Rotterdam, Zalmhaven Tower | Settlement Zalmhaven Tower going according to plan

Geotechnical advice, including in the implementation phase

Gradually, the Salmon Harbor Tower is beginning to take its place in the Rotterdam skyline. The tower with 260 apartments, offices and a restaurant will eventually reach - with antenna - a height of 215 meters. This will make it the tallest building in the Benelux. Next to the tower will be two residential buildings 70 meters high on a four-story plinth of single-family homes. Geobest from Vianen provided the geotechnical advice to arrive at a sound foundation for this special building project.  to come. And it didn't stop there....

Text | Tjerk van Duinen Image | Geobest

Managing risk is the line of business in which the geotechnical consultant operates on a daily basis. In this case, the primary task was to figure out how to achieve acceptable settlement of the tower and adjacent buildings. "To this end, soundings were carried out up to 85 meters deep, in order to get a picture of the structure of the subsurface," explains Principal Consultant Robert Schippers of Geobest. "Almost all buildings in Rotterdam rest on the first layer of sand at a depth of about 25 meters, but you can't build a tower of over 200 meters on that. That is because you would get too much settlement of the underlying clay layer. That's why the tower stands on 65-meter-long Tubex piles, which rest on the next layer of sand."

Setting

Meanwhile, the tower is over 60 meters high and the measured settlement is now exactly at what Geobest calculated. Schippers: "When the tower is finished, the foundation slab will show 4 centimeters of settlement and another 3 centimeters will be added over the next 50 years. This is also roughly the settlement we calculated for the lower 70-meter towers, which are founded on the first layer of sand, so I don't expect any disruption or cracking."

The Salmon Harbor Tower stands on 65-meter-long Tubex piles.

Expanded role

Geobest was involved in the development of the Salmon Harbor Tower at an early stage. Schippers: "Normally the process starts with a project developer who commissions a structural engineer to do calculations based on the advice of a geotechnical consultant. That advice includes a foundation design and cost estimate. Once the environmental permit is obtained, the geotechnical consultant's role is usually over. In the development on the Zalmhaven, project developers Amvest and AM had contractor Royal BAM Group on board at an early stage and they involved us in the preliminary process and also in the realization phase. All the variants we investigated were included in the preliminary process. That provided the contractor with additional relevant information for setting up the construction process and certainly prevented duplication of effort. Our input was so well received by the developer and contractor that we also remained involved in the implementation phase. For example, to keep watching the installation process and assessing execution data. Professor Frits van Tol provided the second opinion."

Dreams

Geobest now has a lot of experience with the Rotterdam subsurface. Schippers: "We can dream the parameters of the geological formation under Rotterdam and interpret the differences between the projects well. We can benefit from this in subsequent projects. We have a lot of in-house knowledge and work with scenarios so that we are not surprised by unexpected ground conditions. We are hired to manage risks. If something goes wrong, the whole train stops behind us and there are always high repair costs, but I haven't experienced that yet. We are there to unburden the contractor, give confidence and meet schedules."