Lightweight Jigsaw Puzzle
March 30, 2017
Eurojust will soon move into its new headquarters on the 'green side' of The Hague's World Forum area. A special feature of the newly-built office building is the white fibre-reinforced polymer façade. The agency that within EU member states combats cross-border organized crime set strict requirements to be met by its builders. Project Manager Marco Moonen of façade builder TGM-NL B.V. takes us behind the scenes.
Although fibre-reinforced polymer has been used for dozens of years, for example in the yacht building and automotive industry, it is a relatively new product for the construction industry. ‘This is our first fibre-reinforced polymer façade,’ says Marco Moonen, Eurojust Project Manager with façade builder TGM. ‘Increasingly more architects are seeing the benefits of fibre-reinforced polymer as a construction material. Still, the material is not yet widely accepted in our sector. This is primarily related to its high production costs in relation to, for example, aluminium, steel or wood.’
Fibre-reinforced polymer is a material made of one or more materials. Often the materials used are fibre-reinforced plastics, such as polyester. Composite plastics essentially consist of two materials: resin to keep everything together and fibreglass to strengthen the plastic.
Freedom of design
Composite materials are often stronger than other well-known materials (wood, aluminium, concrete, steel) of the same dimensions. Marco: ‘For example, the twelve-metre long elements in the shape used here are almost impossible to make with steel or aluminium. Other reasons why fibre-reinforced polymer is increasingly being used include the freedom of design, the lack of welding seams, resistance to corrosion and low maintenance.’
In addition to its own production facility, TGM also cooperates closely with permanent partners, each of whom is responsible for part of the façade. ‘A single façade element consists of a basic SIPS element, an aluminium frame, glass, and a white fibre-reinforced polymer exterior façade.’
‘The backbone of the façade construction is the SIPS element, which consists of a wood inner and outer panel with an insulating filling covered with water repellent vapour permeable foil. The frame and glass are placed within this element at the factory. These complete puzzle pieces are then transported to the construction site by low-loader, where they are mounted into the building structure.’
In July 2014, Marco and his team began working on the design phase. ‘Our technical engineers spent over a year working on this exceptional design. Several mock-ups were created during the development phase that were subjected to various tests. The façade meets strict criteria, such as water and air-tightness, and noise attenuation. In addition, out‑of-sight measures were taken to protect the building against attacks and break-ins. Following the test phase, we started with the production of the façade elements.’
Because assembly is faster than production, Marco and his team were required to accumulate a buffer of more than 400 elements. ‘We produced the remaining 300 elements during the construction phase.’
After the wood SIPS elements were installed, aluminium hooks were installed from which the polyester elements were suspended. ‘The hooks are screwed into the wooden SIPS elements with a two-millimetre tolerance. The fibre-reinforced polymer elements are also equipped with these hooks.’
Marco: ‘The polyester façade elements were suspended from the SIPS elements – one by one, from the bottom up, in proper sequence – and screwed down at various points. Although the construction site is a mere four hundred metres from the sea, we were fortunately hardly inconvenienced by strong winds. We would have had to halt hoisting operations at wind force 4. Although the building has now been handed over, the work does not stop here for us. Over the next fifteen years we are responsible for the technical maintenance and cleaning of the façade.’
‘The construction process of our fibre-reinforced polymer façade elements is as follows: every façade element type has its own mould in which small dry fibreglass mats are placed in accordance with a predetermined pattern,’ Marco continues. ‘The laying pattern and the thickness determine the strength of the elements. Next, we cover the mould with foil, which is made airtight along the edges, after which we vacuum seal the total package.’
‘After this, we inject liquid resin into the mould through hoses from one or more places. Due to the pressure differential, the resin automatically flows throughout the entire fibre pack. Once the mould is completely filled with resin and has cured, we remove the façade component from the mould. After that we touch up any roughness and cover the façade element with a white top coat.’