ACOUSTIC BARRIERS. A SYSTEM FOR REDUCING NOISE AND ENVIRONMENTAL IMPACT IN URBAN AREAS

The acoustic screens placed adjacent infrastructures, in order to reduce the noise emission towards inhabited centers, are commonly referred to as "noise barriers", and have recently populated urban and peri-urban environments, currently representing the most widespread type of acoustic mitigation intervention. The introduction of noise barriers, following the "European Directive 2002/49CE", has made the problem of finding design solutions, that can give answers to the relationship between infrastructure and city, even more urgent, especially in consolidated urban areas. This topic was the subject of design research conducted for RFI in order to define a type of standard barrier for railway use. This research was an opportunity to redefine design and technical solutions to mitigate the impact of the infrastructure on the city. The result was a sound barrier project that was subsequently implemented and is currently being used by RFI. The research started from the indications emerged from the study "EUROECRAN - european programme for elaboration of competitive railways noise barriers" for the definition of the geometries and characteristics of the materials to be used for the best noise abatement, evolving in the creation of a technological system of components that can be assembled and combined. The problem is twofold, like the two sides of the barriers: on the one hand the relationship with the infrastructure, with its constraints and its noise abatement requirements. On the other, the relationship with the urban environment crossed by the railway. Two faces, then: the first that responds to physical and geometric demands dictated by acoustic rules, the second that aims to make the barrier a changing architectural object that adapts to different contexts. The principles underlying the project were: • The construction of noise barriers takes on a physical dimension and urban role for a large architectural structure inside the city. • The barrier with many "faces" which can be modified to react to different contexts of crossing. • The barrier object, rather than a product, must be a technological system with maximum flexibility of use. From a technological point of view, the barrier object is made up of three elements: the Skeleton, which constitutes the load-bearing structure, an Inner skin, which constitutes the acoustic screen, and the Sensitive Skin, which constitutes the changeable skin conceived as a second skin hooked to the special Skeleton predispositions, which gives rise to multiple setup options relating to the specificities of the contexts crossed.