Acoustical performance of complex-shaped earth berms

Overview & Synopsis

Earth berms have been used for many years along railways and motorways as noise abatement systems. On one hand their construction is often cheaper than traditional barriers with less negative environmental impacts and better visual integration. On the other hand they need more space to be built and are always proposed with the same global symmetrical, smooth shape. In this work we propose to assess the efficiency of various complex-shaped earth berms dedicated to ground transportation using a 2D Boundary Element Method. For urban roads and tramways innovative low-height berms - no more than 1 m high - are proposed and study. For railways and motorways taller complex-shaped systems up to 6 m high are assessed. The analysis is carried out for 1.5 m high receivers areas (pedestrians, cyclists) as well as 4 m high ones (buildings). Results are expressed in terms of acoustic gain obtained with the complex-shaped earth berm solution referred to a straight rigid barrier located at the infrastructures edge.