Hendriks precon moulding tables for the prefab façade elements of De Zalmhaven TowerUnprecedented pace of construction and minimal inconvenience

Rotterdam’s skyline is changing dramatically. Byldis is constructing De Zalmhaven Tower near the Erasmus Bridge in Rotterdam. One of its most striking features in its construction is the use of prefab elements, which considerably reduces construction time. Hendriks precon supplied the moulds for the prefab elements.

At 215 metres, De Zalmhaven Tower will be the highest prefab concrete residential tower in the world. Spread over 52 floors, the tower will have 452 apartments and penthouses, as well as a parking garage, offices, commercial spaces, a garden roof and a restaurant.

A lifting shed is used in the construction of De Zalmhaven Tower and crawls up along the façade, as it were. This self-climbing work platform consists of a covered air-conditioned and fully fitted-up construction site in which all activities take place. By making use of this shed and by making use of prefab elements, it is possible to construct one floor each week. Furthermore, this way the logistics movements at this busy inner-city location and at the construction site are kept to a minimum, and the shorter construction time reduces any inconvenience to the surrounding local community.

Ready-made sandwich elements

We spoke with Karel Mandemakers of Byldis about the prefab elements: ‘The prefab elements are made by us in our plant. This includes flat prefab elements, as well as angular elements used to construct the building’s corners. The elements consist of a concrete inner leaf, which is insulated and finished with a natural-stone outer leaf. The resulting sandwich elements are delivered ready-made. The windows are also incorporated into these elements. As a result, the elements can be immediately installed at the construction site, at the same time making the building wind and watertight.’

Steel moulding tables and 3D mould

The company uses moulding tables supplied by Hendriks precon for the production of the concrete cavity leaves. ‘This includes three flat moulding tables,’ Karel Mandemakers explains. ‘The dimensions of these tables are 4.00 x 12.00 m, 4.00 x 10.40 m and 4.00 x 3.30 m. Depending on the element, four to six openings are built in to accommodate the windows. Due to the large quantity of reinforcement steel in the cavity leaves, it was decided to make the bottom of the moulds of steel as well. For the corner elements we are using a mould to manufacture the 3D corner elements. The dimensions of this mould are 8.00 x 7.50 x 3.50 m. While the façade elements are poured horizontally, the corner elements are poured vertically. To be able to take the pressure involved in this process, the decision to use a steel mould was a foregone conclusion.’

The thickness of the cavity leaves varies: for the bottom four floors it is 40 cm and for the floors above this, it is 30 cm. Karel Mandemakers is very satisfied with the quality of the steel moulds. ‘Each steel mould is good for at least 200 “pours”. This means that we can make all of the elements for the 52 floors with the same mould. As a result, the service life of these moulds is at least equal to the duration of the entire project. This might not have been possible had another method been used.’

Just-in-Time

Karel about the cooperation with Hendriks precon: ‘Hendriks precon is a reliable partner for us. In this project, too, we intensively worked together. It all started with the very first idea. We then met together, after which Hendriks precon developed the concept. After some finetuning we were able to get down to work. Thanks to these moulds, production and assembly are in perfect harmony.’