Royal HaskoningDHV wins CTBUH 10 Year Award for best time-proven and innovative tall building

At the 2022 CTBUH (Council on Tall Buildings and Urban Habitat) International Conference in Chicago, Royal HaskoningDHV and Ibelings van Tilburg Architects received the 10 Year Award for De Karel Doorman building in Rotterdam.
Award winners
The jury acknowledges the ‘extraordinary contribution to the advancement of tall buildings and urban environment and demonstration of its longevity and relevance in a decade of operational use’. ‘By celebrating the best projects, the CTBUH International Conference delivers a comprehensive and sophisticated view of important buildings, spaces, and technologies, while answering the challenging questions of what constitutes excellence in the future’.

The decisions we make and the work we do today, will have great impact ten, fifty years from now. Our work is always about the long-term effect, which isn’t always easy when there’s a lot of focus on short-term results. This award demonstrates that it pays off to act with the long-term goals in mind.

Michiel VisscherStructural Engineer
The U-shaped apartment building De Karel Doorman in the heart of Rotterdam’s shopping area celebrates its 10-year anniversary this year. The challenge at the time: urban densification with low-impact construction. 

The solution that Royal HaskoningDHV and architects Ibelings van Tilburg decided on is a combination of restoration and a so-called ‘top up’. The low-rise three-story shopping center dating back to 1950 is a monument of the post-war reconstruction period but had lost its glory. To avoid demolition, it would be restored and with the shopping center as its foundation, a 16-story high-rise apartment building would be constructed on top.

A great idea on paper, but is this even possible? Our structural engineering experts knew it would be. By connecting the existing building to two new stabilizing cores (which could be used for stairs, elevators, and air ducts) it was able to support a lot more weight. In addition, we designed an ultra-lightweight steel and timber building system, reducing the average weight of an apartment block by 80%.

What was already a very innovative solution at the time is even more relevant today. Because of its sustainable and circular nature, creating more space to live and work by re-using and ‘topping up’ existing buildings directly contributes to achieving our sustainability goals. 

Still today De Karel Doorman is the world’s tallest building that was constructed on top of a low-rise building and the world’s tallest concrete steel-timber hybrid building. 

The steel-timber hybrid building system is modular and circular by design. Even though we developed the first design concepts quite some time ago, it offers a great opportunity for everyone looking to build in a carbon-neutral and circular way.

Maurice HermensLeading professional Structural engineering