Innovative quay wall anchored with strand anchors

As a foundation specialist, De Vries Titan is involved in the Innovation Partnership Kademuren in Amsterdam. The company manufactures anchors and anchor piles and has been operational for almost 25 years in the Netherlands, as well as in Belgium and Germany. Because of the good relationship with Gebr. de Koning B.V., they became involved in this project as early as the tender phase. Here they were contracted as a permanent subcontractor by G-Kracht.

This year a first pilot project was carried out at the Singel. De Vries Titan was responsible for the anchoring. Hendrik van de Woestijne, manager: "The spearhead of the project is the wall construction with drilled piles. That is unique in the Netherlands. One of the objectives was to limit the time, inconvenience and impact with innovative techniques; in short, to execute the project as optimally as possible towards the environment."

Least impact

To be able to work vibration-free, De Vries Titan chose to use permanent strand anchors. These anchors are equipped with prestressing cables. The anchors are double-tubed. When the drill pipes are at depth, the inner tube is removed. The strand anchor is placed in the large outer tube, after which the outer tube can also be pulled out. Along the strand anchor, De Vries Titan injects grout, creating a bundle of strands of grout in the load-bearing sand layer.

Hendrik: "The drilling is completely vibration-free, which is a great advantage for the environment. The drill pipes go through all existing structures and the existing elements of the quay wall can remain behind. We also used this technique on the Singel. The existing construction consists of the old, brick quay wall, wooden floor and wooden piles."

The double-tube drilling method has the least impact on the environment. Drilling always has an impact, but this method produces the most favorable result and has the least chance of settlement. And that is an important issue in the downtown area.

The anchors are equipped with double corrosion protection, guaranteeing a lifetime of at least 100 years. The design of the anchors is coordinated with the underlying adjacent buildings, so that settlement of the monumental buildings is excluded.

Logistical challenge

The supply of all materials and machinery of De Vries Titan took place from the construction hub entirely electrically by water. In this way the road network of Amsterdam could be relieved as much as possible. 

To prevent surface water pollution, special pumping systems were deployed that allowed the rinse water and released grout to be pumped to tanks.

De Vries Titan conducted the pilot with so-called Stage V machines, the most modern diesel machines of the moment. Hendrik: "We are working on the electrification of equipment and hope to make great strides in this in G-Force's follow-up projects."