J.M. Barrigón Morillas

AN ENVIRONMENTAL NOISE STUDY IN THE CITY OF CACERES, SPAIN

Abstract An urban noise survey was conducted in the city of Caceres (Extremadura, Spain). In order to select the different points where measurements were to be taken, the streets were classified according to their use in communicating the different zones of the city. The four categories considered were all through roads (service roads were excluded): arterial roads outside the central zone, arterial roads in the central zone, other two-way roads connecting different zones, other one-way roads. The first two categories were found to be statistically indistinguishable, and together with the third had the highest noise levels—median Leq above 70 dB(A). The one-way roads were some 5 dB(A) quieter. Thus the sound levels in Caceres, a small city, are quite high, with 90% of our measurements surpassing an Leq of 65 dB(A) during working hours. Finally, relationships were established between the equivalent level, traffic flux, and the main noise level percentiles, with results in good agreement with those of other authors. We can also conclude that city noise can be usefully studied by classifying the streets according to their use.

Effects of Leisure Activity Related Noise in Residential Zones

An analysis of two noise surveys of the city of Cáceres is presented. The first was made for 400 inhabitants living throughout the city, and the second for 50 inhabitants of a conflictive zone due to noise during the night, mainly at weekends. The similarity of the two groups of persons interviewed was studied and verified. Then a comparison was made of the responses referring to disturbing noise sources and effects of noise. The results showed appreciable differences between the two surveys. Some continuous sound pressure level measurements made over several days are also presented. They show major differences in the sound levels between the zone and the rest of the city.

Numerical Analysis of Acoustic Barriers with a Diffusive Surface Using a 2.5D Boundary Element Model

Acoustic barriers are a well-known environmental noise mitigation solution, which is widely used nowadays. In this work, it is expected to contribute to the body of knowledge regarding the physical and technical behavior of those barriers by developing and implementing a set of models that allow an accurate analysis of noise barriers with new configuration types. A 2.5D boundary-only numerical model is developed and implemented, and computational analyses are performed in order to compare different surface profiles of the acoustic barriers. The particular case in which two acoustic barriers are used, one at each side of the road, is addressed.