Il tessuto connettivo della città come veicolo di rigenerazione urbana. Lione e Barcellona, due esperienze a confronto.

Uncontrolled sprawling and urbanization produce changes and malfunctions of the urban system: environmental matrix alteration, ecological system fragmentation, social and economic issues. Actually, the current rate of expansion is leading many cities to an abnormal growth causing “the loss of those characteristics that make the city attractive and represent the basis of human life” (Indovina et al 2005). The present paper discusses the urban connective system, considered as the whole of open spaces for rest and movement, the “continuous distributor of mobility” the “place through which the city expresses its very functions” (Caniglia Rispoli 1970). This system represents a priority intervention area for the natural recovery of urban and peri-urban areas affected by degradation (National Strategy for Biodiversity 2010). Its strategic characteristic lies in permeating within the urban fabric representing the widespread support for urban regeneration. Design strategies consider time dimension to control transformation processes, and technological solutions able to improve the available resources management. As demonstrated by recent transdisciplinary researches, the intervention on open spaces helps to solve some of the problems afflicting the urban fabric, such as the regulation of the energy flows, water and waste cycles, social and economic issues (Ruros 2005; Urbspace 2011). With the aim to reach an environmental balance of urban fabric and a new relationship between man, nature and urban habitat, the present paper shows and compares strategies, processes, tools, and design solutions acting in two sustainability sensitive European cities: Lyon and Barcelona. The paper shows the two cities best practices of intervention on the connective system, describing procedures, strategies and design aspects and identifying the transcalar and transdisciplinary characters of transformation interventions.