Pile Design and Construction Practice, Fifth edition

From Figures 6.29a and b the computed deflections are as tabulated below.

x (m) Z x/R ym yA 95.9ym(mm) yh yB 24.1yh(mm) yA yB(mm)

00 1.00 95.9 1.45 34.9 130.8
0.5 0.08 0.85 81.5 1.37 33.0 114.5
1.0 1.15 0.75 71.9 1.30 31.3 103.2
1.5 0.23 0.65 62.3 1.20 28.9 91.2
2.0 0.31 0.57 54.7 1.11 26.7 81.4
2.5 0.38 0.52 49.9 1.05 25.3 75.2

From the p–ycurve

x (m) y (mm) p (kN/m) pp/1.3 (kN/m^2 )Esp/ y (kN/m^2 /m)

0 130.8 385 296 2.3
0.5 114.5 420 323 2.8
1.0 103.2 455 350 3.4
1.5 91.2 470 362 4.0
2.0 81.4 470 362 4.4
2.5 75.2 470 362 4.8

From Figure 8.19b, the second trial value of , and

This is sufficiently close to the equality line for 6.5 to be accepted as the final value of R
(see Figure 8.19c).
The deflection of the pile head at the loading for the critical value of for soil
rupture is the sum of the following deflections (a) to (c).

(a) Deflection of pile considered as cantilever fixed at sea bed

(b) Deflection of pile at sea bed due to soil compression (from table above) 130.8 mm.
(c) Deflection of pile head due to slope of pile below sea bed.

This can be obtained from the difference of the deflections at the sea bed and 1.0m below
the sea bed. From the above table the deflection at 1 m below sea bed 103.2 mm. Therefore,
slope below sea bed 130.8103.2 27.6 mm in 1 m. Thus, deflection at pile head
26 27.6 718 mm.
Total deflection at pile head 514  131  718 1 363 mm.
It is necessary to check the bending moments at and below the sea bed to ensure that the
resistance moment of the pile section is not exceeded. From Figures 6.29a and b, for

0.421 263 1 000

3  2  105 0.024

514 mm

H 421 kN

R (obtained) (^) ^4

2  105 0.024

3.3

6.2

Es 3.3 103 kN/m^2

Piling for marine structures 429