Crystal Houses
Amsterdam
Architects: MVRDV // Project size: 840 m² GFA // Completion: 2016 // Awards: Glass Innovation Award 2016, Dutch Design Public Award 2016, Façade Award 2016 (SFE), Building of the Year Award 2017 (Archdaily) - Commercial Architecture, Architizer A+ Award 2017 - Mixed Use, Iconic Award 2017 - Best of the Best Architecture
The facade image of Amsterdam's city centre may only be minimally interfered with. Architects MVRDV and Gietermans & van Dijk were commissioned to design a new facade for a retail shop in the prestigious P.C. Hooftstraat. The appearance had to match the well-known fashion houses such as Prada, Chanel and Dior.
The architect in charge, Winy Maas, told the client: "Let's bring back what is being demolished, let's develop it further!"
The result was unique in the world. A facade with an extraordinary special effect, but at the same time almost poetic in its combination of tradition and modernity.
MVRDV developed a facade made of glass bricks that corresponded in form to the existing façade from the 19th century. ABT was significantly involved in the exceptionally demanding technical implementation. Just finding the manufacturer for the exquisite and stable components, which did not yet exist in this form, was a challenge. The worldwide search for a suitable manufacturer ended with the italian company Poësia, which was able to produce perfectly clear bricks. But how do you neatly join such glass bricks into a masonry structure? And how can it be realised that the façade is not only attractive but also inherently stable?
ABT researched the physical and structural aspects of the glass facade with great dedication at the Stevin Laboratory of the Delft University of Technology. The strength and rigidity of the glass were tested by the Glass Research Group of the TU Delft.
The result is a glass facade made of over 6.500 solid glass bricks. The transition between glass and masonry bricks takes place - similar to a puzzle - in the area of the window frames of the mezzanine floor. Not only the bricks, but also the frames and door leaves are made of glass and contribute significantly to the special look. Never before has a self-supporting façade made of solid glass bricks been realised.
Since the primary supporting structure consists of steel beams, the glass facade does not bear any loads other than its own weight. However, it must be able to safely transfer wind loads. The necessary stability is ensured by internally interlocking load-bearing walls.
Window and door frames were designed as brick arches. The only non-translucent part of the facade is a 60 cm high concrete base hidden behind glass, which ensures stability in the event of a strong impact.
At 10 N /mm², the bricks are four times more resilient than the original brick. To achieve maximum transparency, low-iron glass sand made of sodium lime silicate was used.
The 8.80 m high facade required an extremely precise fit. Each individual glass block was made by hand in a moulding process with rounded corners in a radius of 3 mm. Of the total of five brick sizes, the most common brick size is 210 x 105 x 65 mm. During production, both the flatness/planarity of the surfaces and the maximum dimensional deviation in each direction must not exceed ± 0.25 mm. At the same time, the angles had to be precisely dimensionally accurate in order to be able to join the bricks exactly orthogonally. For this purpose, their surfaces were grinded and polished by machine and partly by hand in a complex process. In order to prevent unwanted residual stress states caused by the uneven cooling of the hot molten glass due to the massive formation of the blocks, they were slowly cooled down in a controlled cooling process (fine cooling). On site, the glass blocks were not joined with a mineral mortar layer, but with a special transparent adhesive that was hardened under UV light.
One of the main advantages is that the material is completely recyclable. During the installation, several imperfect bricks were melted down and remoulded – in fact, the entire facade could be reformed in the future.
Scope of services: Structural engineering, facade engineering, glass engineering, material development, refurbishment
Photos: MVRDV
