| 요약2 |
Noise barrier has the limitation of reducing the road traffic noise in low frequency bands because of its diffraction phenomenon. In order to maximize the noise reduction performance of noise barrier, it is necessary that diffracted noise in low frequency bands should be effectively reduced. The purpose of this study is to investigate the characteristic of traffic noise in main roads and frequency characteristic of it for designing noise barrier by active noise control. Field measurement of road traffic noise at 1~5 m high from the ground on the 6 roads was carried out, and the variation characteristic by traffic flow condition was analyzed in this study. As a result, the road traffic noise showed high in mid and high frequency bands and the highest in 1 kHz. Especially, the noise showed very high levels in 1 kHz in case of high speed of vehicles. Dominant frequency of the noise was appeared in low frequency bands under 100 Hz, especially in 50~87.5 Hz. It is thought that low frequency badns under 100 Hz should be considered to make noise source for active noise control. It is necessary that passive noise control should be applied for reducing the noise in mid and high frequency bands of 1 kHz in designing noise barrier. In addition, active noise control technique should be applied for decreasing the noise in low frequency bands under 100 Hz in order to maximize the noise reduction performance of noise barrier. |