The Large Scale: High-rise Buildings, Landscape and Infrastructure
Are high-rise buildings a suitable densification tool for Zurich?
We examined the potential of high-rises as part of a testplan commissioned by the city of Zurich in 2019–20. With the new urban plans and the spatial vision outlined in‘Zurich 2040’, the city is responding to current growth forecasts which envisages the number of residents to grow by 100,000 by 2040. This forecast is not insignificant by Swiss standards: by comparison, 80,000 people currently live in the city of Lucerne.
Current urban planning guidelines should be revised in view of these trends, and the typological requirements for high-rise building need to be updated, taking into account the pressing challenges of climate change and current requirements in terms of public realm and housing standards.
Is the high-rise an answer to densification and urban warming?
It was clear that the high-rise is a densification tool, but the question was, can it also be implemented in Zurich? The advantages are apparent. It requires a smaller footprint and helps to implement the so-called ‘inner city densification’, since land reserves in the Canton of Zurich are finite. The changed climate conditions in the city – especially urban heat islands – favour the high-rise because, unlike the block, it does not hinder ventilation and night cooling. On the other hand, high-rises have high costs in terms of economy and ecology. ‘Grey emissions’ are exceptionally high in the initial construction phase and, therefore, a careful balance must be struck between the advantages and disadvantages of this building type. And last but not least, high-rise buildings in Zurich elicit strong emotions: they were rejected by the population in the late 1980s, and only became buildable again at the turn of the millennium with the implementation of the high-rise guidelines in 2001.
In parallel with this study which we carried out at EMI, we worked on a brief to design high-rise buildings with students from ETH Zurich. While we focused on urban planning problems in the office, we raised more typological, structural and energy-related questions in the design studio.
Our investigation started from a set of fundamental questions:What do high-rises mean for Zurich? Where are the new high-rises located, and how do they change the perception of urban space?What new typologies can we devise for high-rise building as a result?
The current situation
The current situation is regulated in the city’s building and zoning code which designate three high-rise areas with different heights and specifications. The urban planning principles are simple: on the plain of the Limmat valley floor, around Hardbrücke and towards Altstetten and Schlieren, as well as in Oerlikon, high-rise buildings are tallest, while on the foothills of Käferberg, Zürichberg and Üetliberg, the permitted height is lower. The 2001 guidelines prohibited high-rise buildings in the city centre, around the lake and along the forests.
Furthermore, existing high-rises in Zurich tend towards programmatic and economic exclusivity. They are primarily mono-functional offices or residential towers, and do little for the street and the public realm, although they have a powerful presence and act as place markers visible from afar. Two projects initiated by the city rather than private developers, the Lochergut (1963–66) and the Hardautüme (1976–78) are the exception, with a mixed programme including residential and commercial uses.
What do high-rise buildings mean for Zurich?
Cities managed without high-rise buildings until about 150 years ago, when innovations in building technology, such as steel construction and the invention of the elevator made the high-rise possible.
In Switzerland and Zurich, these achievements came comparatively late and did not become widespread. Economic, political, and geographical conditions have not favoured the construction of high-rise buildings. As a result, they often stand alone in Swiss cities without a compelling or evident causal connection to the built environment as a whole, and each building is, to a certain extent, an experiment in itself.
This observation is not a judgment but a description of a Swiss specificity. Switzerland does not have a centralised political system with its attendant representative buildings but has always been organised in a decentralised, small-scale and direct manner. Consequently, it lacks distinctive centres, which are the prerequisite for the emergence of urban cultures. Switzerland's proverbial anti-urban reflex is emblematic of this mentality.
Therefore, high-rises are not an expression of urban culture, nor are they symbols of political and economic power and the like. There are no downtowns or financial districts with associated skylines. Thus, high-rise buildings are not an expression of unleashed economic liberalism as in American or Asian cities. In Zurich, clusters of high-rise buildings are sometimes randomly situated in the urban landscape: the tallest skyscrapers have been bult over the last 20 years in former industrial areas, such as the MAAG district near Hardbrücke or Oerlikon. These new skyscrapers are emblematic of the transformation of an industrial society into a society of service providers.
Switzerland recognises large buildings of public importance primarily in the form of infrastructure: bridges, dams, tunnels, railways, bunkers, motorways. These are constructions without explicit cultural connotations. They are primarily functional, rather than representative, and designed to tame the forces of nature.
We have taken this interpretation of Switzerland's urban character and its approach to ‘large buildings’ as the starting point for our urban idea: our intention was to emphasise the large scale of the city, its topography, infrastructure and landscape elements by using skyscrapers as markers.
This idea accompanied a shift in what we understand a city to be: the contemporary city is no longer just the sum of what is built, it is an urban territory and encompasses ‘culture’ and ‘nature’. Thus, high-rises are about orientation, legibility and identity within an evolved, hybrid structure that is both natural and cultural.
Where are new high-rise buildings located, and how do they change the perception of urban space?
Our strategy was to regard high-rises as markers in the territory to highlight the following topographical, landscape and infrastructural features of Zurich: the city entrances as superordinate axes, infrastructure such as bridges, tunnels and railways, topography with the valley and its hills, and saddles, the edges of the forest, the lake and the two rivers.
All the new areas which we already proposed have high-rises which would be incorporated into our new plan ‘retroactively’. The link with territorial elements also made it possible to connect high-rises to large-scale open spaces and think of urban densification scenarios which include the necessary green recreational spaces.
The synthetic map shows the seven areas in superimposition: a network of high-rise buildings traverses the city, as linear clusters cross the urban along its north-south axis.
City entrances
Important city accesses such as Gleisfeld, Pfingstweidstrasse or Birmensdorferstrasse are already located within the high-rise area and lined with high-rise buildings. Other streets such as Forchstrasse, Wehntalerstrasse, Sihlstrasse and Winterthurerstrasse are important thoroughfares whose urban role would be strengthened by high-rise buildings.
Bridges, tunnels and railways
Kornhausbrücke, Hardbrücke and Europabrücke each cross the railway and the Limmat and provide significant north-south connections between the lower and upper parts of the city. High-rise buildings along this intersection emphasise the overlapping infrastructure on the valley floor.
The saddle
Topographically, Bucheggplatz is of outstanding importance. It lies between Zürichberg and Käferberg, in the transitional space between the Limmat and Glatt valleys, on the threshold between the city centre and the northern part of the city. Here, high-rise buildings mark this important area that links the north and south of the city.
The valley
Climate change is causing temperatures to rise during the summer months. This is particularly noticeable in densely built and sealed areas on summer nights, when heat stored in buildings heats up the city and prevents it from cooling down at night. High-rise buildings, with their smaller footprint, allow the wind to flow through the city and cool the air at night.
The forest edges
Zurich’s inner city is framed by the forested hills of Hönggerberg, Käferberg and Zürichberg to the northeast and Üetliberg to the southwest. High-rise buildings along the edges of the forest connect it to the city and provide high-density areas with important open spaces for local recreation.
The lakeshore
Lake Zurich is a recreational area, and has an important role in terms of public and goods transport.However, Zurich developed along the Limmat and not around the lake basin, as is still clearly visible in the cityscape today. Beyond the quays and the Zürichhorn on the right bank, only traffic infrastructures line the shore, and the city ends abruptly. On the left bank, the urban character ends at the Mythenquai lido. The lakeshore was excluded from the current high-rise area so as not to compete with the ‘charisma and presence of the lake’. Conversely, it was important for us to make Zurich visible from the waterfront, transforming it into a city on the lake by placing high-rise buildings prominently on the lakeshore.
The riverbank
Zurich is a city by the river. Historically, it developed along the Limmat, as is still clearly visible in the buildings of the Limmatquai. It is along the river that the city's economic and demographic development took place in the early modern era. The expansion of the city into a metropolis at the turn of the century was also planned along the Limmat, which remains important to this day and is still a significant part of the city's identity. Especially in the summer months, with its unusually high number of river swimming spots, Zurich becomes a bathing city for all generations.
What new typologies for high-rise building?
These considerations help reframe the new high-rises as urban infrastructure designed for city dwellers that also provides a service to the public, rather than merely part of specific Zurich urban landscapes. The notion of giving something back to the city is crucial, as skyscrapers take up airspace far above the ground, and should therefore benefit the public in return.
We proposed several features for Zurich, which I will only briefly outline here. Ground floors dedicated to truly public uses as free as possible from compulsive consumption –schools, health centers, and cultural facilities – are essential. The typological mix of public uses at ground level and more private residential uses above would positively counteract the mono-functionality and exclusivity of high-rises.
According to Arno Schlüter, it is realistic to envisage building envelopes capable of producing CO2-free heating, cooling and electricity. The potential for electricity generation in winter is particularly interesting, as is the heating and cooling of high-rises using lake or river water. High-rise buildings contributing to the city’s overall energy supply through an energy network would be visionary. Thanks to the shading and cooling of unbuilt areas, high-rises could positively affect the urban climate.
Since 2004 Elli Mosayebi has led Zurich-based architectural practice EMI, together with Ron Edelaar and Christian Inderbitzin. Housing and urban design have been a particular focus of their work, with many projects won through competitions. From 2004–08, she was research assistant for the Chair of Architecture Theory under Professor Ákos Moravánszky, where she completed her doctoral dissertation on the work of Luigi Caccia Dominioni. From 2012–18, she was Professor of Design and Housing at TU Darmstadt, where she conducted a comparative study of postwar European housing. Since 2018 she has held the position of Professor of Architecture and Design at ETH Zurich. In 2019, EMI won the Swiss Art Award. Her book,The Renewal of Dwelling (Triest Verlag, 2023), won the DAM Architectural Book Award in 2023.
