»Emptiness as a feature that fosters identity«

Kai Vöckler
On the plans for the new HfG Offenbach building by Xaveer de Geyter Architects/Topotek 1

Photo: Felicitas von Lutzau

The competition for the new build HfG Offenbach University of Art and Design posed two key challenges for the architecture practices invited to take part. First, the site is divided by a public thoroughfare into two separate areas on which one coherent university building will be constructed. Second, the task involves not only the construction of a new building with international appeal that is hugely significant for the city of Offenbach and the State of Hessen, but also the fulfilment of a promise for the future in situ: the university as a central driving force for urban development – against the background of the university (still) being located on Schlossplatz, the very place where Offenbach itself began. In this respect, all participants were faced with the question of how to solve the formal problem of the divided site, but also how an identity-forging design might do justice to the importance of the university in Offenbach as a university town. The following remarks outline how the design that won the first prize in the competition by Xaveer de Geyter Architects (XDGA) with Topotek 1 Zurich and Topotek 1 Berlin responds to precisely these two challenges in impressive fashion.

The urban fabric in which the new building is to be embedded is likewise characterized by internal division. On one side, lies Offenbach’s Nordend district, very much a migrant area with more than 50 percent non-German residents and more than 80 percent of its population with a migrant background. It’s an area where people live under a strong social burden – in short, with many people living in precarious conditions and at the same time trying to gain a foothold in the “arrival city” of Offenbach. On the other side, is the new harbor district developed on the site of the former industrial harbor, which seeks to strike a social balance with the neighboring Nordend district through gentrification and was geared towards the influx of high-income (including migrant) households (as can be seen from the high proportion of owner-occupied apartments). The development of the new urban district, and particularly its open space, is exemplary. The harbor district is characterized by a very high proportion of public spaces: Essential elements include the Hafenplatz square with the steps adjoining the marina, the Gutschepark, which is yet to be completed and adjoins the new HfG Offenbach building, and the park at the tip of the harbor peninsula, with the aim here being to link up to the adjacent Nordend district via the public spaces. This has actually been successful, and now all social groups from the disadvantaged districts mix here – the Hafenplatz square and the steps (with a view of the Frankfurt skyline) are some of the most popular spaces in Offenbach, often visited by wedding parties who see this as an appropriate backdrop to their vows for the future. While this development and the very accomplished open-space design of the harbor district are undoubtedly positive, there are nevertheless shortcomings in the urban-design master plan, as reflected in the development plan.

The 190 x 26-meter inner courtyard links the urban space with the campus via the public thoroughfare, opens up to the city via the funnel-shaped entrances, and at the same time creates an introverted space for the university (source: XDGA/ Topotek).

The university is accessed like a small town via an inner street on the first two floors, which links the two parts of the building (source: XDGA/Topotek).

Subtractions within the two parts of the building create public university spaces: the main entrance and the terraces and patios, which create vertical connections (source: XDGA/Topotek).

The “empty space” that opens up to university life and the urban neighborhood alike is the central element of the design’s urban planning, architecture, and open-space concept which, together with the square grid, brings structure and order to the campus (source: XDGA/Topotek).

The development plan stipulated (in its legally binding nature, even if there is room for interpretation on the part of the approving municipal building authority) that the designers had to comply with the specifications that were clearly set out in the competition text. These included ensuring the public thoroughfare dividing the construction site was not built over (or under) and maintaining a building top edge at a height of 18.50-19.50 meters along the Hafenallee to the south (which corresponds to five stories). On top of this, there were specifications regarding the areas of land that could and could not be built on. A proportion of green space of at least 25 percent was also specified, one third of which has to be planted with trees and shrubs. Another particular challenge lay in the bend in the plot away from the dividing public thoroughfare. And the publicly accessible thoroughfare leading on from Ludwigstrasse in the Nordend, which formed a line of sight that is taken up as open space beyond the marina in the development opposite, is nevertheless lost somewhere.

The urban figure underpinning the development plan encloses the harbor area to the north and south with a rigid building edge that encases the development site like a bracket, and is structured by visual axes that appear infinite. All this, as the submitted competition designs show, visibly confounded the designers and challenged them to compensate for the urban-planning deficiencies through the design of the new university building.

The winning design solved the task described above with a conceptually and strategically ingenious way: In terms of method, it applies a subtractive design as an architecture of removal that creates meaning from emptiness and at the same time provides the qualities demanded in the university’s spatial program, transforming the specifications of the development plan into a meaningful spatial figure that connects with the surrounding space. Evidently, the architects first filled the entire site with a four- to five-story block that reached to the edges of the site in order to then subtract the public thoroughfare (as well as the expansion area to be made available). The next step was then to cut out the rectangle that makes up the entire open-space area of the campus site as an impressive defining figure. Since this “garden courtyard” measuring 190 x 26 meters does not follow the bend in the building, it forms an impressive and clearly spatial gesture that links the two sections of the building and is extraordinarily impressive in its terms of its ability to forge a clear identity. In its connection with the public thoroughfare, this spatial figure fulfills what the university had called for in its guiding principles for the new building: The two building plots are bonded to constitute a single design space into which the public thoroughfare is integrated. The campus courtyard is enclosed by the building structure and opens up to the city – the emptiness of the open space accommodated by the university building is what gives it its openness, while at the same time literally releasing its potential, since the courtyard can be used in different ways by students and teachers; it is a place of work, communication, and recreation. This programmatic elimination of parts of the structure is continued by the designers; the subtraction of individual volumes gives the two buildings greater differentiation and rhythm.

This applies, for example, to the two- to three-story special areas, the entrance area, and the terraces and meeting zones, which are all linked by the circumferential “bioclimatic gallery” as an internal street. The latter functions not only as an access route but also as a work and exhibition space, becoming the university’s display window along the Hafenallee, and can actually be opened up at the southern edge of the inner courtyard. Without going into further detail here, it is clear that the designers not only meet the specifications of the spatial program and the associated functional requirements, but also solve the formal problem of the two-part university building through the connecting large-scale form of the open space. At the same time, they develop an identity-forging spatial figure that opens up to the city and connects to it.

At the same time, the prime artistic quality of the design is fitting for an academy of art in the 21st century. The designers themselves provide (hidden) clues to the architectural tradition with which they themselves identify. If you look at the rendering of the campus courtyard with the student activities depicted there, you’ll see a playful-looking cube sculpture in the middle. Together with the façades designed in a square grid, it is reminiscent of the Family Court on Hallesches Ufer in Berlin, designed by Oswald Mathias Ungers and completed in 1995, with its volume developed from the square and the façades aligned with the square grid – and the cube sculpture in front of it by US artist Sol LeWitt. The nod to Ungers, the most influential and internationally best-known German architect of the late 20th century, is also evident elsewhere.

The design strategy of subtractive design can be found in the 1977 urban-planning concept “The City in the City – Berlin: A Green Archipelago”, which Ungers developed together with Dutch architect Rem Koolhaas and in which emptiness was used as a design element in urban planning for the first time. The background to this reconceiving of urban planning was the dwindling population in then West Berlin and the resulting vacant buildings, which made it impossible to maintain a homogeneous urban form. Instead, the city was reconceived as a heterogeneous constellation of urban islands each with specific qualities, while development of the areas in between them was to be deliberately pared back. Koolhaas adopted this strategy with his firm OMA (Office for Metropolitan Architecture) in the urban planning for the redesign of the La Défense district in Paris, which was based on the principle of a continuous tabula rasa. The design from 1991 proposed getting rid of the existing buildings in five-year stages, with the exception of a few valuable buildings. The resulting empty space was to be reorganized with a neutral grid (borrowed from that of Manhattan), setting a frame for future developments without anticipating and planning them. The aspects of uncertainty and indetermination thus found their way into urban-planning design practice. In 1989, too, in the competition entry for the “Très Grande Bibliothèque” in Paris, OMA applied the design methodology of cutting out the publicly accessible areas from a building structure as empty spaces and consciously made an architectural element out of the potentiality of emptiness.

These designers have adopted a similar approach: The campus courtyard as an empty space and promise for the future is underpinned by a square grid, which is used to structure the different areas and requirements, both in the two parts of the building and in the courtyard itself (with the very nice detail of the free-standing tall pine trees in the grid, which rhythmically structure the façades – reminiscent of Bruno Taut’s housing estates in Berlin-Zehlendorf). It is precisely the consistent adherence to the square grid that creates cohesion, even if, due to the kink in the smaller part of the building, the resulting oblique angles have to be reconciled with the functional usage requirements in subsequent design planning. The alignment towards the square also formulates an aesthetic promise: The building reveals itself as a geometric construct, referring to the notion of an ideal order. This, in turn, points directly to Oswald Mathias Ungers, whose buildings from around 1980 onwards were strongly geared to a geometricizing expression based on the square (such as the above-mentioned Family Court in Berlin). The timeless validity of geometric laws of form, as canonized in Classical architectural doctrines, became the basis of his work in his time. He thus drew on the Classical tradition that had shaped the various classicisms since Ancient Greek times, which found its organizing principles in moderation, measure, and numbers. Ungers had been searching for a new sense of regularity in his designs, for the ultimate justifications of architecture from within itself. He calls for a reduction of architecture to its own essence, a “new abstraction” that revives the basic concepts of space that have appeared in all historical epochs. For Ungers, the timelessly valid principles are “clear geometric and volumetric forms that represent a quality of permanence as a universal order of abstraction.”

This is where XDGA/Topotek 1 follow through, relying in formal-aesthetic terms on the square as an organizational principle that thus underlies the concise large shape of the empty space and leads through the two-part structure to the details. A building that articulates a vivid unity through the geometric organizational principle and in this way gains its own artistic value. At the same time, with the empty space of the campus courtyard, they create an identity-forging “large form”, a memorable image of a university of design that opens up not only symbolically, but very concretely towards the city and thus fulfills its promise for the future in an unspectacular way at the interface of the two socially differentiating city districts: as a place open to all people.