In the two decades to come, Chinese cities will be confronted by a reform of the hukou (housing registration) system and consequently by new challenges of urban growth and densification. The hukou system is an administrative instrument of the central government used to control labour mobility and welfare distribution by dividing Chinese citizens into rural and urban households. The forthcoming reform will abolish this fundamental rural-urban dichotomy.

The 250 million strong floating population of China will be moved to the cities. The reform will explicitly change social and spatial stratification in China and will result in urban intensification by causing increased urban mobility and increased demand for welfare. The expected urban growth will further dissolve cityness and will exacerbate the existing urban sprawl, which is caused by the current predominant Chinese planning model of the mega-plot, which only allows urban intensification through the proliferation of modular units. Therefore, over the next few decades the hukou reform will result in an excessive form of urbanisation without differentiated mid-sized and large urban centres, and will turn one third of Chinese territory into a continuous urban region. Although the hukou reform is foremost social and political, the interrelationship between different urban social and political agendas also makes the reform fundamentally urban.

The history of Chinese planning follows a cellular logic of development, growth and control (for example, the courtyard house, danwei and mega-plot models) that embodies changing ideas of collectivity and autonomy in both socio-philosophical and spatial terms and depends on repetitive modular urban units. While these previous models assume a coherent social structure, the increased mobility and mix of urban populations that will result from the hukou reform will undermine this very assumption: the concept of a stable and clearly defined social tie. Therefore, the idea of collectivity and autonomy as the two fundamental characteristics of a cellular logic, initially enforced by the hukou, will eventually be destroyed by the reform. By fundamentally breaking the cellular logic, the hukou reform will radicalise the Chinese cities of the future.

A New Infrastructural Logic Proposed to Overlay Existing Cellular Urban Structure in Shanghai

The research intends to examine this fundamental and inevitable urban transformation and how the current cellular logic of urban planning and governance will be challenged by a necessarily differentiated infrastructural logic. A new welfare distribution system in spatial and social terms will be required as labour mobility increases. The application of an infrastructural logic will break the unspecific distribution, creating a new and differentiated welfare distribution that coincides with spatial infrastructures and an emerging networked urban structure.

Urban Atrium in Context - North Sichuan Road, Hongkou District, Shanghai

Where cellular and infrastructural logics interact, an urban atrium is proposed to articulate the nodal point of the new network relations and form a model that holds together new scales of collectivity defined by the provision of standard welfare and education as its extension.

The urban atrium is predominantly designed through sectional relationships. It consists of four layers: a sunken plaza accommodating the ticket hall of the station, an open ground plain, a hanging ramp and a lifted podium hosting freely arranged rooms.

07 Plans of the Urban Atrium: sunken plaza level, ground level, ramp level and podium level

Although educational programmes are essential to the new collectives, a group of people brought together for the purpose of shared learning is just one constituency of the urban atrium. The new welfare agency requires that the urban atrium is also designed for welfare receivers. Given its construction on a metro station, it must also meet the demands of commuters as another collective group. How an urban atrium hosts collective spaces for diverse constituencies will be explained through its four levels (the sunken plaza, the open ground, the ramp and the podium) and the different scenarios they illustrate.

The urban atrium defines collective spaces according to diverse activities each with their different constituencies and spatial requirements. Therefore, the atrium space does not only exist as a derivative of public transport, but also has meaning on its own for collectivities. The role of the atrium space shifts in time, from a functional space during peak hours to a spontaneous gathering space for communal, institutional and even political activities during off-peak periods. This collective space thus brings diverse social groups into contact with one another.

In summary, the urban atrium is proposed as a transition point of different networks; it links public transport network with the welfare system: spatial infrastructure with social infrastructure. Therefore, it is a three-dimensional point of connectivity and growth, and radically different from the mega-plot model as a form of parcellation of land. The urban atrium is an organisational element embedded in its surrounding urban context and part of a networked infrastructure at multiple scales, thus becoming a constructive element of a new urban structure. Based on this understanding, four matrices show how the urban atrium as a specific proposal transforms into a typological instrument of a new master plan.

With the urban atrium as its essential instrument, the network can be understood as a master plan that is based on typological diagrams of infrastructure and reshapes and regulates the existing cellular urban structure. In conclusion, the infrastructural logic redefines two key aspects of Chinese cities: a new welfare system and new scales of collectivity. Based on the understanding that Chinese cities are governed through collectives, collectivity is what an infrastructural logic needs to retain from the cellular logic. A redefinition of collectivity is fundamental to the infrastructural network's ability to generate a new urban model in China. Coinciding with the new welfare distribution, which is now separated from the Communist Party organisation, an infrastructural logic will eventually presents the possibility of a radically new form of urban governance in China.