30.  Pile cap will laterally stabilize individual
piles thus increasing overall stability of the
group.
 Pile cap must be rigid to transfer loads from
column to the piles.
 Two methods of design pile caps;
 Truss Analogy Method
 Beam Theory Method

31.  Pile cap treated as an inverted cantilever
beam.
 Design for the usual conditions of bending
and shear.
 Applied to larger groups of piles.

32.  Based on truss theory.
 Load from column transmit to piles by
triangular truss action.
 Concrete take as compressive members and
steel rebar as tensile members.
 Limited up to file piles.

33.  Determine size of pile cap based on pile
spacing of 3d and edge distance between
150~250mm.
 Pile cap depth to be assumed as follows;
 Working load of pile normally based on
geotechnical capacity because structure
capacity is higher.
Pile
size
150 200 300 350 450 600 750
Depth 450 600 700 900 1000 1400 1800

34.  Determine rebar by Beam Method or Truss
Method.
 Checking for shear at column face and
critical section (20% or 1/5 of pile diameter).
Allow shear enhancement.
 Checking for punching shear if pile spacing
more than 3d(diameter of pile).
 Checking detailing requirements such as
anchorage, bar spacing and cover.

35. PILE CAP DESIGN

36.  Based on BS 8110
 Design concept Beam Theory Method
 Strength of concrete, fcu= 30N/mm2
 Strength of reinf., fy = 460 N/mm2.
 Min. cover to main reinf., c = 50mm
 Column service load, F = 1660 KN
 Column size = 400mm x 400mm
 Bored pile diameter = 600mm

37.  Min. cap design (length)
= 2(tolerance of pile) + bored pile diameter
= 150mm + 600mm
= 750mm say use 1000mm.
 Min. cap design (breadth)
= bored pile diameter + 2(tolerance of pile)
= 600mm + 150mm
= 750mm say use 1000mm.

38.  Check length to determine min. depth;
L = 2d(diameter of bored pile) + 100mm
= 2 (600mm) + 100mm
= 1300mm say 1500 mm
Or we can use Table Pile Cap Depth depends on
Size of Piles;
 So use 1400mm for 600mm bored pile
diameter.
Pile size 150 200 300 350 450 600 750
Depth 450 600 700 900 1000 1400 1800

39.  Hence, adopt single bored-pile cap size
= 1000mm x 1000mm x 1400mm
 Effective depth;(ass. dia. of bar = 25mm)
= 1400mm – 75mm - 25mm
= 1300mm

40.  Main bar = 0.15% bd
= 0.15% (1000)(1300)
= 1950 mm2
Provide 6T25( 2950 mm2 > 1950 mm2)
 Provide similar bar for both ways 6T25 and
tie bars for 3T16.
 Provide anti-crack bar at top of pile cap for
more than 0.9m = 0.13% bh
= 0.13% (1000)(1400)
= 1820mm2
Provide 6T25( 2950 mm2 > 1820 mm2)

41.  Detailing;
P
L
A
N

42.  Detailing;
S
E
C
T
I
O
N

43. PILE CAP DESIGN

47.  Detailing;
P
L
A
N

48.  Detailing;
S
E
C
T
I
O
N

49. BH 2
BH 3
BH 4
BH 5
BH 1
BH 7
BH 6

50.  A very good soil were found at approximately
7.5 m from ground level for BH1, BH2, BH3
and BH4.
 A bored pile system were adopted to cater
for the large column load and estimated
shallow penetration for precast pile.
 Bored pile with sizes varying from 500mm
dia. to 750mm dia. were adopted in this
exercise.