Entre ville et campagne | EPFL Graph Search

Environmental, social and economic concerns linked to the sustainable development of the built-up environment are increasingly calling into question models of territorial development based on urban sprawl. This is because the process of dispersed urbanization generates social inequalities; it is based on the extensive use of automobiles, and leads to increased spending on infrastructure networks. This phenomenon tends to be explained by the search for a combination of life in the city and life in the wide-open which creates new life-styles based on the extensive use of transportation and communication systems. The analysis of these emerging practices indicates that they arise from a double pressure exerted on the population: on one hand, attraction to rural and mountain areas, and on the other hand the economic and cultural dependency vis-à-vis the large urban centers. In this context, the regeneration of urban wasteland areas appears to be a strategy capable of favoring a better anchoring between urbanization and public transport. The dynamics of off-shoring enterprises has freed up a large number of plots that are however connected to existing networks, and benefit from good accessibility and sometimes enviable centrality. The requalification of industrial wasteland has been the object of much research in the nineties, which has led to establish as principles density, mixed use and the preservation of the industrial heritage (for instance Escher-Wyss in Zurich-West, Sulzer in Winterthur, ABB in Baden, SIP in Plainpalais-Geneva). In the same way, following the abandonment of some mobility structures, research has started to focus on the fate of urban railroad wastelands. These are considered to be strategic locations to develop "compact cities", attractive for habitat and favorable for the development of social and cultural activities. Several examples in Switzerland illustrate these attempts: Ecoparc in Neuchâtel, Zurich HB, La Praille in Geneva, etc. Today, in order to offer alternatives to the urban paradigm of the compact city we focus our attention on a different type of railroad wasteland. By regional railroad wasteland we refer to areas located close to a train station, either abandoned or in the process of being abandoned, and situated in suburban or periurban zones. Though these regional railroad wastelands present advantages similar to those of the urban wastelands in terms of accessibility to public transport, they are very different by their relationship to the landscape and nature. In addition, much more affordable land prices than in city centers allow more flexibility in the choice of programs and target users. In line with the thinking led by Thomas Sieverts among others, we attempt to go beyond the antagonisms between city and country, by formulating the hypothesis that these regional railroad wastelands bring an answer that is able to reconcile the aspirations to life in the country with the requirements of sustainable territorial development. The present research aims to explore a series of urbanism strategies induced by the simultaneous and inseparable presence of the railroad and natural dimensions, which constitutes the specificity of these periurban and suburban sites. In a first phase, in order to reveal these specific characteristics we conducted a typology exercise on a sample of thirty railroad sites located on the Geneva to Sankt-Gallen axis. It extends the whole length of the country from Lake Geneva in the southwest to Lake Constance in the northeast and goes through the main city areas of the country as well as several so-called calm areas. These thirty wastelands were measured, photographed, described, analyzed and finally represented according to an innovative methodology that combines architectural, urbanism and sociological approaches. This first phase concludes with the construction of the "face" of each site; beyond the fundamental distinction between urban and regional wastelands, it leads to the identification of six individual types. In a second phase, the focus moves to the project process. In order to understand precisely the mechanisms and the stakes at play, we have analyzed several case studies of urban wastelands in various stages of advancement, going from construction finished (Zurich-West), to the beginnings of the launch of a project (Fribourg), the first stages of construction (Zurich Stadtraum-HB) and planning in the course of development (Lausanne-Malley). We thus show the main obstacles to development, then the levers, triggers or planning instruments capable of surmounting them. Finally, in the last part, we elaborate development scenarios up to 2025 for three regional wastelands of the Lake Geneva urban hub, which come from a distinct group within the typology: Versoix, La Plaine and Palézieux. The project recognizes two scales of intervention: the train station and its immediate surroundings on one hand, and the extended perimeter on the other hand, which includes land within a 500 meter radius around the station. The developments of these two perimeters are intimately linked: the creation of a pole of urbanization may induce an improvement of the rail service and vice-versa. These two embedded scales thus constitute a complex dynamic system, within which specific, though coordinated urbanism strategies are implemented, and the stakes proper to each perimeter dictate these. For the station and its immediate surroundings, the goal is primarily to increase the hospitability of the site, that is principally to increase the symbolic role of the station, to plan the equipment and infrastructure necessary in view of the increased flows of travelers, and arranging the external space by accentuating the presence of vegetation, in agreement with the local character. All of these interventions lead to the creation of a "railroad landscape" which is the regional counterpart to the urban public space. Within the extended perimeter, the project strategy rests upon the recognition of five complementary qualities: inhabited, equipped, wild, productive, to be contemplated, whose proportions vary according to the territorial insertion of the wasteland. Densification is then effected in a punctual and targeted manner, in coherence with the logic resulting from the encounter between rail and nature.

Méthodologie de gestion durable des ressources du sous-sol urbain

Pascal Blunier

The world is becoming more and more urban. During the last fifty years, the population in Swiss cities has grown from 45% to 70% of the total population. This change is characterised by urban sprawl and by an increase in the consumption of resources, particularly those coming from rural areas. This evolution is not compatible with the principles of sustainable development. To solve this problem, new urban policies are being developed. They favour development within the urbanised areas and reduced use of exogenous resources. The urban underground contains resources – space, geomaterials, groundwater and geothermal energy – which can efficiently support such policies. This project analyses how these resources have been exploited until now and how they could be used with sustainability in mind. The use of underground resources was analysed in five cities : Mexico, Paris, Helsinki, Tokyo and Montreal. It appears that, although resources participate in the urban metabolism, there is an important lack of planning and coordination in their use. Developments follow a sectional approach where the resources are considered independently, and only at the scale of a given construction project. As a consequence, conflicts occur between uses and resources are wasted. An understanding of the urban underground as a system was developed with the aim of preventing conflicts and promoting synergies. To this effect, the way in which resources interact was considered attentively. Situations in which interactions occur were described and analysed and compatibility conditions were suggested. A methodology was elaborated to evaluate the resource potential of an urban underground. It aims at considering the resources and the interactions between their uses from the beginning of the process of urban planning. The methodology is based on the use of Geographical Information Systems and 3-D modelling of geological and hydrogeological conditions. It aims at reversing the current paradigm, that proceeds from the needs to the resources, into an approach based on resources to satisfy the needs. Spatial information was exploited to determine indicators and maps of potentiality and of restrictions. The derived results will help support decision making by planners and policy makers who seek to better exploit the resources from the urban underground. The methodology was tested and applied on a case study : Geneva. The developed approach allows more efficiency in the use of urban underground resources, it can help prevent conflicts between uses and develop synergies. When integrated in the urban planning process, it highlights new opportunities and helps to develop projects that take into account the physical conditions of the underground.

EPFL2009

Concevoir à grande échelle

Mathieu Louis Pierre Mercuriali

Large-scale design - Mobility interface models and urban transformation strategies This research project is based on the hypothesis that the urban transformations generated by mobility interfaces constitute a key component of successful sustainable urban development. Effectively visioning and understanding these multimodal interchange hubs must therefore become a major strategic objective, in order to conceive an urban model that is compact - and networked and intelligent. With this aim in mind, this research aims to propose innovative strategies for transforming these communication interfaces into central reference points within the contemporary metropolitan landscape. Projects of this kind have already been designed and realised in most major European cities during the second half of the 20th century. These designs, characterised by their complexity and scale, formed the starting point of the major railway stations in today's cities, incorporating different forms of mobility over the course of time. Today they appear not just detached from their urban contexts - the very contexts in which they are embedded - but also unable to meet the current demand for functional mixity and communication effectively. They are undergoing obsolescence and finding it difficult to adapt to the paradigm shifts that have intervened - socially, economically and spatially. At a time when the city can no longer be conceived exclusively in terms of ex-nihilo construction, but must be viewed in terms of transforming an existing built fabric, what future can be proposed for these existing transport interfaces? What strategies can be developed to anchor them in their surrounding urban context? What capacity do they have for hosting new activities, new public and private spaces? Finally, what forms is it possible to imagine for this kind of design? Three hypotheses emerge: the development of mobility interfaces has generated specific architectural and urban forms correlating to the evolution of mobility forms themselves; the transformation and obsolescence phases of mobility interfaces offer potentials for metropolitan regeneration; and the process of producing a complex design calls for articulation and interrelation between different architectural and urban scales. To verify these hypotheses, the first part of this thesis is focused on the comprehension and analysis of these multimodal hubs, based on a review of architectural and urban theories that address the issue of how major urban projects relate to transport infrastructures. This is followed by close analysis of a series of relevant case studies within the Paris metropolitan area. The second part of the thesis proposes design tools to generate new urban and architectural design processes, derived from a process of design-based research. The final part of the thesis aims to demonstrate that this type of intervention is a design project with its own specific scale and complexity: between large building and urban fragment.

EPFL2015

Scrutinizing the Circular Economy concept applied at the urban level:A contribution based on the analysis of urban circularity indicators, the categorization ofCircular Economy interventions, and the identification of factors fostering the adoption ofcircular innovation.

Valeria Superti

Problem. Our current economic systems are deemed unsustainable. Although a global issue, the objective of living in a sustainable society is increasingly an urban challenge, as a rising 50% of the world's population currently dwell in cities. To secure a better urban future, integrated and actionable urban knowledge focused on what urban sustainability entails and how to achieve it is needed. In this context, the Circular Economy (CE) concept fosters efficient resource use through value-retention processes and waste minimization. Despite the wide attention on the CE, its interconnectedness with, and contribution to, sustainability, and whether these concepts might support or hinder each other, have not yet been clarified. Besides, knowledge is needed to guide cities towards a CE, for example, by identifying the types of interventions needed to achieve circularity, and the factors affecting the adoption of innovation that can foster it.Aim. This dissertation aims to scrutinize the CE concept applied in urban settings. It is based on a) the analysis of indicators used to assess circular cities, b) the categorization of interventions aimed at achieving a CE, and c) the identification of factors that affect the adoption of recycled products, as one measure towards CE.Approach. Indicators used to assess circularity and sustainability in urban settings were analyzed and compared. Semi-structured expert interviews were performed to iterate a framework that categorizes interventions that foster the achievement of a CE. A behavioral framework was developed that combines insights from the theory of adoption of innovation and behavioral theories, to identify and analyze the factors that can affect architects' decisions to recommend recycled concrete. A survey was used to gather quantitative insights from architects on their beliefs about the selected product.Insights. The results show that the concept of an urban CE is embedded in the broader concept of urban sustainability; however, the use of CE indicator sets entail a more detailed focus on certain thematic groups (e.g., waste production and management), for which more indicators are available in comparison with what offered by urban sustainability indicator sets. To categorize CE interventions, the proposed framework (RISE: Research & Realize, Implement, Support, Enable) offers a tool to guide the achievement of CE targets. In current circularity assessments, specifically in the construction sector, most attention is paid to implementation interventions (e.g., the quantity of material recycled). However, some of them (e.g., recycling strategies) still face barriers. Focusing on one recycling strategy (i.e., recycling concrete aggregates for recycled concrete) we inquired about the factors that affect this product's adoption. A senior position, a high level of knowledge of the material and a specific label, beliefs about the material's lower environmental impact, and prescriptive social norms affect the selected innovation's adoption. Finally, we suggest leveraging specific predictors of behavior to increase the recommendation of recycled concrete.Conclusions. This work contributed to shed light on the CE concept. This research challenged the added value of focusing on a CE rather than sustainability. Furthermore, it put forward a) an integrative perspective on achieving a CE focusing on a systemic approach, and b) a holistic behavioral framework for analyzing innovation adoption.

EPFL2021