Because of the soft soil conditions, the majority of engineered structures in (the western part of) the Netherlands are founded on deep (piled) foundations. In simple terms, a pile is a slender structural element (steel or concrete column) that uses soilstructure interaction to transfer loads to deeper, stronger soil layers.
Numerical models capable of modelling pile installation are not developed and thus designers rely on semi-empirical design approaches (using alpha factors linked to in-situ Cone Penetration Tests, which are used to characterize the soil deposits).
The Port of Rotterdam (POR) and Rijkswaterstaat (RWS) are amongst the biggest consumers of piles in the Netherlands. Despite the lack of incidence of pile failures changes to pile design standards (as of January 1st 2017) has resulted in the installation of longer or more piles, and increases in both construction time and associated installation risks. The direct impact is an estimated increase in construction costs of 10-20% for all deep foundations projects in the Netherlands.
The change in design standards arose due to a gap in the knowledge surrounding some key aspects of deep foundation behaviour that include: soil fatigue effects during cyclic pile installation and loading, soil ageing around piles, the effects of natural soil stratification and the use of potentially conservative limiting soil strength values in the Dutch NEN design code.
This proposal will develop a holistic solution which will improve involving field testing, lab and numerical modelling in conjunction with advanced statistical approaches to provide accurate calculation procedures to determine the axial capacity of a pile.

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