Vroom Funderingstechnieken and Van ‘t Hek have jointly certified the pile systems DPA and DPA-PLUS with a self-declaration in accordance with NPR 7201.
This process took over two years and involved load tests in which test piles, equipped with extensometers, were loaded to failure. In addition, an expert committee appointed by the Netherlands Standardization Institute assessed both the installation of the piles and the test results.
Multiple load tests were carried out during the process to accurately determine the shaft resistance and base resistance of both pile systems. The piles were subsequently extracted and analysed. This investigation was conducted in cooperation with the expert committee from NEN and an independent specialist. The resulting pile class factors for shaft and base were recorded in a self-declaration. These pile class factors and corresponding pile diameters replace the αp and αs values from table 7c of NEN 9997. From 20-03-2025 onwards, the self-declaration must be used for the design of DPA and DPA-PLUS piles.
The findings align with the expectations of both companies. The determined pile shaft resistance proves to be higher than previously stated in the standard. This contributes to improved application of the pile systems and offers new possibilities for foundation design.
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