Impact sound pressure values - Field measurements for different configurations of concrete slabs on the ground

2021 ◽  
Vol 263 (6) ◽  
pp. 54-65
Author(s):  
Bernt Mikal Larsen

The presentation will summarize and discuss values of field measured normalized impact sound pressure level L'n,w measured sideways with different configurations of concrete slabs on ground within buildings. All results are adjusted to receiving room volume of 100 m3 and with thickness of concrete slab 80-100 mm. Measurement on continuous concrete slab on expanded polystyrene gives L'n,w between adjoining rooms of 74 dB. Different principles of splitting have been investigated to evaluate the effect on L'n,w. The configuration where only the concrete slab is split (and with a plastic film between the concrete base and the upper layer of expanded polystyrene), gives L'n,w of approximately 66 dB which is 8 dB lower than for a continuous bare concrete slab. When both the concrete slab and the upper layer of expanded polystyrene are split, measurements show L'n,w of 58-61 dB for the case of no flooring, which is 13-16 dB lower than for a continuous concrete slab (no split). When both concrete slab and all layers of polystyrene are split down to continuous foundation measurements show L'n,w of 55 dB. The situation with concrete slab and all layers of polystyrene split and with no foundation beneath gives L'n,w of 46 dB. Consequences for airborne sound and R'w will be discussed as well for the above mentioned configurations.

1995 ◽  
Vol 2 (3) ◽  
pp. 487-500 ◽  
Author(s):  
X.W. Meng ◽  
G. De Borger ◽  
M. Van Overmeire

In this paper, the acoustical features are described of a multi-purpose auditorium of the Free University of Brussels which were investigated both with field measurements and computer simulation. The convergence of the algorithm of the simulation package RAYNOISE was investigated as a function of the influence on the calculated results of the choice of the number of rays and the reflection order. By comparing the numerical and experimental values of the sound pressure level and early decay time, it is demonstrated that sufficiently accurate acoustical models can be developed. Based on these models, acoustical quantities such as the early energy fraction, sound pressure level, early decay time and early lateral energy fraction were calculated and employed to evaluate the acoustical quality of this multi-purpose hall.


2018 ◽  
Vol 47 (5) ◽  
pp. 808-825 ◽  
Author(s):  
Yumeng Jin ◽  
Hong Jin ◽  
Jian Kang ◽  
Ziyue Yu

The streets in the traditional residential areas of severe cold cities in China often have openings leading to enclosed courtyards. These openings connect the street to the courtyard space, which affects the physical environment of the residential streets. This paper uses field measurements and numerical simulation to study the wind–sound environment in the street, comparing and analysing the effects of the existence, size and form of openings on the wind–sound environment in the street. The results indicate that both the average wind velocity and sound pressure level have some degree of reduction around the opening, with the difference of wind velocity reaching 1.0 m/s and the difference in sound pressure level reaching 0.5–1.6 dB. Additionally, the T30 changes from 0.2 s to 0.4 s around the opening, while the average T30 in the street also varies. Increasing the width of the opening by 1 m increases the influential range of the opening on the sound environment by 0.5–4 m. In contrast, the width of the opening has little effect on the sound pressure level and the T30. Compared with an entrance of the same width, a gap intensifies the fluctuation of the local wind velocity and causes the average T30 to reduce by 0.3 s. The results of this paper lay a data foundation for further studies on the optimized design of the physical environment in enclosed residential areas.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Marco Caniato ◽  
Federica Bettarello ◽  
Andrea Gasparella

AbstractThe COVID-19 pandemic significantly modified our urban territories. One of the most strongly affected parameters was outdoor noise, caused by traffic and human activity in general, all of which were forced to stop during the spring of 2020. This caused an indubitable noise reduction both inside and outside the home. This study investigates how people reacted to this new unexpected, unwanted and unpredictable situation. Using field measurements, it was possible to demonstrate how the outdoor sound pressure level clearly decreased. Furthermore, by means of an international survey, it was discovered that people had positive reaction to the lower noise level. This preference was generally not related to home typology or location in the city, but rather to a generalized wish to live in a quieter urban environment.


2012 ◽  
Vol 18 (3) ◽  
pp. 386-392
Author(s):  
Modestas Kligys ◽  
Marijonas Sinica ◽  
Georgijus Sezemanas ◽  
Kęstutis Miškinis ◽  
Saulius Vaitkus

The paper describes the study on the operational properties of lightweight composite with density of 150–350 kg/m3. It was established that these properties depend on the ratio of porous cement matrix and inclusions of crushed expanded polystyrene packing tare waste per unit volume of the lightweight composite. Studies have demonstrated that when the density of lightweight composite varies in the above mentioned limits, the compressibility amounts to 2.4–0.8 mm, point load – 0.38–3.39 kN, dynamic stiffness – 35–135 MN/m3, and reduction in normalised impact sound pressure level – 26–17 dB. The dependences between the established properties and the density of lightweight composite are showed in the equations of regression. Possible versions for the use of lightweight composite in different constructions of floors and roofs are also provided.


2020 ◽  
Vol 63 (4) ◽  
pp. 931-947
Author(s):  
Teresa L. D. Hardy ◽  
Carol A. Boliek ◽  
Daniel Aalto ◽  
Justin Lewicke ◽  
Kristopher Wells ◽  
...  

Purpose The purpose of this study was twofold: (a) to identify a set of communication-based predictors (including both acoustic and gestural variables) of masculinity–femininity ratings and (b) to explore differences in ratings between audio and audiovisual presentation modes for transgender and cisgender communicators. Method The voices and gestures of a group of cisgender men and women ( n = 10 of each) and transgender women ( n = 20) communicators were recorded while they recounted the story of a cartoon using acoustic and motion capture recording systems. A total of 17 acoustic and gestural variables were measured from these recordings. A group of observers ( n = 20) rated each communicator's masculinity–femininity based on 30- to 45-s samples of the cartoon description presented in three modes: audio, visual, and audio visual. Visual and audiovisual stimuli contained point light displays standardized for size. Ratings were made using a direct magnitude estimation scale without modulus. Communication-based predictors of masculinity–femininity ratings were identified using multiple regression, and analysis of variance was used to determine the effect of presentation mode on perceptual ratings. Results Fundamental frequency, average vowel formant, and sound pressure level were identified as significant predictors of masculinity–femininity ratings for these communicators. Communicators were rated significantly more feminine in the audio than the audiovisual mode and unreliably in the visual-only mode. Conclusions Both study purposes were met. Results support continued emphasis on fundamental frequency and vocal tract resonance in voice and communication modification training with transgender individuals and provide evidence for the potential benefit of modifying sound pressure level, especially when a masculine presentation is desired.


2020 ◽  
Vol 68 (2) ◽  
pp. 137-145
Author(s):  
Yang Zhouo ◽  
Ming Gao ◽  
Suoying He ◽  
Yuetao Shi ◽  
Fengzhong Sun

Based on the basic theory of water droplets impact noise, the generation mechanism and calculation model of the water-splashing noise for natural draft wet cooling towers were established in this study, and then by means of the custom software, the water-splashing noise was studied under different water droplet diameters and water-spraying densities as well as partition water distribution patterns conditions. Comparedwith the water-splashing noise of the field test, the average difference of the theoretical and the measured value is 0.82 dB, which validates the accuracy of the established theoretical model. The results based on theoretical model showed that, when the water droplet diameters are smaller in cooling tower, the attenuation of total sound pressure level of the water-splashing noise is greater. From 0 m to 8 m away from the cooling tower, the sound pressure level of the watersplashing noise of 3 mm and 6 mm water droplets decreases by 8.20 dB and 4.36 dB, respectively. Additionally, when the water-spraying density becomes twice of the designed value, the sound pressure level of water-splashing noise all increases by 3.01 dB for the cooling towers of 300 MW, 600 MW and 1000 MW units. Finally, under the partition water distribution patterns, the change of the sound pressure level is small. For the R s/2 and Rs/3 partition radius (Rs is the radius of water-spraying area), when the water-spraying density ratio between the outer and inner zone increases from 1 to 3, the sound pressure level of water-splashing noise increases by 0.7 dB and 0.3 dB, respectively.


Sign in / Sign up

Export Citation Format

Share Document