SHIELDING THE NOISE OF CONSTRUCTION EQUIPMENT

Abstract

Experimental studies of the noise characteristics of construction equipment have been carried out. It has been found that in most cases, the excess of the maximum permissible sound pressure values is no more than 20–25 dB. This makes it possible to use acoustic screens to normalise noise levels at workplaces and territories. The advantage of screens is their ease of manufacture and low cost. This makes it possible to use shielding structures of large areas. The contribution to noise absorption of the most typical underlying surfaces was determined. These data allow us to make adjustments to the required efficiency of acoustic screens. The amplitude-frequency characteristics of typical noise sources at construction sites are investigated. Calculations are presented to predict the effectiveness of acoustic screens depending on the conditions of their use. The presence of diffraction phenomena at the edges of the screens for large values of diffraction angles is taken into account, taking into account the location of the screen on the surface and above the surface. The calculation of the value of the sound wave diffraction coefficient is presented, taking into account the distance from the sound source to the screen and its edges, as well as the distance from the screen edges to the sound reduction zone. The physical characteristics of the material from which the acoustic screen is made are taken into account. Practical recommendations for improving the effectiveness of acoustic screens are given, taking into account the location, shape of the screen and amplitude-frequency characteristics of the noise to be screened.