Holistic optimization of noise barriers from acoustical and non-acoustical parameters

We present the last results obtained within WP5 "Holistic optimizations" of the QUIESST European Project dedicated to the assessment of Noise Reducing Devices' acoustical performances. A first task was a state of the art of existing methods followed by choices of best solutions for holistic optimizations of complex-shape noise barriers. Results of application to extrinsic performance optimizations are then presented taken into account acoustical, economical and environmental parameters in a multiple-objectives approach. The variety of studied noise barriers ranges from straight and flat, to strongly non flat or capped, with a total number of nine noise reducing device families to optimize. Acoustical performances are obtained from numerical calculations using the 2D-BEM (Boundary Element Method) and applied to a set of realistic road and rail configurations. The economical performance is calculated through the construction, maintenance and demolition costs when four environmental performance indicators are considered, based on a life-cycle assessment analysis. All performances are expressed as a gain relative to a reference straight concrete barrier. It is shown that the optimization procedure allows one to obtain a wide variety of optimized noise reducing devices, and hence provides a helpful design tool able to focus on specific acoustical and non-acoustical parameters.