INVESTIGATION OF NOISE LEVELS DURING THE RECONSTRUCTION AND RESTORATION OF BUILDINGS AND IDENTIFICATION OF NOISE REDUCTION MEASURES

Abstract

The levels of construction equipment used for repair and restoration of buildings within residential areas are investigated. It is established that in most cases there is an excess of maximum permissible values for populated areas. The analysis of measurements in octave frequency bands shows that low-frequency noise prevails. To effectively reduce this noise, it is advisable to use resonant absorbers. A calculation formula for determining the resonant frequency of a panel is presented. Adjusting the panel to the sound frequency of the highest amplitude values exceeds the effectiveness of protection. The noise levels of the most common backup power generators have been measured. It was found that the noise of diesel generators does not exceed the maximum permissible levels. The noise of petrol generators significantly exceeds the limit levels. The procedure for developing a protective structure is proposed. It is advisable to choose the frequency of sound with the highest amplitude as the critical frequency. To do this, it is advisable to obtain the most continuous sound spectrum at the preliminary design stage. A two-layer panel is used for simultaneous sound and infrasound shielding. Each layer (panel) is tuned to a specific frequency – resonant and critical. This makes the structure broadband. To increase the efficiency of the structure, the gap between the two panels should be filled with soundabsorbing material, such as granular polystyrene foam. If possible, the distance between the two panels should be a quarter of the wavelength of the maximum amplitude.