Although construction site manager Eric van Nes has been working in Zuidas for a while – he was involved in the construction of 2Amsterdam and the O|2 lab building – he had never before worked on diaphragm walls. When it is completed in 2023, research will be conducted in the building using highly sensitive microscopes with lasers. ‘Our brief is to erect a building that will not have an effect on the research results. This means that the research building will need to be extremely rigid and protected against vibration and external movements. That’s quite a challenge for an area like Zuidas, which is certainly not deserted and is developing fast.’
The new research building will be made up of two sections: a high-rise section for teaching and a low-rise section for research. The latter section needs to be vibration-free. In order to make that possible, the excavation work was particularly important. The diaphragm walls will serve as an additional protective shield around the basement of the low-rise building. Around the future building, Van Nes and his team dug a U-shaped trench, 120 m long in total, 1 m wide and a full 25 m deep. To prevent the trench collapsing, they had to replace the soil removed immediately with a type of liquid clay. They then allowed the reinforcement to sink into this liquid clay. They were then able to pour in concrete, while simultaneously pumping away the liquid clay. This created the diaphragm wall that will prevent vibration from the high-rise building and traffic in De Boelelaan penetrating the low-rise building.
Pouring concrete floor
In combination with the sheet piling, the diaphragm walls will form the construction pit in which foundations and a basement have now been built. ‘In the construction pit, we’re now continuing work on the basement shell. The next milestone will be in the spring, when we’ll pour the concrete floor for the ground floor. We can then start heading upwards and you will see the building gradually starting to take shape.’
Overview of everything
Van Nes finds the logistical constraints involved in construction work in Zuidas to be challenging. ‘You have to have a constant overview of everything. If you forget something, it can have major consequences.’ As an example, Van Nes points at the two tower cranes on either side of the construction site: to the east and to the west. ‘Ideally, we would have positioned them to the north and south, so that you have a crane for the high-rise building on the De Boelelaan side and one at the back where the low-rise building will be. But because of the arrival route for the Amsterdam UMC emergency helicopter, that wasn’t possible. So, you have to arrange the building site like this, to make it work despite the constraints. But, of course, these are issues that we need to plan well in advance.’
The new research building will be in the new Innovation District – also known as Knowledge Quarter – that Zuidas is developing in partnership with VU Amsterdam and Amsterdam UMC. The area is to the south of the A10, between Parnassusweg/Buitenveldertselaan, Amstelveenseweg and A.J. Ernststraat. The Innovation District will include around 2,700 homes, space for knowledge-related businesses, a primary school, culture, and hospitality and catering. This will be a neighbourhood that brings together healthcare, science, and entrepreneurship.