Practical use of an additional noise barrier for high speed train

Additional noise barriers made of transparent polycarbonate are installed on the existing concrete noise barriers to improve noise reduction effect for the high speed train. The height of the additional noise barriers are limited with due consideration on structural strength of the viaduct. The higher the additional noise barriers installed are, the larger the wind load acting on the viaduct is. Therefore, it is inevitable to reinforce the viaduct sufficiently for raising the height of noise barriers than ever before. The authors have proposed a novel noise barrier which can reduce the wind load by swing mechanism. In a strong wind condition, a part of the noise barrier opens to reduce the burden to the viaduct, while it keeps closing to work as a noise barrier in an ordinary wind condition. In this study, sound reduction index of the proposed noise barrier was measured by sound intensity method. The swing mechanical structure was examined by wind tunnel tests and a field test. As a result, it was confirmed that the noise insulation performance was sufficient and the swing mechanism was efficient in reducing a wind load acting on a viaduct.