NEN 9997-1 has been revised, which has major implications for the design of displacement screw piles.
Due to the reduction of the pile class factor αₚ, the calculated capacity of the pile tip significantly decreases in many cases. Fortunately, a self-declaration published by NEN applies to our DPA screw piles and DPA-PLUS screw piles, allowing deviations from the standard values.
Research by Van ’t Hek Groep and Vroom Funderingstechnieken confirms that this reduction is justified, but also shows that a well-manufactured DPA or DPA-PLUS screw pile derives a much higher shaft capacity than previously assumed. These innovative pile systems therefore offer a reliable and powerful alternative.
Also view the 3D animations of these pile systems:
DPA screw piles
DPA-PLUS screw piles
DPA-combi screw piles




