The evaluation of the efficiency of the l-shaped noise barrier while working with the programme CadnaA

Abstract

Due to the diffraction of sound the idea to change the form of the barrier using various designs of the top edge of the barrier has become a very significant factor while increasing the acoustic effect of the barrier. Newly designed shapes of a barrier edge is a means helping to solve problems related to the construction of noise barriers, such as too high, inefficient barriers having no aesthetic appeal. Besides, models of a specially designed barrier edge might be adjusted to already constructed noise barriers to achieve greater efficiency. There are various barrier models: T-, Y-, U-, arrow, fork, and cylinder shaped barriers and so on. In this article the efficiency of the noise barrier is estimated using noise dispersion modelling programme CadnaA. A typical situation is being modelled: using a noise barrier with cantilever, calculations of noise levels are done shielding a linear source of noise. The impact of a barrier cantilever on noise dispersion behind the barrier depending on the direction and angle of its declination is being evaluated. While changing the direction of the cantilever declination („right“ or „left“), configurations of 90°, 130° and 160° angles were being modelled. In the noise suppression environment the features of noise dispersion appearing because of an obstacle, i.e., because of an impact of the noise barrier, are observed in vertical direction receding from the barrier in 1, 3, 6, 9 and 12 m distances, in 1-6 m height.