'Park070 gives former atomic shelter a valuable new use'

Giving a valuable new purpose to existing and obsolete real estate. That is today's social task, to which SWINN is happy to contribute. Following in the footsteps of the former UWV office in The Hague and the old Sportfondsen swimming pool in Schiedam, the Gouda-based engineering firm recently investigated the structural possibilities of the atomic bomb shelter under the former CBS building in Voorburg. A new, green and highly sustainable residential area is currently being built on this existing structure: Park070.

A tremendous amount is possible in the redevelopment of existing real estate, provided a complete and reliable picture of the structure can be formed based on original calculations, drawings and foundation data, emphasizes Erik Verweij, project manager at SWINN. "In this project, that was quite possible. We were invited back in 2014 to investigate the load-bearing capacity and possibilities of the existing basement structure. Various elaborations passed the revue, after which it was decided to maintain the existing atomic and shelter basement of approximately 12,500 m2 and convert it into a parking basement, including storerooms and technical rooms. On, half over and next to the basement, 250 modern town houses and apartments of various sizes will be built."

To make sure that the bearing capacity of the pile foundation and the reinforcement of the existing basement were suitable for the realization of this new building, SWINN dove into the municipal archives. "Our research showed that some structural parts had more capacity than others," Verweij said. "That's why, for example, it was decided to place the 44-meter-high residential tower on the original tower foundation of the CBS building. In the areas with a little less capacity, lower construction will be provided." A large part of the basement will also be laid out as a city garden, he says. "To support the weight of this lower construction as well as the city garden, reinforcements were added in the form of additional piles in several places. Moreover, we took care of the structural design for the new construction parts around the basement, such as the new entrances and the houses that will be built half over and next to the basement. Of course, this took into account the settlement differences between the new and existing foundations."

The residential tower will be placed between the houses and on tall columns measuring 550 x 1875 mm. "These columns are a nod to the former columns of the CBS building and stand on the existing columns in the basement," Verweij concludes. "The two- and three-story disc-shaped columns carry the building. Moreover, they ensure stability in the transverse direction."