Acoustic Requalification of an Urban Evolving Site and Design of a Noise Barrier: A Case Study at the Bologna Engineering School

Abstract

The increase in new infrastructure development has raised closer attention to the environmental noise of new expansion areas. This study investigates the urban evolution of Terracini Street’s surrounding area in the Navile district, Bologna, Italy. In the last 20 years, this area has undergone various transformations, from a suburban industrial area to a new university and residential one. First, the morphologic and infrastructural characteristics of the site are established. Then, the existing regulations (acoustic, urban, and infrastructural regulations, whether local or national) are evaluated. Next, the results of environmental noise measurements are presented. Since a heavily trafficked infrastructure is very close to the occupied public area, noise limits are severely exceeded. A noise mitigation design stage follows, focusing on a novel noise barrier design. Specifically, particular attention is paid to the visual and ecological impact of the noise barrier on the area’s landscape, which must be representative of the new location of the School of Engineering. The sonic crystal technique is exploited to implement an effective noise barrier (average insertion loss of 10 dB(A) in the 200 Hz–1 kHz range), allowing air ventilation and visual transparency. This case study could further evolve using other acoustic metamaterial techniques or in different application sites.

Sonic Crystal Noise Barrier with Resonant Cavities for Train Brake Noise Mitigation

“…The performance of these NB structures can be enhanced by carefully tailoring their geometrical properties, including the shape of their edges and the curvature of their primary surfaces, to control sound diffraction [11,12]. In addition, the incorporation of porous materials into NBs further improves their acoustic efficacy, particularly with respect to the reflection of sound waves between the source and the barrier structure [13,14].…”