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object:Geology Court, University of Freiburg type:area for the public
location:Freiburg state:Germany
architect:Olaf Nicolai, Rainer Thurau, Freiburg materials:precast concrete
published:BFT 12/2005 page:6 - 8

Science meets nature

The geological square in Freiburg

In their ideas for designing grounds and areas for the public, the designers of open spaces are departing more and more from the standard method of simply using the well-known types of coverings. Nevertheless, concrete and the precast parts made from this, remain the preferred materials for covering surfaces. The Geology Court at the University of Freiburg is an example here of how this can be done.
Despite being very central, you still have to ask a resident who knows the city well in order to find this both very intimate and yet appealing square in Freiburg.
It owes existence to the subsequent developments for greater concentration in the fields the institute is working in. The university has now constructed a long building complex on parking space.
The area left over was put out to tender. First prize in the competition here went to the Berlin-based artist, Olaf Nicolai. His concept was to surface the court with a geometrical arrangement of squares and circles. Not unlike a pattern for weaving a carpet, the principle for his design is based on a module measuring about 1.84 m. Squares in red and yellow alternate in an apparently arbitrary order. A circular area has been set into the standard module in each case. This either shows the other color, or has been left open entirely and grass can grow inside.
Based on the basic module, two other square sizes have been created and each contains a circle as well. Four or sixteen area units can thus be counted.
Also included in the court are two adventure trails - one for mineralogy and another in geology. On display here are various rock exhibits that in line with their size, have been set either on a small grassy circle or a medium-size arc of lawn. Thus to a certain extent, the court resembles a Breton menhir field.
In the geometrical arrangement of the shapes, the artist sees analogies with the areas of work the university focuses on. The geometrical floorcovering stands for such terms as culture and mathematics whereas the open grassy areas and rock exhibits represents nature. In designing the court in this way, Nicolai was wanting to put the two in a mutual relationship and to visualize this as an experience with the senses.
The main problem on the project was how to route the water over the court. Only a slight gradient of about 1% was possible for topographical reasons. Also, gutters outside of the mosaic for drainage purposes were to be avoided whatever the case. Not only this, that part of the court on the east side is over basement rooms. In the design now realized, the mosaic does not end directly at the old building from the original university but rather transitions by way of a small gap into an asphalt-covered street. The rainwater is taken away until it finally reaches a gutter directly in front of the old building to the west from where it then flows away. It is only on the south-west side of court where there are three steps leading down to the mosaic, that the decision was taken to install drainage by including a narrow split gutter for part of the court.
The precast parts used here were produced by the company of Birkenmeier Stein+Design. Remarkable here besides the already high requirements for the surface quality is the craftsmanship in fabricating the elements. The condition had to be met that the inside of each module be of a different color. This was realized by placing concrete of a different color on the square basic element in a second working operation. The bond between the two different concrete's has been established solely by the roughness of the concrete surface, an applied adhesion background and using armoring pins. So as to realize as high a coherence as possible in the color scheme, particular attention was paid to all elements having exactly the same curing conditions and all being kept in storage for 21 days. The surface of the precast parts should be as flat as possible and furthermore be free of all threaded holes for the installation eyelets. Neither were any covering flaps desired. The Probst company developed a special vacuum-operated suction device just for this project. With two such vacuum suction devices mounted on an extra-long traverse, it was possible to maneuver the ¼-arches easily measuring 5.19 m in diameter. The artist had originally wanted a terrazzo surface without any joints. As this was not to be realized in such dimensions, the decision was taken in good time by the planning committee to use prefabricated parts. Starting from the originally homogeneous ideal, it might appear that together with a chamfer measuring 3 x 3 mm the 8 mm selected as the width for the joint would be detrimental to the overall appearance given by the precast parts. In actual fact, such dimensions are completely lost in the expanse of the court. As part of the last working operation, the whole of the covered surface was then given a dirt-repelling seal.
Robert Mehl, Aachen