Pile Design and Construction Practice, Fifth edition

Resistance of piles to compressive loads 239
If there is concern about long-term corrosion of the steel section in the hydraulic fill, the
cube strength of the concrete filling could be increased so that the whole of the load is
carried by the concrete.
Checking for compliance with the EC7 requirements, the pile is a concrete filled casing
therefore dimensional tolerances are not applied. The shaft resistance is fully mobilized over
the depth below the base of the fill. The partial action and resistance factors are selected
from Table 4.20.
For design approach DA1, combination 1, the partial factors are: Structural action,
A1 � 1.35. Drag-down action, A1 � 1.35, M1 � 1.0, A1 � 1.35. Resistance, R1 � 1.0.
Design value of actions � (900 � 885) � 1.35 � 2410 kN
Design resistance � 2909 � 1.0 � 2909 kN (greater than 2410 kN)
For design approach DA1, combination 2, Structural, A2 � 1.0. Drag-down, M2 � 1.25,
A2 � 1.0. Resistance, R4 � 1.3.
Design value of actions � 900 � 1.0 � 885 � 1.25 � 2006 kN
Design resistance � 2909/1.3 � 2273 kN (greater than 2006 kN)
The above calculations show that the penetration of 28 m for the pile satisfies the requirements
of EC7 in respect of the ultimate limit state GEO.