Copyright: Tree house Rotterdam | Provast
Royal HaskoningDHV is pushing forward the frontiers of innovation in sustainable building design with the 140m high ‘Tree House’ in Rotterdam. The Tree House has been inspired by the eco system of a tree and features a part-timber structure with a concrete core.
Wood is increasingly valued as a more sustainable building material
There is increasing interest in the use of wood in civil engineering projects. It is sustainable – coming from renewable sources. It provides carbon storage and its lighter weight reduces transport costs. It is also durable and can lead to shorter construction times. Research indicates that wood in buildings is beneficial for people’s health and wellbeing.
The drawback is that costs are typically higher than for buildings constructed from steel and concrete. Furthermore, because structural elements like columns are larger, they reduce available space. Together these make it more difficult to generate a viable business case for wooden high-rise buildings. Currently, a small number of wooden towers have been built in Europe, but the maximum height achieved is around 80m.
How to make the business case viable?
This was the challenge facing Royal HaskoningDHV structural designers in their work with developer Provast, London-based PLP Architecture and local architect ZUS to win an international competition for a new mixed-use tower at Rotterdam Central station.
“The business case would not work with a building completely constructed from wood,” explained Walter van Adrichem, structural engineer at Royal HaskoningDHV. “We therefore investigated how we could maximise the use of wood while ensuring the building would be financially viable.”
The solution developed by Royal HaskoningDHV is for a part-timber structure with a concrete core. The first 10 floors housing offices, restaurants and meeting rooms are constructed using steel and concrete. This maximises space and allows flexibility with large, open-span areas. The main construction material for the remaining floors is wood. This is where apartments are located and all columns, floors and beams are constructed from cross-laminated timber. At 140m-high, the Tree House is set to be the tallest hybrid structure in the Netherlands.
Design wins international competition for prime redevelopment site in Rotterdam
The resulting design won the competition for redevelopment of the site adjacent to Rotterdam Central Station. The wooden facade together with abundant greenery on balconies and roof terraces will bring a new character to the area.
In addition, the building’s lighter weight is ideally suited for the location. Rotterdam sits on a layer of clay which is compressed under the weight of new structures and can lead to them sinking by as much as 20cm. By weighing around 40% less than a conventional tower, sinkage will be reduced and is less likely to impact nearby buildings and rail tracks.
Alongside structural design for the project, Royal HaskoningDHV is undertaking mechanical, electrical and plumbing (MEP) engineering, sustainability, fire protection and acoustics. To avoid acoustic and vibration disturbance between apartments, floors will have a concrete topping. Measures have also been introduced where necessary to avoid noise and vibrations associated with the nearby railway.