Page 67 - Handbook GEOTEKNIK_Final_Neat

Relation between SPT, C and  Pile Bearing Capacity
u

SPT C  C SPT C  C • Allowable pile bearing capacity, Q
u
u
u
u
2
(kN/mm ) (kN/mm ) (kN/mm ) (kN/mm ) a
2
2
2

0 0 1.00 0 16 102.14 0.33 34 Q = Q /FOS + Q /FOS b
b
s
s
all
1 5.99 1.00 6 17 108.53 0.31 34
Where FOS : FOS for shaft resistance/skin friction = 2
2 11.97 1.00 12 18 114.91 0.30 34 s
FOS : FOS for base resistance/end bearing = 3
3 17.96 1.00 18 121.30 0.28 34 b
4 23.94 0.99 24 19 127.68 0.27 34
• Hence,
5 29.93 0.91 27 20 134.06 0.26 35
6 35.91 0.84 30 21 140.45 0.26 37 Qall = Q /2 + Q /3
b
s
7 41.90 0.77 32 22 146.83 0.25 37
8 47.88 0.71 34 23 153.22 0.25 38 • Maximum structural capacity of the pile shall be discounted for:
9 54.71 0.64 35 24 159.60 0.25 40 a) No of joints (n), Q reduced by (5n)%
str
b) If slenderness ratio (l/d) greater than 100, Q reduced by (l/d-100)%
10 61.55 0.58 36 25 165.98 0.25 40 str

11 68.39 0.53 36 26 172.37 0.25 40
• Recommended number of joints for piles practiced by JKR is two numbers
12 75.23 0.48 36 27 178.75 0.25 40

13 82.07 0.43 35 28 185.13 0.25 40

14 88.91 0.39 35 29 191.52 0.25 40
15 95.76 0.36 34 30 >191.52 0.25 40

Table 10: Relation between SPT, C and 
u

50 PUBLIC WORKS DEPARTMENT MALAYSIA GEOTECHNICAL ENGINEERING HANDBOOK 51