Construction has recently started on the Circus site in Groningen, part of the CiBoGa site (Circus, Boden, Gasworks site), Groningen’s last inner-city building site. The first project involves the completion of two ‘eroded blocks’ by S333 Architects, the office that won the 1994 Europan competition for this site.
The CiBoGa site totals 14 hectares in size. On completion in 2008, it will contain around 900 housing units, 1200 parking spaces, 10,000 m2 retail space, and 40,000 m2 office space. A number of architects will design different zones of the site. The English office of William Alsop is responsible for the public space. The two buildings designed by S333 are meandering blocks sited on a continuous urban/green landscape. The blocks contain a wide variety of housing types (ranging from apartments for living and working to a five-floor large mansion), winter gardens, roof gardens, patios, two supermarkets, a police station, a playground, and a glazed arbour. The blocks form part of the Ecological Corridor in Groningen. An important 'green' role is accordingly given to public and semi-public spaces, and also to the range of private gardens and terraces.
The concept of eroded blocks developed by S333 for the Europan design has a strong urban-design layout: large urban blocks with flat, relatively neutral facades that blend easily with the surrounding urban fabric. But the concept also has an open landscape character. The traditional distinction between public, semi-public and private (external) spaces, and the related street, square, courtyard, and front and back garden spaces, have been replaced by a continuous landscape where transitions are blurred. The mixture of 'strong' urban elevations and the 'soft' landscaping of the ground plane is also the leitmotif for the further development of the CiBoGa site.
In terms of urban design and landscaping, the two 'eroded blocks' by S333 are linked: they share an underground parking garage. Architecturally, they are treated as two distinct entities. Block 1 is sturdy, extends higher at some points, and the glazed facade is treated as a flat plane with windows stretching from floor to ceiling. The use of various types of glass allows for great variation in terms of transparency, reflectivity, dullness, and colour. Block 2 is faced in cedar-wood panels and is further defined by the ascending landscape of inner courtyards, which progress in stepped fashion from street level to the entrances to the dwellings on the first floor.