Geoscience Reference
In-Depth Information
21.27 Load deflection relationship for concrete piles in sands
•
The deflection is limited by the pile sizes and strength of the soil.
Table 21.27
Load deflection for prestressed concrete piles in sands (From graphs in Barker et al., 1991).
Pile size
Deflection (mm) for friction angle (
◦
) and load (kN)
30
◦
(Loose)
35
◦
(Medium dense)
40
◦
(Very dense)
φ
=
φ
=
φ
=
50 kN
100 kN
150 kN
50 kN
100 kN
150 kN
50 kN
100 kN
150 kN
250 * 250 mm
10
30
30
7
22
30
5
15
30
>
>
300 * 300 mm
5
17
30
4
11
20
4
9
15
350 * 350 mm
4
10
18
3
7
13
3
6
9
400 * 400 mm
3
7
12
3
5
8
2
4
7
450 * 450 mm
2
5
8
2
3
6
2
3
4
-
Bending Moments for the piles range from approximately:
225 kNm to 75 kNm for 150 kN to 50 kN load in loose sands.
200 kNm to 50 kNm for 150 kN to 50 kN load in medium dense sands.
175 kNm to 50 kNm for 150 kN to 50 kN load in very dense sands.
- No significant differences in bending moments for various pile sizes in sands.
21.28 Load deflection relationship for concrete piles in clays
•
The deflection of piles in clays are generally less than in sands.
Table 21.28
Load deflection for prestressed concrete piles in clays (From graphs in Barker et al., 1991).
Pile size
Deflection (mm) for undrained strength (kPa) and load (kN)
C
u
70 kPa (Stiff)
C
u
140 kPa (Very stiff)
C
u
275 kPa (Hard)
=
=
=
50 kN
100 kN
150 kN
50 kN
100 kN
150 kN
50 kN
100 kN
150 kN
250 * 250 mm
5
17
30
3
8
14
1
3
6
>
300 * 300 mm
3
10
21
2
5
9
1
2
4
<
350 * 350 mm
2
7
14
1
4
6
1
1
3
<
400 * 400 mm
2
5
10
<
1
3
4
<
1
<
1
2
450 * 450 mm
1
4
7
1
2
3
1
1
2
<
<
<
21.29 Bending moments for PSC piles in stiff clays
•
The induced bending moments of PSC clays is dependent on the deflection and
pile size.
•
In sands the pile size did not have a significant difference in bending moments.
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