Avoiding the pitfalls of urban densification

For the past 5 years, Andrea Bassi’s research group has been investigating densification and its effects on urban spaces. In the meantime, the Swiss population has voted to put an end to urban sprawl, putting villages and cities under pressure to accommodate growing numbers of residents without spilling over their perimeters. But what does this mean for people living in cities? Can dense urban centers offer them the quality of life they are after? On Thursday, September 19, Andrea Bassi will present findings from a four-year research project, which focused on the transformation of Geneva’s Praille neighborhood, at the Semaine de la densité, held at the Pavilion Sicli in Geneva.

If we look into the past, we come across several failed attempts at urban densification. What have we learned in the meantime that you believe could help us avoid repeating them?
This is true, but it is important to remember that modernity is still only around 100 years old. 50 years ago, we hadn’t yet had enough time to learn how to deal with such high population densities. And like after any other kind of revolution, be it political, scientific, or social, initially, ideologies dominate. In urban planning, the ideology behind zoning, promoted by Le Corbusier in particular, and the separation of residential, commercial, and industrial areas connected by a transportation network prevailed. Today, in contrast, we have reached a level of maturity that allows us to distance ourselves from these strict ideologies. At least here in Switzerland, we see through them and appreciate the pros and cons of each approach. Rather than blindly applying ideological solutions, we respond to challenges using our knowhow and experience.

How can architects address the challenges that come with urban densification?
One of the main challenges we run into in cities is personal mobility, largely due to the separation of residential, commercial, and industrial areas. By promoting urban mixity, that is, the coexistence of spaces dedicated to these activities and to recreational purposes, we can reduce the reliance on motorized means of transport. But to architects, this means that we have to put more emphasis on designing the spaces that connect different activities, which lie somewhere at the crossroads between collective, anonymous, and private spaces, and have an appeasing effect by promoting social interactions. Think about it. If you have to drive your children to school every morning for 5 minutes, you are much less likely to interact with a neighbor than if you walk them to school. And the same is true of shopping, the movies, etc. With increased mixity, city life becomes more organic.

So what will these dense neighborhoods look like?
We understand that there is no single type of building that works best in this context. Instead, we should leverage the diversity of building types and make them coexist – high-end apartments next to subsidized housing, etc. Here, diversity is an important asset. But would we feel comfortable in a city, where some buildings are built using wood, others using concrete, and others still using plastics? I argue in favor of a more homogenous approach based on concrete. In the past century, this would have created a dry, dull atmosphere, but today, we know how to work concrete and take advantage of its many surprising facets.

Would this be sustainable?
It may come as a surprise, but yes. Studies conducted at the federal level have shown that in the middle to long term, building with concrete is more sustainable as building with wood. But it entails a paradigm shift in the way we look at cities. In the past, cities drew on their surroundings for natural resources. Quarries provided stone and sand, while forests provided wood. But today, cities are increasingly becoming their own quarries, where materials from torn down buildings are recycled and provides the primary resources to build new ones. In this case in particular, but also otherwise, the components used to produce concrete are much more local than wood, which is typically transported hundreds of kilometers by truck.

So when do we begin moving in this direction?
We already are! The master plan for the Praille neighborhood in Geneva is based on a mixed, dense program. A national construction program outlining many of these themes is already in place. The Lemanic metropolis has been a reality for the past two years. And cement recycling is already happening. It is an exciting time to be an architect!