Very Deep Piling for The Highrise Zalmhaven I In Rotterdam (NL)-Paper

Paper

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The 215 m De Zalmhaven tower in Rotterdam required deep foundations because conventional piles would have caused estimated settlements of 400–450 mm in the settlement-sensitive Waalre clay formation. The solution was 163 vibration-free, 950 mm diameter steel-cased piles, each approximately 66 m long, extending through the weak formation.<br /><br />Piles were installed in two welded 33 m sections. The first section was drilled using bentonite and filled with concrete to prevent buoyancy; the second was drilled with cement-based grout, then also concreted. Special hardened drill bits helped penetrate historic masonry and wooden-pile remnants. Only two piles encountered obstacles that could not be overcome; both were successfully reinstalled nearby. Installation proceeded at roughly one complete pile per day per rig.<br /><br />Three-dimensional finite element modelling assessed pile-group behavior, long-term consolidation and effects on neighboring buildings. Predicted foundation-slab settlement was about 53 mm at the center and 37 mm at the corners immediately after loading, increasing to approximately 88 mm and 77 mm, respectively, after 20,000 days. The analysis also estimated a maximum angular deflection of 1:750 at the nearby Joulz building, within applicable requirements.<br /><br />Measurements during construction supported the predictions: after the tower reached its 60th floor, settlements at the foundation corners were approximately 42–53 mm. The authors conclude that the deep-pile solution successfully controlled settlement, while analysis of long-term deformation informed the structural design. Further monitoring is planned after completion.

Keywords

De Zalmhaven

Rotterdam tower

deep foundations

steel-cased piles

Waalre clay

settlement analysis

finite element modelling

pile installation

long-term consolidation

structural monitoring