Traffic noise reduction at balconies on a high-rise building façade

摘要

In this report, the noise-shielding efficiency of balconies with ceiling-mounted reflectors ona high-rise building façade is examined using numerical analyses and full-scaled fieldmeasurements. The reflectors are designed to reflect direct and diffracted waves incidenton the balcony ceiling outside the balcony. In the field measurements, the performance ofthe reflectors is tested at intermediate floors of a high-rise dwelling adjacent to a railway. Abalcony equipped with the reflectors reduces railway noise about 5 dB, in A-weighted SPL,compared to an ordinary balcony. The efficiency is also compared to that of a balcony withan absorbent ceiling in both the analyses and the measurements. The efficiency of thebalcony equipped with the reflectors is greater than that of the absorbing balcony whenvertical noise incident angle is equivalent to, or greater than, the design angle of thereflectors. However, it is also shown that when the incident angle of noise on the balcony issmaller than the design angle, the efficiency is reduced.