Urban materials and sustainability in Hamburg

· Which is the problem/the issue?

Which are our (research) motives? – Why this subject is interesting to us?

·        Which are/is the objective(s)?

·        Research position (να σημειώσουμε ότι δεν έχουμε οπτική ντόπιου αλλά ως επισκέπτες)

The city constitutes the place where all kinds and classes of people are mixed to produce a common, though constantly changing and ephemeral life, forcing this heterogeneous ensemble to interact (Harvey, 2012). The essential feature of urbanity is, therefore, concentration and co-existence (Lefebvre, 1968/1996)  and the local centres that emerge in a city are at the core of this process. These “activity nodes” (Alexander, et al., 1977, p. 166) beyond their role in city’s functionality, act as meeting points for citizens, where practices of encounter and exchange (economic, social etc.) take place, where “you can go to see people, and to be seen (…), the place where people with a shared way of life gather together to rub shoulders and confirm their communities” (p. 169). Therefore, a centre in order to be meaningfully successful should be functional for its residents but also vibrant, attractive and accessible for all its users. It should promote active street life, animation in the street, dense and diverse human activity and movement -especially walking- and in summary to create what Jacobs (Jacobs, 1961) called “intricate sidewalk ballet” (p.50) of people walking around neighbourhoods, at different times for different purposes

• Supporting infrastructure ensuring substantial access to the activity nodes emerging in a neighborhood and facilitating human coexistence and interaction in the public space (Alexander, et al., 1977)
• Rehumanizing the public space that is the road by supporting human activity with walkability and active mobility features (Gehl, 2010; Milan, 2009)
• ‘Accessible Centrality’ refers to a fundamental element of human-oriented centralities, which is the meaningful open access to the places of human co-existence and interaction. Consequently, the proposed centrality criteria are defined as follows (Fig. 2):
• 1. ‘Public open places of accessible co-existence (POPoAC)’ criterion refer to the Public Open Spaces of the city, formal and informal, which contribute to liveable and sustainable centralities as they provide a public meeting place with social meaning and open access.

Public space is relational – it establishes links with private places and other public spaces, it joins users together and hosts a variety of common services ranging from functional to symbolic values. Public space may be considered as a continuous system of places, organized in physical, functional and meaning continuity relation. This means we should consider public space systems related to infrastructures or to ecological systemic features, even if they spread outside typical urban settings. So we may organize a Public Space System framework regarding three main elements:

• Components: anchor spaces; connections;
• Dynamics: external; internal links;
• Interaction: landscape; infrastructure; communication.